This Mexican tire and rubber manufacturer’s extended aeration/activated sludge wastewater treatment plant had difficulty getting reliable aeration in its 0.167 MG (630 m 3) aeration basin. The surface aeration system exhibited continuous and expensive operational problems. Sludge had built up in the aeration tank. Treatment of the 0.178 MGD (674m 3/day) flow containing a chemical oxygen demand (COD) influent level of 560 mg/l was a struggle. The plant could not meet its discharge requirements and was out of compliance.
The company heard about the AIRE-O2® aspirator aeration system and decided to try a test using a small 2 hp (1.5 kW) unit. 'We noticed that even though it was a much lower hp (kW) unit than our existing equipment, the AIRE-O2® unit was oxygenating,' said the engineer. 'There was mixing and sludge separation happening.' The test convinced the plant officials to install a full AIRE-O2® system in 1989. 'Since its installation, the aerators have been working continuously and we are now meeting our oxygen requirements for treatment.' The effluent COD level of 45 mg/l equals a removal rate of 92 percent.
The addition of the 20 hp (15 kW) AIRE-O2® aerators, the plant has been working satisfactorily and meeting its oxygen requirements for treatment, according to the engineer. 'The system removed the solids in the aeration basin and our sludge digester is working well now.' He added, 'We are getting what we were promised, and the AIRE-O2® system has been helping our budget through its reliable operation, low maintenance requirements, and lower energy use. This is the system we were waiting for!'