Energy Saving Analysis And Optimal Operation Research Of Sewage Treatment Plant

With the rapid development of our country in recent years,the amount of sewage treatment is increasing year by year.Although the new sewage treatment plant can meet the major requirements of wastewater treatment,but by the Limitations of treatment process and technology constraints,China's sewage treatment energy consumption is relatively high.Many sewage treatment plants get high infrastructure costs and operating costs.So it has become a hot topic to research on the energy saving and consumption reduction of sewage treatment.The energy consumption of sewage treatment plant mainly comes from the electric energy,Chemical reagent and fuel consumption.Taking D sewage treatment plant in North China as the research target in this paper.This sewage treatment plant use triple oxidation ditch as main processing technology.Check scale is 60 thousand cubic meters of water per day,However,the actual processing water only 50 thousand cubic meters of water per day.Effluent water quality meet the national standards,The removal rate of COD and NH3-N reached 88.5% and 90.8%.Tons of water consumption is 0.3643W·h/m3.The sewage plant process can be divided into pretreatment units,biological treatment,depth treatment and sludge treatment four units.Using unit energy consumption analysis method to analyse of the energy consumption of each unit and finding the energy consumption composition and distribution of each processing unit,so as to find the way to optimize the operation.Analyzing the treatment effect by using fuzzy comprehensive analysis when the optimal operation of wastewater treatment plant finished.The main conclusions are as follows:(1)By analyzing the energy consumption of each processing unit,it is found that the biological treatment unit is the largest energy consumption unit in the water plant.Energy consumption accounted for 55.45% of total energy consumption in the whole plant.While the device utilization is the lowest in each unit,it is only 65.9%.Aeration rotary brush in oxidation ditch is the largest energy consumption equipment in the biological treatment unit.The electric energy consumed by the aeration brush can get over 90% of the biological treatment unit.So the biological treatment section is the key unit of energy saving.(2)Redistributing three groups of oxidation ditch water by the principle of water balance and the distribution law of DO in oxidation ditch,the water content of the 1 oxidation ditch was reduced to 84% and the residual water content was allocated to the remaining oxidation ditch equally.After adjustment 1 oxidation ditch water intake is 702m3/h,No.2 and No.3 oxidation ditch water becomes 900m3/h,Resetting the amount of the brush to reduce power consumption according to the new influent flow in each oxidation ditch.The power consumption per ton wastewater can be reduced by 0.0102kW·h/m3,the purpose of saving energy and reducing consumption of certain(3)After the test,the index of effluent water from optimized operation meet the national standards.The removal rates of other pollutants were improved in small amplitude,tons of water to reduce power consumption for 0.3562kW·h/m3.Fuzzy comprehensive evaluation method has been used to evaluate the overall treatment effect of water plant,Set five evaluation levels of "good","better","general","worse" and "very poor".Analysis shows the overall operation of the sewage treatment effect is good.