A food waste biogas demonstration project in the city of Goleta, California, US has introduced new technology to the nation, according to Lystek International Limited.
Lystek is working with the Goleta Sanitary District (GSD), University of California-Santa Barbara (USCB) and the California Energy Commission (CEC) and received partial funding for its food waste-to-energy project from the CEC in 2017.
Under the project, source-separated organic (SSO) food waste from the USCB is pre-processed using European de-packing technology (Smicon) and co-digested in a mobile skid-mounted anaerobic digester. One of the projects key goals is to prove that SSO can be decontaminated to an acceptable level (less than 1%) for efficient anaerobic digestion (AD).
According to Lystek, the Smicon unit is the first deployment of its kind in the US. “The Smicon unit is easy to use and we are pleased with the quality of the slurry from food waste,” said Jim Dunbar, Lystek’s general manager for California operations, who oversees the project. “Even though this is a demonstration-sized unit, we believe that the technology can be scaled-up for full commercial-sized operations, similar to existing units in Europe.”
The digesters are being fed at variable rates to help document the level of biogas generation from the food waste collected. As part of the CEC grant, the project aims to verify the amount of biogas and the energy conversion potential of SSO-processed material. Dunbar added: “This project has the potential to provide real-world information that other wastewater and solid waste professionals can use to determine how best to manage SSO and food waste material.
“California is counting on successful demonstration projects such as this one to develop best management practices that others can utilise.”
In the coming months, Lystek will submit the results from the first phase of the project to the CEC. The next steps will include investigating the use of the company's patented low-temperature thermal hydrolysis process, LystekTHP, and the LysteMize refeed process for AD optimisation. According to the company, this allows for post-digestion processing of biosolids and the recirculation of the processed material, providing an improved biogas yield and increased energy generation.
“Lystek’s continued partnership with the Goleta Sanitary District will provide meaningful data for digester optimisation and increased biogas production,” said Dunbar. “This project will outline a path for GSD to realise its mission of reducing its dependency on carbon-based sources of energy.
“A renewable and sustainable energy supply will further solidify GSD’s position as a true resource recovery facility.”