Each facility shall be designed and constructed in compliance with the standards listed in this section.
(a) Surveyed corners : All site boundary corners at facilities greater than or equal to one (1) acre in size, shall be surveyed and marked with permanent survey caps.
(b) Access restrictions : - (i) The working area of all facilities shall be fenced in such a manner as to prevent people and livestock from entering the facility and to contain litter within the facility.
- (A) Additional fencing may be required to restrict access to reclaimed areas or other areas that may present public health and safety hazards.
- (B) If the landfill is within an industrial property which has a perimeter fence and the public and animals do not have access to the landfill site, the requirement for a fence around the landfill may be waived. However, the administrator may require suitable litter screens or fences.
- (ii) If the public has access to the landfill site, any access road that is used by the public shall be equipped with a gate which can be locked when the facility is unattended.
(c) Posting : Each point of access shall be identified by a sign, which shall be easily readable and shall be maintained in good condition, and which contains at a minimum the following information: - (i) For facilities not used by the public:
- (A) Identification of the site as a solid waste landfill;
- (B) Wastes that are accepted for disposal at the facility.
- (ii) For public facilities:
- (B) The name and phone number of the responsible person to contact in the event of emergencies;
- (C) The hours of operation;
- (D) Wastes that are accepted for disposal at the facility;
- (E) A requirement to notify the landfill operator of any asbestos wastes.
(d) Reserved .
(e) Firelanes : All facilities shall have a fire lane which is a minimum of ten (10) feet wide around all active solid waste management units or within the perimeter fence.
(f) Buffer zones : All facilities shall have a buffer zone which is a minimum of twenty (20) feet within the facility perimeter fence.
(g) Topsoil : Topsoil from all disturbed areas shall be stripped and stockpiled in an area which will not be disturbed during facility operation. These stockpiles shall be identified by signs, and vegetated as required for stabilization. This topsoil will be used for site reclamation. Topsoil shall not be removed from the facility without written authorization from the administrator.
(h) Reserved .
(i) Surface water structures : Surface water structures shall be designed and constructed to control surface water run-on and runoff as follows: - (i) Temporary structures anticipated to be used for periods less than five (5) years shall accommodate a 25-year, 24-hour precipitation event;
- (ii) Permanent structures and temporary structures anticipated to be used for five (5) years or longer shall accommodate a 100-year, 24-hour precipitation event;
- (iii) Sediment control structures shall be designed and constructed in accordance with Chapter 11 of the Water Quality Rules and Regulations.
(j) Engineered containment system requirement : Engineered containment systems comprised of liners and caps, which may include lateral drainage layers, leachate collection systems and leak detection systems, are required at industrial landfills under any of the following conditions, as determined by the administrator: - (i) When native soils underlying the landfill are sufficiently permeable to allow potential contamination of groundwater through operation of the facility; or
- (ii) When waste types or operation practices create a reasonable potential for contamination of underlying soils and/or ground-water; or
- (iii) When site hydrologic conditions create a condition whereby groundwater is not sufficiently protected from contamination; or
- (iv) At any facility which receives greater than 500 tons of industrial solid waste per operating day, on a monthly average, unless the waste stream consists of only coal combustion by-products and up to twenty (20) tons of other industrial waste. Containment systems at these facilities shall include leachate collection and leak detection systems.
(k) Design/construction of engineered containment systems : Engineered containment systems shall be designed and constructed to meet these standards: - (i) Engineered barrier layers forming caps and/or liners constructed of clay shall have a maximum vertical hydraulic conductivity of 1 x l0E-7 cm/sec (0.1 ft/yr). These barrier layers shall have a minimum thickness of 24 inches. Clay barrier layers shall be constructed in lifts which do not exceed six (6) inches in thickness, and uniform compaction of these lifts shall be assured through the use of appropriate equipment. Clay barrier layers forming a cap shall be overlain by a layer of soil which is of suitable thickness to protect the clay barrier layer from frost penetration.
- (ii) All engineered containment system components shall be supported by material of sufficient bearing strength to prevent subsidence and failure of any component. This bearing strength shall be documented through materials testing as specified by the administrator.
- (iii) Synthetic membranes used as part of any containment system shall be of a material and thickness which is suitable for the intended use, but in no case shall be less than 0.030 inches thick (30 mils). All synthetic membranes shall be underlain by a suitable bedding material.
- (iv) Lateral drainage layers included in composite cap and liner system designs shall be composed of either granular material or a synthetic drain net of suitable lateral permeability to promote acceptable drainage, as approved by the administrator. Lateral drainage layers shall be protected from soil clogging by either a synthetic filter fabric or a graded granular layer of a design approved by the administrator.
- (v) Leachate collection systems installed as part of an engineered containment system shall be sized and designed to efficiently collect and transport leachate. Leak detection systems shall be designed to efficiently identify failure of the overlying barrier layer.
- (vi) The quality assurance/quality control (QA/QC) plan for engineered containment systems shall assure adequate construction and testing of the containment system components, as called for in the design specifications in the facility plan.
(l) Volumetric capacity limit for refuse cells with engineered containment systems : No refuse cell for which an engineered containment system is required shall have a volumetric capacity of greater than 300,000 cubic yards unless the operator can demonstrate that the liner leak detection system is capable of isolating the location of any leak which occurs in the primary liner. Cells with engineered containment systems dedicated strictly for the on-site disposal of coal ash generated at coal-fired power plants, which shall have a volumetric capacity limit of not more than 2,500,000 cubic yards.
(m) Slope stability for excavations : Trench walls shall not exceed a ratio of 1.5:1 (horizontal:vertical) unless a slope stability analysis demonstrates steeper slopes can be safely constructed and maintained. This analysis may be based on site specific soil stability calculations, or Wyoming Occupational Safety and Health Administration regulations for excavations.
(n) Litter control structures : Litter control structures shall be designed and constructed to control litter within the facility.
(o) Methane control systems for on-site structures : All structures on the landfill facility will be designed to prevent the accumulation of methane such that the concentration of methane gas in facility structures does not exceed 25 percent of the lower explosive limit (LEL) for methane.
(p) Special waste management standards : Any facility used for the management of a special waste regulated under Chapter 8, Special Waste Management Standards, shall also comply with the applicable design and construction standards established under Chapter 8.
(q) Transfer, treatment and storage facility standards : Any facility used for the transfer, treatment or storage of solid wastes shall also comply with the applicable design and construction standards established under Chapter 6.
(r) Design/construction standards for facilities less than or equal to one (1) acre in size : - (i) The working area of all facilities shall be fenced in such a manner as to prevent people and livestock from entering the facility and to contain litter within the facility.
- (ii) Each point of access shall be identified by a sign, which shall be easily readable and shall be maintained in good condition, and which contains at a minimum the following information:
- (A) For facilities not used by the public:
- (I) Identification of the site as a solid waste landfill;
- (II) Wastes that are accepted for disposal at the facility.
- (B) For public facilities:
- (II) The name and phone number of the responsible person to contact in the event of emergencies;
- (III) The hours of operation;
- (IV) Wastes that are accepted for disposal at the facility.
- (iii) All facilities shall have a fire lane which is a minimum of ten (10) feet wide around all solid waste management units or within the perimeter fence.
- (iv) Topsoil from all disturbed areas shall be stripped and stockpiled in an area which will not be disturbed during facility operation. These stockpiles shall be identified by signs, and vegetated as required for stabilization. This topsoil will be used for site reclamation. Topsoil shall not be removed from the facility without written authorization from the administrator.
- (v) Surface water structures shall be designed and constructed to control surface water run-on and run-off as follows:
- (A) Temporary structures anticipated to be used for periods less than five (5) years shall accommodate a 25-year, 24-hour precipitation event;
- (B) Permanent structures and temporary structures anticipated to be used for five (5) years or longer shall accommodate a 100-year, 24-hour precipitation event.
- (C) Sediment control structures shall be designed and constructed in accordance with Chapter 11 of the Water Quality Rules and Regulations.
- (vi) Engineered containment systems comprised of liners and caps, which may include lateral drainage layers, leachate collection systems and leak detection systems, are required at industrial landfills under any of the following conditions, as determined by the administrator:
- (A) When native soils underlying the landfill are sufficiently permeable to allow potential contamination of groundwater through operation of the facility; or
- (B) When waste types or operation practices create a reasonable potential for contamination of underlying soils and/or groundwater; or
- (C) When site hydrologic conditions create a condition whereby groundwater is not sufficiently protected from contamination; or
- (D) At any facility which receives greater than 500 tons of industrial solid waste per operating day, on a monthly average. Containment systems at these facilities shall include leachate collection and leak detection systems.
- (vii) Engineered containment systems shall be designed and constructed to meet these standards:
- (A) Engineered barrier layers forming caps and/or liners constructed of clay shall have a maximum vertical hydraulic conductivity of 1 x 10E-7 cm/sec (0.1 ft/yr). These barrier layers shall have a minimum thickness of 24 inches. Clay barrier layers shall be constructed in lifts which do not exceed six (6) inches in thickness, and uniform compaction of these lifts shall be assured through the use of appropriate equipment. Clay barrier layers forming a cap shall be overlain by a layer of soil which is of suitable thickness to protect the clay barrier layer from frost penetration.
- (B) All engineered containment system components shall be supported by material of sufficient bearing strength to prevent subsidence and failure of any component. This bearing strength shall be documented through materials testing as specified by the administrator.
- (C) Synthetic membranes used as part of any containment system shall be of a material and thickness which is suitable for the intended use, but in no case shall be less than 0.030 inches thick (30 mils). All synthetic membranes shall be underlain by a suitable bedding material.
- (D) Lateral drainage layers included in composite cap and liner system designs shall be composed of either granular material or a synthetic drain net of suitable lateral permeability to promote acceptable drainage, as approved by the administrator. Lateral drainage layers shall be protected from soil clogging by either a synthetic filter fabric or a graded granular layer of a design approved by the administrator.
- (E) Leachate collection systems installed as part of an engineered containment system shall be sized and designed to efficiently collect and transport leachate. Leak detection systems shall be designed to efficiently identify failure of the overlying barrier layer.
- (F) The quality assurance/quality control (QA/QC) plan for engineered containment systems shall assure adequate construction and testing of the containment system components, as called for in the design specifications in the facility plan.
- (viii) No refuse cell for which an engineered containment system is required shall have a volumetric capacity of greater than 300,000 cubic yards unless the operator can demonstrate that the liner leak detection system is capable of isolating the location of any leak which occurs in the primary liner.
- (ix) Trench wall slopes shall not exceed a ratio of 1.5:1 (horizontal:vertical) unless a slope stability analysis demonstrates steeper slopes can be safely constructed and maintained. This analysis may be based on site specific soil stability calculations, or Wyoming Occupational Safety and Health Administration regulations for excavations.
- (x) Litter control structures shall be designed and constructed to control litter within the facility.
- (xi) All structures on the landfill facility will be designed to prevent the accumulation of methane such that the concentration of methane gas in facility structures does not exceed 25 percent of the lower explosive limit (LEL) for methane.
- (xii) Any facility used for the management of a special waste regulated under Chapter 8, Special Waste Management Standards, shall also comply with the applicable design and construction standards established under Chapter 8.
- (xiii) Transfer, treatment and storage facility standards: Any facility used for the transfer, treatment or storage of solid wastes shall also comply with the applicable design and construction standards established under Chapter 6.