Advanced Treatment For The Landfill Leachate By Oxidation

The Fenton's reagent ,sonication and electrochemical treatment are used in thisthesis to treat the effluent discharged from biological treatment process of landfillleacheat. COD,BOD ,ammonia nitrogen,Cl- and chroma concentration in theeffluent were 789～1602 mg/L,29.7～100mg/L ,411～538.7 mg/L ,1542.8～1923mg/L and 1095～2520 times. The purpose of this experiment is to operate Fenton oxidation process efficiently.The organic was oxidized with the ?OH free racial and coagulated by Fe3+ ions,which were provided by Fenton's reagent . The total COD and chroma removal of theleachate by Fenton oxidation is over 69%,97.82％and COD and chroma value of theeffluent can be 284mg/L,44 times under the following oxidation conditions:reaction:20min reaction time, 15mmol/L FeSO4·7H2O, the H2O2/ FeSO4·7H2O ratio of 4to 1,the optimum pH of 4 for the Fenton oxidation process and 8.0 for the coagulationprocess. Unfortunately ,the Fenton's reagent can not remove NH3-N . The sonicatial treatability of landfill leachate has been investigated in this paper.After ultrasonic 30min in a frequency of 20KHz , the residul COD is 728mg/L and theCOD removal rate is 19.2% with the optimum reaction conditions where are pH=11and sonication strength of 1250W/L . The ammonia nitrogen removal rate and theammonia nitrogen concentration in the outlet are 50.3% and 240mg/L,respectively.COD removal of landfill leachate is not good enough in low frequencyultrasonication. A ternary Rh-Zr-Ru oxide-coated titanium(DSA) anode fixed in a lab-scaleelectrolysis reactor was used to treat landdfill leachate in this investigation. Thelanthanons on the special ternary anode have electrolysis oxidation catalysis Underthe operating conditions of 8A/dm2 current density ,3cm electrode gap and theoptimum pH of 8, 100% of the ammonia nitrogen in the leachate was removed afterelectrolysing for 120min. At the same time ,the COD removal rate is 44.9% and theCOD in the effluent is 652mg/L. Combined Fenton's reagent and electrochmical process is also used to treat thelandfill leachate in this paper .After reaction 120min ,the COD and ammoniaconcentration were down to 93.5 mg/L and 0 mg/L while the removal rate COD andammonia nitrogen were 62.3% and 100%, respectively. In the experiments,the Fenton's reagent is the best process to remove the COD inthe leachate ,while the best process for removing ammonia nitrogen is electrochmicalprocess. So the best treatment process for the leachate is combined Fenton's reagentand electrochmical process, which can make landfill leacheat to meet the nationaldischarge standard 。...