Analysis Of Degradation Characteristics In Menthanogenic With Organic Pollutants Of Coking Wastewater

As a typical industrial wastewater, the coking wastewater consists of manypollutants that contain refractory or toxic compounds, namely high ammoniaconcentration, phenols, aliphatic compounds, poly-cyclic nitrogen-containingaromatics, oxygen-and sulfurcontaining heterocyclic compounds andpolynuclear aromatic hydrocarbons (PAHs). Phenol, quinoline, pyridine, indolewere represented as typical organic compounds among them, which hadcharacteristics of toxicity, carcinogenicity and teratogenicity. Therefore, itsharmless process has been causing people‘s attention. The aim of this paper is tostudy kinetics of methanogenic process with phenol,quinoline, pyridine andindole as sole carbon source respectively, study kinetics of quinoline, pyridineand indole by anaerobic sludge on condition with phenol and study the shift ofmicrobial population, which corresponded to different anaerobic sludge. The main methods and conclusions are as follows:(1)Using the activated sludge from methanogenic section of upflow blanketfilter(UBF) as seed sludge, were added to the reactor with a single carbonsource-phenol, quinoline, pyridine, indole and quinoline, pyridine, indole oncondition with phenol to do a batch tests.(2)With organic matter degradation rate as indicators, research theinfluencing factors of methanogenic process. Batch experiments were carriedout at20℃、25℃、30℃、35℃and40℃. The initial concentration of COD wasaround320mg/L during the start-up period and maintained the initial pH of7.0approximately. We could come to the conclusion that when the temperature wasbetween30℃and37.5℃, the four substracts kept a higher degradation rate. At35℃, the highest degradation was approximately90%. When the temperaturewas less than30℃or greater than37.5℃, the degradation rate decreasedsignificantly.The substract‘s degradation rate was determined in different pH values-7.0、7.5、8.0、8.5and9.0. In pH=7.5, the four substracts could be all removed at83%.The reactor‘s temperature was maintained at35℃+1℃.The initial concentration of COD was around320mg/L during the start-upperiod and maintained the temperature at35℃+1℃approximately. NH4Cl wasused as nitrogen source and the concentration was changing. Methanogenicexperiments were done at the different C/N(organic theoretical COD/NH+4-N)respectively. When C/N was15, the carbon source could be degraded quickly, from10%to87%.Methanogenic process with phenol, quinoline, pyridine and indole as solecarbon source were studied respectively in this paper, getting the optimalsolution:35℃, pH=7.5, C/N=15.(3)The research study the variation of substract reduction at time. Themethanogenic kinetics could be described by the Monod equation and kineticparameters could be obtained. The different biodegradation rate of anaerobicsludge is in sequence of phenol>quinolone>pyridine>indole. First order kineticsequation was adopted to well describe the biodegradation of phenol. Zero-orderkinetics equation were all adopted to well describe the biodegradation ofquinoline pyridine and indole.From study kinetics of quinoline, pyridine and indole by anaerobic sludgeon condition with phenol, we can concluded that anaerobic sludge can removeboth phenol and pyridine or indole simultaneously, and phenol also inhibits theremoval of pyridine or indole. This inhibition was decreased with the initialphenol concentration increased. Anaerobic sludge can remove both phenol andquinoline simultaneously, and phenol also inhibits the removal of quinoline.This inhibition was increased with the initial phenol concentration increased.(4)Total DNA was extracted directly from menthanogenic anaerobic sludgeand was amplified with poly-merase chain reaction (PCR) technique. The PCRproducts were fingerprinted by denaturing gradient gel electrophoresis (DGGE).The DGGE patterns demonstrated the shift of microbial population, which corresponded to different anaerobic sludge. The conclusions are as follows: thesequences of bands in all samples were affiliated with Methanogenic,Ignavibacteria, Thermotogales, respectively.The sequences of band in sample that added phenol was affiliated withPseudomonas Bacteria. The sequences of bands in sample that added quinolinewas affiliated with Bacteroidetes, Acholeplasma, Kosmotoga, respectively. Thesequences of bands in sample that added pyridine was affiliated withSulfate-Reducing Bacteria, Bacteroidetes, Novosphingobium, respectively. Thesequences of band in sample that added indole was affiliated withPhenylobacterium.Using almost the same culture conditions, different substract demonstratedthe shift of microbial population.Among them, different flora was produced,which may cause the different biodegradation rate of different anaerobic sludge.