Dissertation > Excellent graduate degree dissertation topics show

Polycyclic aromatic hydrocarbons degradation of the growth characteristics of bacteria in soil remediation

Author: SiXianPei
Tutor: ShaoChengBin
School: Chongqing Technology and Business University
Course: Environmental Engineering
Keywords: Synchronous fluorescence spectrometry Pseudomonas degradation kinetics metabolic degradation the strain applied
CLC: X172
Type: Master's thesis
Year: 2011
Downloads: 22
Quote: 0
Read: Download Dissertation

Abstract

Biodegradation has high efficiency, no secondary pollution, it is the preferred method for remediation of contaminated soils. In this paper, Studied the characteristics of degrading bacteria selected from contaminated soil by PAHs. Discussion the feasibility of training PAHs degrading bacteria using agricultural waste, and the applications of repairing in contaminated soil.The main contents of this paper and conclusions are as follows: (One) A method of constant energy synchronous fluorescence spectrometry had established for PAHs in soil. The method of soil extraction was extraction method , the optimal extraction temperature is 35℃, the best surfactant was sodium dodecyl sulfate 2 mL. Determination PAHs in soil, the recoveries of pyrene, anthracene were 82.95%,114.65%. the fluorescence measurement precision of pyrene and anthracene were 8.55% and 7.02%. Measured pyrene, anthracene contents were 19.71, 2.47 mg/kg in soil samples.(Two) One strain which could endure the high concentration of polycyclic aromatic hydrocarbon was obtained from oil-contaminated soil in oil gas station area by filtration and separating ,taken the degradation efficiency of pyrene as the target. When the initial concentrations of pyrene was 150 mg/L in the inorganic medium,the degradation rates of pyrene by DY-1 in 7 days was 82.6 %.the degradation rates of fluorethene、naphthalene、phenanthrene、anthracene and biphenyl respective was 29.06%、30.7%、29.12%、17.26%、40.11%. The strain was identified as Gram feminine Pseudomonas based on morphological and physio-biochemical.(Three) Research strains culture conditions and dynamic growth characteristics of the DY-1.taken the degradation efficiency of pyrene as the target, optimized the cultivating condition of bacterium DY-1 by the means of single factors and Orthogonal experiments ,analysis the Dynamic characteristics in the different conditions.the optimum conditions of pyrene degradation by bacterium DY-1 :T 30℃,pH 7.5,rotate speed 120 r.min-1 inoculate quantity 1.5 mL;the degradation of pyrene conforms to the first- order reaction dynamic properties in the different cultivating conditions . (Four) Analysed the effects of different concentrations of heavy metals, total metabolites, DY-1 strain degraded PAHs. The results showed that heavy metal ions had different effects on the DY-1 strains degradation PAHs, which, Cu2 +, Pb2 + ions were the most obvious, were about 20%, the lowest was 10% or less; low concentrations of Zn2 +, Cr6 + ions can promote the strain DY-1degradation PAHs, the degradation rate can reach 30%; low concentrations of metabolism and, by adding sucrose, the pyrene degradation rate reashed 90%, sodium acetate had no significant effect on pyrene degradation; pyrene degradation rate must increase,when the presence of low concentrations of naphthalene or anthracene.(Five) Discusses the feasibility of using corn cob culture the pyrene degrading bacteria (DY-1) .Degradation the corn cob using five core mold, and then culture degradation bacteria using. Experiments show that: the pyrene degradation rate reashed 80% ,when the degradation solution of white rot fungi degraded corn cob Cultures DY-1 strain, instead of sucrose and yeast extract solution as the carbon and nitrogen sources, it can save carbon 50-60% , nitrogen 60-80% and it is an ideal medium for alternatives.(Six) The experiment of DY-1 degrading bacteria remediation contaminated soil. set 6 treatment, A: not sterilized soil; B: soil samples + bacterium DY-1; C: soil + earthworm; D: soil + earthworm + bacterium DY-1; E: soil samples + earthworms + bacterium DY-1 + plants (ryegrass); F: soil +bacterium DY-1 + plants (ryegrass). Analysised the changes of low concentrations pyrene and anthracene concentration with time in soil, measured the activity of bacteria, fungi and actinomycetes, invertase, catalase, protease in soil. The resulted show that: plants, earthworms, DY-1 strain can degrade pyrene and anthracene in soil to some extent, It had best Degradation on pyrene, anthracene when combining earthworms and DY-1 strain.

Related Dissertations

CLC: > Environmental science, safety science > The basic theory for the Environment and Science > Environmental Biology > Environmental Microbiology
© 2012 www.DissertationTopic.Net Mobile