WAC 173-350-400   Limited purpose landfills.  (1) Limited purpose landfills - Applicability. These standards apply to all landfills except:

     (a) Municipal solid waste landfills regulated under chapter 173-351 WAC, Criteria for municipal solid waste landfills;

     (b) Inert waste landfills regulated under WAC 173-350-410;

     (c) Special incinerator ash landfills regulated under chapter 173-306 WAC, Special incinerator ash management standards;

     (d) Dangerous waste landfills regulated under chapter 173-303 WAC, Dangerous waste regulations; and

     (e) Chemical waste landfills used for the disposal of polychlorinated biphenyls (PCBs) regulated under Title 40 CFR Part 761, Polychlorinated Biphenyls (PCBs) Manufacturing, Processing, Distribution in Commerce, and Use Prohibitions.

     (2) Limited purpose landfills - Location standards. All limited purpose landfills shall be located to meet the following requirements:

     (a) No landfill shall be located over a Holocene fault, in subsidence areas, or on or adjacent to an unstable slope or other geologic features which could compromise the structural integrity of the facility.

     (b) No landfill's active area shall be located closer than one thousand feet to a down-gradient drinking water supply well, unless the owner or operator can demonstrate that a minimum of ninety days will occur between the time that a contaminant is detected and the time the contaminant can reach the nearest down-gradient drinking water supply well. Such demonstrations shall be prepared by a licensed professional in accordance with the requirements of chapter 18.220 RCW and shall be included in the permit application. The demonstration shall be based on the details of the sampling and analysis plan and the hydrogeologic properties of the hydrostratigraphic unit.

     (c) No landfill's active area shall be located in a channel migration zone as defined in WAC 173-350-100 or within two hundred feet measured horizontally, of a stream, lake, pond, river, or saltwater body, nor in any wetland nor any public land that is being used by a public water system for watershed control for municipal drinking water purposes in accordance with WAC 248-54-660(4). All facilities shall conform to location restrictions established in local shoreline management plans adopted pursuant to chapter 90.58 RCW.

     (d) No landfill shall be located within ten thousand feet of any airport runway currently used by turbojet aircraft or five thousand feet of any airport runway currently used by only piston-type aircraft unless the federal aviation administration grants a waiver. This requirement is only applicable where such landfill is used for disposing of wastes where a bird hazard to aircraft would be created.

     (e) All landfills shall comply with the location standards specified in RCW 70.95.060.

     (3) Limited purpose landfills - Design standards.

     (a) This section applies to landfills with considerable variations in waste types, site conditions, and operational controls. All landfills shall be designed and constructed to meet the design standards of this subsection, the performance standards of WAC 173-350-040, and shall be appropriate for and compatible with the waste, the site, and the operation. The owner or operator of a limited purpose landfill shall prepare engineering reports/plans and specifications, including a construction quality assurance plan, to address the design standards of this subsection. An owner or operator shall be able to demonstrate during the permitting process that the design of a proposed landfill will mitigate threats to human health and the environment. When evaluating a landfill design, the jurisdictional health department shall consider the following factors:

     (i) Waste characterization;

     (ii) Soil conditions;

     (iii) Hydrogeologic conditions;

     (iv) Hydraulic conditions;

     (v) Contaminant fate and transport;

     (vi) Topography;

     (vii) Climate;

     (viii) Seismic conditions;

     (ix) The total capacity of the facility and each landfill unit;

     (x) Anticipated leachate characteristics and quantity;

     (xi) Operational controls; and

     (xii) Environmental monitoring systems.

     (b) Liner system design.

     (i) Liner system performance standard. Limited purpose landfills shall be constructed in accordance with a design that:

     (A) Will prevent the contamination of the hydrostratigraphic units identified in the hydrogeologic assessment of the facility at the relevant point of compliance as specified during the permitting process; and

     (B) Controls methane and other explosive gases generated by the facility to ensure they do not exceed:

     (I) Twenty-five percent of the lower explosive limit for the gases in facility structures (excluding the gas control or recovery system components);

     (II) The lower explosive limit in soil gases or in ambient air for the gases at the property boundary or beyond; and

     (III) One hundred parts per million by volume of hydrocarbons (expressed as methane) in off-site structures.

     (ii) The jurisdictional health department may allow a limited purpose landfill to be designed and constructed without a liner system if the owner or operator can demonstrate during the permitting process that:

     (A) The contaminant levels in the waste and leachate are unlikely to pose an adverse impact to the environment; and

     (B) The ability of natural soils to provide a barrier or reduce the concentration of contaminants provides sufficient protection to meet the performance standards of WAC 173-350-040; and

     (C) Explosive gases generated by the facility will not exceed:

     (I) Twenty-five percent of the lower explosive limit for the gases in facility structures (excluding the gas control or recovery system components);

     (II) The lower explosive limit in soil gases or in ambient air for the gases at the property boundary or beyond; and

     (III) One hundred parts per million by volume of hydrocarbons (expressed as methane) in off-site structures.

     (iii) Liner separation from ground water. No landfill liner system shall be constructed such that the bottom of the lowest component is less than ten feet (three meters) above the seasonal high level of ground water, unless a hydraulic gradient control system has been installed which prevents ground water from contacting the liner. For the purpose of this section, ground water includes any water-bearing unit which is horizontally and vertically extensive, hydraulically recharged, and volumetrically significant as to harm or endanger the integrity of the liner at any time.

     (iv) Hydraulic gradient control system performance standard. When a hydraulic gradient control system is to be incorporated into a landfill design, a demonstration shall be made during the permit process that the hydraulic gradient control system can be installed to control ground water fluctuations and maintain separation between the controlled seasonal high level of ground water in the identified water-bearing unit and the bottom of the lowest liner system component. The hydraulic gradient control system shall not have negative impacts on waters of the state or impede the capability to collect samples representative of the quality of ground water at the relevant point of compliance. The demonstration shall include:

     (A) A discussion in the geologic and hydrogeologic site characterization showing the effects from subsoil settlement, changes in surrounding land uses, climatic trends or other impacts affecting ground water levels during the active life, closure and post-closure periods of the landfill;

     (B) A discussion showing potential impacts of the gradient control operation to existing quality and quantity of ground water or surface waters. This discussion shall include potential impacts to water users and instream flow and levels of surface waters in direct hydrologic contact or continuity with the hydraulic gradient control system. Any currently available ground or surface water quality data for hydrostratigraphic units, springs, or surface waters in direct hydrologic contact or continuity with the hydraulic gradient control system shall be included;

     (C) Conceptual engineering drawings of the proposed landfill and a discussion as to how the hydraulic gradient control system will protect or impact the structural integrity and performance of the liner system;

     (D) Preliminary engineering drawings of the hydraulic gradient control system;

     (E) Design specifications for the proposed ground and surface water monitoring systems; and

     (F) A discussion of the potential impacts from the gradient control system on the capability of collecting ground water samples that will represent the quality of ground water passing the relevant point of compliance.

     (v) Presumptive liner design. Limited purpose landfills designed and constructed with the following composite liner are presumed to meet the performance standard of (b)(i) of this subsection. An alternative liner system design shall be used when the nature of the waste, the disposal facility, or other factors are incompatible with the presumptive liner. The presumptive liner design consists of the following two components:

     (A) A lower component consisting of at least a two-foot layer of compacted soil with a hydraulic conductivity of no more than 1 x 10^-7 cm/sec.

     (B) An upper component consisting of a high-density polyethylene (HDPE) geomembrane with a minimum of 60-mil thickness. The geomembrane shall be installed in direct and uniform contact with the lower component.

     (c) Leachate collection and control system design. Except as provided in (b)(ii) of this section, limited purpose landfills shall be constructed in accordance with a design that:

     (i) Provides for collection and removal of leachate generated in the landfill;

     (ii) Is capable of maintaining less than a one-foot head of leachate over the liner system and less than a two-foot head in leachate sump areas;

     (iii) Includes a monitoring system capable of collecting representative samples of leachate generated in the landfill; and

     (iv) Provides for leachate storage, treatment, or pretreatment to meet the requirements for permitted discharge under chapter 90.48 RCW, Water pollution control, and the Federal Clean Water Act.

     (d) Run-on/runoff control system design. Limited purpose landfills shall be constructed in accordance with a design that:

     (i) Will prevent flow onto the active portion of the landfill during the peak discharge from a twenty-five-year storm, as defined in WAC 173-350-100;

     (ii) Will prevent unpermitted discharges from the active portion of the landfill resulting from a twenty-five-year storm, as defined in WAC 173-350-100; and

     (iii) When located in a one hundred-year flood plain, the entrance and exit roads, and landfill practices do not restrict the flow of the base flood, reduce the temporary water storage capacity of the flood plain or result in washout of solid waste, to pose a hazard to human life, wildlife, land or water resources.

     (e) Final closure system design.

     (i) Final closure performance standard. Limited purpose landfills shall be closed in accordance with a design that:

     (A) Prevents exposure of waste;

     (B) Minimizes infiltration (at a minimum, the design will prevent the generation of significant quantities of leachate to eliminate the need for leachate removal by the end of the post-closure period);

     (C) Prevents erosion from wind and water;

     (D) Is capable of sustaining native vegetation;

     (E) Addresses anticipated settlement, with a goal of achieving no less than two to five percent slope after settlement;

     (F) Provides sufficient stability and mechanical strength and addresses potential freeze-thaw and desiccation;

     (G) Provides for the management of run-on and runoff, preventing erosion or otherwise damaging the closure cover;

     (H) Minimizes the need for post-closure maintenance;

     (I) Provides for collection and removal of methane and other gases generated in the landfill. Landfill gas shall be purified for sale, used for its energy value, or flared when the quantity and quality of landfill gases will support combustion. Landfill gases may be vented when they will not support combustion. The collection and removal system shall include a monitoring system capable of collecting representative samples of gases generated in the landfill; and

     (J) Meets the requirements of regulations, permits and policies administered by the jurisdictional air pollution control authority or the department under chapter 70.94 RCW, Washington Clean Air Act and Section 110 of the Federal Clean Air Act.

     (ii) Presumptive final closure cover. Limited purpose landfills designed and constructed with the following closure cover are presumed to meet the performance standards in (e)(i)(A) through (D) of this subsection. An alternative final closure cover shall be used when the nature of the waste, the disposal facility or other factors are incompatible with the presumptive final closure cover system. The presumptive final closure cover consists of the following components:

     (A) An antierosion layer consisting of a minimum of two feet (60 cm) of earthen material of which at least twelve inches (30 cm) of the uppermost layer is capable of sustaining native vegetation, seeded with grass or other shallow rooted vegetation; and

     (B) A geomembrane with a minimum of 30-mil (.76 mm) thickness, or a greater thickness that is commensurate with the ability to join the geomembrane material and site characteristics such as slope, overlaying a competent foundation.

     (f) Water balance and ground water contaminant fate and transport modeling. Any modeling performed for evaluating a landfill design shall meet the following performance standards:

     (i) All water balance analysis shall be performed using:

     (A) The Hydrologic Evaluation of Landfill Performance (HELP) Model; or

     (B) Alternate methods approved by the jurisdictional health department. Alternate methods shall have supporting documentation establishing its ability to accurately represent the water balance within the landfill unit.

     (ii) Any ground water and contaminant fate and transport modeling shall be conducted by a licensed professional in accordance with the requirements of chapter 18.220 RCW and meet the following performance standards:

     (A) The model shall have supporting documentation that establishes the ability of those methods to represent ground water flow and contaminant transport under the conditions at the site;

     (B) The model shall be calibrated against site-specific field data;

     (C) A sensitivity analysis shall be conducted to measure the model's response to changes in the values assigned to major parameters, specific tolerances, and numerically assigned space and time discretizations;

     (D) The value of the model's parameters requiring site-specific data shall be based upon actual field or laboratory measurements; and

     (E) The values of the model's parameters that do not require site-specific data shall be supported by laboratory test results or equivalent methods documenting the validity of the chosen parameter values.

     (g) Seismic impact zones. Limited purpose landfills located in seismic impact zones shall be designed and constructed so that all containment structures, including liners, leachate collection systems, surface water control systems, gas management, and closure cover systems are able to resist the maximum horizontal acceleration in lithified earth materials for the site.

     (h) The owner or operator of limited purpose landfills located in an unstable area shall demonstrate that engineering measures have been incorporated into the landfill's design to ensure that the integrity of the structural components of the landfill will not be disrupted. The owner or operator shall place the demonstration in the application for a permit. The owner or operator shall consider the following factors, at a minimum, when determining whether an area is unstable:

     (i) On-site or local soil conditions that may result in significant differential settling;

     (ii) On-site or local geologic or geomorphologic features; and

     (iii) On-site or local human-made features or events (both surface and subsurface).

     (i) Limited purpose landfills shall be designed to provide a setback of at least one hundred feet between the active area and the property boundary. The setback shall be increased if necessary to:

     (i) Control nuisance odors, dust, and litter;

     (ii) Provide a space for the placement of monitoring wells, gas probes, run-on/runoff controls, and other design elements; or

     (iii) Provide sufficient area to allow proper operation of the landfill and access to environmental monitoring systems and facility structures.

     (4) Limited purpose landfills - Operating standards. The owner or operator of a limited purpose landfill shall:

     (a) Operate the facility to:

     (i) Control public access and prevent unauthorized vehicular traffic, illegal dumping of wastes, and keep animals out by using artificial barriers, natural barriers, or both, as appropriate to protect human health and the environment. A lockable gate shall be required at each entry to the landfill;

     (ii) Provide approach and exit roads of all-weather construction, with traffic separation and traffic control on-site, and at the site entrance;

     (iii) Ensure that no liquid waste or liquids are placed in disposal facilities;

     (iv) Provide on-site fire protection as determined by the local and state fire control jurisdiction. Landfills disposing of wastes that can support combustion shall have a method to control subsurface fires;

     (v) Ensure that at least two landfill personnel are on-site with one person at the active face when the site is open to the public for disposal facilities with a permitted capacity of greater than fifty thousand cubic yards per year;

     (vi) Provide communication between employees working at the landfill and management offices, on-site and off-site, sufficient to handle emergencies;

     (vii) Control fugitive dust;

     (viii) Perform no open burning unless permitted by the jurisdictional air pollution control agency or the department under chapter 70.94 RCW, Washington Clean Air Act;

     (ix) Collect scattered litter as necessary to prevent vector harborage, a fire hazard, aesthetic impacts, or adversely affect wildlife or its habitat;

     (x) Prohibit scavenging;

     (xi) Ensure that reserve operational equipment shall be available to maintain and meet these standards; and

     (xii) Ensure that operations do not endanger any containment or monitoring structures such as liners, leachate collection systems, surface water control systems, gas management, cover systems and monitoring wells.

     (b) Operate the facility in compliance with the following operating standards unless a demonstration can be made during the permitting process that due to the nature, source of the waste, or quality of the leachate generated, these standards are not necessary for the protection of human health or the environment:

     (i) Implement a program at the facility for detecting and preventing the disposal of dangerous waste fully regulated under chapter 173-303 WAC, municipal solid waste and other prohibited wastes. This program shall include, at a minimum:

     (A) Random inspections of incoming loads unless the owner or operator takes other steps (for example, instituting source controls restricting the type of waste received) to ensure that incoming loads do not contain prohibited wastes. Random inspections shall include:

     (I) Discharging a random waste load onto a suitable surface, or portion of the tipping area. A suitable surface shall be chosen to avoid interference with operations, so that sorted waste can be distinguished from other loads of uninspected waste, to avoid litter, and to contain runoff;

     (II) The contents of the load shall be visually inspected prior to actual disposal of the waste. The facility owner or operator shall return prohibited waste to the hauler, arrange for disposal of prohibited wastes at a facility permitted to manage those wastes, or take other measures to prevent disposal of the prohibited waste at the facility;

     (B) Maintaining records of inspections, or the results of other procedures if appropriate;

     (C) Training facility personnel to recognize regulated dangerous waste, prohibited polychlorinated biphenyls (PCB) wastes and other prohibited wastes; and

     (D) Immediate notification of the department and the jurisdictional health department if a regulated dangerous waste or prohibited PCB waste is discovered at the facility.

     (ii) Thoroughly compact the solid waste before succeeding layers are added except for the first lift over a liner.

     (iii) Cover disposed waste to control disease vectors, fires, nuisance odors, blowing litter, and scavenging. Putrescible waste shall be covered at the end of each operating day, or at more frequent intervals if necessary. The jurisdictional health department may grant a temporary waiver, not to exceed three months, from the requirement of this subsection if the owner or operator demonstrates that there are extreme seasonal climatic conditions that make meeting such requirements impractical. Materials used for cover shall be:

     (A) At least six inches (15 cm) of earthen material, such as soils; or

     (B) Alternative materials or an alternative thickness other than at least six inches (15 cm) of earthen material as approved by the jurisdictional health department when the owner or operator demonstrates that the alternative material or thickness will control vectors, fires, nuisance odors, blowing litter, scavenging, provide adequate access for heavy vehicles, and will not adversely affect gas or leachate composition and controls.

     (iv) Prevent or control on-site populations of disease vectors using techniques appropriate for the protection of human health and the environment; and

     (v) Implement a program at the facility to control and monitor explosive gases and to respond to the detection of explosive gases in a manner that ensures protection of human health. This program shall include, at a minimum:

     (A) Ensure that explosive gases generated by the facility do not exceed:

     (I) Twenty-five percent of the lower explosive limit for the gases in facility structures (excluding the gas control or recovery system components);

     (II) The lower explosive limit in soil gases or in ambient air for the gases at the property boundary or beyond; and

     (III) One hundred parts per million by volume of hydrocarbons (expressed as methane) in off-site structures;

     (B) A routine explosive gas-monitoring program to ensure that all standards are met. The minimum frequency for monitoring is quarterly. The type and frequency of monitoring shall be determined based on the following factors:

     (I) Soil conditions;

     (II) The hydrogeologic conditions surrounding the facility;

     (III) The hydraulic conditions surrounding the facility; and

     (IV) The location of facility structures and property boundaries;

     (C) If explosive gas levels exceed those of this subsection take all necessary steps to ensure protection of human health including:

     (I) Notifying the jurisdictional health department;

     (II) Monitoring off-site structures;

     (III) Monitoring explosive gas levels daily, unless otherwise authorized by the jurisdictional health department;

     (IV) Evacuation of buildings affected by landfill gas until determined to be safe for occupancy;

     (V) Within seven calendar days of the explosive gas levels detection, placing in the operating record the explosive gas levels detected and a description of the steps taken to protect human health and provide written notification to the jurisdictional health department; and

     (VI) Within sixty days of the explosive gas levels detection, implementing a remediation plan for the explosive gas releases, describing the nature and extent of the problem and the remedy. This shall be sent to the jurisdictional health department for approval as an amendment to the plan of operation. A copy of the remediation plan shall be placed in the operating record;

     (D) Construction and decommissioning of all gas monitoring and extraction wells in a manner that protects ground water and meets the requirements of chapter 173-160 WAC, Minimum standards for construction and maintenance of wells;

     (c) Inspect and maintain the facility to prevent malfunctions and deterioration, operator errors, and discharges that may cause or lead to the release of wastes to the environment or cause a threat to human health. The inspections shall be at least weekly, unless an alternate schedule is approved by the jurisdictional health department as part of the permitting process. The owner or operator shall keep an inspection report or summary including at least the date and time of inspection, the printed name and the signature of the inspector, a notation of observations made, and the date and nature of any repairs or corrective actions;

     (d) Maintain daily operating records on the weights (or volumes), number of vehicles entering and the types of wastes received. Facility inspection reports shall be maintained in the operating record. Significant deviations from the plan of operation shall be noted on the operating record. Records shall be maintained for a minimum of five years and shall be available upon request by the jurisdictional health department;

     (e) Prepare and submit a copy of an annual report to the jurisdictional health department and the department by April 1st of each year. The annual report shall cover landfill activities during the previous calendar year and shall include the following information:

     (i) Name and address of the facility;

     (ii) Calendar year covered by the report;

     (iii) Annual quantity and type of waste accepted in tons or cubic yards with an estimate of density in pounds per cubic yard;

     (iv) Results of ground water monitoring in accordance with WAC 173-350-500;

     (v) Applicable financial assurance reviews and audit findings in accordance with WAC 173-350-600; and

     (vi) Any additional information required by the jurisdictional health department as a condition of the permit;

     (f) Develop, keep, and abide by a plan of operation approved as part of the permitting process. The plan shall describe the operation of the facility and shall convey to site operating personnel the concept of operation intended by the designer. The plan of operation shall be available for inspection at the request of the jurisdictional health department. If necessary, the plan shall be modified with the approval, or at the direction of the jurisdictional health department. Each plan of operation shall contain:

     (i) A description of the types of solid waste to be handled at the facility;

     (ii) A description of how solid wastes are to be handled on-site during its active life including:

     (A) The acceptance criteria that will be applied to the waste;

     (B) Procedures for ensuring only the waste described will be accepted;

     (C) Procedures for handling unacceptable wastes; and

     (D) Unloading and staging areas, transportation, routine filling, compaction, grading, cover or other vector controls, and housekeeping;

     (iii) A description of how equipment, structures and other systems, including leachate collection, gas collection, run-on/runoff controls, and hydraulic gradient control systems, are to be inspected and maintained, including the frequency of inspection and inspection logs;

     (iv) Safety and emergency plans including;

     (A) Procedures for fire (including subsurface fires) prevention, a description of fire protection equipment available on-site and actions to take if there is a fire or explosion;

     (B) Actions to take if leaks are detected or for other releases, such as failure of runoff containment system, if such systems are required;

     (v) The forms for recording weights and volumes; and

     (vi) Other such details to demonstrate that the landfill will be operated in accordance with this subsection and as required by the jurisdictional health department.

     (5) Limited purpose landfills - Ground water monitoring requirements. Limited purpose landfills are subject to the ground water monitoring requirements of WAC 173-350-500.

     (6) Limited purpose landfills - Closure requirements. The following closure requirements apply in full to facilities with limited purpose landfills:

     (a) The owner or operator shall notify the jurisdictional health department, and where applicable, the financial assurance instrument provider, one hundred eighty days in advance of closure of the facility, or any portion thereof. The facility, or any portion thereof, shall close in a manner that:

     (i) Minimizes the need for further maintenance;

     (ii) Controls, minimizes, or eliminates threats to human health and the environment from post-closure escape of solid waste constituents, leachate, landfill gases, contaminated runoff, or waste decomposition products to the ground, ground water, surface water, and the atmosphere; and

     (iii) Prepares the facility, or any portion thereof, for the post-closure period.

     (b) The owner or operator shall commence implementation of the closure plan in part or whole within thirty days after receipt of the final volume of waste and/or attaining the final landfill elevation at part of or at the entire landfill as identified in the approved facility closure plan unless otherwise specified in the closure plan.

     (c) The owner or operator shall not accept waste, including inert wastes, for disposal or for use in closure except as identified in the closure plan approved by the jurisdictional health department.

     (d) The owner or operator shall develop, keep, and abide by a closure plan approved by the jurisdictional health department as part of the permitting process. At a minimum, the closure plan shall include the following information:

     (i) A description of the final closure cover, designed in accordance with subsection (3)(e) of this section, the methods and procedures to be used to install the closure cover, sources of borrow materials for the closure cover, and a schedule or description of the time required for completing closure activities;

     (ii) Projected time intervals at which sequential partial closure and final closure are to be implemented;

     (iii) A description of the activities and procedures that will be used to ensure compliance with (a) through (g) of this subsection; and

     (iv) Identify closure cost estimates and projected fund withdrawal intervals for the associated closure costs, from the approved financial assurance instrument.

     (e) The owner or operator shall submit final engineering closure plans, in accordance with the approved closure plan and all approved amendments, for review, comment, and approval by the jurisdictional health department.

     (f) When landfill closure is completed in part or whole, the owner or operator shall submit the following to the jurisdictional health department:

     (i) Landfill closure plan sheets signed by a professional engineer registered in the state of Washington and modified as necessary to represent as-built changes to final closure construction for the landfill, or a portion thereof, as approved in the closure plan; and

     (ii) Certification by the owner or operator, and a professional engineer registered in the state of Washington, that the landfill, or a portion thereof has been closed in accordance with the approved closure plan.

     (g) The owner or operator shall record maps and a statement of fact concerning the location of the disposal facility as part of the deed with the county auditor not later than three months after closure.

     (h) The jurisdictional health department shall notify the owner or operator, the department, and the financial assurance instrument provider, of the date when the jurisdictional health department has verified that the facility, or a portion thereof, has been closed in accordance with the specifications of the approved closure plan and the closure requirements of this section, at which time the post-closure period shall commence.

     (7) Limited purpose landfills - Post-closure requirements. The following post-closure requirements apply in full to facilities with limited purpose landfills:

     (a) The owner or operator shall provide post-closure activities to allow for continued facility maintenance and monitoring of air, land, and water for a period of twenty years, or as long as necessary for the landfill to stabilize and to protect human health and the environment. For disposal facilities, post-closure care includes at least the following:

     (i) Maintaining the integrity and effectiveness of any final closure cover, including making repairs to the closure cover as necessary to correct the effects of settlement, subsidence, erosion, or other events, maintaining the vegetative cover, and preventing run-on and runoff from eroding or otherwise damaging the final closure cover;

     (ii) General maintenance of the facility and facility structures for their intended use;

     (iii) Monitoring ground water, surface water, leachate, or other waters in accordance with the requirements of WAC 173-350-500 and the approved monitoring plan, including remedial measures if applicable, and maintaining all monitoring systems;

     (iv) Monitoring landfill gas and maintaining and operating the gas collection and control systems;

     (v) Maintaining, operating, and monitoring hydraulic gradient controls systems if applicable;

     (vi) Monitoring settlement; and

     (vii) Any other activities deemed appropriate by the jurisdictional health department.

     (b) The owner or operator shall commence post-closure activities for the facility, or portion thereof, after completion of closure activities outlined in subsection (6) of this section. The jurisdictional health department may direct that post-closure activities cease until the owner or operator receives a notice to proceed with post-closure activities.

     (c) The owner or operator shall develop, keep, and abide by a post-closure plan approved by the jurisdictional health department as a part of the permitting process. The post-closure plan shall:

     (i) Address facility maintenance and monitoring activities for at least a twenty-year period or until the landfill becomes stabilized (i.e., little or no settlement, gas production or leachate generation), and monitoring of ground water, surface water, gases and settlement can be safely discontinued; and

     (ii) Project time intervals at which post-closure activities are to be implemented, and identify post-closure cost estimates and projected fund withdrawal intervals from the selected financial assurance instrument, where applicable, for the associated post-closure costs.

     (d) The owner or operator shall complete post-closure activities for the facility, or portion thereof, in accordance with the approved post-closure plan and schedule, or the plan shall be so amended with the approval of the jurisdictional health department. The jurisdictional health department may direct facility post-closure activities, in part or completely, to cease until the post-closure plan has been amended and has received written approval by the health department.

     (e) When post-closure activities are complete, the owner or operator shall submit a certification to the jurisdictional health department, signed by the owner or operator, and a professional engineer registered in the state of Washington stating why post-closure activities are no longer necessary.

     (f) If the jurisdictional health department finds that post-closure monitoring has established that the landfill is stabilized, the health department may authorize the owner or operator to discontinue post-closure maintenance and monitoring activities.

     (g) The jurisdictional health department shall notify the owner or operator, the department, and the financial assurance instrument provider, of the date when the jurisdictional health department has verified that the facility has completed post-closure activities in accordance with the specifications of the approved post-closure plan.

     (8) Limited purpose landfills - Financial assurance requirements.

     (a) Financial assurance is required for all limited purpose landfills.

     (b) Each owner or operator shall establish a financial assurance mechanism in accordance with WAC 173-350-600 that will accumulate funds equal to the closure and post-closure cost estimates over the life of the landfill, or over the life of each landfill unit if closed discretely.

     (c) No owner or operator shall commence or continue disposal operations in any part of a facility subject to this section until a financial assurance instrument has been provided for closure and post-closure activities in conformance with WAC 173-350-600.

     (9) Limited purpose landfills - Permit application contents. The owner or operator shall obtain a solid waste permit from the jurisdictional health department. All applications for permits shall be in accordance with the procedures established in WAC 173-350-710. In addition to the requirements of WAC 173-350-710 and 173-350-715, each application for a permit shall contain:

     (a) Demonstrations that the facility meets the location standards of subsection (2) of this section;

     (b) Documentation that all owners of property located within one thousand feet of the facility property boundary have been notified that the proposed facility may impact their ability to construct water supply wells, in accordance with chapter 173-160 WAC, Minimum standards for construction and maintenance of wells;

     (c) Engineering reports/plans and specifications that address the design standards of subsection (3) of this section;

     (d) A plan of operation meeting the requirements of subsection (4) of this section;

     (e) Hydrogeologic reports and plans that address the requirements of subsection (5) of this section;

     (f) A closure plan meeting the requirements of subsection (6) of this section;

     (g) A post-closure plan meeting the requirements of subsection (7) of this section; and

     (h) Documentation as needed to meet the financial assurance requirements of subsection (8) of this section.

     (10) Limited purpose landfills - Construction records. The owner or operator of a limited purpose landfill shall provide copies of the construction record drawings for engineered facilities at the site and a report documenting facility construction, including the results of observations and testing carried out as part of the construction quality assurance plan, to the jurisdictional health department and the department. Facilities shall not commence operation until the jurisdictional health department has determined that the construction was completed in accordance with the approved engineering report/plans and specifications and has approved the construction documentation in writing.



[Statutory Authority: Chapter 70.95 RCW. 03-03-043 (Order 99-24), § 173-350-400, filed 1/10/03, effective 2/10/03.]