Saving Money Under the Sun

Jan. 9, 2008

About the author: Bob Nobile is marketing manager for SolarBee, Inc. Nobile can be reached at 203.569.5000 or by e-mail at [email protected].

New hydraulic technology, combined with solar power, slashes expensive aerator run time for wastewater treatment ponds. Offering reliable around-the-clock circulation and mixing of wastewater, solar powered long-distance circulators lower energy consumption and maintenance while assuring that discharge water meets high- quality standards. With the energy and maintenance costs of aerators continuing to climb to dramatic new levels, managers of municipal and industrial wastewater treatment plants are compelled to find alternate technologies to do the job for less money.

Solar power, combined with a breakthrough in long-distance laminar flow pumping, has made it highly practical for treatment plants to offload at least part of their energy-intensive aeration and mixing functions to a low-energy and low-maintenance cost solution provided by SolarBee circulators.

SolarBee’s unique hydraulic technology conserves dissolved oxygen by mixing and distributing super saturated surface water throughout the pond. The biggest inefficiency of mechanical aeration occurs when using an excessive number of units beyond the necessary horsepower in an attempt to mix the entire pond. The low-energy circulation and thorough pond mixing provided by SolarBee, with its long-distance high flow, provides effective aeration and significant reduction of biochemical oxygen demand (BOD), total suspended solids (TSS) and ammonia. It also solves odor problems and reduces sludge buildup.

Cost Savings

The cost of electricity, which was primarily powering a number of 125-hp mechanical aerators in two wastewater lagoons, was very high for a Rochester, N.H., wastewater treatment plant. Worse, the plant’s aging aerators would soon need a major upgrade estimated at about $1.5 million. David Green, the plant’s chief operator, was determined to implement a cost-effective solution.

Five SolarBee SB10000 units were installed in the plant’s lagoons. Thanks to solar power, SolarBee’s gentle laminar flow runs virtually free and achieves excellent levels of odor-free compliance for BOD, TSS and ammonia.

Using these units helped Rochester achieve energy savings of more than $10,000 per month, eliminating the prospective $1.5 million cost for the upgrade. “We’re thrilled with SolarBee’s performance,” Green said.

Power Savings

Drayton Valley, AB, Canada, is a fast-growing community of almost 7,000. Its wastewater treatment plant was using 240- to 320-hp centrifugal blowers in the system’s wastewater lagoons. High energy and maintenance costs were a major problem. The plant suffered from low dissolved oxygen (DO), sludge buildup and short-circuiting. In addition, it faced difficulties in meeting Alberta’s Environment standard effluent limits. Seeking an environmentally friendly way to lower operating and maintenance costs, and to solve the problems in its wastewater lagoons, Drayton Valley turned to SolarBee water circulators.

Five SolarBee SB10000 units were installed. No infrastructure changes were required, the system realized an immediate 30% reduction in kW hours and electric consumption has continued to decrease since installation of the SolarBee units. Additionally, Drayton Valley has achieved the following results:

  • An average BOD removal increase from 88% to 95%.
  • Fecal coliform counts are consistently below the limits.
  • Chlorine dosage has been reduced by an average of 68%.
  • The system lifespan has increased and is working 50% over the design capacity.
  • DO levels have increased and sludge digestion has improved markedly.
  • Greenhouse gas emissions have been reduced.

Existing Aerators Become Backup Units

At Pactiv Corp., Red Bluff, Calif., two SolarBee SB2500 circulators have alleviated the cost of energy and maintenance at its aeration basin. In fact, the circulators work so effectively that the plant’s four electric-powered mechanical aerators (three 30-hp aerators and one 10-hp ejector aerator) have become backup units.

The facility discharges 2 million gal of wastewater per day into the Sacramento River. Aeration in Pactiv’s secondary treatment pond used to be provided by electric-powered aerators that operated 24/7. They were costing the company increasingly larger amounts of money. The circulators run 24/7 on solar power with occasional AC power assistance.

“There’s a noticeable reduction in our electricity usage,” said Roger Phillips, a Pactiv water technician, “and almost no maintenance is required.”

Of the utmost importance, SolarBee’s efforts are helping Pactiv meet all discharge requirements, limiting both BOD and TSS to 30 mg/L.

Odor Control

Aside from their effectiveness in aeration, the circulators are also being used wherever noxious odor and potentially hazardous aerosol are a concern. The circulation occurs with a near laminar long-distance flow pattern that provides an oxygenated odor cap across the entire surface, thereby keeping a lid on odor and aerosols.

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About the Author

Bob Nobile

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