更高出水标准的南方某全地下污水处理厂设计

Design of a Fully Underground Wastewater Treatment Plant in South China Meeting Higher Effluent Standards

摘要:

污水处理厂出水标准的要求越来越高，探寻适应进水C/N比低且脱氮效率高、出水水质好的污水处理工艺甚为迫切。深圳市某片区需新建1座设计规模为10×10⁴ m³/d、生活污水与工业废水合建（系统独立运行）的全地下污水处理厂。以生活污水处理系统为研究对象，采用“粗格栅—细格栅—曝气沉砂池—多级AO生反池—二沉池—磁混凝高效沉淀池—精密过滤器—紫外消毒”工艺，出水执行《地表水环境质量标准》（GB3838—2002）准Ⅲ类标准（COD_Cr、TN除外）。生反池采用多级AO和AOA可切换双工艺，绿色低碳，且满足提标要求；污泥干化热源和综合楼空调采用污水源热泵，碳排放量减少23%以上；基坑内支撑创新采用预制装配式钢桁架，建设工期节约2个月，节约成本10%。工程用地标准仅为0.25 m²/（m³·d^-1），仅为深圳市用地指标的50%。

Abstract:

As the effluent standards for wastewater treatment plants (WWTP) are getting higher and higher, it is urgent to explore the sewage treatment processes that are suitable for low influent C/N ratio, high denitrification efficiency and good effluent quality. A new WWTP with the design scale of 10×10⁴ m³/d is required to build in an area of Shenzhen, which is a fully underground WWTP in the co-construction form of domestic sewage and industrial wastewater (operated independently). Taking the domestic sewage treatment system as the research object, the process of "coarse screen - fine screen - aerated grit tank - multi-stage AO biological reaction tank - secondary sedimentation tank - magnetic coagulation efficient sedimentation tank - precision filter - UV disinfection" is adopted, and the effluent meets the quasi-class Ⅲ standard of the Environmental Quality Standards for Surface Water (GB3838—2002), excluding COD_Cr and TN. The multi-stage AO and AOA switchable dual process is adopted for the biological reaction tank, which is green and low-carbon and meets the requirements for upgraded standards. The sewage-source heat pumps are used for the sludge drying heat sources and air conditioning in the complex building. The carbon emissions have been reduced by more than 23%. The innovative prefabricated steel trusses are used for internal support in the foundation pit, which save the construction period by 2 months and reduce the costs by 10%. The land use standard for the project is only 0.25 m2 / (m3·d?1), which is just 50% of land use indicator in Shenzhen.