MANUAL FOR LAND
    TREATMENT OF
    WASTEWATER
    A Guide to Site Selection, System Design, and
    Permitting Requirements
    362-2000-009
    For more information, visit www.depweb.state.pa.us
    ,
    keyword: Wastewater.

    DEPARTMENT OF ENVIRONMENTAL PROTECTION
    Bureau of Water Standards and Facility Regulation
    DOCUMENT NUMBER:
    362-2000-009
    TITLE:
    Manual for Land Treatment of Wastewater
    EFFECTIVE DATE:
    Upon final publication in the
    Pennsylvania Bulletin
    AUTHORITY:
    The Clean Streams Law of Pennsylvania
    POLICY:
    This document provides guidance regarding the land treatment of
    wastewater.
    PURPOSE:
    This document is intended to provide general guidance on the existing
    methods and types of land treatment systems and their relative
    effectiveness and limitations. It is not to be construed as an endorsement
    of any particular system. Factors are presented which must be considered
    when determining whether land treatment is a feasible and
    environmentally sound alternative. This manual also contains information
    on the general design, installation and maintenance of land treatment
    systems. The information presented in this document will need to be
    supplemented with additional detailed research once a land treatment
    method has been selected. The Department of Environmental Protection
    (DEP) will evaluate each land treatment proposal relative to its adherence
    to all applicable guidelines, policies, regulations and laws. The manual
    replaces in entirety DEP’s
    Manual for Land Application of Treated
    Sewage and Industrial Wastewater,
    DEP ID: 362-2000-009.
    APPLICABILITY:
    The guidance document applies to consulting engineers, geologists and
    soil scientists on site selection, system design, and permitting
    requirements for the land treatment of sewage and industrial wastewater.
    DISCLAIMER:
    The policies and procedures outlined in this guidance are intended to
    supplement existing requirements. Nothing in the policies or procedures
    shall affect regulatory requirements.
    The policies and procedures herein are not an adjudication or a regulation.
    There is no intent on the part of DEP to give the rules in these policies that
    weight or deference. This document establishes the framework within
    which DEP will exercise its administrative discretion in the future. DEP
    reserves the discretion to deviate from this policy statement if
    circumstances warrant.
    PAGE LENGTH:
    58 pages
    LOCATION:
    Volume 31, Tab 06
    362-2000-009 / DRAFT March 21, 2009 / Page i

    TABLE OF CONTENTS
    Page
    I.
    INTRODUCTION AND SCOPE
    ..................................................................................................1
    A.
    Introduction.........................................................................................................................1
    B.
    Scope...................................................................................................................................1
    II.
    LEGISLATIVE AND REGULATORY AUTHORITY
    .............................................................2
    A.
    Sewage .................................................................................................................................3
    B.
    Industrial Wastewater ..........................................................................................................3
    C.
    Seasonal Land Application ..................................................................................................3
    D.
    Hazardous Wastewater and Residual Waste........................................................................3
    E.
    Agricultural Wastewaters.....................................................................................................4
    III.
    PRELIMINARY PLANNING AND ASSESSMENT
    .................................................................4
    A.
    Preliminary Site Data...........................................................................................................4
    B.
    Wastewater Flows................................................................................................................4
    C.
    Wastewater Quality..............................................................................................................6
    1.
    Chemical and Biological Characteristics .................................................................7
    2.
    Physical Characteristics ...........................................................................................7
    D.
    Effluent Quality ...................................................................................................................8
    E.
    Methods and Conditions of Application..............................................................................8
    F.
    Land Ownership and Management ......................................................................................8
    IV.
    SITE EVALUATION
    ....................................................................................................................8
    A.
    Topography ..........................................................................................................................9
    B.
    Soil Characteristics ..............................................................................................................9
    1.
    Physical Characteristics ...........................................................................................9
    2.
    Chemical and Biological Characteristics ...............................................................11
    3.
    Land Limiting Constituent Analysis......................................................................12
    4.
    Interrelationships and Conclusions ........................................................................12
    C.
    Hydrogeology ....................................................................................................................12
    1.
    Direction of Groundwater Flow.............................................................................13
    2.
    Dispersion Plume Analysis...................................................................................13
    3.
    Limiting Geologic Conditions ...............................................................................14
    4.
    Groundwater Mounding.........................................................................................15
    D.
    Hydrology ..........................................................................................................................16
    1.
    Perennial Stream ....................................................................................................17
    2.
    Intermittent Stream ................................................................................................17
    3.
    Lakes and Impoundments ......................................................................................17
    4.
    Floodplains and Floodways ...................................................................................17
    5.
    Wetlands ................................................................................................................18
    6.
    Springs and Seeps ..................................................................................................18
    362-2000-009 / DRAFT March 21, 2009 / Page ii

    E.
    Hydraulic Loading Rate....................................................................................................18
    F.
    Site Access ........................................................................................................................20
    G.
    Horizontal Isolation Distances..........................................................................................20
    1.
    Spray Distribution Systems ..................................................................................20
    2.
    Subsurface Distribution Systems..........................................................................21
    V.
    PERMITS
    .....................................................................................................................................22
    A.
    Sewage ...............................................................................................................................22
    B.
    Industrial Wastewater ........................................................................................................22
    VI.
    SITE MONITORING
    ..................................................................................................................23
    A.
    Purpose...............................................................................................................................23
    B.
    Monitoring Methods ..........................................................................................................23
    1.
    Monitoring Wells and Piezometers........................................................................23
    2.
    Lysimeters..............................................................................................................24
    3.
    Facility Sampling Port ...........................................................................................24
    4.
    Springs ...................................................................................................................24
    C.
    Sampling Plan ....................................................................................................................25
    1.
    Monitoring Frequency ...........................................................................................25
    2.
    Sampling Procedure ...............................................................................................25
    VII. SLOW RATE INFILTRATION
    .................................................................................................25
    A.
    System/Site Overview........................................................................................................25
    B.
    Pretreatment .......................................................................................................................26
    C.
    Site Preparation..................................................................................................................27
    D.
    Climate...............................................................................................................................27
    1.
    Temperature ...........................................................................................................27
    2.
    Precipitation ...........................................................................................................28
    3.
    Wind.......................................................................................................................28
    4.
    Weather Monitoring...............................................................................................29
    E.
    Vegetation ..........................................................................................................................29
    1.
    Assimilative Capacity ............................................................................................29
    2.
    Site-Specific Considerations..................................................................................31
    3.
    Management and Economic Considerations..........................................................31
    F.
    Distribution Systems..........................................................................................................33
    1.
    Surface Distribution Systems.................................................................................33
    2.
    Sprinkler Distribution Systems ..............................................................................35
    G.
    Process Design ...................................................................................................................37
    1.
    Hydraulic Loading Rates Based on Soil Permeability...........................................37
    2.
    Hydraulic Loading Rates Based on Nitrogen Limit ..............................................38
    3.
    Storage Requirements ............................................................................................39
    4.
    Phosphorus Removal .............................................................................................41
    5.
    Removal of Trace Elements and Other Parameters of Concern ............................41
    6.
    Microorganism Removal .......................................................................................42
    362-2000-009 / DRAFT March 21, 2009 / Page iii

    VIII. SUBSURFACE INFILTRATION
    ..............................................................................................42
    A.
    System/Site Overview........................................................................................................42
    B.
    Underground Injection Control Requirements...................................................................43
    C.
    Soils/Pretreatment ..............................................................................................................44
    D.
    Hydraulic Loading Rates ...................................................................................................45
    E
    Time Dosing.......................................................................................................................45
    F.
    Protecting Soil Permeability ..............................................................................................46
    G.
    Distribution System Design ...............................................................................................46
    H.
    In-ground Trench Systems - Leaching Chambers .............................................................47
    1.
    Description.............................................................................................................47
    2.
    General Requirements............................................................................................47
    3.
    Design Requirements .............................................................................................47
    4.
    System Layout and Design Specifications.............................................................48
    5.
    Installation..............................................................................................................48
    I.
    At-Grade Bed System........................................................................................................49
    1.
    Siting Requirements...............................................................................................49
    2.
    Design and Installation Requirements ...................................................................49
    J.
    Drip Distribution System ..................................................................................................50
    1.
    Treatment ...............................................................................................................50
    2.
    Siting Requirements...............................................................................................50
    3.
    Design Requirements .............................................................................................50
    4.
    Construction...........................................................................................................52
    5.
    Operation, Maintenance, and Warranty .................................................................53
    K.
    Soil and Vegetation Management......................................................................................53
    Tables:
    Table 3.1 Peak Daily Wastewater Flows, Organic Load and Runoff Period ..............................................5
    Table 7.1 Potential for Surface Application ..............................................................................................26
    Table 7.2 Recommended Reductions in Application Rate Due to Slope ..................................................35
    Table 7.3 Example Storage Requirement Spreadsheet ..............................................................................40
    Table 8.1 Sample Chamber Dimensions....................................................................................................48
    362-2000-009 / DRAFT March 21, 2009 / Page iv

    I.
    INTRODUCTION AND SCOPE
    A.
    Introduction
    This manual contains guidance for consulting engineers, geologists, and soil scientists in
    the general design, installation, and maintenance of land treatment systems. It also
    describes state and federal requirements and procedures regarding permit applications for
    installation of wastewater treatment systems that are based solely or in part on the use of
    soils.
    Factors are presented which must be considered when determining whether land
    treatment is a feasible and environmentally sound alternative. Nondischarge alternatives
    must be considered in watersheds designated as high quality (HQ) or exceptional value
    (EV) in Title 25 Pa. Code Chapter 93. Land treatment is one option that must be
    considered. Refer to Chapter 93 and DEP’s
    Water Quality Antidegradation
    Implementation Guidance,
    DEP ID: 391-0300-002, available on DEP’s Web site at
    www.depweb.state.pa.us, for additional information.
    The design guidance in this manual is based on best currently available information and
    the experience of Department staff in the review, permitting, and monitoring of land
    treatment systems. Reasonable safety factors have been built into the designs considering
    the uncertainty of estimated long term wastewater acceptance rates. The project
    sponsor/owner should consider other safety factors such as reserving additional land area
    to allow for continued operation if system performance is less than expected and required
    to protect public health and the environment.
    B.
    Scope
    This manual contains guidance on the design of natural soil systems for the treatment of
    domestic and/or industrial wastewater where design flows are greater than those covered
    under Title 25 Pa. Code Chapter 73. This includes spray irrigation systems designed to
    serve other than a single residential dwelling, all other projects proposing soil treatment
    of domestic wastewater flows greater than 10,000 gpd, and all projects proposing
    treatment of industrial waste amenable to soil attenuation. Coordination with other
    Department programs such as residual waste management and nutrient management may
    be necessary to determine whether some industrial and agriculture wastes are covered
    under this manual or another Department guidance manual.
    Domestic wastewater includes wastewater generated by residential, commercial,
    institutional, and recreational establishments. Industrial wastewater generally includes
    any wastewater, other than sewage, generated by an establishment as defined in the
    Pennsylvania Clean Streams Law.
    Land treatment is defined as the controlled application of wastewater onto the land to
    achieve a designed degree of treatment through natural physical, chemical, and biological
    processes within the plant-soil-water matrix. Methods of land treatment described in this
    manual include slow rate infiltration and subsurface infiltration defined as follows:
    362-2000-009 / DRAFT March 21, 2009 / Page 1

    Slow rate infiltration –
    application of wastewater to a vegetated land surface where a
    portion of the flow is used by the on-site vegetation. The wastewater is typically applied
    through a sprinkler distribution system and the portion that does not escape to the
    atmosphere through evapotranspiration percolates to groundwater.
    Subsurface infiltration
    – application of wastewater into the soil below final grade of the
    infiltration area where most of the applied flow percolates to groundwater. Various
    distribution system designs, including perforated piping, drip emitters and leaching
    chambers, are available for installation within the natural soil profile, or above the
    surface of the natural soil and below final grade of the system.
    The methods of land treatment described in the manual are limited to those that are most
    frequently utilized and most appropriate for the soil, geology and climate in the
    Commonwealth. Other methods may be considered on a case-by-case basis.
    This manual provides guidance on the site evaluation, design, permitting and monitoring
    of slow rate and subsurface infiltration systems, but does not include detailed guidance on
    the design of any pretreatment that may be required, nor the design of septic tanks that
    may be utilized by individual homes from which wastewater is received. Guidance
    regarding design of pretreatment facilities is contained in the Department’s
    Domestic
    Wastewater Facilities Manual
    , DEP ID: 362-0300-001, and the Department’s
    Industrial
    Wastewater Treatment Manual
    , DEP ID: 362-0300-004. Standards for individual septic
    tanks are set forth in Title 25 Pa. Code Chapter 73. All are available on the Department’s
    web site at www.depweb.state.pa.us
    .
    II.
    LEGISLATIVE AND REGULATORY AUTHORITY
    The basic structure of the Federal Water Quality Act (the Act) originated with the Federal Water
    Pollution Control Act of 1972 (PL 92-500). The name was changed to the Clean Water Act by
    the 1977 amendments, and then to the Water Quality Act by the 1987 amendments.
    Section 101 of the Act is a declaration of a national goal, policy, and objective to restore and
    maintain the chemical, physical, and biological integrity of the nation’s waters. The national
    goals include water quality that provides for the protection and propagation of fish, shellfish, and
    wildlife, and provides for recreation in and on the water by July 1, 1983, and elimination of the
    discharge of pollutants to navigable waters by 1985.
    Efforts to address the national goals have taken various forms, but clearly land treatment of
    wastewater using proper design, operation, and maintenance will eliminate the discharge of
    pollutants directly to our streams, lakes, and groundwater.
    The importance of providing acceptable methods of land treatment has intensified because of the
    increasingly stringent requirements associated with the discharge of wastewater to surface water
    bodies and the need for wastewater treatment where streams are not readily accessible.
    Excessive costs of water supply treatment, demands for water recreation, and increasing
    evidence of the significant destruction of various aquatic species all demonstrate a need to utilize
    land treatment of wastewater.
    362-2000-009 / DRAFT March 21, 2009 / Page 2

    Land treatment systems are a demonstrated and acceptable method of treatment for sewage and
    some industrial wastewaters. DEP’s authority to regulate their use in the treatment of
    wastewater is based on the Pennsylvania Clean Streams Law. Planning and permitting criteria
    are described below.
    A.
    Sewage
    The Pennsylvania Sewage Facilities Act, Act 537, requires an applicant to complete the
    appropriate sewage facilities planning modules before applying for a Water Quality
    Management (WQM) permit required under the Clean Streams Law for land treatment of
    sewage. Planning information and forms can be obtained from the appropriate DEP
    regional office
    Planning approval is a prerequisite to the submission of a WQM permit application. The
    applicant must submit documentation of planning approval with the
    Water Quality
    Management Permit Application
    , DEP ID: 3800-PM-WSFR0400, available on DEP’s
    Web site or from DEP’s regional offices.
    B.
    Industrial Wastewater
    A WQM permit is required for land treatment of industrial wastewater. The WQM
    permit application can be obtained on DEP’s website or from the appropriate DEP
    regional office.
    C.
    Seasonal Land Application
    Seasonal discharges to surface waters are permissible when conditions preclude land
    application. Operators of sewage or industrial wastewater land treatment systems must
    obtain a National Pollutant Discharge Elimination System (NPDES) permit for seasonal
    discharge in addition to the WQM permit. The NPDES permit application packages
    listed below can be obtained on DEP’s website or from the appropriate DEP regional
    office.
    1.
    Application for Permit to Discharge Industrial Wastewater
    ,
    DEP ID: 3800-PM-WSFR0008
    2.
    Application for Permit to Discharge Sewage (Long Form)
    ,
    DEP ID: 3800-PM-WSFR0009
    3.
    Application for Permit to Discharge Sewage (Short Form)
    ,
    DEP ID: 3800-PM-WSFR0018
    D.
    Hazardous Wastewater and Residual Waste
    This manual does not cover land treatment of wastewater that is defined as hazardous
    under Title 25 Pa. Code Chapters 260a - 270a, or wastewater and residual waste covered
    under Title 25 Pa. Code Chapters 287 - 299. Any questions concerning land treatment of
    hazardous wastewater, or residual waste and wastewater should be directed to DEP’s
    Bureau of Waste Management.
    362-2000-009 / DRAFT March 21, 2009 / Page 3

    E.
    Agricultural Wastewaters
    Land application of agricultural wastewater for agricultural use does not require a WQM
    permit. Descriptions of procedures for proper design, operation, and management of
    these activities can be found in a guidance manual titled
    Manure Management for
    Environmental Protection
    , DEP ID: 361-0300-001. Additional sources of assistance
    include county agricultural extension agents and the local offices of the United States
    Department of Agriculture (USDA) Natural Resource Conservation Service.
    Land application of most agricultural wastewater for nonagricultural use will require a
    WQM permit. These sites follow the same procedures as proposals for land application
    of industrial wastewater. Questions regarding the classification of a site or wastewater
    should be directed to the appropriate DEP regional office.
    In 1993, the Pennsylvania Nutrient Management Act became law and created the
    framework for addressing nutrient management for certain operations. A Nutrient
    Management Plan may be required to be developed and implemented under the Nutrient
    Management Act. Additional information on the act and which operations are required to
    develop a Nutrient Management Plan can be found in a guidance manual titled
    Manure
    Management for Environmental Protection
    , DEP ID: 361-0300-001 and Title 25
    Pa. Code Chapter 83.
    III.
    PRELIMINARY PLANNING AND ASSESSMENT
    During the preliminary planning phase, basic data that are common to all wastewater treatment
    alternatives must be collected and analyzed along with land treatment system requirements to
    determine whether land treatment is a feasible alternative. If no factors that would eliminate land
    treatment from further consideration are identified, the next steps are to identify potential land
    treatment sites and evaluate the feasibility of each site. Site specific data, including influent
    wastewater quality and quantity, and the required effluent quality can then be used to determine
    if a candidate site is feasible for the proposed land treatment system before an in depth site
    investigation is conducted.
    A.
    Preliminary Site Data
    Preliminary site data are collected after candidate sites have been identified and are used
    to make a preliminary determination of the feasibility of the candidate site for land
    treatment of wastewater. Data that should be collected and evaluated for each candidate
    site include monthly climatic data, soil surveys, geologic and groundwater surveys, well
    drilling logs, chemical analysis of groundwater, and topographic maps. Other site-
    specific data may be required in the preliminary evaluation.
    B.
    Wastewater Flows
    Land treatment systems should be designed using the wastewater flows listed in Table 3.1
    below. As design flow increases, the more likely it will be that the system will achieve
    average rather than peak flow. In such cases, reducing the design flow below that which
    is listed in this table may be considered. The design flow may not be reduced by more
    362-2000-009 / DRAFT March 21, 2009 / Page 4

    than 50% of the difference between the flows in Table 3.1 and actual anticipated flows.
    An implicit safety factor is built into the flows in Table 3.1 and is assumed when
    determining hydraulic loading rates as described in section IV.E. of this manual.
    Table 3.1
    Peak Daily Wastewater Flows, Organic Load, and Runoff Period
    Type of Establishment
    Gallons/
    day
    BOD
    (lb/day/cap)
    Runoff
    Period
    (hrs)
    Residential
    Hotels and motels (per unit)
    100
    0.30
    24
    Multiple family dwellings and apartments
    400
    1.13
    24
    Rooming houses (per unit)
    200
    0.6
    24
    Single family residences of 3 bedrooms or less
    *
    for each bedroom over 3, add 100 gallons
    400*
    0.90
    24
    Commercial
    Airline catering (per meal served)
    3
    0.03
    24
    Airports (per passenger—not including food)
    5
    0.02
    24
    Airports (per employee)
    10
    0.06
    24
    One licensed operator/one chair beauty shops
    200
    8
    Bus service areas not including food (per patron and
    employee)
    5
    0.02
    24
    Country clubs not including food (per patron and
    employee)
    30
    0.02
    16
    Drive-in theaters (per space—not including food)
    10
    0.06
    4
    Factories and plants exclusive of industrial wastes (per
    employee)
    35
    0.08
    Hours of
    operation
    Laundries, self-service (gallons/washer)
    400
    2.00
    16
    Movie theaters (per auditorium seat—not including food)
    5
    0.03
    Hours of
    operation
    Offices (per employee)
    10
    0.06
    Hours of
    operation
    Restaurants (toilet and kitchen wastes per patron)
    (Additional for bars and cocktail lounges)
    10
    2
    0.06
    0.02
    Hours of
    operation
    Restaurants (kitchen and toilet wastes, single-service
    utensils/person)
    8.5
    0.03
    Hours of
    operation
    Restaurants (kitchen waste only, single-service
    utensils/patron)
    3
    0.01
    Hours of
    operation
    Stores (per public toilet)
    400
    2.00
    Hours of
    operation
    Warehouses (per employee)
    35
    Hours of
    operation
    Work or construction camps (semipermanent) with flush
    toilets (per employee)
    50
    0.17
    Hours of
    operation
    Work or construction camps (semipermanent) without
    flush toilets (per employee)
    35
    0.02
    Hours of
    operation
    362-2000-009 / DRAFT March 21, 2009 / Page 5

    Type of Establishment
    Gallons/
    day
    BOD
    (lb/day/cap)
    Runoff
    Period
    (hrs)
    Institutional
    Churches (per seat)
    3
    Churches (additional kitchen waste per meal served)
    3
    Churches (additional with paper service per meal served)
    1.5
    Hospitals (per bed space, with laundry)
    300
    0.20
    24
    Hospitals (per bed space, without laundry)
    150-250
    24
    Institutional food service (per meal)
    20
    24
    Institutions other than hospitals (per bed space)
    125
    0.17
    24
    Schools, boarding (per resident)
    75
    0.17
    24
    Schools, day (without cafeterias, gyms or showers per
    student and employee)
    7
    0.04
    8
    Schools, day (with cafeterias, but no gym or showers per
    student and employee)
    10
    0.08
    8
    Schools, day (with cafeterias, gym and showers per
    student and employee)
    13
    0.10
    8
    Recreational and Seasonal
    Camps, day (no meals served)
    10
    0.12
    16
    Camps, hunting and summer residential (night and day)
    with limited plumbing including water-carried toilet
    wastes (per person)
    50
    0.12
    24
    Campgrounds, with individual sewer and water hookup
    (per space)
    100
    0.50
    24
    Campgrounds with water hookup only and/or central
    comfort station which includes water-carried toilet
    wastes (per space)
    50
    0.50
    24
    Fairgrounds and parks, picnic—with bathhouses,
    showers, and flush toilets (per person)
    15
    0.06
    24
    Fairgrounds and parks, picnic (toilet wastes only, per
    person)
    5
    0.06
    16
    Swimming pools and bathhouses (per person)
    10
    0.06
    16
    C.
    Wastewater Quality
    Prior to land treatment, all wastewaters should undergo pretreatment. Higher degrees of
    treatment or lower hydraulic loading may be required for high strength wastes and/or to
    overcome site limitations. Wastes containing greases and emulsions that clog soils, plug
    nozzles, or coat vegetation should not be discharged to the soil treatment area. In
    addition, wastes that are non-biodegradable, non-exchangeable with the soil, toxic to
    vegetative cover, or that are persistently toxic in the environment should not be applied to
    the soil.
    The pretreatment needs are based on site characteristics, the type of application system
    proposed, and the site-specific objectives of the system. In some cases, the application of
    effluent pretreated to advanced levels can be used to overcome site characteristics that
    362-2000-009 / DRAFT March 21, 2009 / Page 6

    would render a site unsuitable for use under typical minimum pretreatment
    considerations.
    Influent wastewater quality samples may not be available during the preliminary phase of
    design. In these instances the influent wastewater quality should be estimated based on
    the type and number of facilities proposed to discharge to the system. The following
    wastewater quality information should be collected and utilized in system design and
    monitoring.
    1.
    Chemical and Biological Characteristics
    The chemical and biological parameters typically significant in wastewater
    treatment and disposal include pH, phosphorus, nitrate, nitrite, ammonia, Kjeldahl
    nitrogen, chloride, sulfate, sodium, total suspended solids (TSS), biochemical
    oxygen demand (BOD), and fecal coliform. Frequently, community sewage
    systems will also contain metals or various organic chemicals. The specific
    parameters must be identified and quantified.
    Prior to land application, wastewater effluent must be monitored to ensure
    sufficient pre-treatment and compatibility with site soil and proposed vegetation.
    This includes monitoring for the chemical constituents designated for treatment
    along with any treatment byproducts such as chlorides.
    2.
    Physical Characteristics
    These characteristics include, but are not limited to:
    a.
    Density
    Because groundwater travels so slowly through most aquifers, the
    anticipated final effluent may float, sink, or dissociate evenly upon entry to
    the groundwater system. Wastewater density information is necessary
    when designing the monitoring system to ensure that water quality samples
    are taken at the appropriate depths.
    b.
    Chemical Differentiation
    Occasionally, the chemical constituents of some plumes can be expected
    to stratify within the aquifer. Certain parameters travel faster than others
    and should be listed in a theoretical order of appearance. An accurate
    stratification model will aid in assuring that monitoring points are located
    at optimum locations for sampling parameters of concern.
    c.
    Adsorption/Absorption
    The chemicals contained within the dispersion plume can adsorb or absorb
    to the soil or rock material permanently, temporarily or variably.
    Adsorption and absorption of certain wastewater constituents could result
    in changes in soil properties over time. Depending on the wastewater
    362-2000-009 / DRAFT March 21, 2009 / Page 7

    content, it may be necessary to adjust soil properties by the application of
    chemical amendments. It is recommended that the level of trace elements
    of concern in the soil be monitored every 3-5 years so that the rate of
    accumulation can be observed and toxic levels avoided.
    D.
    Effluent Quality
    DEP’s guidance document
    Principles for Ground Water Pollution Prevention and
    Remediation,
    DEP ID: 383-0800-001, available on DEP’s Web site, sets forth the
    principles for ground water quality protection in the Commonwealth. The guidance
    describes the principles established by the Department to protect ground water through
    permitting, requirements for ground water monitoring, and consideration of priority
    ground water areas. This manual requires compliance with those principles.
    For any designs for which a surface water discharge is expected, surface water quality
    criteria must be met in the surface water body. These criteria are set forth in Title 25
    Pa. Code Chapters 16 and 93. An NPDES permit will be required for any discharges to
    surface waters.
    E.
    Methods and Conditions of Application
    While there are several methods of applying the effluent to the soil or soil surface, it
    should become apparent based on review of site-specific characteristics and design
    considerations that certain application methods may be more applicable to the site in
    question than others. The more favorable alternatives are those that can be more reliably
    managed and easily operated. Proposed application methods should include a detailed
    management and operating plan, combining site, seasonal, and weather related specifics
    with automated application and storage capabilities.
    F.
    Land Ownership and Management
    It is desirable that the land on which the treatment system and storage facilities are
    located be owned by the permittee. In these cases, there should be a covenant in the deed
    providing for land treatment in perpetuity, as long as the land is needed for treatment. In
    those situations where the treatment area and storage cells are on property not owned by
    the permittee, the permittee must either secure a 20-year lease renewable for an additional
    20 years or acquire development rights and perpetual rights for the amount of land
    required.
    IV.
    SITE EVALUATION
    The purpose of any land treatment system is to provide additional treatment of wastewater by
    passage through the soil mantle and possible uptake by vegetation. The most important factors
    in evaluating and designing a site for a land treatment system include:
    Topography
    Soil characteristics
    Hydrogeology
    Hydrology
    362-2000-009 / DRAFT March 21, 2009 / Page 8

    Hydraulic Loading Rate
    Site Access
    Horizontal Isolation Distances
    An accurate evaluation of these factors is critical to the assessment of any land treatment
    proposal.
    A.
    Topography
    The applicant must determine the average and maximum slopes within a proposed site to
    prevent potential difficulties during construction. A large-scale two-foot contour map of
    the site including existing features should be prepared and available prior to soils
    evaluation. The slope, shape and soil profile position should also be noted on the
    large-scale map. The applicant should also assess the relationship between the slope and
    the configuration of the system. The system must meet the maximum and minimum
    depth standards across the slope and must have sufficient down gradient area available
    for lateral liquid dispersion. Concave slope shapes tend to concentrate the water into one
    area and may result in a malfunction. These areas should be identified during site
    evaluation to prevent later problems with the system. Excavating or filling a site to
    achieve proper slopes will disqualify the site for a land treatment system. Additional
    information on the slope, shape, and soil profile position can be found in the
    Field Book
    for Describing and Sampling Soils
    (Shoeneberger et al.) available at
    ftp://ftp-fc.sc.egov.usda.gov/NSSC/Field_Book/FieldBookVer2.pdf and the
    National Soil
    Survey Handbook
    (Soil Survey Staff, Natural Resources Conservation Service,
    title 430-VI (2001)) available at http://soils.usda.gov/technical/handbook/download.html.
    B.
    Soil Characteristics
    Undisturbed soil is a natural filter that provides effluent renovation using physical,
    chemical, and biological processes. Physical characteristics influence the permeability of
    the soil. The permeability must be within a range that will provide adequate residence
    time for renovation and prevent rapid downward movement of effluent, but not be so low
    as to cause saturated conditions resulting in excessive biomat growth, groundwater
    mounding, and inadequate treatment. Chemical characteristics affect cation/anion
    attenuation, buffering, and viral inactivation. Biological considerations include the plant
    and microorganism communities residing within the profile that impact on such processes
    as nutrient and metal uptake, pathogen inactivation, and denitrification. The land limiting
    constituent analysis takes into account the above characteristics to ensure the hydraulic
    capacity of the soil is not exceeded.
    1.
    Physical Characteristics
    Physical characteristics are important in determining a potential hydraulic
    acceptance rate for the site. The applicant should evaluate the texture,
    consistence, structure and morphological properties from the soil descriptions to
    determine which, if any, soil horizons within the profile will limit the downward
    passage of effluent.
    362-2000-009 / DRAFT March 21, 2009 / Page 9

    The applicant should characterize all soil series and phases present on the site.
    The initial stages of this evaluation should include soil test probes. All soil test
    probes or soil test pits must be described to a depth of 7 feet, backhoe refusal, or
    other condition that prevents description, whichever is shallower. These test
    probes should be of sufficient number and location to either confirm the Natural
    Resources Conservation Service mapping or recharacterize the soils if the
    mapping is inconsistent with the field determination. The Department regional
    soil scientist will make the final determination, based on the information
    submitted by the permit applicant and a site evaluation, whether the number and
    location of the test locations are adequate to evaluate the soil characteristics of the
    proposed absorption area.
    The recorded description of soil profiles should contain information regarding the
    soil’s morphological features including, but not limited to:
    a.
    Soil depth to bedrock or unconsolidated coarse fragments with insufficient
    fine earth materials.
    b.
    Soil depth to evidence of seasonal high water table, depth to seepage or
    standing water within the profile.
    c.
    The soil profile should be divided into horizons and each separate horizon
    within the soil profile should be further described with respect to the
    following:
    Thickness of the soil horizon
    Soil color
    Soil texture
    Soil consistency (workability or plasticity)
    Soil structure
    Redoximorphic features
    Boundary distinctness
    Abundance of coarse fragments
    Abundance of roots
    Any other non-typical but potentially significant feature within the
    horizon
    A soil scientist should determine the most restrictive (least permeable) horizon
    between the land surface and the bottom of the soil test pit by testing saturated
    vertical hydraulic conductivity to establish the hydraulic loading rate for the
    proposed system. The tests should be of sufficient number and location to
    adequately evaluate the soil characteristics in the proposed absorption field. All
    horizons above the water table must transmit the effluent faster than they receive
    it. This prevents the possibility of excessive groundwater mounding or
    incomplete renovation of the effluent.
    The saturated vertical hydraulic conductivity (K) of the most restrictive horizon
    should be measured using an approved ASTM procedure or other method
    362-2000-009 / DRAFT March 21, 2009 / Page 10

    approved by the Department. A list of ASTM standards is available at
    www.astm.org/digitallibrary. ASTM standards for measuring infiltration rate
    should not be used to measure hydraulic conductivity.
    Soil characteristics should be described using USDA Natural Resources
    Conservation Service (NRCS) nomenclature and assessed by using standardized
    field soil evaluation procedures as identified in the
    Field Book for Describing and
    Sampling Soils
    , and the
    National Soil Survey Handbook
    . A site plan, which is
    required as part of the approval process, must show the survey location of all soil
    test probes.
    A qualified soil scientist must perform the soil morphological evaluation and the
    report must be attached to the permit application. A qualified soil scientist is a
    person certified as a sewage enforcement officer and who has documented 2
    years’ experience in the characterization, classification, mapping and
    interpretation of soils as they relate to the function of onlot sewage disposal
    systems and either a Bachelor of Science Degree in soils science from an
    accredited college or university or certification by the American Registry of
    Certified Professionals in Agronomy, Crops, and Soils. If the initial evaluation of
    soil test probes reveals adequate soil characteristics, a more in-depth evaluation of
    other physical, biological and chemical soil characteristics will be required.
    2.
    Chemical and Biological Characteristics
    Chemical and biological characteristics of the soil are important factors
    controlling the level of treatment. Some wastewater may contain one or more
    chemical parameters that are significantly elevated in concentration, relative to
    the other parameters. The effect of this potential chemical imbalance will need to
    be evaluated with respect to the selected pretreatment options, the chemical
    affinities of the proposed vegetation, the total land area available and the ability of
    the soil to renovate, or remove the parameters of concern. The soil chemical
    characteristics that are important in making these judgments include:
    Soil pH/buffering capacity
    Cation Exchange Capacity (CEC)
    Sodium Absorption Ratio (SAR)/exchangeable sodium percentage
    Presence or absence of organic matter
    Soil carbon to nitrogen ratio (C:N)
    Base saturation
    Background metal concentrations in the soil
    Using this information, the applicant can assess whether a proposed land
    treatment system will be capable of renovating or removing the parameters of
    concern.
    362-2000-009 / DRAFT March 21, 2009 / Page 11

    3.
    Land Limiting Constituent Analysis
    A land limiting constituent analysis establishes the interrelationships between the
    following:
    The proposed waste to be applied
    The rate at which it may be applied
    The plant/soil/groundwater system
    The relationship between the wastewater constituents of concern and the
    capability of the soil to renovate those constituents should be analyzed. As
    effluent is applied, the eventual inability of the soil to treat specific parameters
    may limit the hydraulic loading rate. This is especially true for industrial waste
    effluents, although application of sewage effluents may be limited by nitrogen in
    areas of elevated background nitrate concentration. If it is found that the soil
    cannot adequately renovate one or more constituents of concern, it may be
    necessary to increase the size of the absorption area or provide additional pre-
    treatment.
    Another component of the land limiting constituent analysis involves
    consideration of the vegetative cover and the soil microbes. The applicant should
    characterize native vegetation and evaluate assimilative capacities. New
    vegetative cover may need to be established to ensure uptake or renovation of
    specific effluent parameters. Some waste material may require amendment of the
    soil’s microbiological community to renovate constituents that are not typically
    renovated by naturally occurring processes.
    4.
    Interrelationships and Conclusions
    Having a professional soil scientist evaluate the complex interrelationships of the
    various soil characteristics and conduct the land limiting constituent analysis is
    critical to the proper design of a land treatment system. A precise evaluation of
    pertinent site-specific information will yield a design that will provide for a long-
    term functioning land treatment system.
    C.
    Hydrogeology
    Hydrogeologic characteristics of the proposed site should be included to assess the
    impact the effluent may have on water uses and water resources. The locations of rock
    outcrops and sinkholes, along with the depth to the water table and bedrock, are
    important factors for determining if the effluent will have adequate residence time for
    renovation in the unsaturated zone. The applicant should evaluate the geology and
    hydrogeology of the proposed land treatment area to determine the following:
    Direction of groundwater flow
    Dispersion plume analysis
    Limiting geologic conditions
    Groundwater mounding
    362-2000-009 / DRAFT March 21, 2009 / Page 12

    1.
    Direction of Groundwater Flow
    The applicant is required to determine the direction of groundwater flow at the
    proposed land treatment site. The design of the land treatment system and
    groundwater monitoring points should be consistent with regional and local
    groundwater flow patterns. Knowledge of the direction of groundwater flow is
    critical for design of the monitoring network along with groundwater mounding
    and dispersion plume analysis.
    Because gravity is the dominant force in the movement of groundwater, the
    regional water table often exists as a subdued image of topography. However on
    a larger scale, groundwater flow is often influenced by structural and stratigraphic
    characteristics. These factors include lithology, bedding planes, folds, fractures,
    fracture traces, lineaments, faults, joints and cleavage planes. Groundwater flow
    is generally anisotropic in that it tends to follow bedding planes and migrates
    through fractures and joints. Applicable hydrogeologic data must be submitted as
    part of the Department’s permit application review.
    The direction of groundwater flow is determined by measuring the water table
    elevation at multiple observation wells or through the use of springs. The depth
    to groundwater must be determined to correctly map the hydraulic head gradient.
    This will generally require measurements from piezometers, wells, or springs.
    Pennsylvania Water Resource Report publications are available at the following
    address:
    State Bookstore
    Pennsylvania Historical and Museum Commission
    Commonwealth Keystone Building
    Plaza Level
    400 North Street
    Harrisburg, PA 17120
    717-787-5109
    2.
    Dispersion Plume Analysis
    The applicant should conduct a dispersion plume analysis for any chemical
    parameters that are not adequately removed by pretreatment, crop uptake, or the
    soil. For example, because nitrate-nitrogen (NO
    3
    -N) from domestic sewage is not
    removed by the soil, the applicant should estimate its concentration at the
    property line when appropriate pretreatment or adequate crop uptake is not
    provided. The concentration of nitrate-nitrogen at the property line should be less
    than 10 mg/L.
    The applicant must also estimate the extent and shape of the dispersion plume,
    including the mixing and buffer zones. This should be estimated for both normal
    precipitation and drought years.
    362-2000-009 / DRAFT March 21, 2009 / Page 13

    The following information is needed to complete the dispersion plume analysis:
    Direction of groundwater flow
    Location of potential groundwater divides
    Site-specific background groundwater quality data for parameters of
    concern
    Area of project site
    Locations of existing or potential water supplies on the project site,
    surrounding properties, and within the projected dispersion plume
    Infiltrating recharge, which should reflect precipitation losses to surface
    runoff, evapotranspiration, and groundwater withdrawal
    During the preliminary analysis, only the land application area should be used to
    estimate recharge. Vertical mixing within the aquifer cannot be considered in the
    initial dispersion plume analysis for parameters that float. Constituents of
    industrial wastewater may need to be modeled differently depending upon
    wastewater characteristics.
    To obtain approval for a land treatment system, an applicant should be able to
    demonstrate that the contaminant plume will not adversely impact existing or
    potential water supplies or compromise the existing and/or designated uses of
    receiving surface waters. Where a hydrogeologic study has shown that a
    contaminant plume will exit the site or adversely impact existing or potential
    groundwater supplies, the applicant should provide for mitigation that may
    include pre-treatment or lower hydraulic loading rates.
    .
    3.
    Limiting Geologic Conditions
    A limiting geologic condition may include situations where wastewater
    infiltration is either too fast or too slow to effectively renovate wastewater
    constituents prior to infiltration to groundwater. The following should be
    evaluated:
    a.
    Surficial Rock Outcrops
    Land application of sewage effluent upon rock outcrops is forbidden.
    Rock is not an effective media for renovation of sewage effluent since
    fractures often provide a direct conduit to groundwater. Surface or near
    surface bedrock conditions may result in untreated or partially treated
    effluent reaching and adversely impacting groundwater quality. In some
    geologic settings a geophysical survey may be required to adequately
    define depth to bedrock over the proposed land application area. Alluvial
    deposits or colluvium may render the site unsuitable for land application
    of sewage effluent or require application at a reduced rate.
    b.
    Karst Settings
    Karst topography is present in areas underlain by carbonate bedrock and is
    characterized by the presence of sinkholes, surface depressions, sinking
    362-2000-009 / DRAFT March 21, 2009 / Page 14

    streams, springs and caves. Limestone and dolomite are the principal
    carbonate rocks of concern for karst development in Pennsylvania. Land
    application of effluent in a karst setting may not provide the necessary
    renovation in the unsaturated zone and may exacerbate the formation of
    sinkholes. Additional information on sinkholes is available in the fact
    sheet,
    Sinkholes
    , DEP ID: 5300-FS-DEP4045.
    Depth to bedrock can vary significantly in karst areas over a relatively
    small area. This type of setting should be avoided as a site for land
    application of sewage effluent. Borings and/or a geophysical survey may
    assist in evaluating the depth to bedrock and to investigate the presence of
    karst features such as subsurface rock pinnacles, voids or large solution
    channels beneath the proposed site.
    c.
    Depth to Water Table
    The water table is the depth below which saturated conditions exist in
    fractures and pores of rock and sediment at atmospheric pressure. A
    perched aquifer is a shallow interval of either saturated unconsolidated
    sediment or bedrock underlain by either a clay-rich layer or impermeable
    bedrock, respectively. The water table is prone to seasonal fluctuations
    and should be evaluated to assure the required minimum unsaturated
    thickness is maintained beneath the absorption field.
    A shallow water table may result in an insufficient unsaturated zone
    thickness to adequately treat effluent. Data showing the elevation of a
    high water table is especially critical to the design and utility of land
    application systems. However, eventual groundwater mounding may
    render the unsaturated soil thickness inadequate.
    d.
    Restrictive Layers
    A restrictive layer is a unit with low hydraulic conductivity which inhibits
    infiltration of land-applied effluent. A geologist must determine the
    presence of any restrictive layers below the soil test pit. A cross-section
    identifying the different lithologic strata under the proposed land treatment
    area should be provided. If a restrictive layer is present, hydraulic
    conductivity testing is required of that zone for the purpose of sizing the
    absorption field.
    4.
    Groundwater Mounding
    A groundwater mound is a mound-shaped rise of the water table above natural
    levels that occurs when effluent recharge from the land treatment system exceeds
    the infiltration capacity. Groundwater mounding occurs with land treatment
    systems because of additional recharge from the applied wastewater.
    Groundwater mounds can become large enough to reduce the amount of required
    unsaturated soil thickness necessary for treatment, or result in a malfunction of
    the system by effluent breaking out onto the land surface.
    362-2000-009 / DRAFT March 21, 2009 / Page 15

    The spatial configuration of the mound and seasonal variations in mounding
    elevations must be determined. The mounding analysis must be completed for a
    minimum period of ten years. Groundwater mounding analysis requires
    evaluation of aquifer characteristics including: depth to water table, hydraulic
    conductivity, transmissivity, storativity, and specific yield. The aquifer
    characteristics should be determined by aquifer test methods described in Part II
    of the
    Public Water Supply Manual
    , DEP ID: 383-2125-108, Aquifer Testing.
    A groundwater mounding analysis should be performed after preliminary sizing
    of the land treatment area using hydraulic loading rates resulting from saturated
    vertical hydraulic conductivity testing and soil morphological evaluation. The
    method and extent of the groundwater mounding analysis should be based on site-
    specific conditions including: soil characteristics, depth of soil, and depth of the
    groundwater on the site. Groundwater modeling methods include both numerical
    and analytical methods. The applicant should address the interference of
    groundwater mounds from multiple absorption fields in the hydrogeologic report
    submitted to support the system design.
    A groundwater mound should not be permitted to rise to an elevation where it will
    interfere with any natural treatment processes in the soil horizons, or the ability of
    soil to accept the discharged effluent. If the groundwater mound rises within the
    specified vertical isolation distance the following actions may be required:
    increase the application area, reduce the application rate or volume, use smaller
    separate infiltration areas with alternate dosing, or change the length to width
    ratio of the system to reduce the groundwater mound.
    D.
    Hydrology
    Degraded groundwater from an improperly designed, constructed, or operated land
    treatment system may discharge to and adversely impact a surface water body. Lake
    studies linking eutrophication to an excessively dense use of onlot septic systems
    illustrate the need to consider the interaction between groundwater and surface water.
    Hydrologic factors that should be considered include: slope, topography, presence or
    absence of floodplains and springs, soil erosion characteristics, and stream flow patterns.
    Because of the potential impacts of wastewater upon surface water, the applicant should
    describe and delineate, on a large-scale plan, all surface waterbodies that may be affected.
    Surface waters, as defined by the Clean Streams Law
    , includes, but is not limited to:
    perennial and intermittent free-flowing waterbodies, lakes, ponds, wetlands,
    impoundments, springs, seeps, drainage swales, surface relief channels, and other natural
    conveyances. Floodplains and floodways that are associated with any of these
    waterbodies also require delineation in the plan.
    362-2000-009 / DRAFT March 21, 2009 / Page 16

    1.
    Perennial Stream
    A perennial stream generally has some surface water flow throughout the year. A
    Perennial stream is defined in Title 25 Pa. Code Chapter 92 as follows:
    Perennial Stream
    - A body of water flowing in a channel or bed composed
    primarily of substrates associated with flowing waters and capable, in the absence
    of pollution or other man-made stream disturbances, of supporting a benthic
    macroinvertebrate community which is composed of two or more recognizable
    taxonomic groups of organisms which are large enough to be seen by the unaided
    eye and can be retained by a United States Standard No. 30 sieve (28 meshes
    per inch, 0.595 mm openings) and live at least part of their life cycles within or
    upon available substrates in a body of water or water transport system.
    2.
    Intermittent Stream
    An intermittent stream may lack surface water flow during some portion of the
    year. It is defined in Title 25 Pa. Code Chapter 92 as follows:
    Intermittent Stream
    - A body of water flowing in a channel or bed composed
    primarily of substrates associated with flowing water, which, during periods of
    the year, is below the local water table and obtains its flow from both surface
    runoff and groundwater discharges.
    3.
    Lakes and Impoundments
    Because of their long retention time of effluent products, lakes and impoundments
    may be adversely affected by a land treatment system. Extensive eutrophication
    or other problems may occur in a lake or impoundment when a properly designed
    land treatment system is improperly sited. Alternatively, the construction of an
    impoundment may impair the effectiveness of a properly designed and operated
    treatment system by artificially raising the groundwater table.
    4.
    Floodplains and Floodways
    Floodplains and floodways border all surface waterbodies. Due to a lack of
    treatment during periods of floods, land treatment systems in a floodway are not
    permitted. Suitable documentation and design considerations may permit land
    treatment within the general floodplain outside of the 100-year floodway.
    Title 25 Pa. Code Chapter 105 defines flood, floodplain, and floodway as follows:
    Flood
    - A general but temporary condition of partial or complete inundation of
    normally dry land areas from the overflow of streams, rivers, or other waters of
    this Commonwealth.
    Floodplain
    - The lands adjoining a river or stream that have been, or may be,
    expected to be inundated by floodwaters in a 100-year frequency flood.
    362-2000-009 / DRAFT March 21, 2009 / Page 17

    Floodway
    - The channel of the watercourse and those portions of the adjoining
    floodplains which are reasonably required to carry and discharge the 100-year
    frequency flood. Unless otherwise specified, the boundary of the floodway is as
    indicated on the maps and flood insurance studies provided by the Federal
    Emergency Management Agency (FEMA). In an area where no FEMA maps or
    studies have defined the boundary of the 100-year frequency floodway, it is
    assumed, absent evidence to the contrary, that the floodway extends from the
    stream to 50 feet from the top of the bank of the stream.
    5.
    Wetlands
    Wetlands interrelate with many of the hydrologic systems discussed in the
    preceding chapters and also require delineation on a large-scale plan. Title 25
    Pa. Code Chapter 105 defines wetlands as follows:
    Wetlands
    - Those areas that are inundated or saturated by surface or groundwater
    at a frequency and duration sufficient to support, and that under normal
    circumstances do support, a prevalence of vegetation typically adapted for life in
    saturated soil conditions, including swamps, marshes, bogs, and similar areas.
    The term includes but is not limited to wetland areas listed in the State Water
    Plan, the United States Forest Service Wetlands Inventory of Pennsylvania, the
    Pennsylvania Coastal Zone Management Plan, and any wetland area designated
    by a river basin commission.
    6.
    Springs and Seeps
    Springs often provide information as groundwater discharge points and potential
    monitoring locations. Establishing locations of springs and seeps may require
    intensive fieldwork. USGS topographic maps are not sufficient to locate all
    springs.
    E.
    Hydraulic Loading Rate
    The applicant should determine a hydraulic loading rate that will not cause saturation of
    the system, and in some cases provide adequate nutrient removal by vegetation. If the
    hydraulic loading rate is too high relative to the soil permeability, the site will become
    inundated, causing runoff and preventing adequate treatment of the applied wastewater.
    Soils that are highly permeable may not provide adequate removal of pathogenic bacteria
    and viruses. In such cases, system design should include disinfection pretreatment.
    If the proposal includes a claim of nutrient removal by on-site vegetation, the rate of
    application should be such that rapid movement of the wastewater through the root zone
    and beyond does not occur. The chosen rate should ensure that the on-site vegetation can
    make use of these nutrients.
    The hydraulic loading rate, based on soil permeability, should be determined based on the
    overall field measured saturated vertical hydraulic conductivity of the most restrictive
    soil horizon for the proposed site, taking into consideration soil morphology. Refer to
    362-2000-009 / DRAFT March 21, 2009 / Page 18

    table 10-7 in section 10.3 of US EPA
    Process Design Manual for Land Treatment of
    Wastewater
    , for hydraulic loading rate percentages. Hydraulic conductivity testing
    should be conducted at a minimum of four representative locations for each proposed
    effluent application area. Additional test locations may be necessary based on variable
    soil characteristics across the site, topography, system configuration, and significant
    deviation from the hydraulic loading rate based on soil morphology. The test locations
    and methods should be discussed with DEP prior to conducting soil evaluations.
    The soil scientist or geologist performing the evaluations and tests should determine the
    appropriate statistical method to calculate the overall saturated vertical hydraulic
    conductivity of the most restrictive soil or bedrock horizon based on the individual
    saturated vertical hydraulic conductivity tests (section IV.B). If the soil profile is
    uniform, the saturated vertical hydraulic conductivity is assumed to be constant with
    depth and the overall saturated vertical hydraulic conductivity can be computed as the
    arithmetic mean of the saturated vertical hydraulic conductivity test results. If bias or
    preference for a certain K value is not indicated by statistical analysis of field test results,
    it has been shown that the geometric mean provides the best estimate of the overall
    saturated vertical hydraulic conductivity. The size of the absorption bed is therefore
    based on the above-calculated hydraulic conductivity. More information about these
    statistical methods is available in the U.S. Environmental Protection Agency’s (EPA)
    Process Design Manual - Land Treatment of Municipal Wastewater Effluents
    ,
    EPA/625/R-06/016. The soil scientist or geologist should submit the rationale used in
    selecting the chosen method. The DEP regional soil scientist will make the final
    determination whether the appropriate method was selected or if another method best
    describes the soil conditions.
    The percentage of field measured vertical hydraulic conductivity used in determining the
    hydraulic loading rate depends on a number of conditions, including the uniformity of the
    soils and the level of treatment prior to land application. The percentages at the low end
    of the range should be used for variable or poorly defined soil conditions. Applying a
    small percentage within this range to the measured hydraulic conductivity accounts for a
    number of possible system conditions including, a reduction in the surface infiltration
    rate over time due to surface clogging, thus approximating the long-term acceptance rate.
    This hydraulic loading rate should be compared with the hydraulic loading rate based
    upon the National Resource Conservation Service soil classification determined from the
    deep probe soil morphology evaluation. If the hydraulic loading rate based on the soil
    morphology evaluation does not correlate with the hydraulic loading rate based on
    saturated vertical hydraulic conductivity testing further investigation to determine the
    optimum hydraulic loading rate may be warranted. The hydraulic loading rate based on
    saturated vertical hydraulic conductivity should be compared to the suggested hydraulic
    loading rates in the table from:
    Tyler, E. J., 2000. University of Wisconsin-Madison,
    Department of Soil Science, Madison, WI
    . Suggested loading rates based on soil
    morphology should consider site and soil conditions such as:
    Topographic and soil conditions such as regional hydrology and landscape
    position
    Slope
    Soil depth
    362-2000-009 / DRAFT March 21, 2009 / Page 19

    Soil texture
    Soil structure
    Depth to restriction or limiting zone
    Soil consistence
    Clay mineralogy
    Soil compaction
    Soil density
    Site uniformity
    More detail on determination of the hydraulic loading rate is provided in Sections VII
    and VIII of this manual.
    F.
    Site Access
    An access road should be provided to allow for entry of construction and maintenance
    vehicles. The access road should be designed to prevent compaction of the land
    treatment area. Whenever possible, equipment including well rigs, soil test pit
    excavators, and vehicles used to transport and set permeability test equipment should not
    travel in proposed absorption areas. Compaction of the absorption area during
    construction may require that the compacted area not be used as part of the land treatment
    system. If travel within the area is necessary, then travel paths should be minimized. If
    an access road is not planned, justification must be provided.
    G.
    Horizontal Isolation Distances
    Land treatment systems should meet the minimum horizontal isolation distances
    identified below, except as noted. Where geological or other conditions warrant, greater
    horizontal isolation distances may be required.
    1.
    Spray Distribution Systems
    Spray distribution systems require isolation distances that account for wind
    conditions. Longer downwind distances than those listed below may be necessary
    to protect various features such as streams and lakes, wells, occupied dwellings
    and sinkholes. Some horizontal isolation distances may be reduced if the
    isolation area is vegetated with a continuous barrier of trees or shrubs of adequate
    height on the date of system startup. The potential over-application of downwind
    portions of a site should be addressed.
    If site-specific design modifications or other methods cannot be used to overcome
    wind drift limitations, velocity and direction criteria should be proposed that
    would cause cessation of application with subsequent effluent storage.
    The following minimum horizontal isolation distances should be maintained
    between the features named and the wetted perimeter of the spray field:
    a.
    A horizontal isolation distance of 400 feet should be provided from
    potable water supply wells that exist or have been approved for
    362-2000-009 / DRAFT March 21, 2009 / Page 20

    construction, except that a horizontal isolation distance of no less than
    100 feet may be acceptable if justified by a hydrogeologic study.
    b.
    The horizontal isolation distance from special protection waters should be
    determined such that when the dispersion plume intersects the special
    protection waters, contaminants have been diluted to background
    concentrations.
    c.
    A horizontal isolation distance of 100 feet should be provided from any
    surface waters.
    d.
    A horizontal isolation distance of 100 feet should be provided from any
    property line.
    e.
    A horizontal isolation distance of 100 feet should be provided from any
    public access road or driveway.
    f.
    A horizontal isolation distance of 400 feet should be provided from any
    residence, dwelling, or occupied structure.
    g.
    A horizontal isolation distance of 100 feet should be provided from the
    perimeter of a sinkhole or closed surface depression.
    h.
    A horizontal isolation distance of 50 feet should be provided from any
    rock outcrops or surface drainage ways.
    2.
    Subsurface Distribution Systems
    The following minimum horizontal isolation distances must be maintained
    between the features named and the wetted perimeter or aggregate of the
    subsurface distribution absorption area:
    a.
    A horizontal isolation distance of 400 feet should be provided from
    potable water supply wells that exist or have been approved for
    construction, except that a horizontal isolation distance of no less than
    100 feet may be acceptable if justified by a hydrogeologic study.
    b.
    The horizontal isolation distance from special protection waters should be
    determined such that when the dispersion plume intersects the special
    protection waters, contaminants have been diluted to background
    concentrations.
    c.
    A horizontal isolation distance of 100 feet should be provided from any
    surface waters.
    d.
    A horizontal isolation distance of 100 feet should be provided from any
    property line.
    362-2000-009 / DRAFT March 21, 2009 / Page 21

    e.
    A horizontal isolation distance of 25 feet should be provided from any on-
    site or public access road or driveway.
    f.
    A horizontal isolation distance of 100 feet should be provided from any
    residence, dwelling, or occupied structure.
    g.
    A horizontal isolation distance of 100 feet should be provided from the
    perimeter of a sinkhole or closed surface depression.
    h.
    A horizontal isolation distance of 50 feet should be provided from any
    rock outcrops or surface drainage ways.
    i.
    A horizontal isolation distance of 25 feet should be provided from any
    natural or manmade slope greater than 25%.
    V.
    PERMITS
    This section provides further detail on the procedures that must be followed to obtain a WQM
    permit. As noted in section II, land application systems may be permitted for both sewage and
    industrial wastewater.
    A.
    Sewage
    Typically, both the sewage treatment plant facilities and the land treatment system are
    permitted under a DEP issued WQM permit which also authorizes the applicant to
    discharge to groundwater. WQM permits are distinguished from NPDES permits which
    authorize discharges to surface receiving waters. Projects that propose seasonal land
    treatment of wastewater with discharge to surface waters during some portion of the year
    require both a WQM and a NPDES permit.
    Procedures for applying for these two types of sewage permits are detailed in the DEP
    Domestic Wastewater Facilities Manual
    (DWFM), DEP ID: 362-0300-001, available on
    DEP’s Web site. Application forms and design modules are also available on DEP’s
    website.
    In addition to the information required in the WQM permit application, the
    Design
    Engineer’s Report
    for a land treatment system must contain detailed information on the
    hydrogeology, soils, crop management procedures when providing nutrient removal,
    nutrient loading information, and proposed groundwater monitoring systems. This part
    of the
    Design Engineer’s Report
    must satisfy the design considerations that are given in
    subsequent sections of this manual.
    B.
    Industrial Wastewater
    Application procedures for a permit for land treatment of industrial waste are similar to
    those applicable to sewage, except that no Act 537 planning approval is necessary. All
    land application distribution and treatment facilities may be covered under a single WQM
    permit. If a seasonal discharge to surface receiving waters is proposed, an NPDES permit
    is also required. Procedures for applying for these two types of industrial waste permits
    362-2000-009 / DRAFT March 21, 2009 / Page 22

    are detailed in DEP’s guidance document,
    Industrial Wastewater Management,
    DEP ID: 362-0300-004, available on DEP’s Web site.
    The WQM permit application must contain detailed information on hydrology,
    hydrogeology, soils, crop management procedures, nutrient loading information, and
    groundwater monitoring. This portion of the
    Design Engineer’s Report
    must satisfy the
    design considerations that are given in the subsequent sections of this manual.
    VI.
    SITE MONITORING
    A.
    Purpose
    Land treatment systems should be monitored to ensure that they are not causing
    groundwater or surface water pollution. Due to the variety of soils and geology in
    Pennsylvania, each monitoring system should be custom designed. This will require the
    expertise of hydrogeologists, soil scientists, and engineers.
    The applicant must design and submit a monitoring plan as part of the WQM permit
    application. The monitoring plan should characterize the wastewater, estimate the
    direction of groundwater flow, and describe the proposed monitoring methods in detail
    for groundwater, soil moisture, and weather. DEP’s
    Groundwater Monitoring Guidance
    Manual,
    DEP ID: 383-3000-001, available on DEP’s Web site, provides details on
    monitoring well construction and sampling.
    B.
    Monitoring Methods
    The applicant must submit a plan for monitoring the land treatment system. Common
    monitoring methods include water table monitoring wells, piezometers, lysimeters,
    facility monitoring ports, and spring sampling.
    1.
    Monitoring Wells and Piezometers
    Monitoring wells are used to determine water levels and for collection of water
    quality samples in unconfined aquifers. Piezometers are designed to determine
    water levels in discrete and isolated depth ranges such as in a thin porous sand
    horizon or a confined aquifer. In this case, the water table may actually be above
    the ground surface, causing the well to flow.
    Monitoring wells and piezometers are commonly used to assess dispersion plume
    and groundwater mounding conditions. Water table wells are typically used for
    monitoring land application systems. Monitoring wells and piezometers should
    be designed and constructed according to DEP’s
    Groundwater Monitoring
    Guidance Manual
    .
    Only by using the groundwater flow data collected during the site evaluation can
    effective monitoring well locations be chosen. At least one monitoring well
    should be located up gradient of the land treatment area to establish baseline
    groundwater quality. A minimum of two wells should be located down gradient
    of the area. Additional wells may be required in areas with complex geology.
    362-2000-009 / DRAFT March 21, 2009 / Page 23

    Wells should be placed in sufficient quantity to characterize the quality of the
    dispersion plume from the land treatment operation. If after land application
    begins, monitoring of wells does not detect wastewater constituents for a given
    discharge, further exploration may be necessary to assure that the plume is not
    escaping detection, either horizontally or vertically.
    After construction, the consulting hydrogeologist should provide a site map
    showing the location of the monitoring wells and a water table contour map. The
    wells should be developed until the water is clear. Some development methods
    include over-pumping, mechanical surging, jetting, and air-lift pumping. A large
    quantity of literature is available on drilling techniques and well construction
    practices and materials. Some suggested references are the
    Groundwater and
    Wells
    text (Driscoll, F. G., 1986) and the National Ground Water
    Association (601 Dempsey Road, Westerville, OH 43081, 800-551-7379).
    2.
    Lysimeters
    Lysimeters are devices used for collecting soil water samples at various depths
    from the pore spaces of soils under both saturated and unsaturated conditions.
    The number and location of lysimeters must be proposed to monitor treatment
    performance within the absorption field. Lysimeters should be placed within the
    land treatment area to assure that the required treatment is occurring in addition to
    providing information on the final effluent entering the groundwater.
    3.
    Facility Sampling Port
    At least one sampling port should be located and designed to produce a
    representative sample of the partially treated effluent just prior to discharge to the
    final soil portion of the treatment system.
    4.
    Springs
    Springs located around the land treatment area may provide an excellent
    supplemental location for monitoring; however, care must be taken to ensure that
    the groundwater emanating from the spring has originated from the area in
    question. Precipitation, temperature, and turbidity data must be provided to
    support proposals for use of springs as supplemental monitoring points.
    Nearby small springs originating from the soil or bedrock may be sampled to
    monitor the local impact of a site. Large springs flowing from carbonate
    bedrock (e.g., limestone and dolomite) may drain entire watersheds or even
    adjacent watersheds. Consequently, samples from such springs may not
    demonstrate the localized impact of the land treatment site.
    362-2000-009 / DRAFT March 21, 2009 / Page 24

    C.
    Sampling Plan
    Each site proposal should outline a plan that describes the frequency and method of
    sampling for each chemical parameter designated for monitoring.
    1.
    Monitoring Frequency
    The applicant should propose a sampling schedule for each monitoring location.
    The monitoring schedule should present a sampling frequency for each parameter.
    Some parameters may require sampling more often than others depending upon
    site-specific conditions. Most applications will propose sampling with a
    combination of chemical parameters sampled quarterly and annually. DEP
    regional staff will determine the appropriate monitoring frequency based upon all
    the information submitted with the application.
    2.
    Sampling Procedure
    All groundwater samples should be representative of the water in the aquifer and
    not what has remained stagnant in the borehole. Therefore, the wells should be
    sufficiently purged. During the purging of the well, temperature, pH, and specific
    conductance must be monitored frequently. These parameters should be
    measured in-line if possible. When the measurements have stabilized, the
    groundwater that is being removed can be assumed to be formation water. In the
    absence of monitoring equipment, three to five borehole volumes can be used as
    an approximation of sufficient purging.
    Samples should be collected and preserved in such a way that no significant
    changes in composition occur before the sample is analyzed. Special procedures
    are necessary for samples containing organic compounds and trace metals.
    Constituents that may be present in small concentrations could be totally or
    partially lost if proper sampling and preservation procedures are not followed.
    The latest revision of
    Standard Methods for the Examination of Water and
    Wastewater
    (Clescer, L.S., A.E. Greenberg and R.R. Trussel (eds.)) should be
    consulted for general guidelines or more specific references. A description of the
    evacuation and sampling method should be included in the permit application.
    VII. SLOW RATE INFILTRATION
    A.
    System/Site Overview
    The slow rate infiltration (SRI) system involves application of pretreated sewage or
    industrial wastewater to the land surface for percolation and renovation within the soil
    mantle with a groundwater recharge. Methods of application include spray,
    ridge-and-furrow, and surface flooding. Spray distribution is the most frequently used
    method of application in Pennsylvania.
    Spray distribution of wastewater for treatment and subsequent groundwater recharge can
    occur at hydraulic loading rates higher than agronomic rates. This term should not be
    confused with spray irrigation that involves hydraulic loading rates less than the
    362-2000-009 / DRAFT March 21, 2009 / Page 25

    agronomic rates and no groundwater recharge. Construction and operation of a SRI
    system requires a WQM permit, and permit applications must address all the design
    considerations discussed in the previous sections of this manual.
    All slow rate infiltration systems are required to have an operator certified under the
    Pennsylvania Sewage Treatment Plant and Water Works Operators’ Certification Act for
    the appropriate system class and treatment subclassification. When no subclassification
    exists for the type of treatment provided, any subclassification certification is acceptable.
    Slopes in the range of 0-40 percent may be considered for different types of SRI systems
    (see Table 7.1). However, surface runoff resulting from applied wastewater is not
    permitted. Vegetation is a critical component of any SRI system for managing nutrients,
    hydraulics, slope stability, and erosion potential. A soil and vegetation management plan
    should be submitted as part of the WQM permit application documenting control of these
    issues.
    Table 7.1
    Potential for Surface Application
    Percent Slope
    Cultivated Agriculture
    Turf Agriculture
    Forest Land
    0 - 4
    High
    High
    High
    4 - 12
    Low
    Moderate
    High
    12 - 20
    Excluded
    Low
    Moderate
    20 - 40
    Excluded
    Excluded
    Low
    B.
    Pretreatment
    Unless deemed inadequate to ensure protection of groundwater quality, secondary
    treatment is the minimum treatment required.
    1.
    Secondary treatment for municipal wastewater must achieve the following:
    a.
    A minimum 85 percent removal of carbonaceous biochemical oxygen
    demand (CBOD
    5
    ) and total suspended solids (TSS)
    --- AND ---
    b.
    The following effluent quality concentration levels, based on a 30-day
    average:
    CBOD
    5
    25 mg/L
    TSS
    30 mg/L
    Additionally, disinfection of the effluent by chlorine or ultraviolet light is required
    to meet a fecal coliform level of 200/100 mL as a monthly geometric mean.
    Ultraviolet radiation should be used as the primary disinfectant whenever
    possible. If a chlorine disinfectant is used, residuals must be kept to a minimum.
    The pH should be between 6.0 and 9.0 and should be compatible with the crop
    selected for the system. Toxic substances should generally be reduced to parts per
    362-2000-009 / DRAFT March 21, 2009 / Page 26

    million levels. Best available treatment of industrial wastewaters will produce an
    effluent acceptable for SRI, if the concentration of toxic pollutants is below the
    human health criteria or maximum contaminant levels for public water supply, or
    their attenuation or degradation through the soil will result in acceptable
    concentrations in the groundwater.
    C.
    Site Preparation
    Each SRI technology has specific site preparation requirements. Generally, the sprinkler
    distribution method requires the least amount of land surface modification. However,
    this method may require a significant amount of excavation to place the piping below the
    frost line if the lines are not designed to be drained during freezing conditions. The
    various “flooding” methods may
    require a large amount of ground surface preparation
    including grading, leveling, and filling to provide a network of distribution ditches for
    uniform effluent loading. The need for deep excavations for buried piping is largely
    reduced.
    The use of temporary or moveable piping networks, while requiring little if any initial
    surface preparation or excavation, will require a significant amount of daily maintenance.
    This includes management of the entire surface area so as not to interfere with placement
    or proper function of the system. If center pivot sprinklers are being used, stone should
    be placed in the wheel tracks prior to start-up to prevent rut formation.
    D.
    Climate
    Although climate is the least site-specific consideration of a land treatment proposal, it
    may ultimately be a major operational concern. Climatic conditions may require the most
    costly additions to a site, such as storage and surface/subsurface drainage structures.
    Climatic considerations may include the duration and volume of storage needed due to
    cold, wet, or windy weather and alternative system management procedures during
    precipitation events. The applicant must evaluate the effects of temperature, precipitation
    and wind on all land treatment systems. These factors may result in the cessation of land
    application and subsequent utilization of effluent storage facilities.
    1.
    Temperature
    Low temperatures are critical and must be addressed if the proposed operation
    will occur during cold weather. Short-term periods of cold weather may cause
    problems in the physical operation of the distribution system. Pipes may become
    blocked with ice and damaged if the distribution piping is not properly designed
    to promote drainage after each application. Spray distribution facilities may have
    problems when the spray nozzles become affected by ice build-up.
    More serious problems occur when land application is proposed during long-term
    periods of cold weather. Frozen or ice-covered ground can result in direct runoff
    of wastes. Soil temperature must therefore also be monitored to ensure proper
    operation of the land treatment system. For spray distribution systems, soil
    temperature at a depth of 1 inch below the soil surface should be recorded. When
    362-2000-009 / DRAFT March 21, 2009 / Page 27

    the temperature is 32ºF or below, the cessation of effluent application and
    subsequent storage of the effluent is necessary.
    2.
    Precipitation
    Compared to cold weather occurrences, precipitation is typically a short-term
    event. It does, however, have major implications for land treatment systems.
    Some design factors that should be evaluated based on wet weather conditions
    include the following:
    a.
    Hydraulic Budget
    A hydraulic budget accounting for applied wastewater, precipitation,
    evapotranspiration, and runoff should be addressed on no less than a
    monthly basis. In general, effluent should not be applied on a long-term
    basis if it will cause significant groundwater mounding and interfere with
    proper system function. Applied wastewater plus precipitation should not
    exceed the actual evapotranspiration rate of the site plus up to 10 percent
    of the saturated vertical hydraulic conductivity of the most restrictive
    horizon (IV.B.). This relationship will typically be of greatest concern
    before and after the height of the growing season.
    b.
    Hydraulic Acceptance Rate
    Hydraulic acceptance rate is that rate at which effluent can be applied to a
    soil without runoff. When soil moisture content is low, the soil can accept
    effluent at a rate greater than the same soil under increased moisture
    conditions or saturation. The method and schedule for applying the stored
    effluent during appropriate weather conditions should also be addressed.
    c.
    Periods of Excess Soil Moisture Content
    After significant precipitation or during snowmelt events, the topsoil and
    upper portions of subsoil may remain saturated or excessively wet for long
    periods of time. This may interfere with proper function of the land
    treatment system.
    3.
    Wind
    Natural or man-made obstruction to wind should be placed upwind with respect to
    the prevailing wind direction to reduce the wind velocity across the proposed site.
    Small diameter and/or low trajectory sprinkler heads, “trickle” flow applicators,
    sheet flow applicators, etc. should be incorporated into the application design to
    keep the effluent closer to the ground surface and away from areas typically
    impacted by the wind.
    362-2000-009 / DRAFT March 21, 2009 / Page 28

    4.
    Weather Monitoring
    Since weather conditions largely determine when and how much effluent may be
    applied at a specific site, the proposal should contain provisions for monitoring
    the weather. The operator of the system should record the weather conditions
    during each day of land application. The records should contain a log of
    temperature, precipitation form and amount, wind direction and speed, and field
    conditions.
    E.
    Vegetation
    The selection of cover vegetation is important in most land treatment systems. The
    vegetation must be able to survive extremely wet conditions, reduce erosion potential,
    tolerate the various chemical parameters in the effluent, assure the desired level of
    nutrient uptake, and provide additional treatment capacity if possible. Some land
    treatment systems require specific types of vegetation that will generate certain surface
    flow patterns or remove certain chemicals from the wastewater. Management of the
    vegetative cover should also be considered (i.e., harvesting, usability, reestablishment).
    There are many factors to consider in the selection of appropriate vegetative covers for a
    land treatment site. The primary consideration is how the vegetation will work with the
    SRI system. Another consideration is the final use of the vegetation. Every effort should
    be made to grow a viable economic crop. Otherwise, it may require appropriate disposal
    once it is harvested. Before choosing the appropriate vegetative cover, the applicant must
    determine the assimilative capacity of the vegetation and must consider management,
    economic, and other site issues, as discussed in the following sections. A good reference
    is the U.S. Environmental Protection Agency’s (EPA)
    Process Design Manual - Land
    Treatment of Municipal Wastewater Effluents
    , EPA ID: 625/R-06/016 or
    Phytotechnology Technical and Regulatory Guidance Document
    , Interstate Technology
    Regulatory Council, April 2001.
    1.
    Assimilative Capacity
    The vegetation selected must be able to assimilate the specific type of effluent
    being applied to the soil. Typical sewage effluent has different characteristics
    than industrial waste effluent, which is widely variable depending on the process
    and pretreatment methods involved. The applicant should address the following
    conditions or characteristics in order to select the vegetative cover most capable
    of assimilating the effluent.
    a.
    Hydraulic Load
    When a significant hydraulic load is to be placed on the land treatment
    system, the vegetation must be able to tolerate the wetness and still
    provide assimilative capacity to remove the chemical parameters of
    concern. Under certain conditions, vegetation should be selected that will
    take up and transpire significant quantities of water, thereby lessening the
    hydraulic loading to the groundwater and decreasing the potential for
    groundwater mounding.
    362-2000-009 / DRAFT March 21, 2009 / Page 29

    b.
    Anions
    Anions, particularly nitrate (NO
    3
    -
    ), are generally not afforded significant
    renovation by the soil profile. Therefore, the major
    assimilative/renovative pathway for anions is vegetative uptake. The
    fraction of all anionic species not removed by vegetation moves largely
    unchanged into the groundwater where dilution takes place. A crop that
    can remove significant quantities of anions (mostly NO
    3
    -
    ) from the soil
    water/effluent will lessen the impact of those parameters on groundwater.
    This is an especially important consideration if background groundwater
    quality concentrations are elevated.
    c.
    Cations and Metals
    Cations are typically complex and tightly held within the soil. However,
    certain processes within the treatment system may cause them to become
    mobile. Some plants have a natural affinity for uptake and storage or
    transport of certain metals not bound within the soil. Certain vegetation
    will show the effects of toxicity to certain metal species at much lower
    concentrations than others. Even essential cations like iron, chromium and
    potassium may be toxic if levels significantly exceed those required for
    growth.
    While uptake of cations can be a major benefit of a vegetative species, the
    level of metal concentrations and other soil/wastewater factors must be
    kept in equilibrium. Typical farm management operations such as liming
    and fertilizing may need to be limited as they can complicate the
    relationships within the system over time, as cationic concentrations build
    in the soil.
    d.
    Oil, Grease, and Organics
    Oil, grease, and organics as discussed in this section refer to plant and
    animal based fats and oils and not petroleum by-products. Petroleum by-
    products are not amenable to soil renovation and should not be considered
    for land treatment.
    The soil’s microbial population accounts for most of the breakdown of
    oils, greases, and organics. However, treatment is greatly inhibited by
    lower temperature, and soil pores may clog causing the system to
    malfunction.
    Vegetation will assimilate certain organics and metabolites of organic
    compounds. The organics will typically be stored within the plants’ tissue
    and may become toxic to the plant or render the vegetation unsuitable for
    some uses after harvest. Oil or grease may also clog the surface of plants,
    significantly reducing or halting transpiration.
    362-2000-009 / DRAFT March 21, 2009 / Page 30

    2.
    Site-Specific Considerations
    In general, the vegetation chosen should provide control against erosion and
    significant runoff as well as assisting in furnishing the desired treatment. Steeper
    slopes typically require a vegetation cover having well-developed roots that will
    aid in holding the soils in place. Land application must be limited to areas
    containing growing vegetation.
    A year-round application proposal should consider use of forest vegetation on the
    wintertime site. The well-developed root system and organic blanket associated
    with forest vegetation deters significant frost effects. Storage is necessary for
    weather conditions that do not allow application of effluent. Conventional tillage
    and row crops should be used on very gentle slopes.
    Slopes of up to twelve percent can typically be considered for most land treatment
    systems. However, with detailed substantiating data and specific design
    inclusions, proposals for spray distribution may be considered on slopes up to
    forty percent.
    3.
    Management and Economic Considerations
    Well-managed SRI systems will treat influent wastewater at the design flows and
    will be aesthetically acceptable. They can also be economically beneficial to the
    operator by providing return on the harvested vegetation, by reducing the cost of
    conventional treatment, and/or by eliminating the need for stream discharge of
    effluent.
    A schedule of anticipated crop rotations and operations should be provided with
    the permit application. This schedule may need to be altered if there are wet soil
    conditions, because significant soil damage can occur under some farming
    operations. Harvesting or management should be conducted when facilities are
    shut down and no effluent is being produced. Additional wastewater storage may
    be required due to variations in practices (i.e., crop rotation, harvesting). The
    proposal for an SRI system should include a vegetation management plan and
    should address the following management and operational considerations:
    a.
    Crop Establishment
    The type or species of vegetation may require different methods and
    durations for establishment. Forage crops may take only a few weeks to
    reach a stage of growth when application could commence. However, tree
    species may take several months to a year. A cover crop of some “rapid
    growth” vegetation should be considered to reduce the risk of erosion if
    the proposed vegetation will take a significant period of time to reach full
    establishment. Further, the season of the year should be considered since
    few types of vegetation can be established in late fall or winter.
    362-2000-009 / DRAFT March 21, 2009 / Page 31

    b.
    Crop Rotation
    Planting of perennial species or forest is typically a one-time or long-term
    operation. Use of annual crops and intense crop rotations will require
    reestablishment on a much more frequent basis.
    c.
    Harvesting
    Vegetation should be harvested or removed from the site periodically. If
    this does not occur, all the parameters of concern that have been taken up
    by the vegetation will simply return to the soil causing an eventual
    overload of some parameter to the overall system.
    Typically, forage crops should be harvested several times per year while in
    the vegetative (rather than productive) stage when they are assimilating
    nutrients at optimum rates. Row crops should be harvested at appropriate
    times based on applicable farming operations. Application to sites where
    crops have been completely removed is not advisable
    until other
    vegetation is established (such as harvesting of small grains with
    subsequent planting of annual rye or winter wheat).
    Forest crops should also be harvested periodically, although typically less
    frequently than forage crops. Both whole tree harvesting and stem
    harvesting are utilized during different stages of forest growth. After the
    initial 1-2 years of growth, when a root system has been established,
    growth rates and nutrient uptake increase and remain relatively constant
    until maturity is approached. This can take 20 to 25 years for southern
    pines and 50 to 60 years for hardwoods. During this stage, stem
    harvesting is commonly practiced to ensure removal of parameters of
    concern from the system. Once maturity is reached and growth rates slow,
    whole tree harvesting takes place to ensure maximum removal of
    parameters of concern. Whole tree harvesting may also be practiced well
    in advance of maturity with a short-term rotation management plan.
    d.
    Usage/Disposition
    The ultimate disposition of harvested vegetation should be addressed.
    Some crops have an inherent value and may be utilized or sold, whereas
    some vegetation is planted simply to provide uptake of certain
    contaminants. Land application should
    only be used on crops intended for
    non-human consumption when effluent quality and application are
    consistent with DEP’s
    Reuse of Treated Wastewater Guidance Manual
    ,
    DEP ID: 362-0300-009. The proposal should indicate whether the crop is
    intended for animal consumption, industrial usage, horticultural usage,
    fertilization of “other” lands, landfilling, or other uses.
    362-2000-009 / DRAFT March 21, 2009 / Page 32

    e.
    Natural Range
    An obvious consideration in the selection of a plant species is whether it
    will survive in the climate or on the specific site. A plant species may
    possess the proper assimilative capacity, provide required tolerances and
    positive economic returns upon harvest, however, if the species cannot
    survive the climate or site-specific conditions, these attributes are all
    irrelevant.
    f.
    Soil and Vegetation Management Plan
    Vegetation and soils should be managed in accordance with an approved
    annual crop and soil management plan. The plan should include the
    following elements:
    Soil nutrient analysis
    Discussion of selected vegetation
    Maintaining the vegetation
    Trimming and removing crop or plant residues
    Lime and fertilizer applications
    Provisions to ensure the vegetation does not interfere with or
    impair the proper operation of the land treatment system
    Annual projected nitrogen loading from fertilizer and wastewater
    Nitrogen balance calculations
    Weed control
    Prevention and alleviation of surface soil compaction
    F.
    Distribution Systems
    Once it is determined that the final effluent will meet all applicable surface and
    groundwater quality standards and requirements, the wastewater can be distributed and
    applied to the land.
    The two common methods for land application of wastewater are surface and sprinkler
    distribution. Selection of either of these methods depends on the objectives of the project
    and the limitations imposed by physical conditions such as topography, type of soil, crop
    requirements, and degree of pre-treatment. Surface distribution requires careful grading
    of surfaces, extensive systems of channels for distribution, and ditches to collect effluent
    and surplus water. Sprinkler distribution is virtually independent of the shape and
    contour of the area.
    1.
    Surface Distribution Systems
    Canals or pipelines are normally used to convey wastewater to a surface
    distribution system. This method of distribution is more suited to soils with
    moderate to low intake rates. Graded land is essential for proper performance of
    surface systems. Design standards for these wastewater conveyance systems, and
    for flow control and measurement techniques are published by the American
    362-2000-009 / DRAFT March 21, 2009 / Page 33

    Society of Agricultural and Biological Engineers. Methods of distribution to
    fields include turnouts, siphon pipes, valved risers, gated surface pipe, and
    bubbling orifices.
    Surface distribution methods include ridge and furrow distribution and surface
    flooding distribution.
    a.
    Ridge and Furrow Distribution
    The ridge and furrow method consists of installing distribution streams
    along small channels (furrows) bordered by raised beds (ridges) upon
    which crops are grown. Furrows may be level or graded, straight or
    contoured. A variation of this is corrugation distribution that consists of
    furrows excavated from the surface without creating raised beds.
    For furrow distribution, the water only partially covers a given field area
    and moves both downward and outward. Factors that are critical for
    design of ridge and furrow are furrow stream size, length, slope, and
    spacing.
    Distribution systems most commonly used for ridge and furrow consists of
    open ditches with siphon pipes or gated surface piping. Distribution
    ditches may supply open ditch systems or canals with turnouts or by
    buried pipelines with valved risers. Gated surface piping systems
    generally consist of aluminum pipe with multiple gated outlets, one per
    furrow. The pipe is connected to hydrants that are secured to valved risers
    from underground piping systems.
    b.
    Surface Flooding Distribution
    Surface flooding distribution is a method in which a sheet flow of water is
    directed along border strips or cultivated strips of land bordered by small
    levees. It is suited to close-growing crops such as grasses that can tolerate
    periodic inundation. Border strips usually have slight, if any, cross slopes
    and may be level or graded in the direction of flow. They also may be
    straight or contoured. Water is applied in the same manner as in ridge and
    furrow distribution. The stream is normally shut off when it has advanced
    about 75 percent of the length of the border.
    The objective is to have sufficient water remaining on the border after
    shut-off to irrigate the remaining length of border to the proper depth with
    very little runoff. The widths of border strips are usually selected for
    compatibility with farm implements, but they also depend to a certain
    extent upon slope, which affects uniformity of distribution.
    Other design factors for border strip systems include soil intake
    characteristics, border strip lengths and slopes, and soil roughness, which
    is a measure of resistance to flow caused by soil and distribution.
    362-2000-009 / DRAFT March 21, 2009 / Page 34

    Distribution systems for surface flooding are similar to ridge-and-furrow
    distribution systems. Use of gated strips provides more uniform
    distribution at the head of border strips and allows the flexibility of easily
    changing to ridge and furrow distribution if crop changes are desired.
    2.
    Sprinkler Distribution Systems
    The more significant design considerations for sprinkler system selection include
    field conditions (shape, slope, vegetation and soil type), climate, operating
    conditions, and economics.
    The determination of a sprinkler system design involves the optimum rate of
    application, sprinkler selection, sprinkler spacing and performance characteristics,
    lateral design, and miscellaneous requirements. Detailed design requirements for
    specific systems may be obtained from equipment suppliers. The optimum
    application rate for a sprinkler system will provide uniform distribution under
    prevailing climatic conditions without exceeding the surface infiltration rate of the
    soil, and provide for intermittent application to allow reaeration of the soil.
    The design application rate to prevent runoff may be increased 50 to 100% over
    the bare soil application rate based on site vegetation. The low end of this range
    is appropriate for full-cover crops and the upper end for mature (greater than 4
    years old) permanent pastures. Surface infiltration is not normally a limiting
    factor for forested areas in establishing the design application rate.
    The application rate should be reduced based on the slope of the site in accord
    with Table 7.2.
    Table 7.2
    Recommended Reductions in Application Rate Due to Slope
    Percent Slope
    Percent Reduction in Level
    Ground Application Rate
    0 – 5
    0
    6 – 8
    20
    9 – 12
    40
    13 – 20
    60
    over 20
    75
    Sprinkler selection is dependent on the type of distribution system, pressure
    limitations, application rates, clogging potential, and effects of wind. Sprinklers
    used for application of wastewater are usually of the rotating head type with one
    or two nozzles capable of applying at a rate of 0.2 to 0.3 in/hr. Manufacturers
    should be consulted for specific sprinkler specifications.
    Water Cannons, other high volume irrigators, or spray methods that launch
    effluent at an angle above horizontal are not advisable. These methods may
    promote runoff or can result in effluent drifting with the wind onto un-permitted
    areas.
    362-2000-009 / DRAFT March 21, 2009 / Page 35

    Sprinkler spacing and performance characteristics are jointly analyzed to
    determine the most uniform distribution pattern at the optimum application rate.
    Since the amount of water applied by a sprinkler decreases with distance from the
    nozzle and the distribution pattern is circular, sprinklers and laterals are spaced to
    provide overlapping of the wetted diameter. Choice of spacing between
    sprinklers is closely associated with both the application rate and the amount of
    pressure at the nozzle. The primary factor that affects the choice of spacing is the
    vegetative cover (i.e., open field crops or forests). A spacing of 80 feet between
    sprinkler heads and 100 feet between laterals is preferred for open fields, and a
    spacing of 60 feet between sprinkler heads and 80 feet between laterals is
    preferred for wooded areas. These appear to give the best relationship between
    good distribution and reasonable costs. Other spacing alternatives may be
    determined empirically or by using published guidelines.
    Once the preliminary spacing has been determined, the nozzle discharge capacity
    to supply the optimum application rate is found by the following equation:
    C
    Q=
    (S
    L
    x S
    M
    x I)
    Q
    = flow rate from nozzle,
    gallons/minute
    (liter/second)
    S
    L
    = sprinkler spacing along lateral,
    feet
    (meters)
    S
    M
    = sprinkler spacing along main,
    feet
    (meters)
    I
    = optimum application rate,
    inches/hour
    (centimeters/hour)
    C
    = constant = 96.3 fps system (360) mks system
    This establishes the basis for final sprinkler selection, which is a trial and
    adjustment procedure to match given conditions with performance characteristics
    of available sprinklers.
    Lateral design consists of selecting sizes to deliver the total flow requirement of
    the lateral with friction losses limited to a predetermined amount. A general
    practice is to limit all hydraulic losses in a lateral to 20 percent of the operating
    pressure of the sprinklers. This will result in sprinkler discharge variations of
    approximately ten percent along the lateral.
    System automation selections should be based on a comparison of labor costs
    with the cost of controls at the desired level of operating flexibility. Common
    control devices include remote control valves energized electronically or
    pneumatically to start or stop flows in a lateral or main.
    a.
    Fixed Sprinkler Systems
    Application to forested, variably covered, or large areas of gentle to steep
    slopes up to 40 percent, are usually compatible with application by “fixed”
    sprinklers, which are part of a buried distribution network. Typically,
    fixed systems are arranged on several circuits that provide very specific
    design application patterns and rates. The sprinkler circuits generally
    362-2000-009 / DRAFT March 21, 2009 / Page 36

    distribute effluent to an area large enough to accept a single day’s design
    flow with a predetermined rest period between applications. Alternative
    arrangements can be considered to manage other hydraulic or vegetative
    aspects of the SRI operations.
    b.
    Moveable Sprinkler Systems
    Sites that are low-flow, small, steep, seasonal, or heavily forested may
    require the use of temporary or moveable sprinklers and distribution lines,
    low-trajectory/low-pressure sprinklers, small diameter sprinkler heads or
    “drip” emitters. The applicant should consider these methods, which may
    provide both cost effective and even distribution of effluent.
    c.
    Center Pivot Sprinkler Systems
    Central pivot irrigation is a form of overhead irrigation consisting of
    several segments of pipe joined together and supported by trusses,
    mounted on wheeled towers with sprinklers positioned along its length.
    The system moves in a circular pattern and is fed with water from the
    pivot point at the center of the circle. Center pivot sprinkler systems are
    typically limited to gently sloping agriculture land and are not conducive
    to winter operation. Storage should be adjusted accordingly if center pivot
    sprinklers are planned.
    G.
    Process Design
    1.
    Hydraulic Loading Rates Based on Soil Permeability
    Hydraulic loading rates should be within measured soil capabilities. Loading is to
    be based on a water balance that includes precipitation, evapotranspiration, and
    wastewater percolation. The total monthly loading should be distributed
    uniformly, taking into consideration planting, harvesting, drying and other periods
    of no application.
    The basic steps in the procedure are as follows:
    a.
    Determine the design precipitation for each month based on a 10-year
    return frequency analysis for monthly precipitation.
    b.
    Estimate the evapotranspiration rates (E
    t
    ) of the selected crop for each
    month.
    c.
    Determine the overall saturated vertical hydraulic conductivity of the site using
    the soil evaluation performed in section IV.
    d.
    Establish a maximum daily design percolation rate that does not exceed
    the rate found in section IV.E. of the overall saturated vertical hydraulic
    conductivity measured at the site, taking into consideration suggested
    hydraulic loading rates based on soil morphology. As discussed in
    362-2000-009 / DRAFT March 21, 2009 / Page 37

    section IV.E., lower percentages are recommended for variable or poorly
    defined soil conditions.
    e.
    Calculate the monthly hydraulic loading rate using the following equation:
    L
    w
    =
    E
    t
    -P+W
    p
    L
    w
    = wastewater hydraulic loading rate, inches per month
    P
    = design precipitation, inches per month
    E
    t
    = evapotranspiration (or crop consumptive use of water), inches per
    month
    W
    p
    = percolating water, inches per month (use a percentage of the minimum
    saturated vertical hydraulic conductivity from section IV.B).
    f.
    Calculate the loading rates for each month with adjustments for those
    months having periods of non-application. Periods of non-application
    may be due to wet weather, cold weather, vegetation management or
    maintenance.
    The monthly hydraulic loading rates are summed to yield the annual
    hydraulic loading rate based on soil saturated vertical hydraulic
    conductivity and soil morphology.
    2.
    Hydraulic Loading Rate Based on Nitrogen Limit
    Nitrogen management for the SRI process principally involves crop uptake with
    some denitrification. Aerobic nitrification involves the breakdown of organic-
    nitrogen to ammonia and ammonium. Through the action of bacterial organisms
    such as
    Nitrosomonas
    , the ammonium ion is broken down to nitrite-nitrogen.
    This is further broken down through the action of
    Nitrobacter
    bacteria to
    nitrate-nitrogen. Denitrification involves the biological reduction of nitrate to
    nitrite and finally nitrogen gas. Such biological denitrification requires bacteria
    (Pseudomonas, Micrococcus, Bacillus, and Acomobacter
    ), anoxic conditions and
    a source of organic carbon.
    The following procedure should be used to determine wastewater loading rates
    when nitrogen concentration in the groundwater is a concern:
    a.
    Calculate the allowable monthly hydraulic loading rate based on nitrogen
    limits and monthly design flow information using the following equation:
    362-2000-009 / DRAFT March 21, 2009 / Page 38

    [(1
    )( )
    ]
    ( )(
    ) ( )(4.413)
    np
    pr
    t
    n
    fCC
    CPE
    U
    L
    −−
    −+
    =
    L
    n
    = wastewater hydraulic loading rate,
    in/month
    C
    p
    = nitrogen concentration in percolating water,
    mg/L
    P
    r
    = precipitation rate,
    in/month
    E
    t
    = evapotranspiration rate,
    in/month
    U = crop nitrogen uptake,
    lb/acre month
    C
    n
    = nitrogen concentration in applied wastewater,
    mg/L
    f
    = fraction of applied nitrogen removed by denitrification and
    volatilization
    Design values for crop nitrogen uptake (U) will depend on actual crop
    yields. Local agricultural agents should be contacted for site-specific
    information.
    Denitrification and volatilization are difficult to determine under field
    conditions, but losses generally range from 15-25 percent of the applied
    nitrogen. Conditions favorable to denitrification include soils that are fine
    textured and high in organic matter, frequent wetting, high temperatures,
    vegetative cover, high groundwater table, and neutral to slightly alkaline
    pH. Under these conditions, the high end of the range should be used.
    b.
    Compare the value of the hydraulic loading rate based on nitrogen to the
    hydraulic loading rate based on the saturated vertical hydraulic
    conductivity of the soil for each month of the year. The lower of the
    values should be used for that month as the design hydraulic loading rate.
    The sum of the lower monthly values can then be used as the annual
    design hydraulic loading rate.
    c.
    After the appropriate loading rate is determined, the area of the absorption
    field can be calculated.
    3.
    Storage Requirements
    The applicant should calculate the minimum storage requirement for all land
    treatment systems that distribute wastewater effluent onto the ground surface.
    Local climatic records as well as nationally available climatic data, such as that
    available from the National Oceanic and Atmospheric Administration’s database,
    should be evaluated to estimate the number of days each month wastewater will
    not be applied to the site due to weather conditions. Contact information for the
    National Climatic Data Center is as follows:
    362-2000-009 / DRAFT March 21, 2009 / Page 39

    Climate Services Branch
    National Climatic Data Center
    Room 468
    151 Patton Avenue
    Asheville, NC 28801-5001
    828-271-4800
    FAX: 828-271-4876
    Wastewater should not be applied if any of the following site conditions exist:
    Amount of snow on the ground is greater than one inch
    Rainfall in the previous 24-hour period exceeds one half inch
    Soil temperature measured one inch below the soil surface is less than
    32°F
    More conservative values may be used.
    Table 7.3 is an example of a water balance spreadsheet that can be used to
    calculate the required storage volume.
    Table 7.3
    Example Storage Requirement Spreadsheet
    Month
    Days
    in
    Month
    Net Daily
    Wastewater
    Flow
    (1000 gal)
    Monthly
    Wastewater
    Available
    (1000 gal)
    Volumetric
    Wastewater
    Hydraulic
    Loading
    Rate
    (1000
    gal/day)
    Days
    Wastewater
    Able to be
    Applied
    Monthly
    Wastewater
    Applied
    (1000 gal)
    Change
    in
    Storage
    (1000 gal)
    Cumulative
    Storage
    (1000 gal)
    Oct
    31
    85
    2635
    150
    17
    2550
    85
    85
    Nov
    30
    89
    2670
    150
    18
    2700
    -30
    55
    Dec
    31
    83
    2573
    150
    16
    2400
    173
    228
    Jan
    31
    85
    2635
    150
    0
    0
    2635
    2863
    Feb
    28
    80
    2240
    150
    0
    0
    2240
    5103
    Mar
    31
    78
    2418
    150
    17
    2550
    -132
    4971
    Apr
    30
    79
    2370
    150
    18
    2700
    -330
    4641
    May
    31
    82
    2542
    150
    20
    3000
    -458
    4183
    Jun
    30
    86
    2580
    150
    22
    3300
    -720
    3463
    Jul
    31
    100
    3100
    150
    25
    3750
    -650
    2813
    Aug
    31
    78
    2418
    150
    25
    3750
    -1332
    1481
    Sep
    30
    72
    2160
    150
    25
    3750
    -1590
    0
    The columns in the water balance sheet are defined as follows:
    Net Daily Wastewater Flow -
    the average daily net volume of wastewater
    applied to the system.
    362-2000-009 / DRAFT March 21, 2009 / Page 40

    Monthly Wastewater Available -
    the total volume of wastewater influent to the
    treatment system for each month. This is calculated by multiplying the net daily
    wastewater flow by the number of days in the given month. This calculation must
    include rainfall contribution to and evaporation from the storage lagoon(s).
    Volumetric Wastewater Hydraulic Loading Rate
    - the maximum volume of
    wastewater that may be applied to the absorption field daily. This rate is the
    product of the hydraulic conductivity, a factor no greater than 10 percent, and
    total area of the absorption field
    plus
    the average daily evapotranspiration
    minus
    average daily rainfall.
    Days Wastewater Able to be Applied
    - the total days of the month in which
    wastewater can be applied. This is a site-specific value, which is determined
    using historic weather data and also must allow for maintenance shutdowns.
    More information is available in section VII.D.
    Monthly Wastewater Applied
    - the total volume of wastewater that can be
    applied in a given month. Calculated by multiplying the wastewater hydraulic
    loading rate by the number of days wastewater can be applied.
    Change in Storage
    - the total amount of storage necessary for a given month.
    This is calculated by subtracting the monthly wastewater applied from the
    monthly wastewater available.
    Cumulative Storage
    - A running sum of the total amount of storage necessary for
    the system to operate. This is calculated by adding the change in storage for a
    given month to the cumulative storage of the previous month. The maximum
    value in this column is the minimum total storage necessary to operate the system.
    4.
    Phosphorus Removal
    Phosphorus is removed from solution by fixation processes in the soil, such as
    adsorption and chemical precipitation. Removal efficiencies are generally very
    high for slow rate systems and more dependent on the soil properties than on the
    concentration of phosphorus applied. Phosphorus retention can be enhanced by
    the use of crops such as grass with large phosphorus uptake. Field determination
    of levels of free oxides, calcium, aluminum, and soil pH will provide information
    on the type of chemical reaction that will occur. Determination of phosphorus
    absorption capacity of the soils requires laboratory testing of field samples.
    Systems with strict phosphorus limits in the percolate should include monitoring
    for nutrient soil phosphorus to verify retention in the soil.
    5.
    Removal of Trace Elements and Other Parameters of Concern
    The concentrations of trace elements and other parameters of concern vary
    significantly, depending on wastewater characteristics. Trace elements include
    metals, pesticides, volatiles, and acid extractable and base neutral organics. Trace
    element assessments are necessary to assure that levels will not be toxic to cover
    vegetation or impair groundwater quality. In some cases where applied
    362-2000-009 / DRAFT March 21, 2009 / Page 41

    concentrations of trace metals are excessive, it may be necessary to maintain soil
    pH at 6.5 or higher.
    Other constituents of concern include greases, emulsions and salts. These may
    clog soils, plug nozzles, coat vegetation, be persistent or
    non-biodegradable/non-exchangeable with soil materials, or be toxic to vegetative
    cover. Effluent that exhibits these properties should not be applied to the land
    surface.
    6.
    Microorganism Removal
    The potential for public health risks from microorganism contamination as a
    result of land treatment of wastewater varies greatly depending upon site-specific
    conditions. The factors include type of application, pre-application treatment,
    public access to the site, population density, adjacent land use, climate, type of
    on-site buffer zones, and type of vegetative cover.
    The applicant should evaluate these variables to achieve the goal of minimizing
    public health risks from land treatment of wastewater. All wastewater that
    contains pathogens must be disinfected prior to application.
    VIII. SUBSURFACE INFILTRATION
    A.
    System/Site Overview
    A large volume subsurface infiltration system is an individual or community onlot
    sewage system that applies wastewater to the soil below final grade and has a design
    capacity in excess of 10,000 gpd. The system depends on soil for part of the sewage
    renovation. The guidance in this section should be used in conjunction with sections I
    through VI to design and operate a subsurface infiltration system.
    The sewage enforcement officer for the local agency issues permits for onlot sewage
    disposal systems when projected peak daily sewage flows are equal to or less than
    10,000 gpd. When the design peak daily sewage flows exceed 10,000 gpd, the onlot
    sewage system is classified as a large volume onlot sewage system and is permitted by
    DEP under a WQM permit.
    The system consists of primary or secondary treatment followed by storage and a
    pressure distribution system placed in a soil treatment area. Additional pretreatment may
    be required to overcome site-specific conditions such as high concentrations of certain
    contaminants. The addition of any pretreatment facilities will require extensive
    documentation to show that the proposed system will consistently treat the contaminant
    of concern.
    A minimum of 3 days influent storage is necessary
    for all subsurface infiltration systems
    to provide for flow equalization, system maintenance, and wet weather and emergency
    operation. The soil treatment area should be time dosed by pressure distribution
    equipment and consist of a minimum of 4 absorption zones. The zones may be composed
    362-2000-009 / DRAFT March 21, 2009 / Page 42

    of an aggregate or leaching chamber inground trench system, an at-grade bed system, or
    drip distribution system.
    All subsurface infiltration systems are required to have an operator certified under the
    Pennsylvania Sewage Treatment Plant and Water Works Operators’ Certification Act for
    the appropriate system class and treatment subclassification. When no subclassification
    exists for the type of treatment provided, any sub classification certification is acceptable.
    Additional information on wastewater operator requirements is available from the
    following Web page:
    http://www.dep.state.pa.us/dep/deputate/waterops/Redesign/indexgood.htm.
    B.
    Underground Injection Control Requirements
    EPA is directed by the Safe Drinking Water Act (SDWA) to establish minimum federal
    requirements for state and tribal Underground Injection Control (UIC) Programs to
    protect underground sources of drinking water from contamination caused by
    underground injection activities. A large volume subsurface infiltration sewage system
    that receives any amount of industrial or commercial wastewater (also known as
    industrial waste disposal wells or motor vehicle waste disposal wells), or receives solely
    sewage from multiple family residences or a nonresidential establishment, and has the
    capacity to serve 20 or more persons per day is considered a Class V injection well. All
    Class V injection wells are required to meet UIC Program requirements.
    Owners and operators of large volume subsurface infiltration sewage systems must meet
    state and federal UIC Program requirements. The minimum federal requirements for
    Class V wells prohibit injection that allows the movement of fluids containing any
    contaminant into underground sources of drinking water, if the presence of that
    contaminant may cause a violation of any primary drinking water regulation or adversely
    affect public health. The system owner/operator is obligated to provide inventory
    information (including facility name and location, legal contact name and address,
    ownership information, nature and type of injection wells, and operating status of the
    injection wells) to EPA’s regional UIC Program.
    The EPA’s regional UIC Program coordinator may at contacted at:
    USEPA R3
    SDWA Branch-1650 Arch St.
    Philadelphia, PA 19103
    Phone: 215-814-5445
    Fax: 215-814-2302
    Web site: http://www.epa.gov/reg3wapd/drinkingwater/uic/index.htm
    Additional information may be obtained from the EPA’s Web page at
    http://www.epa.gov/safewater/uic/classv.html. The EPA Inventory of Injection Wells
    reporting form may be obtained from the following Web page:
    http://www.epa.gov/safewater/uic/cl5oper/inventory.pdf.
    362-2000-009 / DRAFT March 21, 2009 / Page 43

    C.
    Soils/Pretreatment
    The soil evaluation should be conducted according to section IV of this manual. The soil
    profile should have a minimum depth to limiting zone of 48 inches unless adequate
    pretreatment as described below is provided. Limiting zones are soil horizons or
    conditions that limit either downward movement or renovation of the effluent. Examples
    include saturated soil conditions, rock with open joints, fractures or solution channels,
    insufficient fine soil between masses of loose rock fragments and rock formations, strata
    or soil conditions that are so slowly permeable that they limit downward passage of
    effluent.
    The depth to the limiting zone is defined as the vertical distance between the bottom of
    the absorption bed, trench or drip tubing and top of the projected saturated soil layer, or
    other limiting zone. This determination is especially critical on sites with shallow
    limiting zones.
    Sites with a depth to limiting zone of greater than 20 inches but less than 48 inches may
    be considered for land treatment systems that propose application of effluent that contains
    equal to or less than 25 mg/L CBOD
    5
    and equal to or less than 30 mg/L TSS as a monthly
    geometric mean. Additionally, disinfection of the effluent is necessary to meet a fecal
    coliform level of 200/100 mL as a monthly geometric mean, and the pH should be
    between 6.0 and 9.0. Ultraviolet light radiation should be used as the primary
    disinfectant whenever possible. If a chlorine disinfectant must be used, residuals should
    be kept to a minimum. The appropriate DEP regional office should be contacted for
    additional information concerning proposals on limiting soils.
    Sites with a depth to limiting zone of greater than 10 inches but less than 20 inches below
    the bottom of the absorption area may be considered for land treatment systems that
    propose application of effluent that contains equal to or less than 10 mg/L BOD
    5,
    equal to
    or less than 10 mg/L TSS as a monthly geometric mean and fecal coliform equal to or
    less than 200/100 mL. DEP’s regional office should be contacted for additional
    information concerning proposals on limiting soils.
    When attempting to site and design large volume land application systems on restrictive
    sites, the shallow depths to rock and seasonal or regional water tables require special
    considerations to avoid hydraulic malfunctions. These special cases may require
    additional site verification work, both on the proposed system site and down gradient
    from the proposed system site. Depending on a proposed site’s soil conditions, slopes,
    topographic position, and contours, special design considerations may need to be
    addressed to reasonably assure the long-term hydraulic function of the system.
    Design considerations may include reduced loading and application rates, split fields,
    rotational and/or timed dosing, longer length to width ratios, and/or the utilization of
    hydraulic linear loading rates. All restrictive sites may not be suitable for large volume
    system applications. The site verification work and design criteria for each individual
    site proposal should be developed with the DEP regional soil scientists, geologists, and
    engineers.
    362-2000-009 / DRAFT March 21, 2009 / Page 44

    If the depth to limiting zone is less than 10 inches, the site will be considered ineligible
    for subsurface land application of wastewater. A site will also be considered ineligible if
    the soil has been disturbed for such purposes as changing slope or adding soil to increase
    the depth to limiting zone.
    Subsurface infiltration systems may be required to reduce total nitrogen to 10 mg/L or
    less prior to the absorption area to prevent off site pollution of groundwater or prevent
    degradation of protected surface water. Proposals for treatment of nitrogen prior to the
    subsurface infiltration system should document consistent, reliable nitrogen reduction.
    At the time of publication of this manual the Department did not recognize further
    reduction of nitrogen levels in the treated effluent via crop uptake or soil processes. If
    future research shows that nitrogen uptake by vegetation can be quantified, the
    Department may allow this reduction to be incorporated into system design.
    Evaluation of trace elements is not required if the system is proposed for the treatment of
    normal household wastewater, and if the system is sited and designed in accordance with
    this manual.
    Basic septic or aerobic tanks generally do not successfully treat modern industrial wastes.
    Many of these wastes include substances such as metals, salts, and oils and greases in
    concentrations that either destroy the biota of a normal septic system or clog soil pores.
    Claims of removal during the pre-treatment stage or in the soils should be documented
    and demonstrated.
    D.
    Hydraulic Loading Rates
    For all large volume subsurface infiltration systems, the soil saturated vertical hydraulic
    conductivity (K) and soil morphological evaluations described in section IV will be used
    to determine an effective effluent hydraulic loading rate. The most limiting soil horizon
    identified during the soils evaluation performed in section IV should be used. The soil
    profiles may be supplemented with the use of a hand auger to confirm soil conditions
    between profiles. Excessive disturbance of soils within the proposed soil absorption
    area(s) should be avoided.
    The applicant should base the actual design hydraulic loading rate on the saturated
    vertical hydraulic conductivity test results from the site, taking into consideration
    suggested hydraulic loading rates based on soil morphology.
    After the appropriate loading rate is determined, the area of the absorption field can be
    calculated. Using the proposed loading rate, the applicant should assess the potential for
    groundwater to mound into the zone of unsaturated suitable soil under the absorption area
    (see section IV.C.4).
    E.
    Time Dosing
    All large volume subsurface infiltration systems must be designed to discharge the
    hydraulic load to the absorption area in six or more doses per day. Timers should
    be used
    to turn the pump on and off at specified intervals so that only a predetermined volume of
    wastewater is discharged with each dose. The doses should be spaced evenly over the
    362-2000-009 / DRAFT March 21, 2009 / Page 45

    entire 24-hour day to optimize the soil’s treatment capacity, and the operator should
    ensure that the infiltration system receives no more than its design flow each day. If the
    operator is not available at all times the system is in operation, alarms should
    be set up to
    notify the operator remotely if a problem should occur. Timed dosing requires that the
    dose tank be sized to store peak flows until it can be pumped. Clear water infiltration,
    leaking plumbing fixtures, or excessive water use can be detected by the high water level
    alarm in the dosing tank.
    Dosing frequency and volume are two important design considerations. Frequent, small
    doses are preferred over large doses. However, doses should not be so frequent that
    distribution is poor. This is particularly true of the pressure distribution networks. With
    pressure networks, uniform distribution does not occur until the entire network is
    pressurized. To ensure pressurization and to minimize unequal discharges from the
    orifices during filling and draining, a dose volume equal to five times the network volume
    is a good rule of thumb. Thus, doses can be smaller and more frequent with dripline
    networks than with rigid pipe networks because the volume of a drip distribution network
    is smaller. The design of the dosing system should be included in the
    Design Engineer’s
    Report
    .
    F.
    Protecting Soil Permeability
    When soil moisture levels are excessive or equipment is too heavy, soils may smear or
    compact, thereby losing their natural permeability. This can occur in the absorption area
    and around the fringe of the system. Clayey or loamy soils are especially susceptible.
    Since subsurface infiltration systems depend upon both vertical and lateral movement of
    liquids through the soil mantle, any loss of permeability may impact system function. To
    avoid potential problems with compaction or smearing the following design
    considerations and construction precautions are recommended:
    Long and narrow system designs allow for less in-bed excavation and materials
    handling.
    For drip irrigation systems, small diameter undergrowth removal should be
    conducted with hand equipment only, to retain the permeability of the upper soil
    horizons. Avoid areas with large trees.
    Isolate the proposed absorption area including a ten-foot buffer area with high
    visibility fencing and prohibit entry of any heavy equipment.
    Before allowing any equipment on the site to construct the system, conduct a soil
    moisture test. Lightly squeeze the soil in your hand, then bounce it lightly in your
    hand or tap it with your finger. If the sample crumbles or breaks up immediately,
    the site can be worked.
    When large absorption areas are being constructed, use a track hoe or other
    equipment that can operate from a position outside the bed area.
    G.
    Distribution System Design
    A pressurized distribution system consisting of a flow equalization/dosing tank, pump
    and a system of manifolds and laterals should be used to convey pretreated wastewater to
    the absorption area. Flow equalization should be designed in accordance with the
    Department’s
    Domestic Wastewater Facilities Manual,
    DEP ID: 362-0300-001, available
    362-2000-009 / DRAFT March 21, 2009 / Page 46

    on DEP’s Web site. The system should be designed to provide for even application of the
    effluent across the entire absorption area. The land treatment area should be divided into
    a minimum of four wastewater application zones. No zone may exceed 5,000 square feet.
    An absorption zone should not be placed hydraulically up gradient or down gradient from
    another, such that flow from the up gradient zone infiltrates the down gradient zone.
    H.
    In-Ground Trench Systems -
    Leaching Chambers
    Each adsorption area design is done on a case-by-case basis. One system may be a better
    alternative over another. Trench systems provide better aeration for improved
    wastewater treatment than some bed designs, and reduce the potential for groundwater
    mounding. The in-ground trench aggregate systems should be designed consistent with
    the standards in Title 25 Pa. Code Chapter 73.
    1.
    Description
    Leaching chambers may be installed in trenches as a substitute for aggregate. At
    the discretion of DEP, up to 30% reduction in absorption area may be allowed in
    the design of a leaching chamber system. No size reductions are permitted if the
    distance to limiting zone is less than 48 inches.
    2.
    General Requirements
    The following requirements must be met:
    a.
    The owner should be provided with a five-year equipment warranty from
    the manufacturer of the leaching chamber unit.
    b.
    The chamber system must be installed in accordance with all applicable
    manufacturer’s specifications and installation requirements. The
    manufacturer should provide large volume design and installation
    specifications.
    c.
    All chambers should
    be certified to withstand the AASHTO H-10-44
    highway structural rating or ASTM C-857 Design Load A-8 without
    damage or permanent deformation.
    3.
    Design Requirements
    System designs using chambers should be limited to the bottom dimensional area
    that the selected chamber occupies. Designs incorporating chambers should be in
    length increments of the selected chamber.
    Chamber sizing for the purpose of calculating the number of chambers for a given
    sewage disposal system is based on the dimensions of the chosen product.
    Table 8.1 displays some sample chamber dimensions. Other chambers with
    varying dimensions may also be used.
    362-2000-009 / DRAFT March 21, 2009 / Page 47

    Table 8.1
    Sample Chamber Dimensions
    PRODUCT
    CHAMBER DIMENSIONS
    Standard Infiltrator
    6.25’ x 2.833’ = 17.71 ft
    2
    Equalizer 36
    8.333’ x 1.833’ = 15.27 ft
    2
    Standard BioDiffuser
    6.25’ x 2.833’ = 17.71 ft
    2
    EnviroChamber Pro 22” Narrow
    7.4’ x 1.833’ = 13.56 ft
    2
    EnviroChamber Pro 15” Narrow
    7.4’ x 1.25’ = 9.25 ft
    2
    EnviroChamber
    6.25’ x 2.833’ = 17.71 ft
    2
    Narrow EnviroChamber
    8.458’ x 1.25’ = 10.57 ft
    2
    Hi-cap EnviroChamber
    6.333’ x 2.791’ = 17.68 ft
    2
    The following method should be used when sizing onlot sewage disposal designs
    incorporating chambers:
    a.
    Calculate the square footage of absorption area per the hydraulic loading
    rate described in section VIII.D.
    Example:
    25,060 ft
    2
    b.
    Divide the square footage of the absorption area by the dimensions of the
    chamber that will be used.
    Example:
    If the Standard Infiltrator will be used;
    25,060 ft
    2
    / 17.71 ft
    2
    per chamber = 1,415.02 chambers. Round up to next
    whole number and use a minimum of 1,416 chambers for design. More
    chambers may be used.
    4.
    System Layout and Design Specifications
    Trenches utilizing chambers should be laid out in the same manner as aggregate
    trenches. Separation distances for trenches and isolation distances from property
    lines, wells and tanks should remain the same as required for aggregate trenches.
    Two chambers may be placed side-by-side in a trench. When using a side-by-side
    combination of different width chambers, place the narrower chamber on the
    uphill side of the trench. This may be of benefit on steep sites.
    Shallow placement trench depth should be a minimum of 12 inches on the down
    slope side of the trench for all chamber styles.
    5.
    Installation
    All chambers should be installed in accordance with the manufacturer’s
    guidelines. The dimension of each product is fixed. Cutting or otherwise
    damaging a chamber is not permitted and will void the product warranty.
    Endplates may be drilled according to installation guidelines to accept a
    pressurized distribution pipe.
    362-2000-009 / DRAFT March 21, 2009 / Page 48

    I.
    At-Grade Bed Systems
    Each adsorption area design is done on a case-by-case basis. One system may be a better
    alternative over another. At-grade beds systems take advantage of the bioreactive soil
    horizons near the land surface to more effectively renovate wastewater. The at-grade bed
    system should be designed as described below until such time as design standards are
    included in Chapter 73.
    1.
    Siting:
    a.
    The slope of the installation site should be less than or equal to 12 percent.
    2.
    Design and Installation
    a.
    The unobstructed absorption area (no stumps or other obstacles) should
    be
    roughed or plowed parallel with the contour to a maximum depth of
    six inches, using a multiple share chisel plow or similar implement
    attached to light-weight equipment. Rotary tilling is prohibited.
    b.
    A minimum of six inches of coarse aggregate meeting the requirements of
    AASHTO No. 3, 5, 57 or 467 should be used below the laterals. The
    absorption area should be constructed in accordance with one of the two
    following options, at the discretion of the designer:
    (1)
    Aggregate should be placed beneath the laterals on contour to a
    uniform depth throughout the absorption area. Additional
    aggregate should be placed over the laterals to a uniform depth of
    two inches. The upslope laterals should be placed one foot from
    the upper edge of the aggregate. The downslope laterals should be
    placed six feet from the downslope edge of the aggregate. There is
    no minimum distance between the upslope and downslope laterals
    within an absorption zone. All laterals must terminate two to
    five feet from the ends of the aggregate. The design should include
    a three-foot subsoil berm around the ends and downslope side of
    the aggregate area in addition to the berm. A 2:1 slope should be
    maintained on the subsoil berm.
    – OR –
    (2)
    The laterals should be installed on a level aggregate bed and spaced
    evenly over the absorption zone. Additional aggregate should be
    placed over the laterals to a uniform depth of two inches.
    Sufficient aggregate should be placed beneath the laterals so that
    they are level.
    c.
    A 2:1 aggregate slope should be maintained on all sides of the aggregate.
    d.
    The bed should be surrounded by a berm consisting of mineral soil
    containing less than 20 percent coarse fragments with no coarse fragments
    362-2000-009 / DRAFT March 21, 2009 / Page 49

    greater than four inches in diameter, more stable and less permeable than
    the sand, and lightly compacted during construction to contain and protect
    the mound interior. The width of this berm should be a minimum of
    three feet at the top of the aggregate.
    e.
    The cover over the aggregate should be eight to twelve inches of soil
    suitable for the growth of vegetation and should be seeded to assure the
    stability of the berm.
    f.
    Lateral end cleanouts are necessary and should be extended to the surface.
    J.
    Drip Distribution Systems
    Each adsorption area design is done on a case-by-case basis. One system may be a better
    alternative over another. Drip Distribution systems take advantage of the bioreactive soil
    horizons near the land surface to more effectively renovate wastewater. The drip
    distribution system should be designed as described below until such time as design
    standards are included in Chapter 73.
    Drip systems are to be designed assuming that the loading area is the footprint of the
    absorption area. This assumption is based on the expectation that little or no biomat will
    be formed if the wastewater receives at least secondary treatment prior to disposal, and
    that there will be proper emitter selection/placement. Additional design information is
    available from a variety of sources including technology manufacturers and a recent
    technical report titled
    Wastewater Subsurface Drip Distribution – Peer-Reviewed
    Guidelines for Design, Operation and Maintenance
    prepared by the Tennessee Valley
    Authority and the Electric Power Research Institute, Inc.
    1.
    Treatment
    All drip distribution systems should meet a minimum of secondary treatment prior
    to the drip distribution tubing.
    2.
    Siting Requirements
    a.
    The slope in each drip distribution zone should
    be between 0 percent and
    25 percent.
    b.
    Isolation distances should be measured from a perimeter extending two feet
    beyond the outermost drip tubing in a drip distribution zone.
    3.
    Design Requirements
    a.
    Filtration
    (1)
    Final filtration should be provided by a hydraulic unit fitted with
    in-line filters.
    (2)
    The filter should have a maximum size opening of 150 microns.
    362-2000-009 / DRAFT March 21, 2009 / Page 50

    (3)
    The filters should include a mechanism to automatically or
    continuously flush the filters. The filters using automatic
    backwashing should backwash before each dose.
    (4)
    Backwash from the filters should
    be returned to the head of the
    treatment system.
    b.
    Each zone should either be automatically flushed a minimum of each
    50 cycles or be continuously flushed to clean drip tubing, maintaining a
    scouring velocity of two feet per second at the distal end of each lateral
    connection. The design should contain calculations to demonstrate this
    velocity will be met via pipe sizing and pumps. Pump specifications and
    performance curves should be included in the design.
    c.
    The system should
    be equipped with a dosing tank alarm to alert the
    operator of problems with the system and a flow meter.
    d.
    Drip Distribution Zone
    (1)
    The drip tubing should follow the contour of the land.
    (2)
    The area of the system should be designed in accordance with the
    manufacturer’s recommendations but the hydraulic loading rate
    should not exceed the minimum saturated vertical hydraulic
    conductivity from section IV.B.
    (3)
    All emitters should be pressure compensating to achieve even
    distribution of wastewater throughout the system.
    (4)
    The tubing emitters should be spaced every two feet with spacing
    between tubing ranging between one and three feet unless
    justification for different spacing is provided (such as trees,
    irregular topography, etc.). Emitter spacing may be as close as
    12 inches in soils where lateral movement of water is restricted.
    All emitters within the zone should provide equal distribution
    between plus or minus ten percent.
    (5)
    DEP may require the site plan for the drip distribution zones to be
    developed by or in consultation with the manufacturer or a
    representative of the manufacturer of the drip distribution system
    being installed.
    (6)
    On slopes greater than five percent, top-feed supply and return
    manifolds are recommended.
    (7)
    A flow meter should be installed to record flow to each zone and/or
    subzone per dose.
    362-2000-009 / DRAFT March 21, 2009 / Page 51

    4.
    Construction
    a.
    Drip lines should be installed below the soil surface using a vibratory
    plow, a standard trencher, or by manual or hand installation to a depth of
    between 6 and 12 inches from the soil surface. Cable pullers should not be
    used. A soil scientist or the system designer should determine the tubing
    installation depth based on the site evaluation and manufacturers
    recommendations.
    Where installation depths less than 6 inches from the soil surface are
    necessary due to stoniness, additional cover of soil suitable for growth of
    vegetation should be added to provide six to twelve inches of cover. The
    soil cover should be seeded to control erosion. This is not the preferred
    method of installation and should only be considered when necessary.
    b.
    The manufacturer’s representative should be present to oversee the
    installation of the system. As an alternative, contractors may attend a
    training course provided by the manufacturer before installing drip tubing
    independent of oversight by the manufacturer.
    c.
    Installation of the drip distribution system should meet the specifications
    provided by the manufacturer.
    d.
    Drip tubing is susceptible to freezing when sufficient turf cover is not
    established in nonwooded areas prior to winter operation. When turf cover
    will not be established prior to winter operation, other measures, such as a
    temporary cover of mulch or straw, should be used to insulate the tubing.
    Any temporary covers are in addition to 6-12 inches of soil suitable for
    growth of vegetation. Turf cover should be established as soon as
    practicable.
    e.
    Protective coverings should
    be placed over any open ends of the drip
    tubing or piping during installation to prevent the introduction of foreign
    material into the lines. If any foreign material enters the lines, the lines
    should be flushed to remove the material prior to connecting to the system.
    f.
    Cold Weather Provisions
    The following minimum provisions for protection of the system during
    winter operation should be addressed:
    All valve boxes that house remote zone valves, air release valves,
    etc., and all connections of the supply, return and manifolds
    installed above the frost line should be insulated. Specifications of
    the type of insulation material and placement should be provided in
    the permit application.
    All valve boxes should have accommodations for heater
    installation. Provisions should be made for heater space and
    wiring for easy installation during system operation.
    362-2000-009 / DRAFT March 21, 2009 / Page 52

    All main supply and return lines should be installed below frost
    depth.
    Provisions should be made for any portion of the distribution
    system installed above the frost line to be drained of free-standing
    water while not in operation. Piping profiles with elevations
    should be included on the design plans to document drain down.
    All flexible loops connecting tubing runs should be elevated to
    promote drain down into the tubing.
    Provisions should be made to prevent freezing of the control panel
    and hydraulic control units.
    5.
    Operation, Maintenance, and Warranty
    Operation, maintenance, and warranty conditions are as follows:
    a.
    The manufacturer’s representative should meet with the permittee and
    operator within one month of system start-up and with DEP upon request,
    to explain the operation and maintenance of the system and provide
    written instructions to the system owner that includes:
    (1)
    Instructions on the operation and maintenance of the system.
    (2)
    The locations of all parts of the system.
    (3)
    A caution notice regarding disturbance of the drip zones that may
    cause system damage (e.g., excavation for trees, fencing, etc.).
    (4)
    An explanation of the automatic alarm system.
    b.
    The manufacturer of the drip distribution system should provide a
    minimum two-year warranty on all defects due to materials or
    workmanship.
    K.
    Soil and Vegetation Management
    Soils and vegetation covering the absorption area should be managed to comply with the
    following guidelines:
    A plan to establish vegetation in the absorption area should be submitted to DEP
    for approval. The plan should include a discussion of the selected vegetation
    establishment and maintenance procedures.
    Low maintenance vegetation should be selected for the site to minimize
    maintenance activity on the site.
    Actions should be taken to ensure the vegetation does not interfere with or impair
    the proper operation of the land treatment system.
    When a drip irrigation system is proposed, vegetation should be established prior
    to the installation of drip tubing if possible.
    The dispersal area should not be used for agricultural production, athletic
    activities, or any activity that may damage the adsorption area.
    362-2000-009 / DRAFT March 21, 2009 / Page 53

    Back to top