Landfill Sites

ReGen Monterey Landfill (Primary landfill site)

ReGen Monterey landfill, located in Marina, California, USA, began permitted waste disposal operations in 1965. Spanning an area of 1.92 km², the landfill was subdivided into seven waste cells. Based on Cascadia (2013), the waste disposed of in ReGen Monterey landfill consists of organics (49.4%), paper (22.4%), construction and demolition (C&D) debris (7.2%), plastics (6.5%), metals (2.0%), glass (1.6%), and miscellaneous materials (10.9%). Since waste disposal began in 1966, the acceptance rate of waste has steadily increased. Currently, approximately 550,000 tons of municipal solid waste are disposed in the landfill annually (ReGen Monterey, 2025). This landfill also houses the LFG collection systems for energy generation and the MRF to support greenhouse gas reduction initiatives and contribute to resource recovery and sustainability efforts. The waste cells are covered by a 15 cm daily soil layer, with intermediate covers measuring 30–45 cm on flat surfaces and 15 cm on slopes.

   Recently, ReGen Monterey landfill switched conventional gas wells to the LoCI system that can read gas compositions, flow rates, temperatures, and pressures every two minutes automatically and continuously. 

 

Western Placer Landfill

The Western Placer landfill, located in Placer County, California, USA, began permitted waste disposal operations in 1979. Spanning an area of 1.29 km², the facility was subdivided into sixteen waste cells in 1992 to manage non-hazardous industrial and municipal solid waste, classified as Class II and Class III, respectively. According to Golder Associates (2017), the site processes an estimated annual disposal volume of approximately 271,500 tons. To advance sustainability and greenhouse gas reduction initiatives, the landfill integrates landfill gas (LFG) collection systems for energy generation, alongside a materials recovery facility (MRF) and a dedicated composting unit. Operational cover protocols include a 15 cm daily soil layer, with intermediate covers measuring 30–45 cm on flat surfaces and 15 cm on slopes. Furthermore, some waste cells have been covered with the final materials in approximately 1.8 m-thickness.

 

Kiefer Landfill

Kiefer landfill, located in Sacramento County, California, USA, began waste disposal in 1967, and the waste disposal plan to be conducted by 2071. Spanning an area of 4.39 km2, the landfill was subdivided into twelve cells. Current annual waste disposal tonnage at the site is estimated at approximately 950,000 tons (Tetra Tech BAS, 2023). However, they haven’t released detailed information related to waste composition. The landfill has LFG collection system for energy generation, but there is no MRF. The waste cells are covered by a 15 cm daily soil layer, with intermediate covers measuring 30–45 cm on flat surfaces and 15 cm on slopes.