Study On Three-phase Air-lift Internal-loop Reactor For Treating Domestic Wastewater

With the development of modern industry and acceleration of urban population, there will be more and more wastewater and increasing water pollution, which have drawn wide attention of the government and people. In China, for a long time, wastewater treatment has been troubled by two aspects as large investment and high operating costs; lower processing efficiency and instability operating effects. Therefore, high efficiency and low consumption of wastewater treatment technology are keys to solve the problem of water pollution.The test uses a new three-phase air-lift internal-loop reactor to treat domestic wastewater. It is obvious that the reactor has the advantage of less land area and low construction investment because of the integration of reactive area and settling area. What's more, low energy consumption and convenient management are the reactor advantages, because the mixed liquid return system and sludge return system are combined into one system. The test results of domestic wastewater treatment show that the reactor has high removal ability of COD and SS, as well as it can remove NH4 -N and TN at the same time. Therefore the reactor has better prospect after it will improve in further.In the test, for domestic wastewater, values of COD are 228.3 mg/L to 592.5 mg/L, values of NH3-N are 29.24 mg/L to 48.72mg/L, values of TN are 32.16 mg/L to 55.67mg/L, values of SS are about 126.83 mg/L to 319.39 mg/L, and values of pH are about 6.8 to 7.2. By controlling the sludge concentration, hydraulic retention time and aeration volume, the removal rate of COD, NH3-N, TN and SS are analyzed. The results of the experiment show that the value of COD is less than 60mg/L and removal rate is about 90.65%, the value of NH3-N is less than 8mg/L and removal rate reaches 87.49%, the value of TN is less than 20mg/L and removal rate is about 60%, as well as the value of SS is less than 20mg/L and removal rate about 92%,which meet the wastewater discharge standards GB18918 -2002 1 B emission standards.The test studies influencing factors of simultaneous nitrification and denitrification in the reactor. Under the case of concentration of the sludge and HRT to maintain a certain situation, it can be reach a better-performing with the DO values of inside and middle tube are 2mg/L and.6mg/L. Using self-regulation of wastewater and adjusting C/N of wastewater, we observe the removal rate of TN. The results show that TN removal efficiency is better, up to 75.2%, under the conditions of the C/N about 10.