Study On The Effect Of Bioactive Water For The Biodegradation Of Naphthalene And Fluoranthene In Contaminated Soil

Polycyclic Aromatic Hydrocarbons(PAHs)are a class of persistent organic pollutants commonly found in soils,including saline-alkali soils and general soils.In order to strengthen soil microbial remediation techniques,two kinds of naphthalene and fluoranthene degrading bacteria were isolated from petroleum-contaminated soils in this experiment,named as NW6 and YN1.And the growth curves of the bacteria,the effects of different pH,temperature and salt concentration on growth were determined.The effects of the two kinds of bacteria on degradation characteristic of naphthalene and fluoranthene and degradation effect of naphthalene and fluoranthene in polluted soil were studied,using bioactive water for Intensive experiments.The results were as follows:1.The strain NW6 belonged to Gram-negative bacteria,and the strain YN1 was a Gram-positive bacteria.After 16s rDNA sequencing,the results showed that NW6 was closely related to Cellulosimicrobium funkei,and YN1 was closely related to Bacillus paramycoides.The optimal growth temperature of the strain NW6 in the inorganic salt medium(DW-MSM)prepared in distilled water was 40℃,pH 8.0 and salt concentration was 2%,in the inorganic salt medium(BW-MSM)prepared by bioactive water.pH=7.0,30℃,2%salt concentration;optimal growth conditions for YN1 were pH=6.0,35℃,4%(DW-MSM),pH=7.0,30℃,4%(BW-MSM).2.In the experimental process of degradation of naphthalene and fluoranthene by bacteria NW6 and YN1,the degradation rate of bacteria NW6 reached 51.38%(DW-MSM)and 55.32%(BW-MSM)on the 10th day;the highest degradation rate of YN1 was 53.24%(DW-MSM),56.12%(BW-MSM).Degradation rate in sandy soil,loess and black soil:the degradation rate of naphthalene by NW6 in DW-MSM was 23.75%,18.51%,and 16.06%,respectively.The degradation rate in BW-MSM was 43.53%.37.68%,25.76%;the degradation rate of YN1 to fluoranthene was 44%,33%,27%(DW-MSM),63%58%,37%(BW-MSM).The addition of bioactive water increased the solubility of the matrix in water.In the experiment of adsorption partition coefficient,the Kd value of B W was the smallest,which promoted the degradation of microorganisms.In the solid phase,the matrix degradation of BW was lower than DW,and the degradation effect was the largest.Therefore,the bioactive water in each soil could provide nutrients to the microorganisms,and promote the degradation rate in the soil contaminated with naphthalene and fluoranthene.3.Under the condition of soil mud of three different diluted saline-alkali soils,the degradation rate of naphthalene by strain NW6 and fluoranthene by strain YN1 was BW>BW+MSM>UPW+MSM>DW+MSM>UPW>DW,which indicated biological activity.Bioactive water(BW)could effectively improve the degradation efficiency of naphthalene and fluoranthene in saline-alkaline soil.Therefore,bioactive water could enhance the availability of microorganisms.