Issue link: http://read.dmtmag.com/i/155925
at cost to the winery. But winery wastewater contains energy that can be used to offset (or eliminate) treatment and disposal costs. BIOELECTRIC SYSTEM TECHNOLOGY Bioelectricity is the generation or consumption of electrical current by living organisms. Certain microbes generate electricity while degrading organic matter, and others consume electrical current while generating value-added products. The EcoVolt system for winery wastewater uses bacteria to carry out both reactions on biologically coated electrodes. Organisms on an anode oxidize organic matter in the wastewater to generate electric current. Organisms on a cathode convert carbon dioxide and this electric current into methane fuel. This process, called electromethanogenesis, occurs in the EcoVolt reactor to convert wastewater pollutants into electricity and subsequently convert electricity into methane fuel. This methane can then fuel a cogeneration turbine to generate electricity and heat that can be used onsite at the winery. Clos du Bois is an appropriate site to test the EcoVolt. The winery has a history of using sustainable practices throughout its operation, and has ongoing goals to reduce water and energy use for wine processing. Clos du Bois produces 2 million cases of wine annually and generates about 14.5 million gallons of wastewater per year. Its ratio of 7.25 gallons of wastewater to one case of wine produced is low by wine industry standards. The winery previously tested an innovative wastewater system, the Biothane Biodigester installed in 2002, an anaerobic system designed to reduce wastewater solids levels by converting them to methane gas (see the article in V&WM's January/ February 2004 issue). Brian Hemphill, director of operations at Clos du Bois, said the Biothane technology was sound, but the system was not properly sized to the facility, and it required significant operator oversight. It was later decommissioned, and Clos du Bois went back to using more traditional aerated wastewater ponds. However, infrastructure for the Biothane system was still in place that could be connected with the EcoVolt, such as a particulate removal and solids settling tank, and an equalization tank to homogenize the wastewater prior to entering the EcoVolt's reactor treatment unit. INSTALLATION AND OPERATION Cambrian previously called its system ExoGen, but it is now EcoVolt. It is designed as a modular system, assembled by Cambrian in standard units the size of cargo shipping containers, which are then shipped to the facility for installation as a complete unit. A system includes at least one shipping container, the "Headworks" unit, con- AT A GLANCE + Bioelectric wastewater treatment utilizes bacteria that generate and consume electricity to convert pollutants into methane fuel. + The system tested at Clos du Bois reduced biological oxygen demand in wastewater by 80%-90% and generated high-quality methane fuel. + Methane can fuel a cogeneration turbine to generate electricity and heat to use for winery processing operations. + EcoVolt systems can reduce a winery's carbon footprint by 2 kilograms per case of wine production. w w w. v w m media.com S e p t - O c t 2 0 13 | V I N E YA R D & W I N E RY M A N A G E M E N T 43