Study On The Startup And Operation Mode Of MIOD Process In Small Town Wastewater Treatment Plant

This research carried out in the test for Modified Integrated Oxidation Diteh process(MIOD) whitch was applied in a wastewater treatment project of Nanping town,Nanchuan district of Chongqing. Some key operation parameters of MIOD process were determined and problems encountered in the process of commissioning were analyzed based on analysis of the law of influent quality and quantity. The optimal equipment operating conditions in different influent quality had been determined and carried on the analysis of the energy consumption through the research of operation mode for the equipment in MIOD process. The main conclusions in this thesis have been summarized as follows.(1) The concentration range of influent COD, NH4+-N, TN, TP for the WWTP in Nanping town was: 26.22 mg/L~222 mg/L, 4.21 mg/L~40.74 mg/L, 5.39 mg/L~45 mg/L, 0.14 mg/L~1.66 mg/L respectively. With characteristics of "small quantity of influent, low concentration of pollutants, quality and quantity of the influent significantly influenced by the weather, lack of carbon source".(2) The inoculation and cultivation method was used in this research. The cultivation and domestication was complished in 2 months. The effluent quality can meet the requirement of the first level B standard specified in GB18918-2002, the effluent COD, NH4+-N, TN, TP was: 24.64 mg/L, 4.21 mg/L, 15.14 mg/L, 0.25 mg/L respectively.(3) Considering the characteristics of influent quality and quantity for WWTP in small town, controlling sludge age at 38 d and the influent distribution ratio of anaerobic and anoxic zones by 2:8. Sunny days with the operation mode of " aeration for 2 h + stop aeration for 4 h", the effluent COD, NH4+-N, TN, TP was: 13.84 mg/L, 2.15 mg/L, 2.48 mg/L, 0.15 mg/L respectively. Rainy days with the operation mode of "aeration for 2 h + stop aeration for 2 h", the effluent COD, NH4+-N, TN, TP was: 12.84 mg/L, 1.76 mg/L, 5.47 mg/L, 0.41 mg/L respectively. Such operation mode can be used to stabilize the effluent quality to meet the requirement of the first level A standard specified in GB18918-2002. The operation mode of "aeration for 2h + stop aeration for 4h" had a lower energy consumption, power consumption for per unit of water was 0.21 k W·h/m3, for remove unit pollutant(measured as COD) was 1.03 k W·h/mg COD.(4) Under the condition of large fluctuation of influent quality and quantity, the MIOD process was optimized through the combination of equipment operation, can ensure the effluent quality meet the standard. Its covers an area of small, simple management and can be characterized as small town or large-scale WWTP selection process.