Reconstruction Processing Of Xiaoshan Sewage Treatment Plant

Development of the world economy has proved that we must solve the contradiction between development and environmental protection in order to achieve sustained and steady economic growth. Along with the rapid development of social and economic in our country, the urban water pollution were becoming more and more serious."Something that pollutes"brought out the shortage of water resources which became a outstanding difficulty that conditioned the sustained development of economy. Therefore it was of great practical significancen to develop new sewage treatment technologies and techniques that suited the specific conditions of our country with high efficiency and low consumption, and met discharge requirements.The sewage discharge amount of dyeing and chemical industries was considerable in Xiaoshan sewage treatment plant, and the dyeing waste- water was hard to biodegradation because of the existence of scores of organic molecules and organic solids. The existing sewage treatment technology was High Performance Compact Reactor process, because of water discharged in a jet of HCR break the activated sludge into pieces and there was no district for the removal of nitrogen and phosphorous, so the biological degradation property of the influent was relatively low, hydraulic retention time of the system was too short, so was the sludge retention time. Aeration was far from the need of pollution removal. So Xiaoshan sewage treatment plants was upgraded in that background and the hydrolysis acidification-reversed A²/O(Anoxic /Anaerobic/Oxic)process was adopted for this project. Reversed A²/O method set the anoxic district ahead of anaerobic hypoxic zone that improved the effectiveness of sewage treatment to a certain extent. The major parameters of reconstruction processing were DO 2-4mg/L in Oxic zone and that less than 0.5mg/L in Anaerobic zone, the concentration of MLSS₁ was about 3000mg/L, hydraulic retention time and sludge retention time were 10h and 7-10d, respectively.According to the conclusion drew from the operation, water quality could achieve the standard of pollutants for municipal wastewater treat- ment plant(GB18918-2002), especially nitrogen and phosphorous.It was proved that the hydrolysis acidification combined with reversed A²/O processes was basically feasible in Wastewater Treatment Plant.