Feasibility Research About The Third Sewage Treatment Plant In Xi'an

The method of large-scale dirty water disposal have many kinds at present. Which craft and relevant construction indexes to choose become the core to which the policymaker pay attention in the construction of the dirty water processing factory. Firstly considering reliability of craft, advance of technology, credibility of operation, and other technique factors, through investigations actually, we choose ORBAL craft in the oxidize ditch ,CAST craft in the SBR, A/A/O craft in traditional activated sludge processing as alternative scheme. Secondly, through comparing technological economy, analyzing a series of factors such as the construction investment, environmental pressure , economic benefits of the third sewage treatment plant in Xi'an, we have offered the theory foundation for feasibility of construction of the third sewage treatment plant in Xi'an.This research is mainly divided into four stages. First ,collect and analyse the information, confirm the basic data and build indexes. The second, compare and choose the project. The third, recommend the design of project phase. The fourth, economic analysis and appraise stage. The results of every stages showed: The source water quality will be improved obviously through the first and the second grade biological disposal. The main pollution indexes: BOD5 of water is dropped to lower than 20mg/l from 200mg/l, COD is dropped to under 60mg/l from 390mg/l, SS is dropped to under 20mg/l from 250mg/l, NH4- N is dropped to under 15mg/l from 30mg/l. But when the three crafts of handling reach an equal basis, there are many differences in handles complexity, construction investment, construction period, economic benefits, operation and management, energy consume.Through the research systematically and scientifically, the results indicate that CAST craft construction needs the lowest investment, the least structures, the shortest construction period and the most convenient operation and management. It received the highest cents in the many factors and is finally determined as the scheme of feasibility research of this sewage treatment plant.This feasibility research has made outline engineering design to the recommendable craft,Considering the sewage deeply disposal and reuse , it makes feasibility research has higher guidance function and practical value, and the key indexes such as treatment craft, project scale, gross investment, construction period etc, are suitable for Xi'an government and related departments to make the decision of the basic municipal construction project, and to supply the reference of preliminary design at the next stage of sewage treatment plant.