Key technologies and engineering practices for upgrading and renovating sewage treatment plants
The Phase Ⅰ and Phase Ⅱ projects of a municipal sewage treatment plant in Hebei Province each have a capacity of 3.0×104 m3·d-1.The core treatment process consists of a"hydrolysis acidification tank"followed by a"continuous inflow cycle circulation aeration activated sludge system(CASS tank)"and an"ozone contact oxidation tank."Due to the extended operation time of the sewage treatment plant,the continuous increase in sewage collection volume in surrounding towns,and the improvement of discharge standards,the treatment capacity of the plant was relatively insufficient,and the outlet water quality cannot meet the required standard.After multiple process demonstrations,and considering factors such as land restrictions,operational status,and economic indicators,the targeting indicators included biochemical oxygen demand(BOD5),chemical oxygen demand(CODcr),ammonia nitrogen(NH3-N),total nitrogen(TN),and total phosphorus(TP).The biochemical treatment section of the sewage treatment plant was converted from a hydrolysis acidification tank to an anaerobic and anaerobic tank.And an improvement measure was implemented by adding elastic fillers to the anaerobic and aerobic tank.The advanced treatment section was converted from an ozone contact oxidation tank to an ozone catalytic oxidation tank.An analysis was conducted on the inlet and outlet water quality of each primary treatment unit during the process debugging period.The results showed that the upgraded and renovated sewage treatment system operates effectively,demonstrating advantages such as a high pollutant removal rate,stable treatment effect,and strong resistance to impact.The discharge concentrations of CODcr and TP were reduced to below 20 and 0.2 mg·L-1,respectively.The effluent water quality stably met the Class Ⅲ water standard in the Surface Water Environmental Quality Standard(GB 3 838-2002).It also met the emission limits of the core control area in the Daqing River Basin Water Pollutant Discharge Standard(DB 13/2795-2018).The research results can provide theoretical references for the upgrading and reconstruction of similar sewage treatment plants.
sewage treatment plantupgrade and projectadvanced treatmentprocess adjustment
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