Patent ID: 7135115

Claim:
A method for treating waste water by a membrane bioreactor comprising the steps: a) treating waste water in a bioreactor to produce excess biological sludge and treated water components; b) extracting the biological sludge from the bioreactor; c) causing contact between the biological sludge and dewatered effluent to form two resulting products; d) recycling a first product of the contacting biological sludge and dewatered effluent; e) the first product containing polyelectrolyte loaded sludge; f) continually adding polyelectrolyte to the polyelectrolyte loaded sludge during dewatering to separately form dewatered sludge and the dewatered effluent of step c); g) extracting, as a second product of step c), polyelectrolyte free effluent; h) recycling the polyelectrolyte free effluent to the bioreactor.