气浮+两级A/O+气浮工艺处理某餐厨沼液

Treatment of biogas slurry of food waste using air floatation-two-stage A/O-air floatation

餐厨垃圾厌氧发酵处理后脱水产生的沼液具有水质变化大、污染物浓度高、含油率高、处理难度大等特点。目前处理工艺以膜处理的组合工艺为主,存在膜通量下降快、过负荷能力差等缺点,同时投资大、运行成本高、浓缩液处理困难。针对上述问题,设计开发了气浮+两级A/O+气浮工艺处理餐厨垃圾沼液。餐厨沼液经该工艺处理后,COD、BOD_(5)的去除率达到98%,NH_(3)-N、TN、TP、SS的去除率达到99%,实际出水的COD、BOD_(5)、NH_(3)-N、TN、TP、SS等均能稳定达到《污水排入城镇下水道水质标准》(GB/T 31962—2015)的要求,可满足当地污水处理厂的接纳要求。该工艺处理成本约为7.72元/m^(3),其中电费7.01元/m^(3),FeCl_(3)0.05元/m^(3),PAM 0.18元/m^(3),碳源0.26元/m^(3),维修费0.22元/m^(3)。运行结果表明,该组合工艺具有出水水质稳定、占地面积小、投资少、运行成本低、操作方便的特点,同时可避免膜浓缩液处理等问题的产生。

The biogas slurry produced by dehydration after anaerobic fermentation of food waste has the characteristics of large fluctuation in water quality,high concentration of pollutant,high oil content and difficult to handle.At present,the combined process of membrane treatment is the main treatment process,which has disadvantages of rapid decline of membrane flux and poor overload capacity,as well as large investment,high operation cost and difficult in treatment of concentrated solution.Aiming at the problems,the combined process of air flotation+two-stage A/O+air flotation process was adopted in treating the biogas slurry.After the process,the removal rate of COD and BOD_(5) reached 98%,and the removal rate of NH_(3)-N,TN,TP and SS reached 99%.The COD,BOD_(5),NH_(3)-N,TN,TP and SS of the actual effluent could steadily meet the requirements of Wastewater Quality Standard for Discharge to Municipal Sewers(GB/T 31962—2015),which could meet the requirements of local sewage treatment plants.The treatment cost was about RMB 7.72/m^(3),including RMB 7.01/m^(3)for electricity,RMB 0.05/m^(3) for FeCl_(3),RMB0.18/m^(3)for PAM,RMB 0.26/m^(3) for carbon source and RMB 0.22/m^(3) for maintenance.The operation results showed that the combined process had the characteristics of stable effluent quality,small site area,low investment,low operation cost and easy operation,while avoiding the problems such as membrane concentrate treatment.