AMAO(多级AO)工艺在污水厂扩建工程中的应用及运行

西安市某污水处理厂二期扩建工程设计规模为2. 5×10~4m^3/d,采用AMAO(多级AO)+高效沉淀池工艺,出水水质执行一级A排放标准。AMAO工艺生物池MLSS可达5 100mg/L,远高于常规AAO工艺(MLSS通常按4 000 mg/L设计),生物池容积可减小20%;无需外加碳源,能优先利用污水中的碳源进行反硝化,省去了常规AAO工艺的混合液回流,脱氮效率大于75%,电耗可降低0. 015 kW·h/m^3。高效沉淀池斜管上升流速设计取低值(11. 37 m/h),省去了后续过滤单元,节约水头约8 kPa,出水SS稳定小于10 mg/L。该工程实际出水水质优于一级A排放标准,部分指标已达到地表水Ⅳ类水质标准,直接运行费用仅为0. 59元/m^3。

Application and Operation of AMAO Technology (Multi-stage AO) for Expansion Project of Wastewater Treatment Plant

The design treatment capacity of the second phase expansion project of a wastewater treatment plant in Xi’an was 2. 5 × 10~4 m^3/d. The combination process of AMAO( multi-stage AO) and high-efficiency sedimentation tank was adopted to ensure that the effluent quality could reach the first class A discharge standard. The MLSS of the bio-tank could reach 5 100 mg/L,much higher than that of the conventional AAO process( MLSS was usually designed at 4 000 mg/L),so the bio-tank volume could be reduced by 20%. No additional carbon source was needed,and the carbon source in the wastewater could be preferentially used for denitrification, eliminating the mixed liquid reflux in conventional AAO process. The denitrification efficiency of the process was more than 75%,and the power consumption could be reduced 0. 015 kW·h/m^3. The upward-flow velocity of inclined pipe in high-efficiency sedimentation tank was designed at low value( 11. 37 m/h),and the subsequent filtration unit was omitted. The water head was saved about 0. 8 m,and the SS of effluent was stably below 10 mg/L. The actual effluent quality was better than the first class A discharge standard,and some indicators had reached class Ⅳ quality standard for surface water. The direct operation cost was only0. 59 yuan/m^3.