Membrane bioreactors for waste water treatment: reduction of sludge production

Abstract

In order to reduce the excess sludge produced by Activated Sludge (AS) wastewater treatment plants, studies have been carried out with a Membrane BioReactor (MBR) to study the maintenance and cryptic growth phenomena of Pseudomonas fluorescens cultures. Experiments with various imposed wasting rates showed that viability and sludge production yield decreased when sludge age increased. A continuous sludge thermal treatment system was operating with MBR to amplify sludge breakage and consequently biomass growth on the lysis products. With the promising results on sludge production yield reduction, this work gives a new outlook on the AS process and leads to the development of processes with control and reduction of sludge production. A global discussion is given on strategies for biological waste water treatment with low AS production.