某石化集团PTA废水采用三级生化处理,拟用连续微滤和反渗透膜组合技术(双膜法)处理该生化系统的排放水,使反渗透膜出水达到循环冷却水水质标准。在该回用系统中浓缩水的处理是关键的一环。作者采用混凝—吸附的方法处理了该RO浓缩水,考察了絮凝剂种类、絮凝剂体积比、总投加量、pH、吸附剂种类、吸附时间、吸附剂用量以及组合处理方式等因素对COD去除效果的影响。结果表明,FeCl3的处理效果明显优于其他4种无机絮凝剂;FeCl3辅以高分子助凝剂PAM的处理效果明显优于单一FeCl3。一定条件下"混凝—活性炭吸附"的出水无色透明,总的COD去除率可达56.9%,满足了石化废水二级排放标准。The effluent after third class biological treatment of PTA wastewater by a petrochemical group is planed for recycling.Continuous micro-filtration(CMF) and reverse osmosis(RO) membrane integrated process(double-membrane process) has been carried out.The water quality of RO effluent has achieved the standard of cooling-circulation water quality.The disposal of the concentrate plays the pivotal roles in the whole recycle system.Coagulation and adsorption methods are then adopted for treating RO membrane unit concentrate.The influences of coagulation nature,volume ratio of coagulant,total amount of coagulant,pH,adsorption agent nature,adsorption time,dosages of adsorption agent and combination manner on the COD removal are investigated in detail.The results show that FeCl3 is the best choice compared to the other 4 kinds of inorganic coagulants used in this experiment.The treatment efficiency of using FeCl3 singly is obviously lower than that of using PAM combined with FeCl3.Under certain conditions,The effluent after"coagulation-activated carbon adsorption" integrated process is colorless and transparent and has a total COD removal of 56.9%,which meets the second grade standard of petrochemical wastewater discharge
