N.J. Admin. Code § 7:26-2A.7

Current through Register Vol. 56, No. 21, November 4, 2024

Section 7:26-2A.7 - Sanitary landfill engineering design standards and construction requirements

(a) The following are the general sanitary landfill engineering design standards and construction requirements:

1. All sanitary landfills regulated by N.J.A.C. 7:26-2A.1(c) shall be designed and constructed with a leachate containment system, leachate collection system, leachate treatment/disposal system, monitoring system, a surface drainage control system, gas venting system, a final capping system and any other systems or control measures required pursuant to the design standards and construction requirements set forth in this subchapter, unless exempted by N.J.A.C. 7:26-2A.6(j)3;

2. An on-site baseline consisting of two vertical and horizontal control monuments shall be constructed and installed in accordance with the New Jersey Map Filing Law, N.J.S.A. 46:23-9, and Department specifications, as provided in the Department's Technical Manual for Sanitary Landfill Permits and Approvals, prepared and made available by the Department.

i. The control monuments shall be installed with, at a minimum, Second Order accuracy in accordance with the "Classification, Standards of Accuracy, and General Specifications of Geodetic Control Survey" published by the U.S. Department of Commerce 1980. The control monuments shall be tied into the national or state geodetic survey network and keyed into the North American Datum of 1983.

ii. Sanitary landfills equal to or greater than 50 acres may be required to construct and install secondary control points in accordance with the Department's specifications listed in "Guidelines for Establishing Vertical and Horizontal Control Monuments on a Sanitary Landfill".

3. The sanitary landfill shall be constructed with a modular design. Each section of the modular design shall be hydraulically isolated from the adjoining section.

4. The degree of hydraulic isolation shall be determined based on the location of the landfill, and shall at a minimum include the following:

i. Sanitary landfills located in areas described in N.J.A.C. 7:26-2A.6(d) and (e), shall, at a minimum, include a temporary berm capable of isolating run-on from adjoining areas and run-off from the active landfill area and contain leachate generated within the sanitary landfill section.

ii. Sanitary landfills located in areas described in N.J.A.C. 7:26-2A.6(e)1 which require, at a minimum, a double composite liner system and a leak detection system shall be designed so that each section drains, at a minimum, to separate sumps capable of isolating any potential leaks from that section.

5. The construction and operation of the modular sanitary landfill design should be initiated in the section which is most down gradient in relation to groundwater flow. Alternative designs to meet this requirement are acceptable in areas where the topography, such as steep surrounding slopes, make this requirement environmentally unsound.

6. The size of each section shall be designed to minimize the exposed active areas.

7. A quality assurance inspector, independent of the quality control inspector, approved by the Department and reporting directly to the Department, shall be at the site at all times during the initial construction phase of the containment and leachate collection systems to observe and perform all required systems audits of the quality control inspections, as set forth at (a)8, 9 and 10 below, to insure proper implementation of the design and permit requirements. For the purposes of this section, quality assurance means the periodic testing and observations performed by the owner and/or operator of a landfill as a check on the construction contractor's quality control activities.

8. A meeting shall be held between the quality assurance inspectors and the Department to establish reporting procedures and frequency, in accordance with the construction scheduling.

9. Quality control inspectors shall be at the site during all phases of construction to ensure and verify that the approved sanitary landfill design and SWF permit landfill construction requirements are properly implemented. The quality control inspectors shall, at a minimum, be at the site at all times during the construction of the containment and leachate collection systems. For the purposes of this section, quality control means those activities and responsibilities assigned to the construction contractor, manufacturer, installer or supplier to measure and regulate the characteristics or properties of an item in order to ensure that the applicable landfill construction requirements at N.J.A.C. 7:26-2A.7, SWF permit conditions and the requirements of (a)12 and 13 below are met. This includes those actions taken before, during, or after construction to ensure that the materials used and the completed workmanship are in conformance with the construction requirements at N.J.A.C. 7:26-2A.7 and the SWF permit.

10. The quality control measures and tests required by this subchapter and described in the QA and QC plan submitted in accordance with N.J.A.C. 7:26-2A.5(a)7 shall be employed to ensure that the construction requirements are properly implemented and that the design and performance standards are achieved.

11. The quality control inspector shall inspect those aspects of the subgrade preparation including, but not limited to, the following:

i. Site preparation, clearing, and grubbing;

ii. Excavation of subgrade to required elevations;

iii. Subgrade preparation to eliminate incompatibilities with the liner system;

iv. Proper application of vegetation suppressant;

v. Compaction of subgrade to design density at proper moisture content to achieve required strength and stability to support the liner;

vi. Moisture content density and field strength tests performed as required;

vii. Compacted lift thickness;

viii. Compaction equipment, weight, speed, and number of passes;

ix. Method of moisture addition;

x. Proof-rolling of subgrade;

xi. Fine finishing of the subgrade to required grades; and

xii. Final inspection of the subgrade for acceptability of area to be lined.

12. The quality control inspector shall inspect those aspects of the containment system including, but not limited to the following:

i. Liner material to ensure that the material being used meets specifications;

ii. Liner material stockpiling, storage, and handling to prevent damage;

iii. Inlet/outlet structure or penetration through the liner to ensure compatibility with the liner system;

iv. Final grades of liner to ensure that they are within acceptable tolerances;

v. Final inspection of liner for acceptability prior to backfill placement;

vi. Backfill placement;

vii. Geotextile placement;

viii. Compacted liners with respect to the following:

(1) Compaction of liner to design density at the proper moisture content to achieve the required hydraulic conductivity and maintain strength and stability;

(2) Uniformity of compactive effort;

(3) Compacted lift thickness;

(4) Compacted liner thickness;

(5) Compaction equipment weight, speed, and number of passes;

(6) Moisture content, density, hydraulic conductivity and field infiltration tests to ensure that they are performed as required;

(7) Mixing and blending of liner material to ensure that the activity is being performed as required; and

(8) Repairs and corrective or remedial action performed as required.

ix. Geomembranes with respect to the following:

(1) Liner panel placement is in accordance with required configuration;

(2) Permanent and temporary anchoring procedures are followed;

(3) The overlap and seam width are in accordance with the design;

(4) The area of seaming is clean and supported;

(5) The uniformity and continuity of seams or welds;

(6) Cap strips are installed on all field seams for bottom liners employing solvent or bodied solvent;

(7) Qualitative and quantitative field seaming tests are performed as required;

(8) Imperfections in seams, wrinkles at seams and fishmouth are repaired as required; and

(9) Corrective or remedial action taken.

13. The quality control inspector shall inspect those aspects of the leachate collection system including, but not limited to, the following:

i. Material stockpiling, storage, and handling to prevent damage;

ii. Drainage layer placement;

iii. Thickness of the drainage layer;

iv. Grain size analysis and relative density or compaction tests are performed as required;

v. Uniformity of the soil;

vi. Filter placement;

vii. Grades and alignments within acceptable tolerances;

viii. Envelope placement;

ix. Proper implementation of action taken to protect the collection pipe and liner from the loads and stresses due to the traffic of backfilling equipment;

x. Sump construction;

xi. Sump water tightness tests; and

xii. Pump placements.

14. Daily QC reports shall be prepared by the quality control inspector or quality assurance inspectors and maintained in a log book or by means of an electronic records storage system approved by the Department which shall be accessible at the job site at all times for inspection by the Department. All lab reports and field testing results shall be signed and dated by the inspector, and shall be attached to the daily QC reports. The daily QC reports shall include, but not be limited to, the following:

i. Identification of project name, location and date;

ii. Weather conditions including:

(1) Temperature (daily high and low);

(2) Barometric pressure;

(3) Wind direction and speed;

(4) Last precipitation event; and

(5) Amount of precipitation.

iii. Description and location of construction currently underway;

iv. Equipment and personnel at work at each unit;

v. Description and location of areas being tested or observed;

vi. Off-site material received and quality verification documentation;

vii. Calibration of test equipment;

viii. Description and location of remedial action taken;

ix. Decisions and comments including conversations, directives and directions for the following:

(1) Acceptance or failure of inspection or tests;

(2) Acceptance or failure of daily work unit performance;

(3) Problems encountered and corrective action taken;

(4) On-going corrective action;

(5) In-field modifications; and

(6) Assessment of overall project quality; and

x. Reference and list Manufacturer's Quality Assurance/Quality Control (MQA/MQC) tracking forms for each roll of geosynthetic materials at the time of delivery at the construction site.

15. The scheduled frequency of inspections by the independent quality assurance inspectors may be reduced or discontinued if approved by the Department. The reductions or discontinuance shall be based on the results of the initial construction tests and the precision and consistency of the quality control test results.

16. At such time as the independent quality assurance inspector is discontinued, as approved by the Department, the activities performed by the quality insurance inspector shall be carried out by the permittee's quality control inspectors in accordance with the approved Quality Assurance and Quality Control plan.

17. The Department may reinstate the independent quality assurance inspection at the site if the results of the construction tests and the precision and consistency of the quality control testing warrant such reinstatement.

18. Best available engineering construction practices shall be employed for all phases of the facility construction.

19. Following the completion of new liner construction involving geomembranes pursuant to (c)4 below, but prior to the submittal of the engineer's certification required at (a)20 below, an electrical leak location or equivalent test shall be undertaken on the newly constructed primary liner. Results of the test shall be appended in the engineer's final documentation report. The final documentation report shall list any repairs that were undertaken on the liner as a result of the electrical leak location test.

20. A New Jersey licensed professional civil or geotechnical engineer shall certify, in writing, to the Department that he or she has supervised the inspection of the construction of each major phase of the sanitary landfill's construction. He or she shall further certify that each phase has been prepared and constructed in accordance with the engineering design approved by the Department, prior to operations. The certification shall include a final documentation report which shall summarize the daily quality control of construction activities as required by (a)14 above, and shall include as-built drawings.

21. A New Jersey licensed professional civil or geotechnical engineer shall certify that the materials utilized in the containment system and leachate collection system are in conformance with and meet the specifications of the approved engineering design.

22. There shall be no deviation made from the approved engineering design specification without the prior written approval of the design engineer and, at a minimum, prior verbal approval by the Department.

23. All certifications shall bear the raised seal of the New Jersey licensed professional engineer, his signature, and the date of certification.

24. The certification required in (a)20 and 21 above shall include the following: "I certify under penalty of law that I have personally examined and am familiar with the information submitted in this document and all attachments and that, based on my inquiry of those individuals under my supervision, I believe the submitted information is true, accurate and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment. I understand that, in addition to criminal penalties, I may be liable for a civil administrative penalty pursuant to N.J.A.C. 7:26-5 and that submitting false information may be grounds for denial, revocation or termination of any solid waste facility permit or vehicle registration for which I may be seeking approval or now hold."

25. The Department shall be notified within 24 hours at the Department hotline at 1-877-WARNDEP, should an emergency or accident involving personal injury occur.

(b) The sanitary landfill shall be designed and constructed on an appropriate foundation meeting the following minimum requirements:

1. The foundation of the proposed sanitary landfill area shall provide firm, relatively unyielding, planar surfaces to support the liner.

2. The foundation shall be capable of providing support to the liner and resistance to the pressure gradient above and below the liner resulting from settlement, compression or uplift.

3. A foundation analysis shall be performed prior to construction, to determine the structural integrity of the foundation to support the loads and stresses imposed by the height and weight of the sanitary landfill and the design loading rate of the facility. These loads and loading rates shall not result or give cause to failure of the containment or leachate collection systems. The foundation analysis shall include the following:

i. The strength of the foundation shall be determined for all appropriate conditions. These conditions shall be evaluated utilizing appropriate American Society of Testing and Materials (hereinafter ASTM), American Association of State Highway and Transportation Officials (hereinafter AASHTO), or other equivalent methods for field testing and laboratory testing to determine properties for calculating settlement. The stability of the foundation shall be determined for static and seismic conditions as follows:

(1) The static analysis shall provide a minimum factor of safety of 1.5 unless otherwise approved by the Department; and

(2) The seismic analysis shall be performed pursuant to 40 CFR Parts 257 and 258 (also known as Subtitle D of the Resource Conservation and Recovery Act of 1976, as amended) and the Department's Technical Manual for the Sanitary Landfill Permits and Approvals. The foundation shall be designed to resist the maximum horizontal acceleration in lithified material for the sanitary landfill. The maximum expected horizontal acceleration, as defined by 40 CFR Parts 257 and 258, shall mean the maximum expected acceleration depicted on a seismic hazard map, with a 90 percent or greater probability that the acceleration will not be exceeded in 250 years.

ii. The total settlement or swell of the foundation resulting from the initial, consolidation and compression settlement shall be determined utilizing appropriate ASTM, AASHTO or equivalent methods. The total settlement or percent consolidation shall not result or give cause to failure of the containment or leachate collection systems;

iii. The ultimate bearing capacity of the foundation shall be determined and the actual loads and stresses imposed by the surface impoundment dikes, storage tanks, manholes, clean-out risers, and sumps shall not result or give cause to failure with a factor of safety of 3 or greater;

iv. The compaction curves or relative density of the foundation shall be determined by the appropriate method in accordance with ASTM, AASHTO, or equivalent methods; and

v. Sampling shall be performed in accordance with the following schedule:

(1) In uniform geological formations, the sampling shall, at a minimum, be performed to give three replicate results per site. Sampling locations shall be in the areas of expected maximum loads and at the toe of the proposed slope. The sampling locations should be delineated in the scope of work submitted in accordance with N.J.A.C. 7:26-2.4(a); and

(2) In non-uniform complex geological formations the number and depth of samples shall be determined on a case-by-case basis. The sampling locations should be delineated in the scope of work submitted in accordance with N.J.A.C. 7:26-2.4(a).

4. The foundation shall be prepared in the following manner prior to placement of the liner:

i. All trees, brush, stumps, logs, tree roots, boulders, and debris shall be removed;

ii. All surface dissimilarities (for example, fractured rock, cobble, angular gravel, organic soils, top soils, etc.) that would result in a potential degradation or failure of the liner systems shall either be stabilized, removed, or covered with a minimum of six inches of sand classified as a SP in the Unified Soils Classification System or equivalent;

iii. If a soil sterilant is to be utilized to inhibit any potential vegetative growth, it shall be an approved United States Environmental Protection Agency product and shall be applied in accordance with label specifications and the requirements of the New Jersey Pesticide Control Code, N.J.A.C. 7:30;

iv. The subgrade shall be compacted by modification of the compactive effort utilizing stage compaction to the design density, at the proper moisture content if applicable, based on laboratory analysis to achieve the required strength;

v. All depressions within the subgrade shall be filled with a suitable soil approved by the quality control inspector, and shall be compacted to the design density, at the proper moisture content if applicable, to achieve the required strength;

vi. Any soil fill utilized shall be spread in horizontal layers not exceeding the effective depth of the compaction equipment utilized, and shall be compacted to the design density, at the proper moisture content if applicable, to achieve the required strength;

vii. Placement of soil fill into frozen ground or placement of soil fill which is in a frozen state is prohibited;

viii. The subgrade shall be proof-rolled with a rubber-tired roller. Any weaving of the subgrade shall be an indication of failure which shall be over-excavated and filled with a suitable soils approved by the quality control inspector, compacted to the design density, at the proper moisture content if applicable, to achieve the required strength;

ix. Construction of the liner on a saturated subgrade is prohibited. After a rainfall event, the subgrade shall be given sufficient time to dry or drain to the design moisture content;

x. Prior to the construction of the liner system, the subgrade shall be tested for density and moisture content, where applicable, at 50 foot intervals on a grid pattern across the subgrade;

xi. In any area where the foundation is excavated, the side slope to the excavation prior to placement or construction of the liner shall not exceed a vertical rise of one foot for each horizontal distance of three feet; and

xii. Depth to groundwater from the top elevation of the foundation or bottom elevation of the liner shall be as follows:

(1) For sanitary landfills located in a stable low permeable formation having a hydraulic conductivity of less than 1x10 [-6] cm/sec., the depth, within the potentiometric surface, may be determined on a case-by-case basis as approved by the Department. This determination shall be based on the flow characteristics and attenuation capabilities of the geologic formation. There shall be, at a minimum, five feet of soil with a hydraulic of 1x10 [-6] cm/sec. or less between the bottom of the liner system and the aquifer. The depth to or within a perched water table may be less than five feet if this level can be cut-off by passive means, such as a cut-off wall or trench; and

(2) For all other sanitary landfills, depth to the seasonally high groundwater from the top elevation of the foundation shall be, at a minimum, three feet.

(c) The following are the design standards and construction requirements for containment systems:

1. The sanitary landfill containment system shall be designed and constructed in such a manner as to provide a closed system for the leachate generated therein during the operational, closure and post closure periods. The design and construction shall include the use of a liner consisting of recompacted or in-situ clay, an admixture material, geomembrance or composite material, or a cut-off wall consisting of clay or an admixture material.

2. A liner shall be provided to restrict the migration of leachate and to prevent pollution of the underlying aquifers. The minimum requirements for liner construction shall include the following:

i. The liner shall be constructed of materials that have appropriate chemical properties and sufficient strength and thickness to prevent failure due to pressure gradients (including static head and external hydrogeological forces), physical contact with the waste and leachate, climatic conditions, the stresses of installation, and the stresses of daily operations;

ii. The final grades of the liner shall result in a relatively smooth surface through either fine finishing of the subgrade with use of a scraper/roller or smooth drum rolling of the compacted liner;

iii. The minimum slopes of the liner shall be designed for two percent on controlling slopes and 0.5 percent on remaining slopes following the projected settlement and consolidation as determined in the analysis required at (b)3ii above. Liner slopes shall not exceed 3:1;

iv. The final grades of the liner shall be true to line and deviation of the controlling slopes of the liner shall not result in excessive ponding on the liner or decreased efficiency of the leachate drainage system. It is recommended that the deviation be less than 0.2 feet measured across any 10 foot section and less than 10 percent on the overall slope based on design elevations;

v. Survey stakes or plates shall be placed in such a manner as to ensure that the final grades meet the design specifications within the allowed tolerance;

vi. For penetrations through the liner (i.e. collection pipe to pump station), indicating devices, such as survey laths or stakes, shall be utilized at the area of penetration. The landfill should be designed to minimize the construction of penetrations through the liner;

vii. A soil backfill meeting the leachate drainage system requirements set forth in (d) below shall be placed on top of the liner to provide protection for the liner and leachate collection piping system in accordance with the following:

(1) Backfill soils should be placed on top of the liner immediately following completion of construction and testing procedures set forth in x. below. If backfilling operations are to be delayed, procedures as delineated in the approved construction contingency plan required by N.J.A.C. 7:26-2A.5(a)5 ii shall be implemented to minimize degradation to the liner system;

(2) The depth of the soil backfill shall be of sufficient thickness to ensure that no damaging load is transmitted to the leachate collection pipe;

(3) The depth of the soil backfill shall be of sufficient thickness to ensure that no damaging load causes the leachate collection pipes to penetrate through the liner;

(4) When placed above a compacted liner the thickness of the soil backfill shall be, at a minimum, 12 inches;

(5) When placed above a geomembrane the thickness of the soil backfill shall be, at a minimum 18 inches;

(6) The soil backfill shall be stable, compatible with the liner system and relatively free of organic matter;

(7) Equipment utilized to place the soil backfill over the liner shall consist of tracked or bulbous tired vehicles or equivalent equipment with relatively low weight transfer ratios; and

(8) Use of the backfill placement equipment shall not result in any damage to the liner system or the final grades. In cases utilizing geomembranes, the use of backfill placement equipment directly on the liner is prohibited and shall be permitted only over a minimum of 12 inches of soil backfill.

viii. All inlet/outlet structures installed through the liner shall be compatible with the liner system and shall be installed in such a manner as to minimize leaking through the penetration in accordance with the following:

(1) The subgrade around the penetration shall be properly compacted to the design density and at the proper moisture content, where applicable, to achieve the required strength;

(2) For compacted liners, the liner material around the penetration shall be hand compacted to the design density, at the proper moisture content to achieve the required hydraulic conductivity and maintain the strength and stability of the liner; and

(3) For geomembranes, a pipe shroud shall be utilized around the penetration. The leg of the pipe shroud shall be of a size equal to the diameter of the pipe. A flange shall be fastened to the leg by factory seaming, and shall overlap the opening in the liner material on all sides by a minimum distance equal to the diameter of the pipe. The pipe shroud leg shall be attached to the inlet-outlet structure by a three-quarter inch stainless steel band.

ix. The liner material shall have a demonstrated hydraulic conductivity or chemical and physical resistance not adversely affected by waste emplacement or leachate generated by the sanitary landfill. Absent historical test results acceptable to the Department, this shall be demonstrated by testing which shall include, but not be limited to, the following:

(1) For compacted liners, E.P.A. Test Method 9100 shall be performed utilizing a solid waste leachate (a synthetic leachate mix approved by the Department may be substituted if existing leachate is unavailable). Initially a baseline hydraulic conductivity of the material shall be established. It is recommended that a modified triaxial device equipped to apply back pressure throughout the entire test be used and that the hydraulic gradient be within the laminar flow range. If changes in the leachate conductivity occur, a minimum of two pore volumes of the leachate shall be exchanged and the changes in conductivity, versus the pore volumes passed, shall be analyzed. Any significant increase in leachate conductivity shall be considered to be an indication of incompatibility and will require a redesign of the containment system; and

(2) For geomembranes, E.P.A. Test Method 9090 shall be performed utilizing a solid waste leachate (a synthetic leachate mix approved by the Department may be substituted if existing leachate is unavailable). The specified physical parameter shall be tested before and after liner exposure. Any significant change in test properties shall be considered to be indicative of incompatibility and will require a redesign of the containment system.

x. The following quality control testing shall be performed on the as-built compacted liner system on an ongoing basis during the construction phase:

(1) Each lift or course of the liner shall be tested for moisture content and density at 50 foot intervals on a grid pattern across the surface. Two tests shall be performed in the immediate area around all inlet/outlet structures;

(2) Measurements shall be made periodically throughout the day during construction of the liner to insure that the lift or course thickness is within the allowable limits and in accordance with the design;

(3) Hydraulic conductivity testing shall be performed on undisturbed core samples of the final graded liner. Initially, such samples shall be taken at 200 foot (61 meter) intervals on a grid pattern across the surface. As the construction progresses, the number of samples may be reduced, as approved by the Department, based on the precision and consistency of the results of the initial sampling program, but at a minimum, one sample per every three acres shall be taken provided the material sources remain constant;

(4) Whenever a sample fails to meet the minimum hydraulic conductivity, the area of failure shall be localized, reconstructed and retested in accordance with the requirements set forth in this subsection;

(5) All core sample holes shall be backfilled and recompacted by hand tamping at the proper moisture content to achieve the minimum liner hydraulic conductivity;

(6) A modified triaxial device, equipped to apply backpressure throughout the entire test, shall be used to measure the hydraulic conductivity after primary consolidation ends. Backpressure should be sufficient to dissolve all air in the specimen and the confining or chamber pressure shall not exceed anticipated landfill design pressure. Deaired tap water or 0.005N CaSO[4] should be used as the permeant and the hydraulic gradient should be within the laminar flow range. Testing shall be conducted in accordance with ASTM Standard D5084-90; and

(7) As a means to verify laboratory permeability tests, field infiltrometer tests (for example, Sealed Double-Ring Infiltrometer Test, Two-Stage Borehole Test) are recommended. Alternatively, a second quality control laboratory may be used to verify the permeability results against the primary results obtained in (c)2x(6) above. The QA and QC plan, submitted in accordance with N.J.A.C. 7:26-2A.5(a)7, shall specify the method of field permeability verification used, if any.

xi. The following quality control testing shall be performed on the as-built geomembrane liner system on an ongoing basis during the construction phase:

(1) All field seams shall be quality tested after they have been allowed to develop to full strength. Such testing shall be carried out through the use of an air lance with 50 pounds per square inch of air directed through a 3/16-inch nozzle or equivalent device. The lance shall be held no more than six inches from the seam edge and shall be utilized to detect any imperfections, tunnels or fishmouths. Any such imperfections in a seam shall be repaired and quality tested until a proper seam is achieved;

(2) Seams shall be tested for peel and shear strength, initially at the beginning of each workday and every 500 linear feet thereafter, on either specially prepared sample seams constructed under the same conditions as the actual seaming process used that day or on a sample cut from the inplace liner; and

(3) During the construction phase, the geomembrane shall be continuously inspected for uniformity, damage, and imperfections (for example, holes, cracks, thin spots, or foreign materials). Immediately after installation, the liner shall be inspected to ensure tight seams and joints. Additionally, the liner shall be inspected to ensure the absence of tears, punctures, or blisters. Any imperfections shall be immediately repaired and reinspected.

3. The minimum requirements and testing for clay material utilized as a sanitary landfill liner shall include the following:

i. The following tests shall be performed on the clay material proposed for use, and all data shall be submitted to the Department. These tests shall be performed in accordance with current ASTM, AASHTO or equivalent methods. The number of samples taken and tests performed shall be adequate to define the material. At a minimum, three analyses shall be performed on three separate samples for each source of clay material:

(1) Classification;

(2) Compaction;

(3) Specific gravity;

(4) Hydraulic conductivity (coefficient of permeability);

(5) Porosity;

(6) pH;

(7) Cation exchange capacity (total and inorganic);

(8) Pinhole test (required only for clay liner construction over a coarse grain subgrade); and

(9) Mineralogy (recommended, not required).

ii. The following tests shall be performed on the in-situ clay material or the clay mined from the borrow site for construction of a recompacted liner. A minimum of one analysis shall be performed on each 16,000 inplace cubic yards of clay:

(1) Grain size analysis;

(2) Compaction; and

(3) Hydraulic conductivity (Index properties and grain size analysis may be used to determine the hydraulic conductivity provided the clay has been calibrated to these tests).

iii. The clay liner shall have a hydraulic conductivity equal to or less than 1x10[-7]cm/sec. A modified triaxial device, equipped to apply back pressure throughout the entire test, shall be used to measure the hydraulic conductivity after primary consolidation ends. Deaired tap water or 0.005N CaSO[4] should be used as the permeant and the hydraulic gradient should be within the laminar flow range. A range of confining pressures, water content, densities and degree of saturation shall be analyzed to determine the optimal design parameters of the clay. Testing shall be conducted in accordance with ASTM Standard D5084-90;

iv. The clay liner shall be applied and compacted in separate lifts, not to exceed the effective depth of the equipment utilized. The thickness of the first lift shall be such that kneading with the subgrade soil does not occur, resulting in even placement of clay on the subgrade. Subsequent lifts should be less than 2/3 of the length of the tamping feet or its equivalent;

v. Prior to compaction the clay shall be mixed by disc-harrowing or an equivalent method to a homogeneous consistency and each lift of the liner shall be compacted, by modification of the compactive effort, to the design density, and at the proper moisture content, based on the laboratory analysis, to achieve the required hydraulic conductivity and maintain the strength and stability of the clay;

vi. The liner shall be constructed in such a manner as to ensure that bonding between lifts is promoted;

vii. Placement of the clay liner on frozen ground or placement of clay material in a frozen state shall be prohibited;

viii. In-situ clay utilized in the design and construction of a liner system unless exempted by (c)1ix below, shall be excavated, mixed by disc-harrowing or an equivalent method to a homogeneous consistency, and recompacted to the density at the proper moisture content, based on laboratory analysis to achieve the required hydraulic conductivity and maintain the strength and stability of the liner; and

ix. In-situ clay liner designs shall be left in the undisturbed state only if it can be fully demonstrated through the use of excavations, test pits, borings, undisturbed permeability testing, or field infiltration/permeability testing that the undisturbed clay will possess a hydraulic conductivity no greater than 1x10 [-7] cm/sec. and will meet all the requirements and standards of this subchapter.

4. The minimum construction and testing requirements for geomembranes utilized as a sanitary landfill liner shall include the following:

i. The material properties of the geomembrane proposed for use shall meet the minimum requirements as outlined in the most recent version of the National Sanitation Foundation's publication, "Standard Number 54 Flexible Membrane Liners";

ii. The geomembrane shall be compounded from first quality virgin materials. No regrinded or reprocessed materials containing encapsulated scrim shall be used in the manufacturing of the geomembrane;

iii. The minimum thickness for geomembranes shall be 30 mils, 60 mils if High Density Polyethylene;

iv. Single geomembrane liner systems are prohibited. Liner systems utilizing geomembranes shall be either a composite or double liner system constructed in accordance with the following:

(1) A composite liner system may be used only if the clay or admixture material is demonstrated to achieve sufficient strength and stability to insure the integrity of the geomembrane;

(2) If excessive settlement of the foundation is evident, as determined in accordance with N.J.A.C. 7:26-2A.8(b)4, the compressive and tensile strength of the clay or admixture material in the composite system shall be determined. An analysis of the clay or admixture liner strength, in conjunction with the subgrade settlement analysis, shall demonstrate that the design will not result or give cause to failure of the geomembrane. The analysis shall include a factor of safety equal to or greater than 1.5;

(3) The clay or admixture liner within the composite liner system shall be constructed in accordance with the requirements and standards of this subsection;

(4) The thickness of the clay or admixture liner within the composite liner system shall be approved by the Department when the applicant demonstrates that it meets the standards set forth at N.J.A.C. 7:26-2A.6;

(5) In double geomembrane systems or double composite systems a leachate collection system to detect and collect leachate, shall be designed and constructed between the primary (top) and secondary (bottom) liner in accordance with (d) below;

v. The liner shall be installed by a company having a documented minimum qualification of two million square feet of previous landfill or comparative geomembrane systems installation experience. This experience shall be available, at a minimum, at the field crew foreman level;

vi. The liner shall be installed in a smooth but relaxed manner. The practice of inserting folds into the liner to compensate for future settlement is not an acceptable practice to prevent failure;

vii. All field seams within the area of an excavated slope shall be made perpendicular to the toe of slope;

viii. Parallel field seams made at the bottom of an excavated slope shall be made no closer than 24 inches in from the toe of slope;

ix. The adhesive system of the field seaming to be employed shall be defined;

x. The peel and shear strength data of the field seams shall be submitted; and

xi. The following field seaming requirements shall be employed, unless manufacturer's recommended procedures demonstrate equivalent or better systems:

(1) Field seams made by employing solvent or bodied solvent adhesive shall have a minimum of six inches of overlap and a seam width of four inches from the edge of the top geomembrane; and

(2) Field seams made by employing heat extrusion or welding shall have a minimum of three inches of overlap and a seam width of one inch from the edge of the top geomembrane;

(3) Field seams for bottom liners employing solvent or bodied solvent, after quality control testing and repairs, shall incorporate a cap-strip of unreinforced material a minimum of four inches in width centered over the seam. The cap-strip shall be field seamed in accordance with (c)4ix(1) and (2) above, and quality control tested as required by N.J.A.C. 7:26-2A.7(c)2 xi;

xii. Field seaming procedures are prohibited when the ambient air temperature is less than 40 [degrees] F (4.5 [degrees] C), during storm events, or when winds are in the excess of 20 miles per hour (32 km/hr). Alternatively, temporary shelters equipped with a heat source may be used so that the ambient air temperature inside the shelter is not less than 40 [degrees] F; and

xiii. The geomembrane shall be anchored a minimum of 24 inches horizontally back from the edge of the top of the slope. The liner shall be anchored by cutting a trench 12 to 16 inches in depth, laying the liner across three sides of the trench, backfilling the trench, and compacting the backfill material.

5. The minimum requirements and testing for geosynthetic clay liner (GCL) utilized in a composite landfill liner material shall include the following:

i. The following tests shall be performed on the geosynthetic clay liner proposed for use, and all data shall be submitted to the Department. All tests shall be performed in accordance with ASTM, AASHTO or equivalent methods.

(1) Bentonite Mass/Unit Area;

(2) Bentonite Moisture Content;

(3) GCL Index Flux;

(4) GCL Tensile Properties;

(5) GCL Permeability;

(6) GCL Hydrated Internal Shear Strength;

(7) GCL Peel Strength;

(8) Woven Geotextile Mass/Unit Area;

(9) Non Woven Geotextile Mass/Unit Area;

(10) Woven Grab Tensile;

(11) Non Woven Grab Tensile;

(12) GCL and Geotextile Metallic Fragment/Broken Needle Detection; and

(13) Manufacturer's verification that metallic fragment and/or broken needles have been removed from the GCL and Geotextile products from (c)5i(12) above;

ii. The geosynthetic clay liner shall be installed by a company having a documented minimum qualification of two million square feet of previous landfill or comparative geomembrane/GCL systems installation experience. This experience shall be available, at a minimum, at the field crew foreman level;

iii. The surface on which the geosynthetic clay liner is to be installed shall be free of all rocks, stones, gravel, sticks, foreign objects or debris of any kind. The surface shall also be free of standing water or excessive moisture at the time of installation;

iv. The geosynthetic clay liner shall be installed in an unhydrated condition and be protected to preclude hydrating until after the geomembrane and drainage material have been installed. Should any or all of the geosynthetic clay liner become hydrated during construction, it shall be removed and replaced with unhydrated geosynthetic clay liner;

v. The geosynthetic clay liner shall be laid flat free of any wrinkles or folds and be in compressive contact with the underlying subgrade;

vi. The minimum overlap of longitudinal seams shall be six inches. The minimum end of roll overlaps shall be 24 inches. Seams at the end of panels shall be constructed such that they are shingled in the direction of the landfill slope;

vii. Granular sodium bentonite shall be applied at the seams at a minimum rate of 0.25 pounds dry bentonite per linear foot of seam;

viii. Only as much geosynthetic clay liner shall be deployed per working day as can be covered with the overlying liner system or temporary plastic sheets. The geosynthetic clay liner shall be covered each night and at the imminent threat of precipitation during the day; and

ix. Metal detection on geosynthetic clay liners with hand-held devices shall be used to verify the manufacturer's quality assurance/quality control data as the GCL is unrolled on the bottom liner system. Scanning may be discontinued following the Department's approval.

6. The minimum requirements and testing for soil cement utilized as a sanitary landfill liner material include the following:

i. The following tests, performed in accordance with appropriate ASTM, AASHTO or equivalent methods shall be performed on the soil cement mixture proposed for use, and all data shall be submitted to the Department.

(1) Grain size analysis of aggregate;

(2) Soil cement content;

(3) Wetting and drying;

(4) Freezing and thawing;

(5) Compressive strength;

(6) Compaction; and

(7) Hydraulic conductivity.

ii. The soil cement liner for Class I sanitary landfills shall be designed and constructed to meet the performance requirements of N.J.A.C. 7:26-2A.6(c)1 and 2. In no case shall the soil cement liner for Class I sanitary landfills be less than two feet thick. For Class II sanitary landfills, the thickness of the liner may be reduced, as approved by the Department, depending on the waste material disposed of and the geologic siting of the sanitary landfill, but in no case shall the liner thickness be less than one foot;

iii. To ensure that complete mixing is accomplished, a central mixing plant shall be used. The plant shall include the means for accurately proportioning the material as determined by laboratory analysis, either by weighing or by volumetric measurement, in order that the mixture shall meet the designed hydraulic conductivity requirement;

iv. The plant shall be capable of producing a uniform mixture, within permissible variation, from the mix formula and shall include a continuous mixer of a twin pug mill type;

v. The following quality control testing shall be performed at the control mixing plant at a minimum of once per every 300 cubic yards of mixture to ensure uniformity of the mix:

(1) Grain size analysis of the aggregate; and

(2) Percent cement.

vi. Placement of soil cement liner is prohibited when the ambient air temperature is below 40 [degrees] F (4.5 [degrees] C) or during storm events;

vii. The transportation time from the central mixing plant to the construction site shall not exceed 30 minutes;

viii. No more than 60 minutes shall elapse between the start of mixing and the start of compaction. The compaction process shall be started within 30 minutes after the material is applied. The compaction process shall be completed within 1 1/2 hours after the mixing process is completed;

ix. It is recommended that the mixture be applied by a mechanical spreader in nine-inch loose lifts, and then compacted to six-inch layers. The soil cement should be compacted initially with a sheep foot roller, and then followed by a smooth wheeled vibrating roller;

x. The soil cement should be compacted to the design density, at the proper moisture content, based on the laboratory analysis, to achieve the required hydraulic conductivity and maintain the strength and stability of the liner;

xi. No later than 24 hours after compaction is completed, a bituminous or asphaltic emulsion seal (MC-20 or equivalent) shall be applied to the completed surface; and

xii. The addition of additives to the mix are prohibited except with the approval of the Department.

7. Minimum requirements and testing for bentonite utilized as a sanitary landfill liner material include the following:

i. The compatibility of leachate with the proposed bentonite amended soil admixture shall be evaluated. In addition, the following tests shall be performed on the bentonite proposed for use, and all data shall be submitted to the Department. All tests shall be performed in accordance with appropriate ASTM, AASHTO or equivalent methods:

(1) Swelling index;

(2) Layer permeability;

(3) Colloidal yield; and

(4) Cation exchange capacity.

ii. The following tests shall be performed on the bentonite/soil mixture proposed for use, mixed under field conditions with site water proposed for use, in accordance with ASTM, AASHTO or equivalent methods:

(1) Grain size analysis of aggregate;

(2) Bentonite content;

(3) Compaction; and

(4) Hydraulic conductivity.

iii. To ensure that complete mixing is accomplished, a central mixing plant shall be used. The plant shall include the means for accurately proportioning the material, as determined by laboratory analysis, either by weighing or by volumetric measurement, in order that the mixture shall meet the required design hydraulic conductivity;

iv. The plant shall be capable of producing a uniform mixture within permissible variation from the mix formula and should include a continuous mixer of a twin pug mill type;

v. The following quality control testing shall be performed at the central mixing plant at a minimum of one test per every 300 cubic yards of mixture to ensure uniformity of the mix:

(1) Grain size analysis of the soil; and

(2) Percent bentonite.

vi. Placement of the bentonite liner in a frozen state or on frozen ground is prohibited;

vii. The bentonite/soil mixture shall be applied by a mechanical spreader in a maximum of nine-inch loose lifts and compacted with a smooth drum vibratory compactor or rubber-tired compactor;

viii. The bentonite/soil mixture shall be compacted to the design density at the proper moisture content range, based on the laboratory analysis, to achieve the required hydraulic conductivity, and maintain the strength and stability of the liner.

8. A cut-off wall shall be constructed in those areas, where needed, to restrict the lateral migration of leachate, provide for a closed containment system, and prevent pollution of the underlying aquifer. The minimum requirements for cut-off wall construction include the following:

i. Borings shall be taken at 200 foot intervals along the proposed route of the cut-off wall. These borings shall extend to a depth at least three feet into the confining layer. In clay cut-off wall constructions, the boring interval may be increased, but shall be no greater than 500 feet, provided the excavation is continuously logged and inspected for conformance with the boring data by a qualified geologist or geotechnical engineer;

ii. Hydraulic conductivity tests of the confining layer shall be performed on undisturbed core samples at every other boring location;

iii. The cut-off wall shall extend a minimum of three feet into the confining layer. A lesser distance may be acceptable, if approved by the Department, provided the wall extends to competent rock;

iv. The cut-off wall shall be stable under all conditions, including long term and end of construction conditions, and shall not be susceptible to displacement or erosion under stress or hydraulic gradient;

v. Prior to construction the cut-off wall material shall be tested in accordance with (c)2ix above, to ensure that the material has a conductivity or chemical and physical resistance which will not be adversely affected by waste emplacement or the leachate generated by the sanitary landfill.

9. In addition to the requirements of (c)8 above, the minimum requirements and testing for clay utilized for cut-off wall construction include the following:

i. The tests performed, as specified in (c)3i and ii above, shall be performed on the clay material proposed for use in the cut-off wall.

ii. The cut face of the excavation shall be stable for all conditions that will be encountered during the excavation, including appropriate factors of safety for the material encountered;

iii. The clay cut-off wall shall be constructed to a minimum thickness of three feet;

iv. The clay cut-off wall shall have a hydraulic conductivity equal to or less than 1x10 [-7] cm/sec.;

v. The clay cut-off wall shall be constructed in separate lifts not exceeding the effective depth of the equipment utilized and in a manner which will ensure that bonding between lifts is promoted;

vi. Each lift of the clay cut-off wall shall be compacted to the design density, at the proper moisture content, to achieve the required hydraulic conductivity and maintain the strength and stability of the cut-off wall;

vii. Each lift shall be tested for moisture content and density at 50-foot intervals along the length of the construction; and

viii. Hydraulic conductivity testing shall be performed on undisturbed core samples of the constructed, compacted clay cut-off wall at 200-foot intervals along the route of the wall in order to verify in-field permeability of the constructed wall. Whenever a section of the compacted clay cut-off wall fails to meet the minimum permeability standard established in the QA and QC Plan submitted in accordance with N.J.A.C. 7:26-2A.5(a)7, that section shall be retested and/or reconstructed as defined by the QA and QC Plan. All core sample holes shall be backfilled and recompacted by hand tamping at the proper moisture content to achieve the minimum requirement hydraulic conductivity. The modified triaxial device procedures, as set forth in (c)2x(6) above, shall be utilized to measure the hydraulic conductivity;

10. In addition to the requirements of (c)8 above, the minimum requirements and testing for soil and bentonite or cement utilized for slurry cut-off wall construction include the following:

i. The tests specified in (c)7i above, shall be performed on the bentonite proposed for use;

ii. The following tests shall be performed on the bentonite slurry proposed for use, mixed under field conditions with site water proposed for use in construction of the slurry wall, and all data shall be submitted to the Department:

(1) Bentonite content and cement content, where applicable;

(2) Marsh Cone viscosity;

(3) Marsh Cone gelation;

(4) Gel strength, initial and 10 minute strength;

(5) pH;

(6) Filtration loss;

(7) Filter cake-thickness and strength; and

(8) Sand content.

iii. The following tests shall be performed on the backfill proposed for use, mixed under field conditions, and all data shall be submitted to the Department:

(1) Grain size analysis;

(2) Slump;

(3) Blowout tests, if the design or existing gradient is greater than 30; and

(4) Cement content, where applicable.

iv. The water utilized in the slurry mix and the backfill shall be analyzed for the following parameters:

(1) pH;

(2) Chloride;

(3) Total dissolved solids;

(4) Hardness; and

(5) Total volatile organics.

v. The water utilized in the slurry mix and the backfill shall be free of oil and organic matter, be relatively free of impurities and be in the neutral pH range;

vi. When the depth to the confining layer is less than 100 feet, the thickness of the wall shall be 0.6 feet per 10 feet of hydrostatic head on the wall and shall, at a minimum, be three feet;

vii. When the depth to the confining layer is greater than 100 feet, slurry wall thickness shall be determined on a case by case basis. This determination shall be based on a comprehensive engineering analysis of the ability of a given wall thickness to resist failure;

viii. There shall be a sufficient percent of fines in the backfill material to achieve a hydraulic conductivity equal to or less than 1x10[-7] cm/sec.;

ix. The backfill material shall be completely mixed in such a manner as to ensure a consistent quality of the material;

x. A slump test and gradation analysis shall be performed at a minimum of one sample for every 300 cubic yards of backfill mixture;

xi. A viscosity and density analysis of the slurry shall be performed at a minimum of twice daily;

xii. The backfill mixture shall not be put in place until the trench has been inspected, measured, approved, and certified by a New Jersey licensed professional engineer, or his agent who shall be a qualified geologist or geotechnical inspector, to ensure that the trench has penetrated a sufficient depth into the aquiclude;

xiii. A minimum of three feet of slurry head shall be maintained in the excavation above the maximum anticipated groundwater level and the slurry head should not fall below one foot of the ground surface elevation;

xiv. The backfilling of the slurry cut-off wall shall be performed by one of the two following methods. In either case, free dropping of the backfill into the trench through the slurry is prohibited;

(1) Backfill shall be placed by use of a tremie process; or

(2) Backfill shall be placed into a pre-cut trench in which a minimum backfill slope of six horizontal to one vertical (6:1) has been established.

xv. The backfill process shall continue until sufficient material has been placed in the slurry trench to permit the backfill material to become exposed at the top of the trench;

xvi. A three-foot thick layer of clay core soil backfill shall be placed on top of the complete portion of the cut-off wall after it has reached its intended level and before it is allowed to dry out;

xvii. Upon the completion and stabilization of the backfilling process of the cut-off wall, hydraulic conductivity testing of undisturbed core samples of the backfilled trench shall be performed at 200 foot intervals to verify the hydraulic conductivity of the wall. Whenever a section of the cut-off wall fails to meet the minimum permeability standard established in the QA and QC Plan submitted in accordance with N.J.A.C. 7:26-2A.5(a)7, that section shall be retested and/or reconstructed as defined by the QA and QC Plan. All core sampling holes shall be refilled and recompacted to meet the minimum hydraulic conductivity; and

xviii. In the event that a failure of the slurry trench or construction platform should occur, the trench and backfill material shall be excavated and reconstructed, at a minimum, for a length of 100 feet from the outside point of failure in each direction. The hydraulic conductivity of the reconstructed portion of the wall shall be verified through hydraulic conductivity testing of undisturbed core samples in accordance with xvii above.

(d) The following are the design standards and construction requirements for leachate collection systems:

1. The leachate collection system shall consist of a leachate drainage system and a leachate removal system;

2. A leachate drainage system shall be designed and constructed to provide for effective drainage of the leachate generated within the proposed sanitary landfill in accordance with the following:

i. The slope, hydraulic conductivity and porosity of the drainage layer and the spacing of the collection pipes of the leachate drainage system shall be designed in such a manner as to ensure that the performance and efficiency requirements of N.J.A.C. 7:26-2A.6(d)1 and 2 are met during the operational life of the facility;

ii. The following tests shall be performed on the soil proposed for use in the drainage layer and all data shall be submitted to the Department. These tests shall be performed in accordance with current ASTM, AASHTO or equivalent methods. The number of samples taken and tests performed shall be adequate to define the material. At a minimum, three analyses shall be performed on three separate samples for each source of drainage material.

(1) Classification;

(2) Porosity;

(3) Relative density or compaction; and

(4) Hydraulic conductivity.

iii. The leachate drainage system shall be designed utilizing the latest version of the Hydrologic Evaluation of Landfill Performance (HELP) model, developed by the United States Army Corp of Engineers (USAE) Waterfront Experiment Station, to evaluate liquid management systems.

iv. Data from the nearest meteorological station to the site with a minimum data base of five years, shall be utilized to design the leachate drainage system;

v. The hydraulic conductivity required by N.J.A.C. 7:26-2A.6(d)2 for the drainage layer may be less than 1x10[-2] cm/sec provided the performance and efficiency required by N.J.A.C. 7:26-2A.6(d)1 and 2 and the performance standard in N.J.A.C. 7:26-2A.6(c) are met. The hydraulic conductivity of the drainage layer shall be equal to or greater than 1x10[-3] cm/sec after compaction. It is recommended that a granular filter or geotextile be designed and constructed above the drainage layer to minimize the intrusion of fines into the drainage layer;

vi. The drainage layer shall be designed and constructed in such a manner as to maintain laminar flow throughout the system to prevent scouring of the liner;

vii. The following quality control tests shall be performed on the soil utilized within the drainage layer of the leachate collection system:

(1) Hydraulic conductivity;

(2) Relative density or compaction;

(3) Grain size analysis; and

(4) Drainage layer thickness.

viii. The tests required in vii above shall be performed in accordance with ASTM, AASHTO or equivalent methods and in accordance with the following schedule:

(1) Hydraulic conductivity and grain size analysis shall be performed once per every 3,000 cubic yards of in-place fill material. The hydraulic conductivity may be determined from the grain size analysis, provided the hydraulic conductivity is calibrated to the particular grain size distribution of the soil used;

(2) Relative density or compaction tests shall be performed on the complete drainage layer at 50 foot intervals on a grid pattern across the surface; and

(3) Drainage layer thickness shall be measured periodically throughout the day during construction to ensure that the thickness is within allowable limits and in accordance with the design.

ix. The drainage layer shall have the appropriate minimum thickness specified in (c)2vii above. Furthermore, based on the design permitted by i above, the drainage layer shall be constructed with a minimum depth equal to, or greater than, the maximum anticipated leachate head generated within the landfill during the operational life of the landfill.

x. A synthetic drainage net may be used in the place of a soil drainage layer required at (d)2i through ix above. A leachate removal system required at (d)3 below shall apply;

(1) The following tests shall be performed on the synthetic drainage net proposed for use in the drainage layer, and all data shall be submitted to the Department. These tests shall be performed in accordance with ASTM, AASHTO or equivalent methods in effect at the time of testing;

(A) Polymer Composition;

(B) Polymer Specific Gravity;

(C) Polymer Melt Index;

(D) Carbon Black Content;

(E) Carbon Black Dispersion;

(F) Thickness;

(G) Mass per Unit Area;

(H) Nominal Transmissivity;

(I) Transmissivity under design conditions;

(J) Wide Width Tensile Strength;

(K) Geotextile AOS; and

(L) Ply Adhesion;

(2) The drainage nets shall be stored and installed in such a manner that they are free of dirt, dust, cuttings or any other damaging or deleterious materials;

(3) The minimum overlap of adjacent rolls shall be four inches;

(4) The overlaps shall be secured by tying achieved by strings, plastic fasteners or polymer braid. Metallic fasteners shall not be permitted; and

(5) Tying of drainage nets shall occur every five feet along the slope, every two feet across the slope and every six inches in the anchor trench;

3. A leachate removal system shall be designed and constructed to provide for removal of the leachate within the drainage system to a central collection point for treatment and disposal in accordance with the following:

i. The following tests shall be performed in accordance with ASTM methods, or an equivalent determination shall be performed on the material proposed to be utilized in the leachate collection piping system:

(1) For rigid pipes, a three-edge bearing test shall be performed under 0.1 inch crack loading and ultimate loading conditions;

(2) For flexible pipe, a parallel plate deflection test shall be performed under five percent deflection and buckling capacity loading conditions;

ii. The piping material utilized within the leachate removal system shall possess an adequate structural strength to support the maximum anticipated static and dynamic loads and stresses that will be imposed on the pipe by the drainage layer, gravel pack, overlying wastes, and any equipment used at the sanitary landfill. The supporting strength of the pipe shall be equal to, or greater than, the loads and stresses imposed on the pipe with, at a minimum, a factor of safety of 1.5;

iii. The material utilized for the piping system shall have demonstrated chemical resistance to the wastes to be disposed of in the landfill and the leachate expected to be produced within the proposed sanitary landfill. The requirement for demonstrated chemical resistance shall be satisfied either by the use of ASTM approved chemically resistant piping material or by testing the piping material in accordance with the requirements of (c)2ix(2) above;

iv. The piping system shall have a slope that will provide a self-cleaning velocity within the pipe based on actual maximum flows from the area of drainage. The minimum flow velocity should not be below two feet per second as designed based on full flow or half flow capacity;

v. The leachate collection piping located within the disposal area shall have, at a minimum, an inside diameter of six inches and shall be capable of handling peak flows;

vi. Leachate collection gravity mains located outside of the disposal area shall have, at a minimum, an inside diameter of eight inches and shall be capable of handling peak flows;

vii. The piping system shall employ flexible joints to allow for at least 0.5 degree movement between the pipe sections;

viii. The final grades of the piping system should be true to line and the departure from grade and alignment of the piping system shall not result in excess ponding on the liner or reduced efficiency of the leachate collection system. The maximum allowable departure from grade should not exceed 10 percent of the inside diameter of the collection pipe;

ix. The collection pipes shall be designed to function without clogging throughout the operational phase of the proposed sanitary landfill. The collection pipes shall be constructed within a coarse gravel envelope inside a geotextile fabric. The material utilized in the coarse gravel envelope shall meet the specifications, or equivalent, of the cumulative grain size distribution curves calculated in accordance with (d)3ix(1) through (5) below, where "D" equals the effective size or diameter of the soil particles;

(1) The envelope aggregate shall be compatible with the material with which it is placed in contact;

(2) D[15] (filter envelope) <5

D[85] (soil backfill)

(3) D[15] (filter envelope) >5

D[15] (soil backfill)

(4) for slotted pipes:

D[85] (filter envelope) >1.2

slot Width

(5) for circular holes:

D[85] (filter envelope) >1.2; and

hole diameter

(6) The envelope thickness should be a minimum of 10 cm. around the pipe and should be related to the D50 of the envelope/drainage layer ratio in accordance with Table II below:

TABLE II

Envelope/drainage layer D[50] ratio	Envelope thickness (cm)
<=24	10
24-28	15
28-40	23
40-50	30

x. When the requirements of (d)3ix above cannot be satisfied by a one-layer envelope, a zoned envelope or equivalent shall be constructed that satisfies the specifications in ix. above;

xi. The collection pipe shall be installed within a depression constructed within the liner or liner and subgrade, and shall meet the following minimum specifications:

(1) A minimum of three inches of bedding material shall be placed at the bottom of the trench; and

(2) The depth of the depression should, at a minimum, be equal to the outside diameter of the pipe plus the bedding material.

xii. An interior grid herringbone or offset herringbone system shall be employed, when needed, to ensure that the maximum leachate head exerted on the liner does not exceed the design head and that it controls the leachate head throughout the proposed sanitary landfill;

xiii. The drainage distance between the collection pipes shall not exceed 300 feet. This drainage distance may be increased if geonets are used in the design in conjunction with drainage pipes;

xiv. Construction and earth-moving equipment shall be prohibited from operating over the piping system, and sanitary landfill equipment shall be prohibited from operating over the piping system until a minimum of five feet of refuse has been mounded over and around the pipe;

xv. Manholes or cleanout risers shall be located along the perimeter of the leachate removal system. The number and spacing of the manholes or cleanout risers shall be sufficient to insure proper maintenance of the leachate removal system by water jet flushing or an equivalent method;

xvi. A rubber gasket or an equivalent seal to ensure a tight joint shall be installed between the sump or manhole inlet and the collection pipe. A flexible pipe joint shall be connected to the manhole and a second flexible pipe joint shall be installed within the piping system within three feet of the first flexible pipe joint;

xvii. Material used for the construction of the manhole or cleanout riser shall have a demonstrated chemical resistance to the leachate expected to be produced within the sanitary landfill;

xviii. The leachate collection system shall be designed to drain by gravity to a sump system. In double lined systems, the leachate collection piping systems shall be designed to drain to separate independent sumps;

xix. The sumps, pumps, and pumping station capacity shall be designed based on an evaluation of percolation, resulting from precipitation and infiltration into the system through the side or bottom of the liner or cut-off wall;

xx. Sumps located outside of the lined area shall be a prefabricated structure coated inside and outside with a minimum of two coats of waterproofing sealant. The joints between the sump section shall be sealed with a rubber gasket or equivalent seal and grouted to ensure a watertight seal;

xxi. All sumps shall be tested for watertightness prior to the startup of landfilling operations in accordance with the following:

(1) The sumps shall be filled with water and covered;

(2) The depth of water elevation shall be measured daily for a period of five days;

(3) Any significant decrease in the depth of water within the sump shall be an indication of failure. The sump which fails the test shall be recoated with waterproofing sealant and the joints regrouted. The sump shall be retested for watertightness in accordance with this subparagraph. If failure of the retest should occur the sump shall be reconstructed.

xxii. Should the sumps be located outside of the lined area, the sumps shall be lined with a geomembrane with a leak detection system;

xxiii. The pump station shall be housed in a suitable structure capable of protecting the pumps, motors and electrical equipment in accordance with, but not be limited to, the following:

(1) Explosion-proof equipment for the pump motors and electrical equipment shall be utilized and shall be constructed in accordance with the most current version of the National Electrical Code, "Special Occupancy, Hazardous Location", Volume 6 of the National Fire Code published by the National Fire Prevention Association;

(2) Adequate lighting and ventilation, where necessary, shall be provided. The ventilation system of the pump station shall be constructed in accordance with the most current version of the National Fire Code, "Explosion Venting" Volume 14, published by the National Fire Prevention Association;

(3) The leachate pumping system shall be designed to prevent overflow in the event of a power outage. It is recommended that back-up electric power be provided at all times from an on-site generator or separate utility substation in the event that the overall leachate storage capacity is compromised during a power outage;

(4) Automatic sound alarms, operating independently of the pump station power, shall be installed to give warning of high water, power failure, or breakdown. The alarm system shall be wired to the location where assistance will be available to respond to the emergency;

(5) The total number of operating pumps as determined in accordance with (6) below, shall be designed to handle the maximum expected leachate production for the area of drainage based on the average peak monthly flow;

(6) A minimum of two pumps shall be provided in the leachate pump station. The number of pumps should be designed based on the requirements of Table III below:

TABLE III

Total Flow to Pump Station	Number of Pumps in the Pump Station
500 gpm	2 pumps (1 standby);
500-1500 gpm	3 pumps (2 operating, 1 standby); and
1500-3000 gpm	4 pumps (3 operating, 1 standby);

(7) If more than two pumps are provided, their capacity shall be such that upon failure of the largest pump the remaining pumps shall be capable of handling the maximum expected leachate production for the area of drainage based on the average peak monthly flow.

4. The leachate collection system shall be connected to the gas collection system required at (f) below as a means to control odors.

(e) A leachate treatment and disposal system shall be designed and constructed in accordance with the following:

1. All leachate treatment and disposal systems shall be required to obtain a NJPDES permit in accordance with the NJPDES regulations, N.J.A.C. 7:14A;

2. The leachate treatment and disposal system shall be designed in accordance with one of the following options:

i. Complete treatment on-site with direct discharge to surface or groundwater;

ii. Pretreatment on-site, if required, with discharge to an off-site treatment works for final treatment; or

iii. Storage on-site with discharge to an off-site treatment works for complete treatment.

3. Leachate recirculation within the sanitary landfill shall not be permitted as a sole leachate disposal option. Leachate recirculation shall, however, be permissible as part of an overall leachate management system (that is, to enhance biodegradation of the landfilled solid waste) provided that the sanitary landfill has, at a minimum, a composite liner system with a leachate collection system which will ultimately discharge the leachate for disposal in accordance with (e)2 above;

4. Leachate storage prior to treatment shall be within tanks constructed and installed in accordance with (e)13 below;

5. Storage of leachate for a period exceeding one month shall be prohibited except as set forth at (e)10iii below during start-up operations;

6. The following requirements shall be met prior to start-up of sanitary landfilling operations:

i. The leachate treatment and disposal system shall be on line and fully operational;

ii. An agreement with a treatment works facility to accept the leachate shall be in place if either option (e)2ii or iii above was elected for use with the sanitary landfill; and

iii. All necessary Federal, State and local permits for the treatment and disposal system shall have been obtained.

7. All leachate treatment and disposal systems shall be designed and constructed to prevent anaerobic conditions from developing;

8. All leachate treatment and disposal systems shall be designed and constructed to control odors pursuant to N.J.A.C. 7:27;

9. For all leachate discharges planned for publicly owned treatment works (P.O.T.W.), the owner and/or operator shall determine the acceptability of such discharges on the operations of the P.O.T.W. in accordance with the NJPDES regulations, N.J.A.C. 7:14A;

10. In addition to complying with the requirements of the NJPDES regulations, N.J.A.C. 7:14A, the Rules and Regulations for the Preparation of Plans for Sewer Systems and Wastewater Treatment Plants, N.J.A.C. 7:9-1, and the Pretreatment Standards for Sewerage, N.J.S.A. 58:11-49.1 et seq., on-site complete treatment or pretreatment facilities shall be designed and constructed in accordance with the following:

i. The on-site treatment unit shall be designed based on the results of a treatability study, the results of the operations of a pilot scale plant or written information documenting the performance of an equivalent leachate treatment system;

ii. On-site treatment units shall be designed and constructed by staging of the units to allow for on-line modification of the treatment facility to account for variability of the leachate quality and quantity; and

iii. The use of mobile or temporary treatment units may be permitted prior to the construction of a permanent facility satisfying the requirements of 6 above, provided that in all cases a permanent leachate treatment and disposal system shall be on-line within 12 months.

11. The residuals from any treatment facility shall be analyzed in accordance with the requirements of the Sludge Quality Assurance Regulation, N.J.A.C. 7:14-4, and disposal of in accordance with the following:

i. The analysis shall be submitted to the Bureau of Recycling and Hazardous Waste Management of the Division of Sustainable Waste Management for classification;

ii. Should the sludge be classified as a non-hazardous waste, the sludge shall be disposed of at a solid waste facility permitted to accept the waste type ID classification; and

iii. Should the sludge be classified as a hazardous waste the material shall be disposed of in accordance with N.J.A.C. 7:26G.

12. In addition to complying with the requirements of N.J.A.C. 7:14A-10.7, the Dam Safety Standards, N.J.A.C. 7:20, and the Standards for Soil Erosion and Sedimentation Control, N.J.A.C. 2:90, surface impoundments utilized as on-site treatment units shall be designed and constructed in accordance with the following:

i. Surface impoundments shall include a liner system that is designed to meet or exceed the performance standards set forth in N.J.A.C. 7:26-2A.6(d)1 and 2 under the maximum anticipated hydrostatic head and the liner shall be constructed in accordance with (b) and (c) above;

ii. Surface impoundments shall be designed and constructed to contain the expected flow with sufficient reserve capacity to contain accumulated precipitation from previous rainfall events and sediment and sludge accumulation;

iii. The stability of the surface impoundment dikes shall be determined, as appropriate, for long term, short term or rapid drawdown conditions by modeling techniques and the factor of safety shall be within the minimum values set forth in Table II in (e)3i above;

iv. The inner and outer slopes of all dikes of the surface impoundment shall not exceed a 3:1 slope;

v. The inflow to the surface impoundment shall be designed and constructed so that any flow of waste into the impoundment can be immediately shut-off; and

vi. Upon closure of the surface impoundment, unless the surface impoundment is within the containment and leachate collection systems of the landfill area, the surface impoundment shall be removed and disposed of in accordance with (e)11 above and NJPDES regulations, N.J.A.C. 7:14A.

13. The minimum standards for the design and construction of leachate storage tanks include the following:

i. The tank shall be constructed of or lined with material which has a demonstrated chemical resistance to the leachate expected to be produced within the landfill and contained within the tank;

ii. The storage tank area shall have a liner system consisting of a minimum of 18 inches of clay or a single 30 mil geomembrane and a leachate collection system. The liner system and leachate collection system shall be capable of containing and collecting any spills of leaks and shall be designed and constructed in accordance with (b), (c) and (d) above. Double walled tanks constructed on a concrete slab are acceptable alternatives.

iii. The storage tank shall be designed in accordance with American Petroleum Institute (API), Underwriters Laboratory (UL), or American Concrete Institute (ACI) standards or an equivalent standard depending on the material used, such as metal, fiberglass reinforced plastic, or concrete, and the minimum shell thickness shall be equivalent to a 3/16th of an inch metal tank;

iv. All storage tanks shall be equipped with a venting and odor control system. The venting system shall be Low-Pressure Storage Tank or an equivalent design and permitted in accordance with N.J.A.C. 7:27-8;

v. Control of emissions and odors from the storage tank shall be in compliance with the rules and regulations of the Bureau of Stationary Sources, N.J.A.C. 7:27;

vi. All storage tanks shall be equipped with a high liquid level alarm or warning device. The alarm system shall be wired to the location where assistance will be available to respond to the emergency; and

vii. All storage tanks shall be constructed and maintained in accordance with applicable provisions of the NJPDES regulations including, but not limited to, N.J.A.C. 7:14A-10.7.

14. Spray irrigation of treated effluent systems shall be designed and constructed in accordance with the NJPDES regulations, specifically N.J.A.C. 7:14A-10.9.

i. The spray irrigation system shall not result in increased hydraulic head on the liner system in excess of the design head.

(f) The following are the design standards and construction requirements for sanitary landfill gas collection and venting system:

1. Sanitary landfill gas collection and venting systems shall be designed and constructed to prevent and control the migration of sanitary landfill gases off-site and shall consist of a perimeter collection system or an interior collection system or both which shall:

i. Prevent and control the accumulation of any methane concentrations in any structure;

ii. Prevent and control damage to vegetation beyond the perimeter of the property on which the sanitary landfill is located; and

iii. Contain malodorous gaseous emissions on-site.

2. Sanitary landfill gas collection and venting systems shall be subject to additional design and operational requirements set forth at the Federal New Source Performance Standards and Emissions Guidelines (NSPS/EG) established at 40 CFR 51, 52, and 60. Further guidance is set forth in the Department's Technical Manual for Sanitary Landfill Permits and Approvals for landfill gas collection and venting systems. All gas venting and collection systems shall be permitted in accordance with the rules of the Department's Bureau of Stationary Sources, N.J.A.C. 7:27;

3. The detection of 25 percent of the lower explosive limit of combustible landfill gases, at the perimeter of the sanitary landfill property, or any concentration of any landfill gases within any structures shall trigger the construction of an induced draft or active venting system which shall be designed and constructed in accordance with the following:

i. The perimeter gas collection and venting system shall be designed and constructed to prevent and control landfill gas migration;

ii. Passive gas venting systems may be designed and constructed initially as a preventive measure against sanitary landfill gas migration. In situations where gas migration is detected in amounts greater than or equal to the limits set forth in (f)3 above, passive gas venting systems are prohibited;

iii. The Department may require the construction of an active gas collection system if a significant concentration of gas is detected within the setback area which in the opinion of the Department poses a threat to the health and welfare of the surrounding community. The design of the gas extraction system shall be based on the following:

(1) The design of an active venting system shall be accompanied by engineering calculations computing the volumes influenced, extraction flow rates (based on zone of influence, ground surface and base grade elevations, gas generation rate and density of refuse) and blower sizing requirements (based on total negative head and volume of gas to be extracted); and

(2) The quantity of landfill gas condensate generated as a function of time shall be computed. Disposal methods for gas condensate shall be described.

(3) Detailed plans of the active venting system shall adequately delineate in plan views and in cross-sectional views, the elevations of all gas collection lines, inverts, valves, extraction well locations and depth of construction materials.

iv. The number of collection well pipes shall be determined by (f)10 below and be sufficient to prevent any off-site gas migration; and

v. The depth of the gas collection wells shall be sufficient to prevent migration of sanitary landfill gases off-site in accordance with the following:

(1) When located within the lined area of the sanitary landfill, the gas collection wells shall not result in or give cause to failure of the liner or leachate collection systems; and

(2) When located outside of the lined area of the sanitary landfill, the gas collection wells shall be constructed, at a minimum, to the bottom of the liner system or to the top of the groundwater table whichever is higher.

4. The sanitary landfill shall not cause any air contaminant, including an air contaminant detectable by the sense of smell, to be present in the outdoor atmosphere in such quantity and duration which is, or tends to be, injurious to human health or welfare, animal or plant life or property, except for malodorous emissions emanating from the sanitary landfill which result in odors in areas over which the owner and/or operator has exclusive use or occupancy. Malodorous gaseous emissions emanating from the sanitary landfill which result in odors being detected in any off-site area of human use or occupancy shall be cause for requiring the construction of the interior gas collection and venting system which shall be designed and constructed in accordance with the following:

i. The interior gas collection and venting system shall be designed and constructed to control malodorous emissions resulting from gaseous emissions. The gas collection system shall also be connected to the leachate collection system to control odors;

ii. The interior collection system shall be an induced draft or active venting system;

iii. The number of collection wells shall be determined by (f)10 below and be sufficient to control malodorous emissions; and

iv. The depth of the collection wells shall not result in or give cause to failure of the liner or leachate collection systems.

5. Sanitary landfills in which active gas collection systems are constructed should, to the extent practicable, develop a gas recovery system in which the gas or converted energy is recovered and utilized;

6. The sanitary landfill gases, prior to the design and construction of the gas collection and venting system in accordance with (f)3 and 4 above, shall be sampled and analyzed to define the quality and quantity of the sanitary landfill gases. Air pollution control permits in accordance with N.J.A.C. 7:27 shall be obtained for all gas venting systems. The sampling and analysis of sanitary landfill gases shall be in accordance with the air pollution control permit for the sanitary landfill gas venting system.

7. The gas collection system shall be designed to control condensate and to drain the condensate into the leachate collection system;

8. Each collection well shall be constructed with a valve to enable control and tuning of the system;

9. The gas collection system within the landfill area shall be designed to compensate for settlement. Collection wells shall be designed with slip joints, telescoping joints or equivalent joints. The valves, condensation traps and manifold connections shall be designed with flexible joints;

10. A gas generation model, approved by the Department, and calculations shall be performed to properly size the number of collection wells required by (f)3iv and 4iii above. The collection well diameters, header lengths, pump capacities and recovery systems shall be properly sized, and designed and constructed in accordance with (f)6 above;

11. The pump station shall be a suitable, permanent structure, which affords protection to the pumps, motors, and electrical equipment, and shall include the following:

i. Explosion-proof equipment for the pumps, motors, and electrical equipment in accordance with the most current version of the National Electrical Code "Special Occupancy, Hazardous Location" Volume 6 of the National Fire Code published by the National Fire Prevention Association; and

ii. Adequate lighting and ventilation which shall be in accordance with the most current version of the National Fire Code's "Explosion Venting" Volume 14 published by the National Fire Prevention Association.

12. Materials used in the gas collection and venting systems shall be compatible with the sanitary landfill environment, sanitary landfill gases and condensate, and the material shall meet ASTM standards for chemically resistant materials;

13. Construction of any buildings on top of landfilled areas shall be prohibited during the operational and closure phases. Construction during the post-closure phase, as approved by the Department, shall be in accordance with the following:

i. The building shall be an above-grade structure. Construction of a basement is prohibited;

ii. The building shall be constructed to prevent gas accumulation within the structure in accordance with the requirements of (f)14 below or an equivalent method, which may include an active gas collection and venting system; and

iii. All utility connections shall be designed and constructed with flexible connections.

14. On-site buildings within the sanitary landfill properties should be designed and constructed in accordance with the following, or in accordance with an equivalent design which will prevent gas migration into the building:

i. A geomembrane or equivalent system with high gas impermeability should be installed between the slab and the subgrade or equivalent design;

ii. A permeable layer of open-graded material of clean aggregate, with a minimum thickness of 12 inches, should be installed between the membrane and the subgrade or slab. The material should be in accordance with the following requirements of the grain size distribution curves:

(1) D[85][LESS THAN]4D[15]; and

(2) D[2][GREATER THAN] 0.1 inch;

iii. A geotextile filter should be utilized to prevent the intrusion of fines into the permeable layer;

iv. Perforated venting pipes shall be installed within the permeable blanket and shall be designed to operate without clogging;

v. The venting pipe shall be designed and constructed with the ability to be connected to an induced draft exhaust system;

vi. Automatic methane gas sensors shall be installed within the venting pipe/permeable blanket and inside the building to trigger an audible alarm when methane gas concentrations are detected; and

vii. All buildings shall be constructed in accordance with the National Fire Code's, Life Safety Code Volume 9 as published by the National Fire Prevention Association.

(g) The following are the design standards and construction requirements for surface drainage systems:

1. Sanitary landfills shall be designed and constructed in such a manner as to hydraulically isolate the sanitary landfill from surface water drainage in a controlled manner. The surface drainage system shall be designed and constructed to protect the sanitary landfill from run-on and control run-off, from, at a minimum, the peak discharge of a 24-hour, 25-year storm;

2. Run-on/run-off structures shall be designed utilizing the United States Department of Agriculture, Soil Conservation Service, methods and in accordance with the Standards for Soil Erosion and Sedimentation Control, N.J.A.C. 2:90;

3. Diversion structures shall be designed to minimize ponding behind the structure;

4. Laboratory classification, and compaction or relative density tests shall be performed on the soils to be utilized in the construction of the run-on/run-off structures in accordance with current ASTM, AASHTO or equivalent methods. The number of tests and samples shall be sufficient to define the material;

5. The run-on/run-off structures shall be constructed by modification of the compactive effort utilizing stage compaction, not exceeding the effective depth of the compaction equipment. The compaction shall be performed to the design density and at the proper moisture content where applicable, based on the laboratory analysis performed pursuant to (g)4 above, to achieve the required strength or hydraulic conductivity;

6. The following quality control tests shall be performed on the soils utilized within the run-on/run-off structure construction:

i. Grain size analysis; and

ii. Relative density/compaction.

7. The tests required by (g)6 above shall be performed in accordance with ASTM, AASHTO or equivalent methods in accordance with the following:

i. Grain size analysis shall be performed once per every 3000 cubic yards of in-place fill material; and

ii. Relative density or compaction testing shall be performed on the completed structures at 50 foot intervals on a grid pattern across the surface;

8. The strength of the run-on/run-off structures shall be determined utilizing appropriate ASTM, AASHTO or equivalent methods for both in-situ and laboratory testing for the appropriate conditions. The stability of the structure shall be determined for long term, short term, or rapid drawdown conditions by modeling techniques and the factor of safety shall be within the minimum values set forth in Table II in N.J.A.C. 7:26-2A.7 (b)3 i;

9. Run-on controls shall meet the following requirements:

i. Diversion structures shall be designed to minimize run-on onto the landfilled areas in accordance with (g)1 above and N.J.A.C. 7:26-2A.6 (g) and (h);

ii. Detention basins used for run-on control, shall be designed to provide temporary storage of the expected run-off from the design storm with sufficient reserve capacity to contain accumulated precipitation and sediment in accordance with the Standards for Soil Erosion and Sediment Control, N.J.A.C. 2:90;

10. Run-off controls shall meet the following requirements:

i. Discharge of run-off from diversion structures installed on stabilized slopes with intermediate cover and graded in accordance with N.J.A.C. 7:26-2A.82(b)11 shall comply with the NJPDES regulations, N.J.A.C. 7:14A where applicable; and

ii. Discharge of run-off from the active face shall be directed to the leachate collection system. Run-off from the final capped areas may be directed to the detention ponds.

(h) The following are the design and construction requirements and standards for monitoring systems:

1. The monitoring system shall be designed and constructed in such a manner as to ensure its ability to observe and record the performance of the sanitary landfill and its various environmental control systems and to detect any potential malfunctions and possible pollutant migration;

2. The Department may require any or all of the following components for the landfill monitoring system designed and constructed pursuant to (h)1 above: groundwater monitoring system, hydrostatic pressure gradient monitoring system, gas monitoring system, leachate monitoring system, meteorological monitoring system, slope and settlement monitoring system, and hydrogen sulfide monitoring system;

3. All monitoring systems, where appropriate, shall be constructed and operated in accordance with the NJPDES regulations, N.J.A.C. 7:14A;

4. A ground water monitoring system shall be designed and constructed in accordance with the NJPDES regulations, N.J.A.C. 7:14A;

5. A hydrostatic pressure gradient monitoring system shall be designed and constructed in accordance with the following:

i. In facilities with cut-off wall designs, a system to measure the hydrostatic pressure across the wall shall be constructed in accordance with the following:

(1) The location of the piezometers shall be directly opposite the groundwater saturated zone wells; and

(2) The depth and location of the piezometers within the sanitary landfill shall not result in damage to the containment system.

6. A gas monitoring system shall be designed and constructed in accordance with the following:

i. The system shall be capable of detecting any possible methane gas migration from the sanitary landfill and shall be located as close to the toe of the slope of the sanitary landfill, depending on the gas flow characteristics of the soils, as is reasonably possible, in order to rapidly detect any possible gas migration;

ii. The methane gas monitoring wells shall be screened in the unsaturated zone to at least five feet below the lowest elevation of the landfill or to the top of the water table;

iii. A period gas survey performed in accordance with N.J.A.C. 7:26-2A.8(h)9 may be substituted for the design and construction of methane gas monitoring wells; and

iv. In accordance with the Permits and Certificates Rules of the Department, N.J.A.C. 7:27-8, a gas monitoring system for the gas collection systems, capable of defining the quality and quantity of the landfill gas, shall be designed and constructed.

7. A leachate monitoring system shall be designed and constructed which shall be capable of measuring the flow, and capable of sampling leaching influent and the treatment system effluent;

8. A meteorological monitoring system shall be installed within the landfill properties to measure and continuously record the daily precipitation onto the sanitary landfill, unless such data from a nearby meteorological station are available;

9. A slope and settlement monitoring system shall be designed and constructed in accordance with the following:

i. In areas which exhibit a high degree of uncertainty of the strength data, such as meadow mat, peat, or expansive clay soils, a system to measure the settlement of the sanitary landfill and liner systems shall be installed which should include, but not be limited to, borehole settlement devices; and

ii. Sanitary landfills, when required by the Department, based on the final elevation and grades of the capping system and the foundation analysis, shall install slope inclinometers to adequately measure the slope stability and integrity; and

10. The Department may require the owner or operator to design and install a hydrogen sulfide ambient air monitoring system based upon the Department's determination that the sanitary landfill is the source of hydrogen sulfide emissions that result in a violation of N.J.A.C. 7:27-5.2 or an exceedance of the hydrogen sulfide standard at N.J.A.C. 7:27-7.3:

i. In determining whether to require a monitoring system for hydrogen sulfide, the Department shall consider:

(1) The cause of the hydrogen sulfide odor;

(2) Actions taken to mitigate the odor;

(3) History of odor violations and complaints attributed to the sanitary landfill;

(4) Location and dimensions of the sanitary landfill;

(5) Locations of off-site areas of human use or occupancy;

(6) Material that has been placed in the landfill;

(7) Material that is planned to be placed on the landfill;

(8) Monitored levels of hydrogen sulfide; and

(9) Any other factors related to hydrogen sulfide emissions from the sanitary landfill and their potential off-site impacts.

ii. Except as set forth in (h)10iii below, the hydrogen sulfide monitoring system shall be designed in accordance with 40 CFR Part 58 , Appendix D and shall also meet the following requirements:

(1) Monitors shall have a minimum hydrogen sulfide detection level at or below 10 ppbv with a minimum accuracy of +/- 10 percent when measuring 30 ppbv of hydrogen sulfide;

(2) Monitors shall either continuously measure and record the ambient hydrogen sulfide concentrations, or measure with measurement intervals not to exceed five minutes to determine a representative ambient hydrogen sulfide concentration over a 30-minute averaging period;

(3) The system shall be designed to account for manufacturer's specifications for instrumentation. For example, instrumentation may require temperature regulated enclosures;

(4) Monitors shall be sited at a minimum of two locations. One location shall be in the area expected to have the maximum, or near maximum, off-site concentrations of hydrogen sulfide releases from the sanitary landfill, and one shall be located approximately 180 degrees from the first location, relative to the landfill. Additional sites may be necessary depending on prevailing meteorology, terrain, and the location of sensitive receptors, for example, schools, hospitals, and nursing homes;

(5) The location of the monitoring sites shall consider obstruction to wind flow from the sanitary landfill to the sensors;

(6) Monitoring sites shall comply with the general probe siting criteria described in 40 CFR Part 58, Appendix E; and

(7) The monitoring system shall include at least one weather station capable of measuring and recording local meteorological data, including wind speed and direction, temperature, humidity, and barometric pressure. An existing weather station can be used if conditions at the weather station are shown to be representative of conditions at the sanitary landfill.

iii. In lieu of complying with (h)10ii above, and subject to Department approval, the owner or operator may design and install a system that is at least as effective at hydrogen sulfide monitoring as a system designed in accordance with (h)10ii above.

(i) The following are the design standards and construction requirements for a final cover system:

1. The final cover system shall be designed and constructed to minimize long term infiltration and percolation of liquid into the sanitary landfill throughout the closure and post-closure periods;

2. A Class II or Class III sanitary landfill, as approved by the Department, may design and construct a final cover with a minimum of two feet of final cover, provided the performance standards of (i)1 above and N.J.A.C. 7:26-2A.6(i) are met.

3. The final cover system, in conjunction with the containment system required pursuant to (c) above, shall completely isolate the landfilled solid waste from the surrounding environment. In accordance with 40 CFR Parts 257 and 258, and the Department's Technical Manual for Sanitary Landfill Permits and Approvals, a final cover system shall comply with the following performance standards:

i. The permeability of the final cover shall be less than or equal to that of the bottom liner system or natural subsoils present, or 1 x 10[-5] cm/sec., whichever is less. The depth of final cover shall be a minimum of 18 inches overlain by a minimum of a six inch erosion layer.

ii. If the sanitary landfill has a synthetic membrane in the bottom liner system, then the final cover shall include a synthetic membrane.

(1) The synthetic membrane of the final cover does not have to be the same type or thickness as the membrane in the bottom liner system. However, a minimum thickness of 30 mils shall be used. In the case of High Density Polyethylene, a minimum thickness of 60 mils is required to ensure proper seaming of the synthetic membrane.

4. The long term stability of the final slopes shall be determined by modeling techniques in conjunction with the information gathered pursuant to (b)3 above and N.J.A.C. 7:26-2A.5(a)6, and the factor of safety shall be within the minimum values set forth at (b)3i and ii above;

5. The grades of the final slope shall be constructed in accordance with the following minimum standards:

i. The top slope final grades, after allowing for settlement and subsidence, shall be, at a minimum, three percent;

ii. The top slope final grades shall be, at a maximum, five percent, except as set forth at (i)5ii(1) below:

(1) Steeper top slopes which will promote drainage and not subject the closed sanitary landfill to excessive erosion shall be permitted provided the maximum erosion rate does not exceed two tons per acre as determined by the United States Department of Agriculture, Universal Soil Loss Equation; and

iii. The side slopes of the final grades shall be no steeper than three horizontal to one vertical (3:1).

6. The final grades of the final cover system shall have a surface drainage system, designed and constructed in accordance with the requirements of (g) above, capable of conducting run-off across the final grades without the development of erosion rills or gullies;

7. The construction of the final cover system shall accommodate initial settlement so that the integrity of the impermeable liner is maintained throughout the closure and post-closure period. A temporary cover may be constructed, provided the leachate collection system is operating properly in accordance with the following:

i. The temporary cover shall be capable of minimizing infiltration into the sanitary landfill unless the sanitary landfill is designed and operated to allow for leachate recirculation in accordance with (e)3 above;

ii. The depth of the temporary cover shall be a minimum of 12 compacted inches and shall be maintained to prevent erosion and exposure of solid waste; and

iii. The temporary cover shall be exposed for no greater than six months unless otherwise approved by the Department;

8. The grading and stabilizing of the final lifts of solid waste shall result in a relatively planar surface and provide a sufficiently firm base for the placement and construction of the impermeable cap.

9. The final lifts of solid waste shall be physically or chemically stabilized in accordance with the following:

i. The density of the final lift shall be increased to the largest extent practicable by:

(1) Reducing the thickness of the layers as compacted;

(2) Increasing the ballast or load of the compaction equipment; and

(3) Increasing the number of passes of the compaction equipment.

ii. Blending of gravel, stone, cobble, or selected demolition material (for example, brick, concrete, asphalt) into the upper 12 to 24 inches of the final lift of the solid waste; or

iii. Chemically stabilizing the upper 12 inches of the final lift of solid waste with the addition of soil cement or lime treated soil with silicates, kiln dust or other proprietary polymeric additives or soil asphalt. Ash-lime treated soil or ash-cement treated soil may be used, provided the ash-lime or ash-cement treated soil has received a beneficial use or reuse authorization pursuant to N.J.A.C. 7:26-1.7(g).

10. The impermeable cap shall be designed and constructed in accordance with the following:

i. The cap shall, at a minimum, be as impermeable as the most impermeable component of the containment system;

ii. The minimum thickness for a clay impermeable cap shall be 12 inches;

iii. The minimum thickness for a geomembrane impermeable cap shall be 30 mils, or for High Density Polyethylene, 60 mils;

iv. The impermeable cap shall be constructed and tested in accordance with (c) above, except that (c)2vii, viii and ix above shall not apply;

v. Geomembranes utilized as an impermeable cap shall be designed and constructed to withstand the calculated tensile forces acting on the geosynthetic materials. The design shall consider the maximum friction angle of the geomembrane with regard to any interface and shall ensure that the overall slope stability and erosion control of the final cover system are maintained;

vi. The geomembrane shall be protected from below and above by a minimum thickness of six inches of bedding and cover which is no coarser than a poorly grade sand (SP), as determined in the Unified Soil Classification System (USCS), and which is free of rocks, fractured stones, debris, cobbles and solid waste. An equivalent geotextile may be utilized as approved by the Department; and

vii. The impermeable cap shall be located wholly below the average depth of frost penetration in the area as determined by United States Department of Agriculture and mapping.

11. A drainage layer shall be designed and constructed in accordance with the following:

i. The design testing of materials and the quality control testing of the drainage layer of the capping system shall be performed in accordance with (d)2ii, vii and viii above;

ii. The material used in the drainage layer shall be an open graded material of clean aggregate. The material shall be in accordance with the following criteria of the cumulative grain size distribution curves:

(1) D[85]<4D[15]; and

(2) D[2]<0.1 inch;

iii. The drainage layer shall be designed and constructed so that the discharge flows freely in the lateral direction to minimize the hydrostatic head on the impermeable cap, flows through the drainage layer, and provides a path for infiltrated liquids to exit the capping system;

iv. The drainage layer shall have a thickness and hydraulic conductivity capable of transmitting all percolation through the overlying soils under saturated conditions. For design purposes, the drainage capacity of the drainage layer shall be greater than the percolation under saturated conditions. The drainage layer shall be constructed, at a minimum, in accordance with the following:

(1) When located above a clay impermeable cap, the drainage layer shall be, at a minimum, six inches thick; and

(2) When located above a geomembrane impermeable cap, the drainage layer shall be, at a minimum, 12 inches thick.

v. Drainage pipes and/or synthetic drainage nets, where necessary to control the hydrostatic head on the impermeable cap, should be located within the drainage layers in accordance with the following:

(1) The drainage pipe should be installed at a distance sufficient to ensure that the hydrostatic head on the impermeable layer does not exceed the thickness of the drainage layer during a 25 year, 24 hour storm;

(2) A coarse gravel envelope, within a geotextile fabric, shall be installed in accordance with N.J.A.C. 7:26-2A.5(e)3 ix around the drainage pipe to minimize the movement of soil particles in the drainage pipe;

(3) Synthetic drainage nets shall comply with the test requirements set forth at (d)2x(l) above; and

(4) The synthetic drainage net shall satisfy the design requirements at (d)11iii and iv above when accounting for calculated design loads imposed on the drainage net. A properly designed synthetic drainage layer shall result in no seepage forces in the overlying cover soil.

vi. A soil filter or geotextile should be designed and constructed above the open graded aggregate in order to minimize the intrusion of fines into the drainage layer.

12. The vegetative layer shall be designed and constructed in accordance with the following:

i. The vegetative layer shall be thick enough to contain the effective root depth or irrigation depth for the type of vegetation planted;

ii. Fertilizer, mulch, and seeding applications shall be performed in accordance with Standards for Soil Erosion and Sedimentation Control, N.J.A.C. 2:90, for permanent vegetative cover for soil stabilization;

iii. The minimum thickness of uncompacted topsoil in the upper layer of the vegetative layer shall be five inches. The topsoil shall meet the Topsoil Standard specified in Section 909.10 of the New Jersey Department of Transportation Standard Specifications for Road and Bridge Construction; and

iv. The application of sludge or the use of Sludge Derived Product (SDP) to the final grades of the vegetative layer shall be performed in accordance with the NJPDES rules, N.J.A.C. 7:14A.

13. A gas venting layer shall be designed and constructed in accordance with the following:

i. The gas venting layer shall be located directly below the impermeable layer and above the compacted waste layer.

ii. The gas venting layer shall be designed and constructed in accordance with the requirements set forth at (f) above.

14. The Hydrologic Evaluation of Landfill Performance (HELP) Model (EPA/600/R-94/168a, U.S. Environmental Protection Agency Risk Reduction Engineering Laboratory, Cincinnati, OH), incorporated herein by reference, as amended and supplemented, shall be used to estimate leachate generation quantities of the sanitary landfill with the impermeable cap during closure and post-closure periods.

N.J. Admin. Code § 7:26-2A.7

Amended by 49 N.J.R. 2935(a), effective 9/5/2017

Administrative Change, 55 N.J.R. 1922(b), effective 7/31/2023