Biomass conference tour to feature two digesters

By Anna Austin | December 07, 2011

The Pacific West Biomass Conference & Trade Show being held in San Francisco, Calif., Jan. 16-18, has announced its official tour sites. They include the city of Santa Rosa’s Laguna Wastewater Treatment Plant and its award-winning Fuel from Aquatic Biomass research project, as well as the Giacomini dairy digester operation in Point Reyes, Calif.

Caden Hare, lead researcher of the Aquatic Biomass Program, said the tour will begin at the LTP where attendees can expect to see treatment of wastewater at the 21-million-gallon-per-day facility.  “LTP is a tertiary treatment plant that uses ultraviolet disinfection,” he explained.

UV disinfection involves exposing contaminated water to radiation from UV light, which penetrates an organism’s cell walls and disrupts the cell’s genetic material, making reproduction impossible.

LPT houses four 1-million-gallon anaerobic digesters that turn sludge separated from the water into Class B biosolids, which are sent across the street to a facility that transforms them into Class A biosolids.

Along with utility gas, the biogas emitted from the digesters is combusted by three 0.8-MW-engines to create a total of one-third of the plant’s electrical needs. “A combined-heat- and-power project to replace the existing facility began construction in spring 2011, and it’s expected to be finished in December of 2012,” Hare said.  “When that’s complete, four 1 MW engine generators will be burning digester gas principally, but also serving as standby power for the plant’s needs during utility outages.” Tour participants will see construction progress firsthand.


 At the Aquatic Biomass research project, native aquatic plants and algae purify secondary wastewater effluent at the LTP in two small channelized wetland modules. “Plants harvested from the wetland modules are brought to two 1,500-gallon anaerobic digesters where they are mixed with waste glycerol from biodiesel manufacturing and winery lees to produce biogas,” Hare said. “The biogas can then be burned in an onsite generator to recharge small electric vehicles used in LTP operations.”

At the Giacomini Dairy, which has been in operation for 52 years and is still going strong, attendees will experience an educational walking farm tour, according to Jennifer Luttrell.  They will learn about the history of the farm and how it’s stayed successful over the years, a role in which renewable energy plays a part, as an anaerobic digester was installed on the farm two years ago. The methane capture operation currently generates 65 percent of the farm’s energy needs.

As an added bonus, tour attendees will enjoy award-winning cheese as part of an on-farm lunch experience.

The Pacific West Biomass Conference & Trade Show tour will begin on Jan. 16, one day prior to the conference, and can accommodate 55 participants. To register, visit