Reduction of operational costs by planned interruptions of aeration in activated sludge plants Available to Purchase

A full scale investigation was carried out at the CETREL activated sludge plant to evaluate the technical feasibility of operational cost reduction by planned interruptions of aeration during the daily periods of three hours of high tariff, imposed by the power supply company. It was experimentally established that the daily interruptions did not affect adversely the effluent quality and that sludge activity as well as the settleability remained unaltered. On the other hand the reduction of energy consumption during the high tariff period generated a decrease of operational costs of more than US$ 400.000 per year. Because of the fact that interruptions of aeration in the activated sludge process was shown to be economically feasible, CETREL was in a position of negotiating a more favourable contract with the power supply company, whereby a lower price for power during off peak hours was obtained in exchange for low consumption during the high tariff hours of peak demand.