The EPA estimates that toilet flushing consumes some 4.8 billion gallons of water each day in the United States alone. Why not turn recycle this waste water and put it to use, say, in the service of generating heat for building? Green tech start-up OriginOil believes it's possible to do just that by collecting the flushed water and re-using it to grow algae, which is then processed into heat. As Smart Planet reports, the company claims that furnishing large buildings with their own algae production "labs" could yield a large heating source that would significantly reduce the structures' overall energy consumption and help them to produce their own clean energy--the first steps towards becoming net zero.
OriginOil has developed a flat panel photobioreactor (PBRs) that can be applied in a manner similar to solar cells and panels, which is to say, they can be placed on large area rooftops and even vertical surfaces of tall office building and high-rise apartment complexes. The algae-laden photobioreactor has one key advantage over other these photovoltaic systems, in that not only can it produce energy, but it can also purify wastewater by absorbing CO2 and other chemicals inherent within it. The company, which is currently testing its systems in France and elsewhere, expects their panels to become competitive at an area of 4000 m2 and beyond. According to the Riggs Eckelberry, OriginOil’s CEO, an algae farm of this size "installed on a 10,000 floor area building would generate 40 kWh per m2 of floor surface per year." For every unit of power produced, there is a return of 4 units of heat, which, when projected at large-scales, can be converted for heating usage.