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0 ® C 11 <br /> North County Sanitary Landfill -2– <br /> Module <br /> 2– <br /> Module 4-Liner Performance Demonstration <br /> San Joaquin County <br /> defines: "Containment" = means the use of waste management unit characteristics or installed <br /> systems and structures to prevent or restrict the release of waste constituents, including waste <br /> constituents mobilized as a component of leachate or of landfill gas. "Containment feature" <br /> (SWRCB) means any feature, whether natural or artificial, used to contain waste constituents, <br /> including waste constituents mobilized as a component of leachate or of landfill gas. <br /> "Containment structure" (SWRCB) means an artificial feature designed and installed to <br /> contain waste constituents, including waste constituents mobilized as a component of leachate or <br /> of landfall gas. " <br /> The Constituent Of Concern list required by Section 20395 (a) and(b) include all waste <br /> constituents, reaction products, and hazardous constituents that are reasonably expected to be in <br /> or derived from waste contained in the Unit. Included on this list are the volatile organic <br /> compounds, which are commonly found in the unsaturated zone and groundwater at landfills <br /> (i.e., Foothill Landfill and Corral Hollow Landfill). Therefore, it is not unreasonable to require <br /> preventive measures, such as monitoring for gases in the unsaturated zone, below a landfill as the <br /> first point of leakage from a liner(containment structure). <br /> Title 27 also requires in Section 20330(a) Liners -Performance Standard—Liners shall be <br /> designed and constructed to contain the fluid, including landfall gas, waste, and leachate..." It is <br /> not unreasonable to require monitoring of the fluids that may leak through a liner- in order to <br /> protect waters of the State. <br /> The County's letter of 25 September 2002 implies that Board staff required a certain thickness of cover <br /> defined as two feet on side slopes and four feet on top slopes. We actually requested additional <br /> thickness of intermediate (interim) cover, greater than the required 12 inches. With regards to North <br /> County, this did not appear to be an unreasonable request since County staff stated there was an <br /> abundance of soil on the site. It was also mentioned that the County was considering an alternative <br /> mono-soil final cover. In this regard,we have built into the draft WDRS a task and compliance date for <br /> submitting a workplan for the design and construction of the intermediate (interim) cover. <br /> Title 27, Section 20080(a)(1) "are minimum standards for proper management of each waste category. <br /> Regional boards may impose more stringent requirements to accommodate regional and site specific <br /> conditions. " This section of Title 27 pertains to discharges of solid waste to land. The rationale for <br /> requiring more stringent requirements for the North County and Foothill Landfills pertain to the <br /> extended life of the uncontained waste and operational history of the facilities. <br /> The estimated life for Foothill Landfill is approximately 56 years, or the year 2050. This landfill is in an <br /> Evaluation Monitoring Program for VOCs in groundwater pursuant to Title 27, 20385(a)(2). The <br /> estimated life for North County is approximately 32 years, or closure in the year 2034. That means that <br /> waste discharged to these two landfills will not be contained for more than 30 years allowing <br /> infiltration/percolation of rainfall into the waste. In order to prevent degradation of waters of the state, <br /> we believe it is reasonable to ensure that the interim cover be constructed to minimize percolation of <br /> liquids through wastes as specified in Title 27, 20705(b). Furthermore, inspections of the North County <br /> Landfill by the County Environmental Health Department show chronic Areas of Concern with regards <br />