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Solid Resources Processing & Construction Division
City of Los Angeles - Bureau of Sanitation

Mulching & Compost - Section


California law (AB 939) required all cities and counties to reduce the amount of waste they sent to landfills by 50% by the year 2000. The City of Los Angeles met and surpassed that goal (more information found at http://lacitysan.org/solid_resources/recycling/index.htm)

One of the largest single components of the City’s waste stream is greenwaste (grass and tree trimmings, leaves, garden waste and other vegetable material). The Bureau of Sanitation operates three mulching/composting facilities: the Harbor Yard Trimmings Facility in San Pedro, which uses the contents of the Bureau-collected residential green bins in the Harbor area; the Griffith Park Composting Facility, which uses greenwaste from Griffith Park, biosolids from the Hyperion Wastewater Treatment Plant and animal waste from the Los Angeles Zoo; and the Lopez Canyon Environmental Center, which uses greenwaste collected by the City’s Bureau of Sanitation and tree trimmings generated by private contractors to mix with horse manure collected from nearby residents. The mulch and compost produced by these three facilities is a high-quality product, used by community gardens, City residents, businesses and farmers.

US Composting Council

Seal of Testing Assurance

The Bureau of Sanitation strives to provide the highest quality compost and adhere to standards adopted by composting industry. Learn more about the Seal of Testing Assurance for our compost at san.lacity.org/srpcd/sta_info.htm. Copies of the most current lab STA data sheets alongside instructions on the recommended use of the STA compost products produced by the City can be obtained for the respective products.

Free Mulch Give-Away

There are currently 11 free mulch give-away sites in Los Angeles for city residents.
For more information about our Free Mulch Give-Away Program:

Summary of Process

The residential yard trimmings from curb side collection are processed at either one of our 3 mulching and composting facilities. When trucks arrive to the facility, they drop off the collected yard trimmings on an asphalt pad. The collected yard trimmings are sometimes riddled with some contamination (anything disposed of besides greenwaste) due to improper use of the green bin. Sometimes there is extremely heavy amount of contamination. Initially, large contaminants are removed by the facility workers. The next step involves use of processing equipment such as a trommel screen, conveyors, and a picking station. The trommel screen helps in separating out small size particles, such as grass clippings. The remaining contaminants are pulled out by the workers at the picking station. The material is then sent to the grinder to be processed to a smaller size. After the grinding is complete, the mulched material is placed into windrows (rows formed by the mulched greenwaste) for the composting process. The finished material is loaded into trucks for delivery to end-use customers. Some of the material is available for free to residents at any of our 11 mulch give-away sites. Substantial quantities of mulch are delivered to farmers to spread in the fields. Farmers appreciate the many beneficial aspects of using mulch.

Learn more about Compost and Mulch including homeowner resources on the matter.

For photographic document explaining the process involved in mulching, Click Here.

Mulching Facility Video

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