Study On The Efficiency Of The Electrochemical Synergistic System For The Treatment Of Landfill Leachate

Landfill leachate is a kind of high concentration organic wastewater which is generated from municipal solid waste landfill.And the treatment of landfill leachate is a huge challenge in the field of wastewater treatment.Electro-chemical oxidation can simultaneously degrade ammonia nitrogen and organic contaminants,which receives great attention in treatment of non-biodegradable wastewater such as landfill leachate,and this technology is a kind of advanced oxidation technologies which utilize hydroxyl radical(·OH)to remove organic compounds.Dimensionally stable anode(DSA anode)is widely used in electrolysis process,but its removal efficiencies of contaminants are being inhanced in some degree.In consideration of the shortcoming in the removal efficiencies of contaminants during electrolysis process by DSA anode,the ultra utilization of weak oxidants are utilized to enhance the generation of·OH,the electro-chemical synergy process is established to treat landfill leachate and biological effluent of landfill leachate.The experimental conclusions are listed as follows.(1)The operating factors such as current density,initial p H,A/V value and Cl~-concentration have significant effect on the removal rate in electro-chemical oxidation process.The distance between electrodes has a little effect on the removal efficiency of contaminants.Increment of current density,Cl~-concentration and A/V value can improve the removal rate of organic compounds and ammonia nitrogen.The removal rate of COD is enhanced through the decrease of initial p H,but the removal rate of ammonia nitrogen is improved through the increment of initial p H.(2)The favorable operating conditions for the electrolysis of landfill leachate by DSA anode are that the current density is 75 m A/cm~2,the initial p H is not adjusted,A/V value is50 cm~2/L,and the distance between electrodes is 1 cm.The corresponding removal rate of COD and ammonia nitrogen is 38.5%and 41.2%,respectively.The favorable operating conditions for the electrolysis of the biological effluent of landfill leachate by DSA anode are that the current density is 50 m A/cm~2,the initial p H is 8.45,A/V value is 50 cm~2/L,and the distance between electrodes is 1 cm.The corresponding removal rate of COD and ammonia nitrogen is 62.8%and 85.3%,respectively.(3)In comparison of electro-chemical oxidation process,electro-coagulation and electro-Fenton,the removal efficiency of COD in the electro-chemical synergy process is increment of 30.6%,24.4%and 13.4%,respectively.And the removal efficiency of ammonia nitrogen in the electro-chemical synergy process is increment of 26.4%,2.6%and21.0%,respectively.(4)The operating factors such as current density,initial p H,A/V value and Cl~-concentration have significant effect on the removal rate in electro-chemical synergy process in the treatment of landfill leachate and biological effluent of landfill leachate.Increment of current density,Cl~-concentration and A/V value can improve the removal rate of organic compounds and ammonia nitrogen.Acidic condition favors the removal rate of organic contaminants.And alkaline condition favors the removal rate of ammonia nitrogen.(5)During the condition such as the current density is 75 m A/cm~2,initial p H is 3,A/V value is 50 cm~2/L,Cl~-concentration is not adjusted,the reaction time is 6 hours,the removal rate of organic compounds and ammonia nitrogen in treatment of landfill leachate by the electro-chemical synergy process is 90.6%and 38.6%,respectively.During the condition such as the current density is 40 m A/cm~2,initial p H is 3,A/V value is 50 cm~2/L,Cl~-concentration is not adjusted,the reaction time is 6 hours,the removal rate of organic compounds and ammonia nitrogen in treatment of biological effluent of landfill leachate by the electro-chemical synergy process is 96.8%and 35.8%,respectively.