Study On The Pilot Trial Of Urban Wastewater Treatment With Pneumatic RBCs

With the development of modern industry and the population explosion, an extreme shortage of water resources and serious pollution happened. Therefore, the modern society has becoming focus on the problem of water pollution.In order to protecting our environment and solving the shortage of water resources problem, people unremitting search for an effective and low costing technology to deal with the treatment of wastewaters. Rotating Biological Contactor (RBC) technology is a kind of biological membrane wastewater biological treatment technology, the organic matters in the sewage have being removed effective, and the removing of nitrogen and phosphorus can be achieved under certain circumstances in the RBC technology. According to the dissolved oxygen content in the sewage of contact reaction tank, the RBCs could be devided into aerobic RBCs and anaerobic RBCs; according to the driving mode, the RBCs could be divided into three categories, for electric RBC, pneumatic RBC and passive RBC. The pneumatic rotating biological contactors are used in this test. And the study found that:(1)The pneumatic rotating biological contactor has a high efficiency in removing organic matter in sewage, and the removal rate could be stably above80%, the effluent COD could reach the grade A standard of GB18918-2002.(2)The semi-submerged pneumatic rotating biological contactor(40%submengerce) has a better effect on treating ammonia nitrogen in wastewater, and the average removal rate can reach about90%,but it cannot wipe off the total nitrogen because of its bio-film was thin. However, the RBC showed a certain ability of anti-shock loading of hydraulic impact;(3)The completely submersed disks(90%) has a general removal rate in removing ammonia nitrogen;otherwise,it has a certain removal effect in total nitrogen, the average removal rate was maintained at about43%.(4)The test also explored the removal efficiency of total nitrogen with the connection series of pneumatic RBCs system at a low temperature(15±1℃).Study found that the system has a obvious removal effect, the average removal rate can reach about45%. (5)Temperature is the most direct factors affecting microbial activity in biofilm. When the water temperature in the contact reaction tank was about25℃,both the pneumatic RBCs have a good removal effect in organic matter and ammonia nitrogen.With the decrease of temperature, the removal effiency was worse. And the pneumatic RBCs had a low loading in wastewater treatment.(6)Through pilot and stable operation of the devices, some problems ware found, such as design of tank semi submerged pneumatic rotating biological contactor has large volume, and the volume is small, this will result in the equipment volume waste; the completely submersed disks had a thick biofilm adhering to dics, it would have a good removal efficiency in deal with total nitrogen in theory, however, beause of the narrow space between the dics, the device has a general removal efficiency, so we can enlarge the space between dics to ventilate the internal, in order to gain a better removal efficiency of total nitrogen; the system of connections of pneumatic RBCs is not very logical, beause of the I contactor has a very large volume and the II contactor’s volume is not enough to nitration reaction. Aiming at these problems, puting forward the corresponding improvement measures, providing a reference for the redesign of RBCs in the future.