Study Of Bioremediation Of Polycyclic Aromatic Hydrocarbons In Water

Polycyclic aromatic hydrocarbons are a class of persistent organic pollutants, in the environment they will accumulate in vivo through the food chain, which can cause teratogenic, carcinogenic, mutagenic to organism. PAHs are mainly distributed in sediments, water phase, soil and atmosphere. The removal ways of PAHs in the environment are photolytic degradation, microbial degradation, phytoremediation, plant-microbial remediation, etc. Microbial degradation has been suggested as the best way to remove polycyclic aromatic hydrocarbons (PAHs) from contaminated environment because of its environmental protection, efficient, cheap. There is much more study of bioremediation of PAHs in soil than in water phase, while bioremediation of PAHs in water phase has not been established. The research purpose of this study is aimed to establish bioremediation of PAHs in water phase.This study screened a group of PAHs-degrading microorganisms from the activated sludge of Wuhan Petrochemical Works by the water-silicon oil biphasic system. PAHs-degrading microorganism W3 and W10 was isolated from the microorganisms.In the mineral salts medium, under initial PAHs concentration of 30 mg/L the degrading rates of naphthalene, phenanthrene, fluorene, pyrene, fluoranthene were 99%,86.6%,90.2%, 91.8%and 95.2%by the PAHs-degrading microorganisms,94%,81.15%,87.65%,91.64% and 87.2%by W3,92.5%,77.3%,87.9%,87.75%,83.25%by W10 after 5 days. W3 was indentified as Pseudomonas sp. according to the results of morphology and the phylogenetical analyses of 16S rDNA sequence. In the laboratory research on application of W3 in water by bioaugmentation with inoculation amount 3%, five days later, degrading rate of naphthalene, phenanthrene, fluorene, pyrene, fluoranthene reached 34.07%,24.78%, 56.95%,19.67%,35.1%with bacterial density of 3.15×106cfu/mL and 59.27%,44.35%, 66.64%,26.4%,53.86%with bacterial density of 4.76×107 cfu/mL. W3 immobilized by polyurethane foam was used to treat PAHs polluted water, in water phase fluoranthene reached the maximum reduce 27.2%. Within retention time of 12 hours, the removal was mainly due to the adsorption of polyurethane foam. The retention time is so short that microbial degradation was not significant.In the study of W3 immobilized by stereo elastic media, the removal rate of naphthalene, phenanthrene, fluorene, pyrene, fluoranthene reached 25.74%,17.58%,31.3%,15.51%,22.31%respectively.