A Study on a Coupling Bioreactor for the Treatment of Domestic Wastewater and Mechanisms of Sludge Reduction

Based on the separate flow theory and the multi-phase reaction principle, this paper examines the use of a coupling bioreactor for wastewater treatment and sludge reduction. Results showed that the coupling bioreactor sustained a COD removal efficiency of at least 85%. The COD loading rate increased from 0.49kgCOD/ (m(3).d) to 1.93kg COD/(m(3).d). By changing operation parameters, it was found that an excellent effluent quality was obtained. When under Micro-aeration, Anoxic and Aeration conditions, a total nitrogen (TN) removal rate of 86.7% was obtained. With HRT 8h and 43% volume ratio of anoxic section, it has an effluent TN concentration lower than 15mg. With the coupling bioreactor, a lower sludge production rate also took place. There was only a mean sludge production rate of 0.068MLSS/kgCOD. In the liquid phase of the dynamic cyclic closed reactor, TN, TP and TC all increased. This was accompanied by the emission of CH(4) gas, from which it can be inferred that the sludge trapped by porous carriers must have biodegraded under the conditions of the inner anaerobic environment. Thus, less or even no sludge was produced.