Yolo County Prepares for SB 1383 Implementation with Launch of New Anaerobic Composter
Yolo County began operating a new anaerobic composter on Oct.1 that can recycle 52,000 tons of organic waste each year into compost, biofuel, and electricity.
The facility will keep that organic material out of the county landfill. In landfills, organic waste decomposes and generates methane, which is a major contributor to climate change.
Instead, food waste, grass clippings, and other organic material collected from local businesses and residents is delivered to the anaerobic composting facility, a 10-acre spot with seven “cells,” at the Yolo County Central Landfill site.
When the organic material is delivered to this site, it is ground up and deposited into cells. Each cell is sealed by spraying the surface with a mixture of cement, fibers, and polymer. Once the bacteria-rich liquid is pumped into the cell, the anaerobic digestion process takes place, and in less than six months, biogas is finally produced.
“Moisture is removed from the biogas produced, and it’s injected into an internal combustion engine that burns the gas, which creates electricity,” said Ramin Yazdani, Director of Yolo County Integrated Waste Management. “The electricity goes on the grid and is sold to SMUD (Sacramento Municipal Utility District).”
After methane production has dropped off, the is operated aerobically, utilizing the aeration piping system. Air is injected into the cells to aerate the digestate material for a two-week aerobic digestion phase. This creates compost.
The material is then excavated, cured, and screened of contamination. Once the process is complete, the county will sell the compost to residents and businesses.
Compost has many beneficial uses, including as a soil amendment and in erosion control. Learn more about compost on our website.
In 2007, Yolo County received a $200,000 CalRecycle grant to run a pilot project that broke down 2,000 tons of organic waste in a smaller cell.
“That created the basis of our current design,” Ramin said, “and it showed us operational challenges that we had to learn from in order to design and operate a better system.”