This Midwestern, USA city wanted to replace an aging trickling filter system with a new, efficient wastewater treatment facility equipped to handle its future growth. Important factors in design were loading demand fluctuations, winter treatment efficiency, effluent discharge restrictions, maintenance considerations, and of course, cost. The city hired a consulting engineering firm to design a facility that would meet all its needs. Oxygen demands double and triple during the poultry processing season. The facility was designed for a capacity of 1.8 MG/day (6813m 3/day) to meet current and future needs. The engineering firm also required a 'guaranteed performance clause.'
Aeration Industries viewed the 'guarantee' as an opportunity to demonstrate good faith in their product, the AIRE-O2® aspirator aeration system. In 1984, eight 20 hp (15 kW) bridge-mounted aerators were grouped in pairs at four locations. The engineer said, 'the use of eight aerators allows for a 4 to 1 turn down in oxygen transfer capability while assuring complete mixing of the ditch under all load conditions. Proof of oxygen transfer efficiency compliance came after the system was up and operational by an independent test directed by the engineering firm.
The AIRE-O2® aerators inject air below the water’s surface. Hence, its high oxygen transfer performance is maintained regardless of freezing winter temperatures. The custom designed bridges for the aerators provide good operator access for routine maintenance. The facility’s superintendent said, 'other operators I’ve talked to with oxidation ditches equipped with brushes or whatever, have problems. We have no problems. We like the AIRE-O2® aeration system, maintenance is easy.' Years of operation are proof that the engineering firm designed a system that met all their needs and at a cost the city could afford.