Bioremediation of Petroleum Hydrocarbons in Crude Oil Contaminated Soil from Wonocolo Public Oilfields using Aerobic Composting with Yard Waste and Rumen Residue Amendments

The efficiency of composting method with yard waste and rumen residue amendments to reduce soil pollution by total petroleum hydrocarbon in Wonocolo public oilfields was investigated in the laboratory scale for 150 days. Crude oil contaminated soil was mixed with yard waste and rumen residue mixture at 1:1 ratio then composted in 2 replicates. Pure crude oil contaminated soil was composted in parallel. The results showed that total petroleum hydrocarbon degradation efficiency of soils amended with yard waste and rumen residue mixture was 31 times higher than contaminated soil, which fulfilled the soil quality standard (6,974.58 mg/kg). The degradation of total petroleum hydrocarbon might be performed by Bacillus sp., and Bacillus cereus as the dominant bacteria at the end of composting process. These results showed that yard waste and rumen residue transformation could accelerate the degradation of aliphatic and aromatic fractions of petroleum hydrocarbon in crude oil contaminated soil. Both of these wastes are generally easy to obtain around Wonocolo public oilfield and highly recommended to use as the main substrate in the composting process

Biological degradation of oil sludge: A review of the current state of development

Oil sludge is a thick viscous mixture of sediments, water, oil and hydrocarbons, encountered during crude oil refining, cleaning of oil storage vessels and waste treatment. Polycyclic aromatic hydrocarbons (PAHs), which are components of crude oil sludge, constitute serious environmental concerns, as many of them are cytotoxic, mutagenic and potentially carcinogenic. Improper management and disposal of oil sludge causes environmental pollution. The adverse effects of oil sludge on soil ecology and fertility have been of growing interest among environmental scientist and an important consideration in the development of efficient technologies for remediation of contaminated land, with a view to making such land available for further use. Oil sludge can be treated by several methods such as physical, chemical and biological processes. The biological processes are mostly cost effective and environmentally friendly, as they are easy to design and implement, as such they are more acceptable to the public. Compost, the product of biological breakdown of organic matter is a rich source of hydrocarbon-degrading microorganisms such as bacteria and fungi. These microorganisms can degrade the oil sludge to less toxic compounds such as carbon dioxide, water and salts. Compost bioremediation, the application of composting in remediation of contaminated environment, is beginning to gain popularity among remediation scientists. The success or failure of compost bioremediation depends on a number of factors such as nutrients, pH, moisture, aeration and temperature within the compost pile. The bioavailability and biodegradability of the substrate to the degrading microorganisms also contributes to the success of the bioremediation process. This is a review on the biological remediation technologies employed in the treatment oil sludge. It further assesses the feasibility of using compost technology for the treatment of oil sludge, as a better, faster and more cost effective option.Key words: Biodegradation, bioremediation, composting, oil sludge, polycyclic aromatic hydrocarbons (PAHs)

Bioremediation of hydrocarbon contaminated soils and drill cuttings using composting with agricultural wastes

PhD ThesisA compost-bioremediation approach was adopted in this study to explore more sustainable and economically viable methods of degrading pollutant hydrocarbons in oil-field drill cuttings and coal tar impacted soils (CTIS). The compost amendments used were agricultural waste products including grass cuttings, spent mushroom compost and straw. Laboratory-scale compost experiments were conducted to test the performance of different compost blends comprised of each contaminated medium and organic amendments in different mix ratios for 53 days. The compost mix type which produced the greatest reduction in pollutant hydrocarbon concentrations was further scaled-up and tested in an outdoor pilot scale compost treatment for 56 days. At the end of the lab-scale treatments, degradations in total petroleum hydrocarbon (TPH) concentrations of 85.1% and 90.6% were recorded for the drill cuttings and CTIS, compared to 36.7% and 28.4% that was achieved in the control experiments, respectively. The concentrations of total n-alkanes and polycyclic aromatic hydrocarbons (PAHs) were significantly decreased in the best performing compost mix types, however most of the 5 and 6-ring PAH compounds in the CTIS treatment compost mix exhibited recalcitrance to degradation and some even appeared to increase in concentration which is ascribed to increased PAH availability to solvent extraction and reduction in the compost mass during the composting-biodegradation process. The best performing compost mix type for treatment of CTIS was subsequently tested in outdoor tumbler compost bins after being scaled-up by a factor of 600; this was found to produce 78% degradation of TPH concentration at the end of the treatment period. Concentrations of total nalkanes and PAHs were also significantly lowered by biodegradation. Low molecular weight (2 and 3-ring) PAHs were almost completely removed and 4-ring PAHs from the coal tar, including fluoranthene, pyrene, benzo[a]anthracene and chrysene were significantly degraded but not the 5 and 6-ring PAH compounds. Phytotoxicity assays showed that the seed germination in the treated matrix was 70% and 20% more, for corn and pea, respectively, 5 days after planting and 78% more for mustard 3 days after planting. Phosphatase enzyme activity was found to decrease in the treated matrices possibly due to the short time between end of composting and testing. The results generated from the chemical and toxicity assays of this study showed the efficacy of the composting treatment for hydrocarbon removal from these contaminated matrices and identified the best performing compost mix types (DGMSt3 and SGSt3) which can be further tested in field scale trials.Petroleum Technology Development Fund (PTDF) Nigeria for providing full scholarship funding for this researc

Natural carriers in bioremediation: a review

Bioremediation of contaminated groundwater or soil is currently the cheapest and the least harmful method of removing xenobiotics from the environment. Immobilization of microorganisms capable of degrading specific contaminants significantly promotes bioremediation processes, reduces their costs, and also allows for the multiple use of biocatalysts. Among the developed methods of immobilization, adsorption on the surface is the most common method in bioremediation, due to the simplicity of the procedure and its non-toxicity. The choice of carrier is an essential element for successful bioremediation. It is also important to consider the type of process (in situ or ex situ), type of pollution, and properties of immobilized microorganisms. For these reasons, the article summarizes recent scientific reports about the use of natural carriers in bioremediation, including efficiency, the impact of the carrier on microorganisms and contamination, and the nature of the conducted research

Bioremediation of oil spills: A review of challenges for research advancement

As the demand for liquid petroleum increases, the need for reliable and efficient oil spill clean-up techniques is inevitable. Bioremediation is considered one of the most sustainable clean-up techniques but the potential has not been fully exploited in the field because it is too slow to meet the immediate demands of the environment. This study reviews the challenges to managing oil spills in terrestrial and marine environments to identify areas that require further research. Current challenges associated with bioremediation of spilled petroleum include resistance of asphalthenes to biodegradation; delay of heavy or high molar mass polycyclic aromatic hydrocarbon (PAH) biodegradation, eutrophication caused by biostimulation, unsustainability of bioaugmentation in the field, poor bioavailability of spilled petroleum, inefficiency of biodegradation in anoxic environments and failure of successful bioremediation laboratory studies in the field. Recommendations offered include encouraging asphalthene biodegradation by combining heat application (80°C), biosurfactant (thermophilic emulsifier) and bioaugmentation (using a consortium containing Bacillus lentus and Pleurotus tuberregium as members) but as a temporary measure, adopting the use of "booms and skimmers" and "organic sorbents" for water and land clean-up, respectively. Heavy PAHs may be rapidly degraded by applying nutrients (biostimulation) and biosurfactants to sites that are oleophilic microbe-rich. Oleophilic nutrients may be the most effective strategy to reduce eutrophication in marine environments whilst on land, slow-release nutrient application or organic-inorganic nutrient rotation may help prevent soil hardening and infertility. The use of encapsulating agents and genetically-engineered microbes (GEMs) may increase the efficiency of bioaugmentation in the field, but temporarily, indigenous oleophilic microbes may be employed in the field. Poor bioavailability of crude oil may be eliminated by the use of biosurfactants. In terrestrial anoxic sites, bioslurping-biosparging technology could be used whilst the marine anoxic site requires more research on how to transport nutrients and biosurfactants to oleophilic anaerobes residing in the ocean beds. The involvement of both governmental and non-governmental environmental institutions in sponsoring field studies in order to improve the reliability of bioremediation research. Further studies to test the practicability and cost of these recommendations in the field are needed

Curve-Fitting of Bioremediation of Polycyclic Aromatic Hydrocarbons (PAHs) By Co-Composting Using Roost Manure

In this work, ten polluted sites with oil were obtained from Niger Delta, mixed homogenously with compost manure and sent to FUGRO International Laboratory PortHarcourt Nigeria, for bioremediation experiments and analyses. The 4800g sample was divided into twelve (12) equal parts of 400g for bioremediation; 6 parts for the experiments and 6 parts for the control. Particular ringed PAH was isolatedly tested for bioremediation for each of the five ringed PAHs (1 to 5 rings) and the 800g sample was used for respiration test of compost incubation. It was found that the efficiency of bioremediation increased from one to three rings and decreased exponentially for the rest of the rings, showing that bioremediation is not effective for higher ring PAHs. It was also found that bioremediation yields best (optimum) result between two and three ringed PAHs. The respiration of the compost microorganisms improved during incubation by more than two-third i.e 67.7%. The result of this work can be used in bioremediation studies when trying to isolate or choose a particular ringed PAHs for such bioremediation job

Mycoremediation of polycyclic aromatic hydrocarbons (PAH)-contaminated oil-based drill-cuttings

Spent white-rot fungi (Pleurotus ostreatus) substrate has been used to biotreat Nigerian oil-based drill cuttings containing polycyclic aromatic hydrocarbons (PAHs) under laboratory conditions. The Latin square (LS) experimental design was adopted in which four options of different treatment levels were tested in 10 L plastic reactors containing fixed masses of the drill cuttings and fresh top-soil inoculated with varying masses of the spent P. ostreatus substrate. Each option was replicated three times and watered every 3 days under ambient conditions for a period of 56 days. Microcosm analysis with a series II model 5890 AGILENT Hp® GC-FID showed that, the PAHs in the drill cuttings were mainly composed of 2 to 5 fused rings with molecular-mass ranging from 128 to 278 g/mol, while the total initial PAHs concentration of the drill cuttings was 806.31 mg/kg. After 56 days of composting, the total amount of residual PAHs in the drill cuttings decreased to between 19.75 and 7.62%, while the overall degradation of PAHs increased to between 80.25 and 92.38% with increasing substrate addition. Individual PAH degradation ranged from 97.98% in acenaphthene to 100% in fluorene, phenanthrene and anthracene. Statistical analysis, using the 2-factor analysis of variance (ANOVA), showed that there were no significant differences (p < 0.05) in the biodegradation of the PAHs due to the substrate levels applied and remediation period, as well as a nonsignificant (p < 0.05) interaction between substrate levels applied and remediation period. These results showed that spent white-rot fungi (P. ostreatus) substrate may be suitable for biotreating PAH-contaminated Nigerian oil-based drill cuttings.Key words: Drill-cuttings, polycyclic aromatic hydrocarbons Pleurotus ostreatus, mycoremediation, compostin