Development of an algorithm for air-scour optimization in membrane bioreactors

Abstract

AbstractMembrane Bioreactors are used in an increasing number of wastewater treatment facilities because of their compactness and efficiency in solid-liquid separation. In this paper the development of an air-scour control algorithm based upon short term and long term membranes permeability evolution is presented. An open loop calibration and partial validation was carried out in a semi-industrial scale pilot plant where manual changes in air-scour flow had been previously carried out. The control system was successfully tested in closed loop in an industrial scale pilot plant, defining a maximum daily air-scour decrease or increase of 6% of the air-scour recommended by membranes suppliers. A maximum air-scour saving of 20%, calculated in terms of air flow saved, was achieved without interfering with the biological nutrient removal and without any apparent long term effect.