March 19, 2019
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History: The end product…strawberries - 2009

By: Irene Hilsendager
August 31, 2018

A system linking clean water, bioenergy and strawberries is now in operation on the grounds of the City of Santa Rosa Laguna Regional Wastewater Treatment Plant. On May 10 Congresswoman Lynn Woolsey joined local dignitaries and officials from the City of Santa Rosa and Sonoma State University in a ceremony to launch the Fuel from Aquatic Biomass, or FAB, demonstration project. Led by the City’s Project Development Manager, Dell Tredinnick and SSU Biology Professor, Michael Cohen, the collaborative FAB research project is developing a low-cost system for integrated bioremediation, bioenergy and food production. The project has gained national recognition with three awards, most recently the Theodore Roosevelt Environmental Award from the Association of California Water Agencies and has garnered support from a variety of sources, including the California Energy Commission and the Bay Area Air Quality Management District.

The FAB process begins with treated wastewater passing through two channelized aquatic wetlands, constructed by local green builder R.S. Duckworth, that remove residual nitrate and other components, such as pharmaceuticals. SSU graduate student Caden Hare, recently awarded the prestigious Switzer Fellowship, is working with undergraduates Linden Schneider and Zane Knight to investigate the relative contributions of aquatic vegetation and microbes to the scrubbing efficiency of the constructed wetlands. The plants and algae in the wetlands create biomass that can be harvested for energy production.

“The most efficient way to harness the energy held in this vegetation,” who says “is to feed it to anaerobic digesters”. To this end, research of SSU graduate student John Kozlowski seeks to optimize anaerobic digestion of the vegetation mixed with agricultural by-products from nearby Hanna winery and local dairies. Methane gas from twin experimental digesters supplies a generator that charges electric vehicles used at the treatment plant. In the key moment of the ceremony, Rep. Woolsey flipped the generator power switch and was driven off by Hare in a bioenergy powered vehicle. “This is a simple system,” said Cohen. “Using conservative estimates Sonoma County could supply a quarter of its natural gas demand by anaerobic digestion of local organic wastes. Germany is now on track to supply 20 percent of their demand by 2020”.

The nutrient-rich solids that remain after the digestion process can be utilized as a soil amendment. SSU graduate student Aaron Agostini is investigating these solids for their capacity to suppress pathogens of strawberry and support plant growth. 

Funded by the California Strawberry Commission, this research is conducted in collaboration with Dr. Mark Mazzola of the USDA Agricultural Research Service. SSU graduate student Mia Maltz and undergraduate Jackie Sankisov are examining use of the solids for stimulating microbial degradation of petroleum.

Hare points out that the FAB project is a marvelous illustration of Buckminster Fuller’s observation: “Pollution is nothing but the resources we are not harvesting. We allow them to disperse because we’ve been ignorant of their value.” 

Project manager Tredinnick commented that it was particularly fitting to have Rep. Woolsey in attendance considering that he met Cohen and Hare at a town hall meeting on global warming organized by her office in 2006. Rep. Woolsey displayed a clear enthusiasm for the FAB project in promising to do her best to find further funding for expansion and thereby lower our local dependence on imported fossil fuels.

Irene Hilsendager’s column each week touches on moments in the history of Cotati, Rohnert Park and Penngrove.