Summary of the Subtitle D Landfill Requirements. The solid waste regulations part of RCRA ban the open dumping of all solid waste; regulations require landfills for household waste (i.e., MSW landfills) comply with detailed minimum protective measures, such as use of liners and leachate collection systems. Landfilling of other types of wastes (e.g., C&D debris) are also governed by US regulations, which require certain basic environmental protection measures (e.g., location restrictions, control of disease vectors), including groundwater monitoring if hazardous wastes are accepted as part of the waste stream. For the complete requirements, please see 40 CFR 258, and/or applicable state regulations. Subtitle D Part 258 regulations (40 CFR 258) relevant to MSW landfills in the US Pacific island territories include location restrictions, operating criteria, design criteria, groundwater monitoring and corrective actions, closure and post-closure care, and financial assurance criteria for MSW landfills. Table 5-2 summarizes the key requirements of the regulations. Some of the practices outlined in the Subtitle D rules are fundamental elements of sanitary landfill practice (e.g., covering the waste), but key features that distinguish a Subtitle D landfill from a sanitary landfill are the requirements of an engineered liner system and a leachate collection and removal system (LCRS). The criteria of Subtitle D Part 258 are the minimum national US standards determined to provide protection of public health and the environment. In one community, due to concerns of the local regulatory agency and local residents, a landfill was constructed with an engineered liner that includes redundant protection from potential release of leachate. A Subtitle D landfill liner consists of 2 feet of compacted soil with a maximum hydraulic conductivity of 10-7 cm/sec overlain by a geomembrane liner (typically a 60-mil HDPE geomembrane). The liner creates a barrier to intercept leachate produced in the landfill. The LCRS consists of a network of drains placed over the sloped bottom liner so that the depth of leachate resting on top of the liner does not exceed 30 cm. Leachate is removed from the landfill by placing pumps at low spots in the LCRS, and the pumped leachate is then treated before being discharged to the environment. Groundwater surrounding the landfill unit must be monitored, and off- site migration of gas must be controlled. Suspension of groundwater monitoring requirements via approval of a submitted non-migration peti...
