| Since the 21st century,with the increase of waste discharge standards,more and more reverse osmosis membranes are used in the last link of landfill leachate treatment in the process of landfill leachate treatment.But at the same time,the reverse osmosis membrane filtration concentrate produced by this process is a kind of organic wastewater with high concentration of organic matter,containing refractory macromolecular substances and poor biodegradability,which is difficult to meet the discharge standard.This experimental study is mainly based on the reverse osmosis membrane filtration concentrate of landfill leachate from the Daxin domestic waste landfill in Shenyang City,Liaoning Province as the research object.The combined process carries out subsequent advanced treatment of this reverse osmosis concentrate.In this study,the physicochemical and biological combined processes were used to treat the reverse osmosis concentrate,and the optimal process conditions for the coagulation sedimentation and electrochemical oxidation of the membrane filtration concentrate and the treatment effect of the combined operation were explored.This experimental study is mainly based on the reverse osmosis membrane filtration concentrate of landfill leachate from the Daxin domestic waste landfill in Shenyang City,Liaoning Province as the research object.The combined process carries out subsequent advanced treatment of this reverse osmosis concentrate.In this study,the physicochemical and biological combined processes were used to treat the reverse osmosis concentrate,and the optimal process conditions for the coagulation sedimentation and electrochemical oxidation of the membrane filtration concentrate and the treatment effect of the combined operation were explored.The experimental study on the reverse osmosis concentrate of landfill leachate pretreatment by coagulation and sedimentation showed that the optimal conditions for the coagulation and sedimentation test reaction were obtained through single factor test analysis:the dosage of polymeric ferric sulfate(PFS)=2000 mg/L,the initial pH When=7,when the precipitation time is 40min,the removal effect is the best.The removal rates of COD,NH3-N and UV254 are 73.865%,33.927%and 64%,respectively,and the concentrations of the three are 346.4mg/L under this condition.,34.842mg/L and 13.225mg/L,which effectively improved the biodegradability of the concentrate.The effluent pretreated by coagulation and precipitation is used as the influent of electrochemical oxidation,and the current densities are adjusted to 5A/dm2,7.5A/dm2,10A/dm2,12.5A/dm2,15A/dm2,respectively,and the electrolytic oxidation time is 20 min,40min,60min,80min,100min and 120min to carry out the reaction.A ruthenium iridium titanium plate electrode was used as the anode material,and a stainless-steel plate electrode was used as the cathode material.The optimal test condition for electrochemical oxidation is:the current density is 15A/dm2,the distance between the plates is 3cm,the reaction time is 120min,the pH value is not adjusted,the removal rate of COD is 67.297%,and the removal rate of NH3-N is 82.699%,the removal rate of UV254 was 80.2974%,the BOD5/COD was increased to 0.5,and the unit energy consumption of COD was 39.4038kwh/kg.Electrochemical oxidation of effluent is carried out for advanced treatment of biological aerated filter.By sequentially increasing the content ratio of concentrate and glucose in the simulated wastewater,the temperature of the biological aerated filter is 20～30℃ during the operation of the biological aerated filter,and the influent flow is controlled at 0.3 L/h,the air-water ratio was adjusted to 4:1,and the simulated wastewater influent was finally maintained,and no glucose was added to the subsequent influent.Under these conditions,the removal rates of COD,NH3-N and UV254 were 71.2938%respectively,73.2083%and 69.3948%.Under these conditions,the concentrations of the three are 32.264mg/L,1.686mg/L and 0.7mg/L respectively.B/C is raised.The operation results of the combined process show that the removal rate of COD is 97.46%,the removal rate of UV254 is 98%,the removal rate of NH3-N is 96.8%,and the effluent concentrations of the three are 32.264 mg/L,0.7 mg/L and 1.686 mg/L,and the effluent quality has reached the Class A standard of the Pollutant Discharge Standard for Urban Sewage Treatment Plants(GB18918-2002). |
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