SoCalGas Grant to Advance Tech that Uses Wastewater to Produce RNG

Southern California Gas Co. (SoCalGas) announced the California Energy Commission (CEC) has awarded the company a $3 million grant to fund the next phase of development of a new technology that doubles the amount of renewable natural gas (RNG) created from the decomposition of organic material at wastewater treatment plants. The new process, known as Hydrothermal Processing (HTP), reduces greenhouse gas emissions by three times that of traditional anaerobic digestion and costs about half, according to SoCalGas.

HTP uses heat and pressure to capture 86 percent of the energy in the waste and using 14 percent to process it. A pilot project will be located at the Central Contra Costa Sanitary District (Central San) Wastewater Treatment Plant in Martinez, Calif. The work is being funded in part by the California Energy Commission, SoCalGas and other private participants.

"Technological advances, like hydrothermal processing, are an important part of SoCalGas' vision to be the cleanest natural gas utility in North America and will help us meet our commitment to deliver renewable natural gas to homes and businesses," said Ron Kent, technology development manager at SoCalGas, in a statement. "This new technology holds the potential to convert not only wastewater but landfill, forestry and food waste into carbon-neutral renewable energy that displaces fossil fuels and helps California meet its climate goals."

"The best thing about HTP is how simple it is," said Corinne Drennan, who is responsible for bioenergy technologies research at the Department of Energy's Pacific Northwest National Laboratory, in a statement. "The reactor is literally a hot, pressurized tube. We've really accelerated hydrothermal conversion technology over the last seven years to create a continuous and scalable process that allows the use of wet wastes like sewage sludge without the need for drying it first. And we're excited to see HTP piloted beyond the lab, at an actual waste treatment plant."

"The project will lay the groundwork for full-scale commercial hydrothermal processing plants that could revolutionize the way renewable energy is produced at wastewater treatment plants," said James Oyler, president of Genifuel Corporation, which produces the HTP equipment patented by PNNL, in a statement. "Unlike anaerobic digestion, this technology completely eliminates leftover biosolids. Getting rid of the biosolids hauled to landfills would significantly reduce costs for wastewater treatment facilities."

The project team comprises a number of industry leaders, including SoCalGas, the Water Research Foundation, Central San, PNNL, Genifuel Corporation, Merrick & Company, Black & Veatch, Brown and Caldwell, MicroBio Engineering, Leidos and others.