Organic Contamination Of Fresh Water By Petroleum Sludge And The Reclamation

As it inherently contains heavy metals,benzene homologues,polycyclic aromatic hydrocarbons(PAHs)and some other toxic substances,petroleum sludge is listed as a class called HW08 waste mineral oil in National List of hazardous waste(2016).The annual output of petroleum sludge increases rapidly with the development of petrochemical industry,but the industrial application process of each disposal technology is very slow.As a result,a large number of petroleum sludge becomes a potentially exposed pollution source.Many previous studies have devoted to the reclamation of petroleum sludge contaminated soil.However,a few studies have concerned the water pollution that caused by directly contacting with petroleum sludge.The results of this study can provide quantitative information to guiding the treatment of contaminated water by petroleum sludge.(1)In order to control the contamination of petroleum sludge,the contents of polycyclic aromatic hydrocarbons(PAHs)in five different petroleum sludge were experimentally studied.The acute biotoxicity of different organic extractions were measured through Vibrio fiseheri.The results showed that the PAHs contents in different petroleum sludge ranged from 496.10 ?g/g to 4233.25 ?g/g and the TEQ of PAHs ranged from 8.41 ?g TEQ/g to 231.56 ?g TEQ/g.The low-polycyclic aromatic hydrocarbons accounted for 42%to 89%of total PAHs,and carcinogenic PAHs accounted for 5%to 55%of total PAHs.N-hexane was the most suitable organic solvent in three tested solvents for testing the acute biotoxicity of petroleum sludge.The biotoxicity light emission inhibitions of BD was 63.15%which was the highest one in five petroleum sludge.(2)The COD value,PAHs contents and acute biotoxicity of water samples contaminated by petroleum sludge were also detected.Results indicated that the COD reached a maximum value when the pollutants became saturated in the water and the water polluted by sludge BD had the highest COD value which was 1200 mg/L after 78 hours contacting.The diffusion velocity of organic pollutants increased with the water-sludge contacting area size,but when the diameter reached to 65 mm,the polluting behavior was almost same like that of 50 mm.The amount of PAHs in contaminated water accounted for 0.16%to 0.51%of total PAHs in petroleum sludge.The acute biotoxicity tests of polluted water showed that the light emission inhibition was linear with COD value.The highest light inhibition rate,87.46%,was much more than the light inhibition rate of 100 mg/mL Zn2+?(3)The BD sludge which has extraordinary high asphaltenes content was selected as raw material to produce AC in this study.The sludge derived activated carbon has a rough surface and a large number of pores with different sizes and the adsorption value of methylene blue is 283.5 mg/g.Petroleum sludge derived activated carbon was used as an adsorbent for contaminated water cleaning and a COD reduction of 90.37%could be obtained.The average removal ratio of toluene and cyclopentanol were 64.99%and 84.27%respectively.Moreover,the maximum acute biotoxicity of the sludge polluted water reduced by 54.59%after adsorption.(4)Thirteen bacteria strains were isolated from oil sludge and the species of these strains were identified by 16S rDNA isolation techniques.Rhodococcus sp.(ZSYB03)and Pseudoxanthomonas sp.(ZSHD04)were chose to degard PAHs.After 30 days of degradation,the degradation rates of Acenaphthylene,Naphthalene,Acenaphthene,Fluorene and Pyrene by Pseudoxanthomonas were 77.4%,61.1%,10.1%,17.7%and 15.2%,respectively.And the degradation rates of Acenaphthylene,Fluorene,Naphthalene and Acenaphthene by Rhodococcus were 66.5%,16.4%,7.4%and 7.1%,respectively.More specifically,Pseudoxanthomonas and Rhodococcus could not degard the high-PAHs.