Anecdotal evidence suggests that cheese and biogas go together like – aw heck, let’s cut the cheese jokes and get straight to the point. The Holmes Cheese Co. is installing a wastewater treatment system at its Millersburg, Ohio factory that will double as a sustainable biogas recovery plant, thus joining a growing number of cheeseries that are generating their own sustainable energy to power equipment.
The new system is a proprietary process called the Upflow Anaerobic Sludge Blanket. It was developed by Biothane, a subsidiary of leading wastewater treatment company Veolia Water Solutions & Technologies. As an added bonus, N.A. Water Systems (another Veolia subsidiary) is installing high-tech filtration and treatment equipment that will enable the effluent from Holmes Cheese to meet strict water quality limits for phosphorus.
Wastewater Treatment and Biogas
Biogas recovery from wastewater has been going on for years in cities like New York, where wastewater is plentiful to say the least. In essence, the process captures methane from the natural biodegradation of the organic material in household wastewater. Food processors and farms also produce copious amounts of organic waste and organic-loaded wastewater, so it was only a matter of time before biogas recovery branched out. Cheesemakers like Holmes, Pearl Valley Cheese Inc., and Fairview Swiss Cheese are among the early adopters, as is the famous Maker’s Mark distillery (known to movie fans from Juno). Dairy farms are also gung-ho over biogas, and New York State has embarked on an ambitious statewide program to enlist dairy farms for small scale biogas recovery, not only for energy conservation but also to help protect drinking water quality in New York City’s upstate reservoirs.
Biogas and the Upflow Anaerobic Sludge Blanket
Biothane’s system integrates biogas recovery with a sophisticated wastewater treatment process. The wastewater first undergoes pre-treatment and is brought to an optimal temperature and pH. Then it is introduced to a bed (the “blanket”) of biomass at the ground level of the system. As the wastewater rises through the biomass, the natural process of organic breakdown releases biogas, while the wastewater sheds tiny particles of matter and other pollutants. The biogas and the clean(er) wastewater are drawn off, while the solids are returned to the blanket.
Cheese and Phosphorus
After the treated wastewater leaves the Sludge Blanket system, it undergoes further treatment with N.A. Water Systems‘ proprietary filtration system. This equipment removes more organic particles that contribute to BOD (biological oxygen demand), which is an essential measurement of water quality. Another essential indicator is phosphorus, which can cause algae blooms. N.A.’s system removes enough phosphorus to meet water quality standards for effluent from the cheese factory, which limits phosphorus levels to 1 mg per liter.
Image: Cheese by Dvortygirl on flickr.com.
Tina Casey specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. You can also follow her on Twitter @TinaMCasey and Google+.