Waimanalo Gulch Landfill & Ash Monofill - Kapolei, Hawaii Solid Waste Management

Waimanalo Gulch Landfill & Ash Monofill is a major solid waste management facility located at 92-460 Farrington Highway in Kapolei, Hawaii. Operated by WM for the City and County of Honolulu, this landfill has been in operation since 1989 and is scheduled to close in 2039. It serves as the primary disposal site for the island of Oahu, handling both municipal solid waste and ash from the city's waste-to-energy facility. The facility operates under the regulatory framework of the US EPA, including RCRA Subtitle D for municipal solid waste landfills and Clean Air Act regulations for landfill gas management. As a large-scale landfill in a densely populated island setting, it incorporates modern environmental controls such as leachate collection systems and gas management infrastructure to mitigate impacts on the surrounding environment. Located near the coast in Kapolei, the landfill plays a critical role in Oahu's waste management infrastructure. Its proximity to residential areas and groundwater resources necessitates rigorous monitoring and compliance with state and federal regulations. The facility's ash monofill component is specifically designed for the safe disposal of combustion residues from the city's waste-to-energy plant, supporting the island's circular economy efforts.

The landfill is situated in a coastal area of Oahu, where groundwater protection is a key concern due to the island's reliance on freshwater aquifers. Leachate management is critical to prevent contamination of nearby water bodies. Additionally, landfill gas generation, primarily methane, requires effective collection and flaring or energy recovery to reduce greenhouse gas emissions. The facility's proximity to residential communities also necessitates careful management of traffic, odor, and litter to minimize local impacts.