超高标准除磷的纳滤再生水工艺设计及工程验证

Design and Engineering Verification of Nanofiltration Process for Super High Standard Phosphorous Removal in Wastewater Reclamation

云南大理某城镇污水处理厂设计产水水质达到地表水Ⅲ类标准(湖、库),采用膜生物反应器(MBR)-纳滤(NF)双膜处理工艺。针对产水总磷≤0.05 mg/L的超高标准除磷需求,对该项目的NF工艺段进行除磷衡算和膜系统设计分析,确定了浓水分段双回流、两段元件排列比4∶1的最佳工况条件。实际工程验证结果表明,产水水质稳定达标,其中总磷为0.013~0.042 mg/L,NF工艺段的电耗、药剂、耗材及膜折旧成本合计0.37~0.55元/m3,NF膜系统清洗周期约为1个月。MBR-NF双膜工艺的常规产水水质指标达到地表水Ⅲ类标准(湖、库),并具有较高的环境生态安全性,适用于富营养化敏感水体治理、工业水回用、再生水地下回灌等。

To meet the effluent quality as levelⅢcriteria of Environmental Quality Standards for Surface Water(GB 3838-2002)(S-Ⅲ),the MBR-NF process was applied in a municipal wastewater treatment plant(WWTP)in Dali,Yunnan Province.Aiming at the super high effluent requirement of TP≤0.05 mg/L,the phosphorus removal balance and membrane system design were analyzed for the NF process section of this project,and the optimal working conditions of double reflux of concentrate and 4∶1 ratio of two-section element arrangement were determined.The verification results of actual project show that the water quality is stable and up to the standard.Among them,the effluent TP concentration was 0.013-0.042 mg/L.The operational cost including energy,chemicals,consumption materials and NF membrane depreciation was 0.37-0.55 yuan/m3.The duration of a membrane cleaning cycle was about a month.The common effluent indexes of MBR-NF process can meet S-Ⅲ,and have high safety to environmental ecosystem,which is suitable for wastewater treatment in eutrophication sensitive areas,industrial water reuse and wastewater reclamation for groundwater recharge.