Beginning in 1979 the New Mexico Landfill accepted municipal waste from neighboring communities and businesses for 21 years. During that time landfill operators buried as much as 1.5 million cubic yards of refuse along the bottom of a local ephemeral drainage basin. Refuse was deposited in a series of trenches excavated from the center of the basin and mounded up to 15 feet over the preexisting grade. In anticipation of cessation of operations the New Mexico Landfill began closure activities in compliance with New Mexico Environment Department regulations. Between 1995 and 2000 a clay liner was constructed over the top of the landfill to prevent surface water infiltration and a number of piezometers and monitoring wells were installed to sample groundwater. Analyses of water samples from monitoring wells hydraulically up gradient and down gradient of the landfill showed downgradient groundwater is being impacted by the landfill. Comparison of the analyses from upgradient and downgradient monitoring wells during an October 2004 sampling event showed the following maximum contaminant concentration increases in downgradient monitoring wells: aluminum 460%, barium 400%, iron 400%, lead 320%, manganese 2,300%, chloride 2,400%, sulfate 1,700%, total dissolved solids 570%, and total phenols were not detectable in the upgradient monitoring well and were in excess of the New Mexico Environment Department drinking water standards in a downgradient monitoring well. This document characterizes groundwater contamination associated with the New Mexico Landfill and presents corrective actions to minimize further leachate generation. Corrective actions proposed for the New Mexico Landfill consist of groundwater and surface water diversion from the refuse material, landfill cap improvement, and leachate collection and treatment. Water inflow to the landfill will be diverted from the refuse with a combination of trenching to sever Groundwater flow paths and cap improvements to reduce infiltration. Leachate will be collected and treated with a filtration system and discharged into a constructed wetland. Contaminant concentrations in water discharged from the treatment system will be equal to or below levels established in the upgradient monitoring well. The total cost of the Corrective Action Plan is estimated to be 1.7 million dollars.
Landfill remediation, Monitoring Wells, Leachate collection, Contamination plume, Constructed wetlands, Impermeable cap
Lane, Matthew. "Corrective Action Plan for the New Mexico Landfill." (2009). http://digitalrepository.unm.edu/wr_sp/119