深圳下坪老龄化填埋场渗滤液处理工艺优化与应用

Optimization and Application of the Leachate Treatment Process in Xiaping Aging Landfill in Shenzhen

深圳下坪老龄化填埋场渗滤液全量化应急处理项目设计处理规模为1200 m^(3)/d,主体处理工艺采用“均化池+两级AO-MBR+NF+RO”。针对原水总氮浓度超高的特性,对渗滤液处理工艺进行了优化设计,包括强化MBR生物脱氮的低能耗技术、膜深度处理系统的创新性组合、浓缩液减量化、全量化处理技术等。设计中对MBR系统进行了优化和改进,包括延长水力停留时间、提高硝化液回流比、采用10 m深水曝气方式及内置式超滤等;对纳滤浓缩液进行了减量化处理,使纳滤系统的整体回收率达到95%;对反渗透浓缩液采用“两段式浸没燃烧蒸发”工艺进行处理。系统整体运行良好,出水水质稳定达标,实现了集约化布置和节能的目标,以及渗滤液的全量化处理。

The design scale of a fully quantified emergency project for the treatment of leachate from Xiaping aging landfill in Shenzhen is 1200 m^(3)/d,and the main treatment process consists of equalization tank,two-stage AO,MBR,NF and RO.Owing to the high total nitrogen in raw water,the leachate treatment process was optimized by strategies such as low energy consumption technology for enhancement of MBR denitrification,innovative combination of membrane advanced treatment system,reduction of concentrate,and adoption of fully quantified treatment technology.In the design,the MBR system was optimized and modified by measures such as prolonging hydraulic retention time,increasing nitrification liquid reflux ratio and adopting deep water aeration approach(height of 10 m)and built-in ultrafiltration.The nanofiltration concentrate was reduced and the overall recovery rate of the nanofiltration system reached 95%.A two-stage submerged combustion evaporation process was employed for the treatment of the RO concentrate.The overall system ran well and the effluent quality stably met the discharge standard.The goal of intensive layout and energy saving was realized,and the treatment of landfill leachate was fully quantified.