消氧强化反硝化脱氮AAO生物池在合肥某污水厂的应用

Application of AAO Biological Tank for Denitrification Enhanced by Oxygen Elimination in a Wastewater Treatment Plant in Hefei

合肥某污水处理厂设计规模为20.0×104m3/d,出水执行地表水准Ⅳ类标准,其中TN≤5 mg/L。由于出水总氮要求高,为降低运营成本,生物池的设计将脱氮作为重点。在分析污水厂流域范围内近几年进水水质变化趋势的情况下,结合水温不同对考核指标要求也不同的特点,对生物池进行重点挖潜,在五段Bardenpho的基础上进行改进,在厌氧池前设置选择池,在好氧区后设置消氧区,同时将第二缺氧区改造为好氧/缺氧变化区,这样在提高生物池脱氮除磷功能的同时也可更好地应对冬春季和夏秋季运营方式的不同需求。深度处理采用混合絮凝+反硝化深床滤池工艺,消毒采用次氯酸钠消毒。实际运行数据表明,工艺流程及设计参数合理可行,出水水质能够稳定达标。

The designed treatment capacity of a wastewater treatment plant in Hefei is 20.0×104 m3/d,and the effluent quality is required to meet surface water classⅣstandard,among which TN in the effluent is no more than 5 mg/L.Due to the high requirement of total nitrogen in the effluent,design of biological tank should focus on nitrogen removal in order to reduce the operational cost.Based on analyzing profile of the influent quality of the wastewater treatment plant in the drainage basin in recent years,combined with the characteristics of different water temperature requirements for assessment indicators,the project focused on modification of the biological tank.Based on improvement of the five stage Bardenpho,a selection tank was added in front of the anaerobic tank,an oxygen elimination zone was set up after the aerobic zone,and the second anoxic zone was transformed into aerobic/anoxic varying zone.In this way,the nitrogen and phosphorus removal performance of the biological tank was improved,and at the same time,it could better meet different operational needs in winter,spring and summer,autumn.The advanced treatment process consisted of mixed flocculation and denitrification deep bed filter,and sodium hypochlorite was employed for disinfection.Actual operational data showed that the process flow and design parameters were reasonable and feasible,and the effluent quality could meet the discharge standard stably.