Sludge Pollution Control from Crude Oil Tank Cleaning

This study investigated the use of microbial analysis as a bioremediation option for remediating petroleum sludge, which is part of the waste stream generated in the petroleum industry. The aim is to reduce environmental burden caused by the discharge of untreated sludge. Sludge sample was cultured in other to isolate microorganisms for the sludge treatment. The selected strain of the organisms after screening were Aspergillus flavus, Aspergillus niger, Verticillus sp, Penicillum sp, and Microsporium audouinii. Bioreactors (labeled A, B, C, D and O) were designed for the treatment of petroleum sludge. These reactors contain 2.0 × 10-2 m3 of the diluted sludge samples and the isolated organisms for the treatment process. On a weekly basis, the control reactors received 1.5 × 10-3 m3 of fresh and saline water respectively. After 12 weeks of treatment, sludge physicochemical characteristics showed distinct variations. From the result, reactor D was the best in terms of remediating the sludge as compared to other reactors. Friedman non-parametric test was performed to check if the weeks of treatment affected the reduction of the total hydrocarbon content (THC) in the five reactors and also checked for significant differences in the THC after treatments. The drop in the THC of the treated sludge ranged from 56.0% to 67.3%. These results showed the possibility of enhanced biodegradation of petroleum sludge by hydrocarbon utilizing microorganisms (fungi).

Rapid aerobic granulation using biochar for the treatment of petroleum refinery wastewater

Aerobic granular sludge technology has great potential for the treatment of petroleum refinery wastewater.However,strategies to shorten the granulation time and improvement the stability still need to be developed.In this work,biochar was prepared from waste petroleum activated sludge(biochar-WPS) and used in a sequencing batch reactor for the treatment of petroleum refinery wastewater.Biochar-WPS presented the surface area of 229.77 m2/g,pore volume of 0.28 cm3/g,H/C and O/C atomic ratios of 0.42 and 0.21,respectively.The porous structure and a high degree of hydrophilicity were found to facilitate microbial colonization and adhesion as well as particle aggregation.Application of biochar-WPS resulted in the formation of more substantial and stable aerobic granules(~66% of granules> 0.46 mm diameter) 15 days earlier compared with the control.The addition of biochar-WPS enhanced the average removal efficiency of chemical organic demand(~3%),oil(~4%)and total nitrogen(~10%) over the control.Increased microbial richness and diversity were observed within the formed granules and had an increased(~4%) proportion of denitrifying bacteria.These results indicate that an aerobic granulation mechanism using biochar-WPS is a feasible option for the treatment of petroleum refinery wastewater.

Bioremediation and detoxification of real refinery oily sludge using mixed bacterial cells

Anaerobic biotreatment of real field petroleum refinery oily sludge(PROS)was investigated under using four different organic loads(OLs)in the order ofOL4>OL3>OL2>OL1,in bench-scale bioreactors.The bioremediation of raw PROS was carried out using mixed culture biocatalyst without chemicals addition or any type of pretreatment.The results revealed a potential performance of the used biocatalyst dominated by Pseudomonas aeruginosa(class:Gammaproteo)and Staphylococcus spp.(class:Bacilli)achieving significant removal of chemical oxygen demand(COD)and total petroleum hydrocarbons(TPH).The highest organic removal rate was recorded in OL4 followed by OL3,0L2,OL1,respectively indicating a positive relationship between the percentage removal of organics and their content.Maximum removal efficiencies of 96.7%and 90%were observed for COD and TPH,respectively in OL4 within 14 days only.Analysis of polycyclic aromatic hydrocarbons(PAHs)demonstrated that acenaph-thylene and phenanthrene exhibited the maximum removal efficiency(almost complete)among the 8-priority PAHs tested in this study.However,the overall degradation of PAHs in the oily sludge was 83.3%.