| Liede sewage treatment plant is located in guangzhou tianhe district, the total size of1.2million m3/d, has built The first three phase of the scale has built0.64millionm3/d, to build scale The fourth stage project need to build0.56million m3/d. Four phase of construction needs to solve two major problems:①build scale of0.56million m3/d, but reserve the right to use construction land is only13.5hectares;②The standard is more strict, traditional secondary treatment process is difficult to meet the requirements. The project, the key lies in the choice of reasonable craft type and design parameters, meet in the fourth stage project for water quality and land use requirements.To meet more stringent effluent standards, this study identified the key processing project of this project for SS, NH4+-n, TN and TP, through processing the key processing projects, degree and difficulty analysis, determine the "to strengthen the secondary treatment, removal of NH4+-n, TN, first to the emission standards. Along with the depth of the processing, further removal of SS, TP, BOD and COD standards" technical route. Focus on two kinds of improved A2/O and UNITANK process was carried out technical and economic comparison,. and ultimately determine the "efficient sedimentation tank+improved A2/O+rotary filter" the technology of the combination.To solve the problem of land for the fourth stage project standard is low, in engineering design, considering appropriate reduce the residence time, narrowing the biochemical pool surface area; By improving the surface load, reduce the second pond surface area. And through the model simulation operation, analyzed its feasibility. At the same time, combining with just three phase of the actual situation of the engineering and operation experience, with the method of biological sludge dewatering directly, cancel the sludge stabilization facilities; Covers an area of less uv disinfection has been adopted and the depth of the rotary filter process. To within13.5hectares of land, to satisfy the four phase of0.56million m3/d processing requirements.The design of3modified A2/O biochemical pool (single seat size:187000m3/d; single seat size:B*L*H=91.50*95.08*10.5m; MLSS concentration:MLSS=3.5g/L; Fw=0.115kg BOD5/kg sludge load:MLSS D; sludge age:theta=11.1D; HRT=9.58h, the pre anoxic tank is0.33h is0.99h, the anaerobic tank, anoxic tank is2.85h, the aerobic zone is5.44h). The3seat two sedimentation tank (single seat size:187000m3/d; one dimension of B*L=90.45×86.40×4.8m; surface load:the average flow of q=1.1m3/(M2·h); precipitation time: T=2.0h). A rotary disc filter (the size is A*B*H=63.5*27.5*3.25m; equipped with28sets of rotary micro filtration; filtration precision10um). The four phase of the project covers a total area of about13.5hectares, the total project investment1744150200yuan, the total cost per unit of new investment1.0498yuan/m3,normal production year unit operating costs0.4517yuan/m3. The effluent quality can meet the national standard "urban sewage treatment plant pollutant discharge standard"(GB18918-2002) level of A standard and Guangdong Province standard "water pollutant discharge limits"(DB44/26-2001) requirements of a standard.This study aims to analyze the system of Liede four sewage treatment plant project design conditions, the key link, process, design, engineering cost and operating expenses, summed up the city of large sewage treatment plants applicable process, evaluation method, design and the problems needing attention in the operation, provide experience reference to the Southern China region of large sewage treatment plant project design. |
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