Solar-powered mixers from SolarBee are designed to solve municipal wastewater quality problems including odor control, discharge permit violations, and high energy costs. The mixers operate continuously, reducing BOD, TSS and ammonia. They also can supply most of the mixing energy required in a treatment pond. Flow rates vary by mixer size, ranging from 1,250 to 10,000 gpm.
Each unit can displace the mixing energy of about 25,000 watts of conventional grid-connected equipment, reducing carbon dioxide emissions by about 148 tons per year. “In a typical partial-mix lagoon system, you might need 20 hp for oxygen and 100 hp to mix,” says Joel Bleth, president.
Two units, each replacing 40 hp, can significantly reduce mixing costs. Typical payback on a $50,000 unit is from one to three years, Bleth says. Further savings can come from reduced dredging costs enabled by improved dissolved oxygen distribution and higher sludge digestion. On the back end of lagoons, solar mixers help control algae blooms, lowering BOD and TSS.
Essentially, in large-volume pumps with a quarter-inch of lift, the mixers are designed to move large amounts of water with minimal horsepower, reducing the run time and operational cost of high-horsepower aerators. The challenge is to capture enough sunlight to supply power.
“In the summer in the United States, all the light squeezed together, from morning to night, is equal to about seven hours at the equator at noon,” Bleth says. “In the winter, it’s like three hours at the equator at noon. So we have to catch enough power in three hours to run the machine for 24 hours.”
The device meets the challenge by capturing twice the radiant energy needed through three adjustable, self-cleaning photovoltaic cells. Power is stored in the mixer’s onboard battery (expected 10-year lifespan) to run the 100-pound, high-efficiency mixing motor and self-cleaning, anti-jam, auto-reverse impeller at the base of the unit.
When used in activated sludge reactor basins, the mixers enable operators to reduce aeration energy during non-peak periods without increasing solids buildup. Solar mixers also can be used in water reuse ponds to limit algae blooms and keep irrigation nozzles from plugging. 866/437-8076; www.solarbee.com.
