Winery wastewater treatment

Many small wineries and breweries lack space to carry out waste treatment. This results in the expensive alternatives of paying high sewage fees or trucking their wastewaters to off-site treatment facilities. Lagunitas Brewery alone ships 3000 truckloads of wastewater per year to the East Bay Municipal Utility District in Oakland, with the resulting diesel air pollution and crowding of our roadways. Our research ultimately seeks to develop a cost effective on-site treatment solution for this problem. 

Since 2015, we have been collaborating with the Okinawa Institute of Science and Technology to test a pilot-scale microbial fuel cell (MFC) system for treating wastewater from wine production on-site at D’Argenzio Winery in Santa Rosa. This continuing project involves Sonoma State students in the operation, monitoring and analysis of the system. The wastewater flows through a 45 L tubular MFC that removes the majority of the organics and then to an earthworm-containing vermifilter, from which it drip-irrigates landscaping. The vermifilter but not the MFC removes colored phenolic compounds from the wastewater. We are  investigating means to enhance the phenolics removing capacity of the vermifilters by isolating phenolic-degrading bacteria and fungi for use as potential inocula of the vermifilter bed media.

We are also testing vermifiltration as a primary treatment for removal of organics from brewery wastewater. Treated winery wastewater exiting the MFC is ‘polished’ to remove residual components by passage through an experimental vermifilter. Earthworms in vermifilters enhance the rate of removal of organics and other nutrients from wastewaters by stimulating microbial-activity in the bed medium. Analysis conducted last spring found that the vermifilter was removing nearly half of the tannins and all of the polymeric anthocyanins from the MFC effluent after only one month of operation. Removal of these typically recalcitrant compounds is particularly important since they are responsible for the dark color of the effluent and can be inhibitory to plant growth.

Extending on our findings, we assessed the effect various bed media on the efficiency of vermifilters to remove organics from the MFC effluent at the current winery site and from brewery wastewater in experiments conducted in the central SSU greenhouse. We obtained brewery wastewater and spent brewer’s grain for use as a bed medium from our partners at Lagunitas Brewery, Petaluma and Fogbelt Brewery, Santa Rosa. Other vermifilters bed media to be tested include the spent ‘Cedar enzyme bath’ mix from Osmosis Spa, Occidental and shredded paper from the SSU Department of Biology. Analysis included measuring the pH, alkalinity and chemical oxygen demand (COD) of the wastewater before the vermifilter and after the vermifiltration process. We once again carried out phenolic profile analysis to determine if the removal activity of the vermifilter has changed after one year of operation. We installed a second vermifilter, fed with the effluent from the first vermifilter. The bed medium in the new vermifilter was pre-colonized with a phenolic-degrading fungal-bacterial assemblage (isolated by an SSU undergraduate researcher) to determine if further polishing of the wastewater is possible by this method. Results gathered from these tests will inform the development of larger-scale treatment systems.