This Northern USA dairy products company always met its wastewater treatment discharge limits. Biological oxygen demand (BOD) was within permit limits. The company tried many methods in treating its three-pond wastewater treatment system: chemicals, filters, surface aeration, and diffused air aeration. But, electricity bills and maintenance difficulties were problems. If the diffused air system went down, the pond had to be drained and sludge waded through…plus the power consumed by its two 60 hp (45 kW) blowers. The operator needed a crane to service the surface aerator.
In 1985, the dairy installed two 25 hp (18.5 kW) AIRE-O2® aspirator aerators in the first of three aerated ponds. The pond has a volume of 2.57 MGD or 9727.5 m 3. The electrical costs improved immediately. 'Replacing one 60 hp surface splasher type aerator with the two units resulted in immediate electrical savings. ' Roughly US $100 per month…and that’s pretty conservative,' said the wastewater operator. In addition, the easy maintenance and improved BOD reduction were additional benefits that sold the company on the AIRE-O2® aerators.
The 0.19 MGD influent flow had a biological oxygen demand (BOD) of 2575 mg/l. With the improved reduction, removal rates increased to 99%. 'The AIRE-O2® system pond doesn’t ice over during winter, making maintenance much easier.' Also, the operator reported, 'these are the best aerators for odor control.' Over time, the dairy has replaced equipment in the other ponds. Currently, the total amount of AIRE-O2® aspirator aerators equals 117.5 hp (88kW). The dairy also has purchased the new 20 hp (15kW) TRITON aerator/mixer from AIII. Located close to company headquarters, the dairy graciously serves as a host to many of Aeration Industries’ worldwide customers over the years. They are the experts on wastewater treatment maintaining a perfect compliance record!