The efficiency of aeration systems at the Moscow wastewater treatment facilities under field operating conditions

Summary

Aeration systems of aeration tanks are key elements of the wastewater treatment facilities. The main task in operating different types of aeration systems is ensuring high efficient atmospheric oxygen utilization at low energy consumption. The specialists of R&D Centre of «Mosvodokanal» JSC investigated the results of the long-term operation of the aeration systems at the Moscow wastewater treatment facilities under field operating conditions. The dependence of the aeration system efficiency on the ratio of surface areas of aerated zone and aeration tank; the air flow rate through one aerator at different options of aerators layout along the aeration tank length was studied. Regulating specific air consumption in the aeration tank zones provides for the optimal use of the available oxidation potential of the facilities without increasing aeration expenses or decreasing the efficiency of wastewater treatment. It was stated that when designing and choosing aeration systems it is necessary to find a balance between the surface area of the aerated zone in the aeration tank and efficiency of the aeration system. It was shown that when introducing nitrification-denitrification technologies without increasing capital and operating expenses for purchasing and maintaining mixing and aeration equipment both short-term and long-term shutdown of the aerators is possible to provide for alternate aeration without any efficiency loss. Perennial studies of the aeration systems produced by different manufacturers showed that the efficiency of the aeration systems during long-term operation is reduced by 25% of the design value. Therefore when choosing and designing an aeration system the reduction of the aeration system efficiency during the operation at the existing treatment facilities shall be taken into account aside from the required number of aerators and their layout.

Summary

wastewater , biological treatment , aeration tank , activated sludge , aeration system , efficiency of oxygen transfer