Characteristics of rural wastewater treatment by no reflux swimming bed biofilm reactor

A novel swimming bed reactor with no reflux which suit for small scale wastewater treatment was developed. The performance of the reactor for treating domestic wastewater was investigated. Steady removal effect with 71.75% of average COD removal rate was achieved in hydraulic retention times (HRT) of 20.74 h ~ 4.30 h. When hydraulic retention time (HRT) was at 8.12h with average NH₄⁺-N volumetric loading of 0.25 kg/(m3.d), 78.5% of average NH₄⁺-N removal rate was obtained. In the optimal condition with pH of 6.7~7.7, 92.2% of average NH₄⁺-N removal rate was obtained. Presence of protozoa and metazoa on the biofilm were observed and steady food chains was contributed to the sludge reduction, 0.2840 of sludge yields (MLSS/CODremoved) was obtained in the experiment.