Landfill Assessment And Closure

The first step in preparing for the redevelopment of a landfill is to assess properly its impact on groundwater, surface water and air quality. This is done by a process similar to that required in the MCP for contaminated sites, however, it does not necessarily require a Licensed Site Professional. The environmental consultant overseeing the assessment must characterize adequately the nature and extent of the contamination in the landfill and assess the risks associated with it to the public health and the environment. Overall, the landfill assessment process involves examining the site history, characterizing the waste beneath the ground surface, determining potential pathways of contaminant migration, identifying all potential sensitive receptors and examining surface water and air quality. The DEP has adopted a three-pronged approach for conducting environmental assessments of landfills. Each phase of the assessment builds on the data collected from the previous phase.

The first phase, called the Initial Site Assessment ("ISA"), consists of conducting an historical and literature review (often found in a variety of municipal departments), preparing a hydrogeological description, conducting a site visit, preparing a regional map, evaluating any existing data, identifying potential sensitive receptors and developing a Scope of Work for the next phase, the Comprehensive Site Assessment ("CSA").

The CSA is a more extensive analysis of the extent of the environmental impact caused by the landfill. The CSA consists of summarizing the ISA, mapping (including any updates or adding site topography), developing a drilling program, determining hydraulic conductivity, developing a sampling and analysis plan and a health and safety plan, identifying a project schedule, and preparing a CSA report.

The third phase in the process is the Corrective Action Alternative Analysis ("CAAA"), which evaluates all the actions necessary to remediate any adverse impacts of the landfill to the environment. The CAAA must include an analysis of options for corrective actions to eliminate or reduce any potential adverse impacts that might be caused by landfill conditions, and a complete final closure plan. The ultimate goal of the CAAA is to establish a permanent solution for the landfill closure and its post-closure redevelopment. Once the preferred option is selected, the next step is to design and implement the corrective action.

The final closure plan report, which requires DEP approval, must address final cover design (such as grading, gas venting, permeability, drainage, filtering, vegetative support and vegetative cover), a leachate collection system, final landfill contours, landscaping, construction plans for on-site structures, if applicable, storm water control, methane gas venting or gas collection and recovery systems, groundwater, surface water and gas monitoring system, and site security.

Since landfills typically settle from approximately 10%-30% of their original thickness, and landfill leachate and methane gas will continue to be generated by a closed landfill for several years, the post-closure regulatory requirements include monitoring and maintaining the landfill for a period of at least 30 years. This period can be shortened by a demonstration that the landfill will not present a threat to the public health safety or the environment.

http://library.findlaw.com/2000/Jun/1/128665.html