Moving bed biofilm reactors and chemical precipitation for high efficiency treatment of wastewater from small communities

A new Moving Bed Biofilm Reactor (MBBR) has been developed, where the biomass is attached to small plastic elements that move freely along with the water in the reactors. Several small biological/chemical wastewater treatment plants are now using the MBBR process. Official control samples have shown that these plants are very reliable. The average effluent concentrations from the plants surveyed, three retrofits and two originally designed with the MBBR process, were as low as 11 mg BOD7/l(similar to 9 mg BOD5/l), 11 mg SS/l and 0.26 mg total P/l. Approximately 2 man hours per week were needed for operation of a plant originally designed with the MBBR process. (C) 1997 IAWQ. Published by Elsevier Science Ltd.