According to P-D writer Jeremiah McWilliams,
In St. Louis, the process starts when wastewater runs in pipes from the brewery to the BERS facility, which is wedged into a complex next to an old locomotive repair shop near the Mississippi River.Employing this process creates multiple benefits. First, the methane created by the closed-loop system can supply between 10 and 15 percent of the energy needed for the breweries that use it. In St. Louis, the system's success at treating wastewater has allowed the local sewer district to close down an aeration facility, saving $250,000 a year in energy costs (not to mention CO2 emissions). Finally, BERS produces another product for A-B to sell: "Over the last two years, the company has sold about 4 million gallons of the "biomass" created in the BERS process to other companies so they can replenish their own energy-capturing systems."
Screens snag large solids such as pieces of spent grain. The filtered water is collected in 1.2-million-gallon equalizer tanks, where temperature and acidity are kept within acceptable ranges.
The wastewater is then sent to airtight reactor tanks. There, anaerobic bacteria — microscopic "bugs" that live without oxygen — swarm around the small organic particles still in the water. The bacteria munch on the organic materials, forming millions of flakes of sludge — or biomass — a few millimeters wide.
The idea is to "make sure (the bacteria) are nice and healthy so they can do their business," said Jeff Pitts, the brewery's manager, during a recent tour of the BERS facility. "All of this … is about happy bugs."
As the bacteria — "the guys," as Pitts calls them — digest the material, they produce methane. The gas is siphoned out of the tanks and back into the brewery, where it helps to fire the boilers that drive the facility's machinery. The newly processed wastewater is sent to the Metropolitan St. Louis Sewer District.
A-B processes an average of 5.5 million gallons of wastewater every day at the St. Louis brewery, its largest. The company says BERS reduces organic waste from its breweries by more than 80 percent. That, in turn, cuts the strain on sewage treatment systems.
While one can definitely argue over whether A-B produces the best beers in town (I prefer Schlafly's myself), there's no doubt that the maker of Budweiser and Busch deserves raised glasses for this innovation in industrial ecology. ::St. Louis Post-Dispatch