Test Study On Bio-contact Oxidization Process Purification For Urban Slightly-polluted Streams

With the rapidly development of industry and agriculture in recent years, river pollution emergencies happened frequently, leading to serious deterioration of river ecosystem. As an important part of urban ecosystem, urban rivers play an significant role in construction of ecology. Consequently, urban polluted river water purification is of great importance for the overall improvement of urban river system and the sustainable development of the city.The micro-polluted water of Fuyang river in Handan, branch of the Ziya river,was considered as the investigation object. In this paper the startup test of a continuous stream biological contact oxidation reactor was investigated.The reactor used elastic space packing as microbial membrane carrier.The activated sludge of aeration tank fro m sewage treatment plant was selected as inoculation sludge.The experimental results showed that: under the condition of sufficient organic and DO, the reactor was easily to hang membrane successfully even in the low temperature.The removal of pollutants slightly decreased when the hydraulic retention ti me of the reactor shortened fro m 20 h, 16 h to 12 h.The removal efficiency of CODCr, TN, NH4+-N, TP, turbidity were 28.5%, 31.6%, 23.4%, 44.5%, 23.4% in the HRT 12 h, respectively. After changing the aeration pattern to intermittent aeration, 50% and 60% of CODCr and turbidity removal efficiency achieved.The TN removal efficiency,however,was greatly affected by the aeration on off time.Besides,the smaller ratio of aeration on/off ti me benefit the denitrification process, lead to a higher TN removal efficiency.In this study, the changes of biofilm and biophase were also investigated.The results indicated that biofacies in the biofilm were rich,and its main components including all kinds of bacteria, fungus rubber group, protozoa, metazoa and so on.The hydraulic retention ti me of 12 h and the 6 h-6 h anoxic-aerobic phase were selected as the optimum operating condition in this study. when comprehensive consider water quality, energy saving and the hydraulic retention ti me should not be too long in the practical engineering design.