| With the acceleration of industrial modernization,a large number of industrial wastewater will be discharged into rivers every year without proper treatment,resulting in surface water pollution in different degrees,such as rivers and lakes.Most waterworks use polluted surface water as raw water.Traditional water treatment technology can not meet the drinking water quality standards.In order to ensure human health,drinking water needs to be treated in depth.Taking the deep purification and transformation project of Changzhou M Water Plant in Jiangsu Province as the research object,this paper investigates the operation and water quality of the original conventional treatment process of M Water Plant.In this paper,three advanced treatment technologies of activated carbon adsorption,membrane technology,ozone biological activated carbon adsorption,chemical oxidation,powder activated carbon adsorption and biological pretreatment were compared and analyzed respectively.Finally,the process combination of pre-adding powdered carbon,ozone oxidation + existing conventional treatment + ozone biological activated carbon adsorption was selected as the advanced purification process of M waterworks.At the same time,according to the requirements of the selected deep purification treatment process,the paper puts forward the relevant construction scheme for the reconstruction and construction of M water plant.In order to further analyze the operation efficiency of the deep purification process in M water plant,five indexes of turbidity,ammonia nitrogen,oxygen consumption,nitrite nitrogen and p H value of the inlet and outlet water of ozone biological activated carbon filter were tested and analyzed once every 8 hours from October 17 to December 25,2018.The results showed that the turbidity of effluent was improved,the removal rate of CODMn increased by 30% on average,and the ammonia nitrogen decreased to some extent.In view of the reasons for the increase of nitrite content and the decrease of p H value in effluent,this paper also analyzed the reasons.After the formal operation of M water plant,the indexes of chroma,turbidity,oxygen consumption,ammonia nitrogen and microorganism quantity are selected to test and compare the water quality of the water plant leaving the factory with that of the same period before the transformation.The results showed that CODMn decreased by 66.6% compared with the conventional process before modification;ammonia nitrogen content decreased;effluent color,turbidity increased,taste improved;bromate,formaldehyde,trihalomethane,halogenated acetic acid and other disinfection by-products content was far lower than thenational standard.This paper also studies the economic operation and engineering benefit of M water plant transformation project.Firstly,the traditional financial analysis method is used to calculate the internal financial rate of return of M water plant operation is7.92% and the payback period of investment is 11.36 years,which meets the national requirements,according to the calculation of water price of 0.44yuan/m3.The break-even point of M water plant is 60.07%.That is to say,the break-even point can be reached when 425,500 tons of tap water are produced per day,and the operation of M water plant has certain risk resistance.Secondly,using DEA data envelopment analysis method,the comprehensive benefits of M water plant reconstruction project are compared with those of W and Q water plant reconstruction project,key input and output data are set up,and DEAP computer software is used to assist the analysis,and the conclusion that the comprehensive benefits of M water plant are the best in three projects is drawn. |
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