Research On The Improvement Of Biodegradability Of Landfill Leachate Pretreated By Microwave-activated Carbon

With the developme nt of soc iety and living standard，the amount of city garbageincreases day by day. Land fill leachate has become a greater threat to the safety o f thewater source，whic h receive exte nsive attentio n. If unha ndled land fill leachate isseeped into groundwater or flows through the surface, the environme nt will bepolluted very serio us ly. So technique of treating land fill leachate has been importantin the fie ld of enviro nmenta l engineering, whic h has an important theoretica l andpractica l significa nce for theoretica l and experime ntal stud y on land fill leachatetreatment technology.At present, stud ies on la ndfill leachate focuse on the physico-chemica l andbiolo gical technolo gy, but these methods are not very effective to treat la ndfillleachate because of comp lex compos ition and high content of re fractory organicmatter. In the previous stud ies, COD and NH₃-N were us ing as test indicators, but thedetermination of BOD was ignored, resulting in not accurately measuring the testimpact on the biodegradability of the leachate. This study adds the BOD as testindicators, measures the leachate biodegradability variation by BOD/COD, and usesseveral phys ico-chemica l methods to treat leachate, to reduce the pollution load insubsequent b iolo gical treatme nt, to identify the rele vant regu lation and the n determinethe most suitable reaction conditions by observing the variation of biodegradability.In this d issertation, leachate fro m the buried land fill of He imife ng in Changshawas studied. At first, a s ingle phys ical and chemica l tests （ultrasonic, microwave）treating land fill leachate was disc ussed, the effect of pH, reaction time, aeration time,power and other factors on remova l rate of COD, BOD and NH₃-N in leachate werealso ana lyzed, the results showed that in these two phys ico-che mical methods,microwave method had the best effect on enha nc ing leachate biodegradability, and theoptimum conditio ns were: PH is8, microwave power is400w, microwave irradiatio ntime is10min. In this cond itions, the remova l rate of COD, BOD and NH₃-N were65%,55.1%,63%,respective ly, BOD/COD rose fro m the stock solution o f0.31to0.398.Then, on the basis of the microwave test, the comb ination of microwave andactivated carbon supported Fe²⁺on the biodegradability o f land fill leachate, andfina lly investigated the processing mecha nis m. Using pH, Fe²⁺/activated carbon （g）,H₂O₂amount, microwave radiatio n power, reaction time as inspection object, desigh orthogona l experime nt in accordance with L25（5⁵） the level of five factors and fivecond itions). The best test processing cond itions by ortho gona l experime nt results: thedosage of activated carbon supported Fe²⁺was25g/L, H₂O₂was3mL/L, pH was3,microwave processing power was400w, microwave processing time was15min.Under these cond itions, the re mova l rate of NH₃-N, COD and BOD was34.87%,81.12%,70.75%, that is, NH₃-N, COD and BOD can be degraded to814mg/L,1321mg/L and644mg/L, BOD/COD rose from the stock solution of0.31to0.48.Fina lly, through the reuse and regeneration tests of activated carbon: the mostappropriate frequency o f use was once. The best reaction cond itions for effectiveregeneratio n in the microwave conditio ns were: pH was4, the power was400w, thereactio n time was4min, the best processing times for activated carbon regeneratio nby microwave is3times.The results show that within a certain range, the combination of microwave andactivated carbon supported Fe2+collaborative treatment techno logy can s ignificantlyreduce the COD and ammo nia in land fill leachate, and to so me extent improve thebiodegradability of la ndfill leachate, Also bio logica l treatment after phys icoche mica lprocess can smoothly proceed to provide the solid guarantee.