Study On The Performance And Mechanism Of Coupled Process Of Electrocoagulation And Eletrofenton-type For Treatment Of The Reverse Osmosis Concentrate Of Landfill Leachate

With the rapid development of economy,the amount of municipal solid waste increases quickly and the composition becomes more and more complex.Landfill leachate generated from sanitary landfill treatment will produce reverse osmosis concentrate after advanced treatment.Recharging is normally used to treat landfill.But with the processing technology and cost constraints,the effect and efficiency are limited.Because the refractory organics and the high salinity have a certain inhibitory effect on microorganisms,it is difficult to reach the standard by using biochemical methods.The use of electrochemical technology in high-salt wastewater can make use of the high salinity and reduce the electricity consumption required for electrocoagulation to treat the wastewater at lower energy consumption.In this study,the landfill leachate reverse osmosis concentrate is treated by electrocoagulation and electro-Fenton-type reaction respectively,to explore the reaction processes and influencing factors of two systems for pollutant removal.By coupling these two reaction systems,the reverse osmosis leachate concentrate of the landfill leachate are treated to determine the influencing factors of the pollutant removal effect and optimize the operating conditions to obtain the best operating parameters.Comparing the research of electrocoagulation,electro-Fenton-type and coupling process on the import and export of water and flocculate components and so on,we can explore the treatment process and reaction mechanism of coupling process.In the process of electrocoagulation reaction,as the voltage of the plate increases and the p H increases,the electrocoagulation reaction is conducive to the improvement of the removal effect of pollutants;the stirring process can accelerate the progress of the electrocoagulation reaction,but it has no effect on the total removal rate of pollutants.In the course of the reaction,the p H gradually increases with the increase of the electric charge,and it continuously produces ferrous ions and iron ions.The generation of iron ions in the reaction can provide the possibility of the coupling reaction.The electroFenton-type process can be constructed by Fe2+ from the cathode and HOCl from the anode,and generate Fe3+ and hydroxyl radicals,which can effectively remove contaminants in the wastewater.During the reaction process,the method of casting ferrous ions and the type and concentration of the iron compound will affect the electroFenton-type reaction,while the p H condition only provide an acidic or alkaline environment which affects the existence of the solute,and does not participate in the actual process of the reaction.Under the conditions of p H 7 and continuous casting of ferrous ions,the electro-Fenton-type system reacts to the degradation of COD in the leachate reverse osmosis concentrate into a pseudo-first order reaction.The coupling process system is constructed,through analyzing the feasibility of thecoupling process.The increase of the voltage and the electricity,and the distance between the plates in the reaction system decide in favour of the reaction process and improve the removal of COD and ammonia nitrogen;the increase of the concentration of suspended matter will increase the removal efficiency of COD,but has little effect on the effect of ammonia nitrogen treatment;p H conditions have little effect on the treatment effect of the coupling process.Electro-coagulation,electro-Fenton-type and coupling processes can remove TOC well in the reaction system,and can effectively remove refractory materials on the treatment of waste permeate reverse osmosis.The XRD results showed that the flocs produced are ferric oxide crystals,and the amount of floc produced under alkaline conditions is greater.The amount of floc produced by the coupling process is less than that under the separate treatment.During the reaction,the chlorine generated at the anode plate of the DSA can react with water to generate hypochlorous acid,and an electro-Fenton-type reaction with the ferrous ion generated at their on plate generates hydroxyl radicals.During the reaction process,the hydroxide formed at the carbon felt reacts with ferrous ions to form flocs that can interact with contaminants and be removed.When ammonium ions are added to the system,ammonium ions are also oxidized by hydroxyl radicals,which promotes the forward reaction.This study shows that the coupling process has a high application value for the treatment of landfill leachate reverse osmosis and can provide ideas and data support for future research.