Municipal wastewater treatment by moving-bed-biofilm reactor with diatomaceous earth as carriers

This study was conducted to examine the feasibility of using a moving-bed-biofilm reactor with internal circulation through aeration for the treatment of municipal wastewater. The attached film was a mixed-microorganism consortium, which used composite-refined-diatomaceous earth as novel biomass carriers to form a diatomaceous-earth-moving-bed-biofilm-reactor (DEMBBR) process. The startup of laboratory-scale, continuous-flow reactor was successfully achieved without seeding activated sludge. The DEMBBR process removed chemical oxygen demand, total phosphorus, ammonium-nitrogen, and turbidity at the highest rate of 88.5, 83, 92.3, and 96.7%, respectively, with a hydraulic retention time of only 2.5 hours. The DEMBBR was less affected by interruption and adverse operation conditions than the conventional-activated- sludge reactor. Thus, the DEMBBR could be proposed to be a cost-effective, small-wastewater-treatment-process unit.