Screening Of Microoganism From Activated Sludge For Biodegradation Of Coal And Degradation Effect Research

Coal reserves is very rich in our country and the consumption of coal is great.At present,burning is the main utilization of coal.Direct combustion of coal may cause serious pollution to the environment and intensifying the haze weather.Therefore,how to realize the clean conversion of coal source is the issue that our country must face while practicing the harmonious conexistence between man and nature philosophy.Purpose of this study is to select bacteriums from avtivated sludge and these bacteriums can degrade coal.It provides a new direction for the coal biodegradation at strain breeding,and lays a foundation for microbal degradation of coal at further study.Firstly,sludge supernatant after enriched was cultured in the conical flask where there are 50 m L inorganic salt culture and 0.5g coal sample.Observation found that some floating bubbles in the bottles of experimental group,but the control group on the contrary.The electron micrograph and infared spectra of coal sample in the experimental group showed that the gap of the coal samples increased,and the molecular structure of coal samples changed.The element analysis result of the supernatant fluid in the experimental group showed that Ca,Mg and P content decreased and Zn content increased.Above changes showed that microorganisms from activated sludge can degrade coal and confirmed that feasibility of selecting strains from activated sludge that capable of degrading coal.Secondly,optimizing clay-to-carbon ratio by control variate method.Using Minitab to design central composite experiment for optimizing ingredient of inorganic salt culture.And culture temperature,pretreatment method of coal sample and pH were also optimized through orthogonal experiment of 3 factors and 3 levels.Eventually,the best culture program was that 3g sludge,0.5g coal sample,50 m L inorganic salt culture,35 ? culture temperature,raw coal sample and pH 8.Among composition of inorganic salt culture are that KH2PO41.1g/L,CaCl21.1g /L,Fe2(SO4)30.4g/L,MgSO40.1g/L,NaCl 0.5g/L,NH4NO35g/L.Thirdly,the screening strains are cultured in the conical flask again where there are 50 mL inorganic salt culture solution and 0.5g coal sample,their liquid supernatant,s element analysis showed that content of Ca,Mg,P and Zn element changed in Z1 srain,s liquid supernatant by comparing with the control group.However,the content element of the rest strains,liquid supernatant changed little.The infrared spectrum analysis of the coal sample showed that aromatic ring structure and oxygen containing functional groups of coal sample changed a little after Z1 ?Z2 and Z3 strain effected.And structure of coal sample of rest strains effected changed little.The electron micrograph of coal samples after these stain Z1?Z2 and Z3 effeted showed that the porosity and degree of loose of coal samples were increased.Therefore,ultimately selected strain Z1?Z2 and Z3 capable of degrading coal.Through water immersion piese and gram stain method analyzing the screened stains preliminarily,the result is that Z1 is actinomycetes,Z2 is mucor and Z3 is yeast.Finally,researched the coal degradation effect of strain Z1?Z2 and Z3.The elements analysis of liquid produts by ICP-OES showed that Ca,Mg and P element content reduced and the Zn element comtent increased.This means that some elements of culture would be burned off as a nutrient elements,and some elements in coal sample would be educted in the process of microbial coal degradation.The infrared spectrum analysis results of solid produts showed that,the aromatic ring structure increased and oxygen containing functional groups and C?C key decreased.This means that aromatic ring structure generated in the products of coal biodegradation and there is oxidative hydrolysis in the degradation process.The calculating results of degradation rate showed that the effect of multiple strains better than single strains for the degradation of coal sample.When Z1,Z2,and Z3 strain degraded coal,the degradation rate of coal sample is best.