Yeast and hops are key ingredients in your favorite beer,
but they also ferment downstream problems for brewers and wastewater treatment
plants. Organic elements in brewery wastewater are oxygen-hungry pollutants that put
considerable strain on wastewater treatment facilities.
Peter Kruger, brewmaster at Northern California's Bear Republic, knows this firsthand. "Like a lot of breweries, we have had phenomenal growth over last 10
years. It's been gradual, but we've switched from a brew pub mentality to that
of a larger manufacturer -- one that makes substantial demands on public
utilities," he says.
brewery, which saw 40 percent growth for each of the past four years, felt those
demands in the form of surcharges from the municipal treatment plant based on
the wastewater's high biochemical oxygen demand (BOD), something the U.S. Environmental Protection Agency regulates under the Clean Water Act.
Over time, this became an untenable situation, but rather than adding a
conventional aerobic digester to reduce BOD levels before wastewater leaves
the plant, Bear Republic is using a new approach from Boston-based Cambrian Innovation. Cambrian has
developed technology that essentially unlocks energy from the organic matter in
the water, by flowing it through a bioelectric chemical reactor, in which bacteria eat
the organic waste and release an electron. The system uses that energy to
create an electrical current, which, combined with carbon dioxide in the water,
forms methane gas. (The technical term, on which Cambrian built its proprietary
approach, is electromethanogenesis.) The methane is then pulled into a combined
heat and power system to create electricity and heat water. When all is said and done, the system, called
EcoVolt and built into portable cargo containers, creates more energy than it
Cambrian grew out of a NASA-funded project that sought ways
to treat wastewater in space. Founder Matthew Silver pursued funding
while earning his PhD in engineering systems from the Massachusetts Institute of Technology (MIT). Since 2006, he has attracted enough funding to grow the company to a team of 20 and advance the
use of bioelectricy to treat wastewater while also generating energy.
"Organics in wastewater actually contain a lot of energy. So if you can
use the right technology, you can tap into that," Silver says.
The water coming out of the EcoVolt is 80 percent to 90
percent free of pollutants. That is plenty clean enough to send to the municipal
wastewater plant, but to reuse the water, Bear Republic will need to first run
it through a reverse osmosis system. Kruger's first goal is to replace the
plant's air-cooled chillers, which are major energy hogs during summer, with
water-based chillers using reused water from the EcoVolt. The company will also
divert some water into irrigation and use some for washing down floors.
Eventually, Bear Republic might reuse 100 percent of the water expelled by the EcoVolt. But Kruger says this is not a foregone conclusion, for two reasons. First: addressing
public perception and concerns around drinking beer made with reused water,
despite its purity, might pose some challenges. Second: the
costs of running all of the water through a reverse osmosis system might be
prohibitively costly, compared to simply using municipal water.
Another benefit of the Cambrian installation: Bear Republic uses a considerable amount of hot water, so the combined heat and power system will cut its hot water costs by 30
Cambrian is targeting EcoVolt at the food and
beverage industry because it "has a critical need" for onsite
wastewater treatment. California's Clos du Bois winery and Lagunitas brewery
are also customers. But Silver says the underlying bioelectric technology could
be used, in combination with additional treatment systems, to clean industrial
wastewater. Eventually, Cambrian hopes to grow its capacity to treat municipal
wastewater. "We're working with the U.S. Army, looking at a system that
could do distributed treatment," Silver says.
Laura Shenkar, founder and principal of consulting firm
Artemis Water Strategy, says companies such as Cambrian are well poised for a
future in which companies will face more urgent needs to address both water
and energy use. In 2012, Artemis named Cambrian Innovation to its annual Top
50 list of promising startups in the water technology sector.
"Investing in ways of making water go further is
important, but the dysfunction is that water is almost free in terms of inputs
for manufacturing," she says.
That's not likely to remain so in the future, especially
in water-poor regions or those, like California, sometimes faced with deep droughts. Shenkar
says as water becomes scarcer, and energy efficiency and greenhouse gas
reduction become increasingly important to businesses, we will see
more and more people adopting technology that simultaneously treats wastewater
while generating energy.
This post was originally published on Smartplanet.com