Study On The Removal Of Compoundf Wastewater Of Industrial Park In A~2/O Process

The Songhua river is a important river of China, but with the development of economy, the Songhua river pollution is increasingly serious, Feiketu river is an important anabranch of Songhua river, industrial enterprise increases gradually along this river, and become Binxi industrial park. Due to the climate of northern region is cold in winter, it seriously impact the treatment effect of wastewater, and the discharge of pollutants exceeds standard badly, so the Binxi industrial park become one of the main sources of Songhua river. Aim at the characteristics of the north cold regions, this subject seems A²/O process as the main research process, and according to the test results, analyzes the change rules of treatment effect with temperature's change, so as to put forward reliable operation mode under the low temperature condition, guide the actual motion of sewage plants, protect the water quality of Songhua river.This test adopt A²/O process with the multi-point cycle control, operation parameters is that anaerobic return sludge ratio is 20%, return sludge ratio from secondary sludge to head end of aerobic pond is 20%, internal recycle ratio is 300%, DO is 2.0³.0mg/L, SRT is 15d, MLSS is 3.0⁴.0g/L. After system was started and operated stably in 23℃the removal efficiencies of COD, NH₃-N, TN and TP were all good, it showed that testing process had strong removal efficiencies on organic pollutants at room temperature.After the system was started and operated stably in 12℃,the average effluence concentration and removal of COD were 42.00mg/L and 84.00%, the average effluence concentration and removal of NH₃-N were 9.24mg/L and 82.00%, the average effluence concentration and removal of TN were 18.80mg/L and 63.50%, the average effluence concentration and removal of TP were 0.18mg/L and 96.63%,It can be seen that the composite low testing process increased removals of COD, NH₃-N, TN and TP by 3.48%, 11.26% , 10.00% and 1.83%. The results showed that, activated sludge-membrane composite technology can strengthen the treatment effect of organic pollutants of low testing process, especially for NH₃-N and TN.The COD removals of system in 23℃, 18℃, 14℃and 12℃were respectively 89.05%, 87.61%, 86.13% and 84.42%, the NH₃-N removals were 98.79%, 98.15%, 90.88% and 84.10%, the TN removals were 76.93%, 75.54% 70.56% and 66.51%, the TP removals were 96.36%, 96.13%, 95.22% and 94.98%. With temperature reduction , the removals of COD, NH₃-N, TN and TP all decreased. But the removals of COD and TP declined less and still can meet demands in 12℃. This is because PAOs arepsychropliles, phosphorus release and denitrification all consume organism. The removals of NH₃-N and TN declined great and cannot meet demands in 12℃.This is because nitrifying bacteria and denitrifying bacteria are all mesophiles, their liveness is low and metabolism is week at low temperature.The text made the economic and environmental benefits analysis on account of the condition that testing process is applied to Binxi sewage treatment plants (104m3/d). The rezults show that the total investment is 25.1736 million yuan, the operation cost is 0.96 yuan, this project is feasible through economic evaluation. In addition, this project can reduce emissions of COD, ammonia nitrogen and TP are respectively 966.50 tons, 164.73 tons and 17.61 tons each year.The test used sludge-membrane composite technology, enhanced biological treatment, increased the removal efficiencies of nitrogen and phosphorus. This method can reduce the emissions of organic pollutants of northern region in winter, protect the water environment near Songhua river, and provide basis and reference for design, operation and regulation of wastewater treatment plants.