Modification of PAHs Biodegradation with Humic Compounds

Environ Health Eng Manag

Takdastan

2020

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Background: Phenanthrene (PHE) is a polycyclic aromatic hydrocarbon (PAH) with crystalline structure of C14H10, which was produced from incomplete combustion of hydrocarbons and fossil fuels and can cause harmful biological effects. Bioremediation using halophilic bacteria is payed attention over chemical methods due to considerable benefits. Methods: In the present study, a halo-tolerant bacterium Bacillus kochii strain AHV-KH14 was isolated from municipal compost, and used for the bioremediation of PHE from the contaminated soil. The effects of operational parameters including soil/water ratio, initial inoculum size, PHE concentration, and salinity on the bioremediation performance were investigated. Results: A biodegradation efficiency of about to 98% was obtained for PHE concentration of 50 mg/ kg and salinity level of 1.5%. By increasing salinity content PHE concentration, PHE biodegradation rate decreased significantly. It was found that the bioremediation efficiency decreased with increasing PHE concentration. It was also revealed that for the unwashed soil sample, cumulative concentrations of different hydrocarbons played an important role in decreasing the efficiency of bioremediation. Conclusion: A natural hydrocarbon-contaminated soil sample with total petroleum hydrocarbon (TPH) concentration of 2350 mg/kg was subjected to bioremediation using the selected conditions of operational parameters, and a biodegradation rate of 17.7% was obtained.

Section: S Rrnamentioning

confidence: 99%

Section: Soil Preparationmentioning

confidence: 99%

Bioremediation of phenanthrene-polluted soil using Bacillus kochii AHV-KH14 as a halo-tolerant strain isolated from compost

Feizi

Environ Health Eng Manag

Takdastan

2020

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“…However, the temperature of 70 o C with removal effi ciency of 42.3% was selected for investigation the effect of pH and persulphate dosage due to no signifi cant deference between removal at 70 o C and 80 o C (p-value of 0.0146<0.05) according to non-parametric Kruskal Wallis statistical analysis. COD removal using SO 4 • radicals is a temperature dependent process and removal could be enhanced through increase k = 5.5×10 5 M -1 S -1 (7) Ji et al (2015) observed that increasing the persulfate concentration from 0.1 mM to 2 mM enhanced the COD removal from 10% to 98% for groundwater remediation 36 . in temperature.…”

Section: Eff Ect Of Temperaturementioning

confidence: 99%

“…The rapid growth of petrochemical industries in last two decades and widespread use of petrochemical products has led to serious environmental contamination, especially water bodies receiving considerable amounts of wastewaters originated from these industries 1 . Petrochemical effl uents contain signifi cant amounts of hazardous organic and inorganic chemical compounds such as halogenated hydrocarbons, aromatic compounds, phenolic substances, oil and grease, aliphatic, polycyclic aromatic hydrocarbons (PAHs) and heavy metals which all possess high toxicity to plants, animals and also human beings 2- 4 . In addition, a major portion of petrochemical wastewaters are characterized as high TDS that along with containing aromatic constituents make them resistant to biodegradation 5 .…”

Section: Introductionmentioning

confidence: 99%

Thermally activated persulfate treatment and mineralization of a recalcitrant high TDS petrochemical wastewater

Polish Journal of Chemical Technology

Pourfadakari

Ahmadi

et al. 2017

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Thermally activated persulfate efficiency for the treatment of a recalcitrant high TDS wastewater was investigated. The specific character of studied wastewater was high TDS content of around 23820 mg/L and BOD5/COD ratio of 0.07. Effective operational parameters including initial pH values of 3–9, reaction temperature of 40–80°C and persulfate concentrations of 0.5–5 g/L for COD removal were investigated in batch mode experiments. Removal efficiency was pH and temperature dependent. The COD and TOC removal of 94.3% and 82.8% were obtained at persulfate concentration of 4 g/L, initial pH value of 5 and temperature of 70°C after 180 min for initial COD concentration of 1410 mg/L. The pseudo first-order kinetic model was best fitted with COD removal (R2 = 0.94).

“…This temperature was held at 240°C for 1 minute. The injector and detector temperatures were set 250 and 300°C, respectively (26,27). The samples were analyzed weekly during 63 days.…”

Section: Methodsmentioning

confidence: 99%

Bioremediation of Pyrene-Contaminated Soils Using Biosurfactant

Jentashapir J Health Res

Rezaee

Jaafarzadeh

et al. 2014

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Background: Polycyclic aromatic hydrocarbons (PAHs) are persistence organic chemicals with proved carcinogenic and mutagenic hazards. These compounds are usually adsorbed in soils in vicinity of oil and gas industries. Bioremediation of PAHs contaminated soils is difficult due to hydrophobic nature of PAHs. Objectives: The main purpose of the current study was to determine the pyrene removal efficiency in synthetically contaminated soil, using biosurfactant. Materials and Methods: Four pure bacterial strains capable of pyrene degradation were isolated from contaminated soils via enrichment techniques. The soil samples were spiked with an initial pyrene concentration of 500 mg/kg and subjected to bioremediation using a mixed culture comprised of previously isolated strains, in addition to application of biosurfactant during 63 days. Results: The pyrene removal efficiency in samples containing biosurfactant, without biosurfactant and controls, were 86.4%, 59.8% and 14%, respectively, after 63 days. The difference of pyrene removal efficiency between the biosurfactant-containing samples and the ones without it was significant (P < 0.05). Conclusions: Application of rhamnolipid biosurfactant produced by Pseudomonas aeruginosa significantly improved pyrene removal in contaminated soils.