The Intensified Pre-treatment With Landfill Leachate By The Combined Physical Chemistry Way

Landfill leachate is an organic waste water whose components are very complicated. It is harmfull to surroundings such as water, ground water, soil, air living beings and so on. It can get into hunman body directly or undirectly and endanger the health of human.The purpose of this research is studing on the strengthened pretreatment of the landfill leachate by serial method such as aeration oxidization coagulation-precipitation and filtration for achieving better removing effects of turbidity degree, COD_Cr, NH₃-N and heavy metal ion. Eagering better condition can be provided for later treatment. In this experiment aeration and composite reagents are tested for removing COD_Cr and NH₃-N from the landfill leachate. Effects of aeration time, pH, dosage, reaction time and water temperature on the removal of pollutants from the landfill leachate are discussed and the removable principles are explored and analyzed.In the aeration trials the results show that efficiency of NH₃-N stripping is over 60% when pH is 10. 5 and aeration time exceeds 6 hours. In the composite reagents experiments first adding oxidant oxidizes leachate 10 minutes and then auxiliary coagulant and coagulant are putted in the landfill leachate. The condition of adding composite reagents are best when dosage K₂FeO₄ is 100mg/L and PAM is 3mg/L and PFS is 300mg/L and pH doesn' t change and sedimentation time is 45 minutes and water temperature is 20℃. In the optimum condition the removable effects of COD_Cr and NH₃-N are more than 66% and 27%. In the filtration experiments the efficiency of COD_Cr stripping increases gradually when the thickness of sand became thicker and thicker and the speed of filtration became slower and slower. When the speed of filtration is 2m/h and the thickness of sand is 60cm the efficiency of COD_Cr stripping is over 32%.The contents of COD_Cr and NH₃-N in the landfill leachate can fall into 1000mg/L and 300mg/L. And the effects in removing COD_Cr and NH₃-N add up to 80% and 70% when the landfill leachate is disposed by serial means such as aeration oxidization coagulation-precipitation and filtration.