One man’s trash is another man‘s electricity in Yolo County, and the feds have noticed.
The Environmental Protection Agency recently recognized the county for its landfill bioreactor, a system that takes the gas generated by solid waste and uses it to generate electricity.
Yolo County‘s bioreactor system succeeded in minimizing the environmental consequences of landfill waste, wrote EPA administrator Elizabeth Shaw in a letter to the county.
The system also succeeded in maximizing gas generation and improving the rate of decomposition of solid waste, she said.
“We are grateful for Yolo County’s early leadership,” Shaw wrote.
The bioreactor is located at the county’s central landfill, which collects waste from all parts of Yolo County, including the city of Davis.
It was implemented as part of an EPA program to test and demonstrate new landfill technologies specifically aimed at protecting the environment. Yolo County participated in the project as a way of demonstrating the possibilities of landfill bioreactors to other waste management agencies.
The system speeds up decomposition and captures the methane gas generated as a result, said Linda Sinderson, Yolo County‘s deputy director of planning and public works. A contractor collects the gas and uses it to generate electricity, which is then sold to the Sacramento Municipal Utility District.
The county receives $9,000 to $10,000 per month from royalties on that electricity, Sinderson said.
Only three such systems have been implemented in the United States to date, but this is the first one to complete the EPA evaluation, said Ramin Yazdani, senior civil engineer for the county.
Yazdani, who is the bioreactor project manager, said he expects the success of Yolo County‘s experiment to encourage the adoption of this technology in other areas, where opportunities are limited because of complex and stringent EPA rules.
“I think it will lead to a revision [of the federal rules] to allow a wider range of applications of this technology,“ Yazdani said.
The landfill bioreactor generates roughly three megawatts of electricity, or enough to power 3,000 homes, he said. In addition to generating energy, the system also increases the amount of waste that can be stored in one place. The system increases the lifetime capacity of the landfill by roughly 25 percent.
In addition to generating energy, the bioreactor brings other benefits as well.
The bioreactor is one of several county projects aimed at minimizing the landfill‘s impact on the environment. Other projects take a different approach, such as alternative landfill covers that reduce greenhouse gas emissions.
All the projects are aimed at reducing the long-term impacts of waste on the environment, Yazdani said.
The county has been working on various landfill research and design projects since 1996, when it began with a similar project on a smaller scale. Though the partnership with the EPA has ended, the bioreactor will continue to accelerate decomposition and generate energy from the county‘s waste.
JEREMY OGUL can be reached at city@californiaaggie.com.
