Biosolids Product Profiles on Third-Party Class A Products
Synagro and Lystek are the two main service providers that Bay Area agencies partner with for processing of solids or biosolids. Many agencies send a portion of their sludge or biosolids to these offsite processing facilities as a strategy to diversify their solids end-use. Synagro and Lystek have the capability to manage the hauling, offsite processing, and beneficial use of the biosolids products.
Compost
Synagro operates the El Nido Central Valley Composting (CVC) facility in Merced County that processes biosolids from several Bay Area agencies. Of the 31 Bay Area agencies that participated in the Bay Area Clean Water Agencies 2021 Biosolids Trends Survey, six sent a portion of their sludge or biosolids to the El Nido CVC facility. After 2021, one additional Bay Area agency started sending a portion of their biosolids to the El Nido CVC facility, for a total of seven, as of April 2024. The El Nido CVC facility can receive digested or undigested dewatered solids. Solids composting produces a Class A product with a myriad of benefits to agriculture, including improving soil texture, soil fertility, and water retention, recycling organic matter and nutrients, and reducing greenhouse gas (GHG) emissions through carbon sequestration and offsetting the use of synthetic fertilizers. Biosolids compost is a well-known and well-accepted product, which can be used in a variety of markets beyond bulk agricultural land application such as in nurseries, parks, and residential and commercial landscaping. For more information about Synagro’s El Nido CVC facility, see: https://www.synagro.com/offerings/composting/.
Biosolids compost (image courtesy of Synagro)
LysteGro
Lystek operates a regional liquid fertilizer facility co-located at the Fairfield-Suisun Sewer District, in Solano County, called the Organic Material Recovery Center (OMRC). In addition to processing all of FSSD’s sludge, 12 Bay Area agencies send a portion of their sludge or biosolids to the OMRC as of April 2024. The OMRC can receive digested or undigested dewatered solids. Solids are fed to thermo-chemical hydrolysis reactors where they are processed with low pressure steam, an alkali addition, and mechanical shearing. The resulting product, trademarked as LysteGro, is a homogenized, high-nutrient, pumpable liquid product at approximately 12 to 14 percent solids concentration. LysteGro is a Class A product and is certified as a fertilizer by the California Department of Food and Agriculture. Lystek manages the land application of their product, which is sub-surface injected into agricultural fields. Like all other biosolids products, it has multiple benefits for agriculture including improved soil fertility and crop yield increase and results in GHG emission reductions through carbon sequestration and synthetic fertilizer offsets. For more information about the Fairfield-OMRC, see: https://lystek.com/projects/fairfield-omrc/.
LysteGro (image courtesy of Lystek)