Richland Horn Rapids Landfill

The Horn Rapids Landfill is owned and operated by the City of Richland Public Works Department. The landfill began receiving waste in 1974. Groundwater contamination was identified in some landfill monitoring wells in the late 1990s. Contaminants found include several volatile organic compounds (VOCs). VOCs are found at other landfills with groundwater contamination caused by landfill gas or migrating leachate.

From 2000-2005, the City conducted a Remedial Investigation/Feasibility Study to investigate groundwater contamination by installing and sampling additional groundwater wells and investigating landfill gas movement. Landfill gas was identified as the source of groundwater contamination. The City constructed a landfill gas control system in conjunction with closure of part of the landfill, and continues to sample groundwater. Groundwater monitoring in 2017 continues to show that VOCs are present in downgradient wells on City property at levels exceeding state groundwater quality criteria. No drinking water wells are impacted.

The contamination present in the groundwater at the Site includes VOCs. VOCs include many chemicals that are harmful to human health and the environment. Ecology wants to address risks to human health and the environment.