| Since the reform and opening up,our country’s economy has been developing rapidly,and the increasing consumption of oil,which is accompanied by social and living standards,has increased year by year.As one of the world’s three major energy sources,our country’s coal is rich,full of variety and widely distributed.So the energy structure of our country presents “rich coal,less oil,less gas”,the characteristics of the Chinese government put forward the development and utilization of clean coal technology as a focus in the study of science and technology.Fischer-Tropsch synthesis is an important step in coal-oil technique,but also produces a large number of wastewater that has complex quality,high COD concentration,nethermore pH and the lack of nutrition elements.Owning to the special character,study of fischer-tropsch synthesis wastewater treatment at home and abrosd is relatively small,and wastewater treatment standards are the important factors affecting the development of coal technology promotion.So this study uses “anaerobic system-multistage aerobic system-advanced treatment process” treatment process,after several months of operation,the effluent of process had achieved “ Comprehensive discharge standards for sewage”(GB8978-96)first class discharge standards.Anaerobic process including oil-removal tank,micro electric reaction tank and external circulation anaerobic tower.The multistage aerobic system including bioaugemntation tool,aerobic pool and MBR.And the advanced treatment using ozone catalytic oxidation tower+biological contact oxidation+sand filter tank.This paper firstly introduced the F-T synthesis、the characteristics of F-T synthesis wastewater and the development of F-T wastewater treatment technology at home and abroad.Also produced the mechanism and development of anaerobic treatment and aerobic treatment,then summarized the mechanism and design parameters of the process that this study used.This paper is through the on site test start,explores the anaerobic,aerobic process startup mode.The COD removal and the change of various process parameters are also studied during the start-up process.This paper is focused on the COD removal and the change of process parameters during two-months stable operation.The optimal of wastewater pH by micro electic reaction after the influenceof different factors were also disscussed,and introduced a large number of bubble problems and solutions encountered in the experiment.The main conclusions are as follows: Practical operation shows that treatment of F-T wastewater by “anaerobic system-multistage aerobic system-advanced treatment process” is stable and reliable,also has the engineering instruction meaning.The operating practice shows: The removal efficiencies of COD by anaerobic tower is fluctuating between 76% and 85%.In the multistage aerobic process,bioaugemntation tool,aerobic pool and MBR for the average COD removal efficiencies are 61%,38%,61% respectively.And the removal rate of COD by the multistage aerobic process is89%~90%.In the advanced treatment,ozone catalytic oxidation tower on the removal rate of COD is 60%~65%,the biological contact oxidation on the COD removal rate reaches 73%,and the final effluent of COD concentration is 20~50mg/L,pH is 7.7~8.5,and SS concentration is 2.0~4.8mg/L,so the effluent is good enough to meet the first charge standard of the Comprehensive discharge standards for sewage.Experiment by changing the voltage at the ends of the electrode plates,plate electrode spacing,external circulation sludge reflux ratio of anaerobic tower,the results showed that the external circulation sludge reflux ratio is 100%,the electric plate on both ends of the voltage is 5V,electrical plate spacing is 3cm,micro electric reaction tank of wastewater pH can be raised from 3.2 to 5.6~6.0.The process and results of this paper are of great importance to the development of F-T wastewater treatment.It is a good reference for the debugging and operation of practical engineering applications in the future. |
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