Research On Pretreating Landfill Leachate With Oxidant

Content of organic matter is high in the landfill leachate,the majority of them is complex organic macromolecules which are more difficult to degradate, high ammonia nitrogen content which increases with the number of landfill years. Leachate also contains class of aromatic compounds containing benzene ring which is with biological toxicity.The traditional biological or physical chemistry techniques can not make the wastewater clean enough to satisfy the treatment criteria at an acceptable expense.Thus it is a difficult problem to be solved to treat the landfill leachate in the city envirionment.The experiment of pretreating landfill leachate adopt chemical oxidation method,making COD,ammonia nitrogen,aromatic compounds achieves a better removal effectiveness,and further study the specific degradating situation of aromatic compounds phenol,thereby reducing the biological toxicity and providing a good condition for following biological treatment.Three kinds oxidants in common which are sodium hypochlorite,calcium hypochlorite,potassium permanganate were be selected to pretreat landfill leachate for comparative experiment.The best oxidants were be selected by comparing the experiment,to study the best removal of COD,ammonia conditions by orthogonal experimental method and study the oxidation characteristics of the synthetic aromatic compounds.The analyses and researches of the experimental results show that: comparies with the other two oxidants,pH value in around 9,sodium hypochlorite has the best effect on the treatment of leachate for the removal of COD and ammonia nitrogen.The affected primary and secondary factor of COD removal effectiveness is the amount of sodium hypochlorite→reaction time→temperature,the affected primary and secondary factor of ammonia nitrogen removal effectiveness is the amount of sodium hypochlorite→temperature→reaction time.The best COD removal effectiveness technological conditions of treating leachate are that the amount of sodium hypochlorite is 10 ml,reaction time is 45 min,temperature is 50℃,the corresponding removal rate of COD is 25.21%,the best ammonia nitrogen removal effectiveness technological conditions of treating leachate are that the amount of sodium hypochlorite is 10 ml,reaction time is 90 min,temperature is 50℃,the corresponding removal rate of NH₃-N is 32.25%.Sodium hypochlorite treat pyridine and phenol have a good effect of oxidation.Phenol in the role of sodium hypochlorite rapidly generates a variety of open-loop short-chain fatty acids.