|Treatment Plants and the environment
Biosolids start as sludge, the solid part of wastewater that arrives at the treatment plant and is processed by separation, heating, and dewatering.
The City of Los Angeles generates an average of 650 wet tons per day (wtpd) of dewatered, digested biosolids at the Hyperion Treatment Plant and 50 wtpd at the Terminal Island Water Reclamation Plant. Sludge from the wastewater that is treated at the Tillman and Los Angeles - Glendale Water Reclamation Plants is piped to the Hyperion Treatment Plant where it is processed into useful biosolids.
The biosolids produced at Hyperion were disposed in the ocean and in landfills until 1989, when the City started an extensive beneficial reuse program which continues today. The City received national awards from the U.S. EPA for rapid conversion from disposal to beneficial use of biosolids in 1989 and outstanding 100% beneficial reuse in 1994. In 2003, special recognition and awards were received from the Association of Metropolitan Sewerage Agencies (AMSA) and U.S. EPA for the City's Exceptional Quality Biosolids Program.
Today, the City is utilizing multiple options for the beneficial reuse of biosolids. In one option, the biosolids are loaded on to trucks at the plants and transported to the 4,688 acre City-owned Green Acres Farm in Kern County, California, where most of the biosolids are applied as a fertilizer and soil amendment. Corn, wheat, and alfalfa are grown on the farm as non-food crops. The biosolids produced at the treatment plants conform to Class A “Exceptional Quality” biosolids standards as defined by the U.S. Environmental Protection Agency. Scientific studies have consistently shown that Class A biosolids are safe and beneficial when used in land application.
In another approach, the City and Terralog Technologies in collaboration with the U.S. Environmental Protection Agency and with research support from the U.S. Department of Energy and the National Science Foundation are using a an innovative technology to convert biosolids into clean energy by deep well injection and geothermal biodegradation. The Terminal Island Renewable Energy (TIRE) project construction is taking place at the City’s Terminal Island Water Reclamation Plant, located in San Pedro, CA. The City has been granted a five-year permit from the U. S. EPA to evaluate the viability of injecting biosolids deep underground. This is the first project of its kind in the United States.
The demonstration project will adapt existing petroleum industry technology to convert the constant and growing supply of biosolids into a new source of alternative energy that helps to reduce the greenhouse gases that contribute to climate change.
A smaller portion of the biosolids is mixed with green waste and zoo manure from the Los Angeles Zoo to produce compost at the Griffith Park Composting Facility.