Bioremediation by Composting of Heavy Oil Refinery Sludge in Semiarid Conditions

Department of Soil and Water Conservation and Waste Management, CEBAS-CSIC, Espinardo, Murcia, Spain.
Biodegradation (Impact Factor: 2.34). 07/2006; 17(3):251-61. DOI: 10.1007/s10532-005-5020-2
Source: PubMed


The present work attempts to ascertain the efficacy of low cost technology (in our case, composting) as a bioremediation technique for reducing the hydrocarbon content of oil refinery sludge with a large total hydrocarbon content (250-300 g kg(-1)), in semiarid conditions. The oil sludge was produced in a refinery sited in SE Spain The composting system designed, which involved open air piles turned periodically over a period of 3 months, proved to be inexpensive and reliable. The influence on hydrocarbon biodegradation of adding a bulking agent (wood shavings) and inoculation of the composting piles with pig slurry (a liquid organic fertiliser which adds nutrients and microbial biomass to the pile) was also studied. The most difficult part during the composting process was maintaining a suitable level of humidity in the piles. The most effective treatment was the one in which the bulking agent was added, where the initial hydrocarbon content was reduced by 60% in 3 months, compared with the 32% reduction achieved without the bulking agent. The introduction of the organic fertiliser did not significantly improve the degree of hydrocarbon degradation (56% hydrocarbon degraded). The composting process undoubtedly led to the biodegradation of toxic compounds, as was demonstrated by ecotoxicity tests using luminescent bacteria and tests on plants in Petri dishes.

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Available from: José L Moreno, Feb 20, 2015
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    • "The temperature increase in the composting process may be due to the differing capacity of microorganisms to degrade the hydrocarbons. Since oil sludge contains highly degradable materials, these microorganisms accept the hydrocarbons as substrates, which enhance their activities, leading to the higher increase in temperature (Bengtsson et al., 1998; Jose et al., 2006 "
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    ABSTRACT: 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.
    AFRICAN JOURNAL OF BIOTECHNOLOGY 11/2013; 12(47):6544-6567. DOI:10.5897/AJB11.1139 · 0.57 Impact Factor
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    • "Microbial inoculum typically used in composting process to increase volume of microbial culture sufficiently large to effect the decomposition of the receiving material at a faster rate [7] [8]. Poultry manure, bean cake and carbamide [3] and pig slurry [6] have been successfully used as microbial inoculum. "
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    ABSTRACT: In bioremediation, oil degrading microorganisms are applied to remediate contaminated soil. Air is an essential factor for activation of degrading microorganisms. Adding some bulky wastes or by-products which enhance the air circulation in the system is one of the economical approaches for aeration. In this study, co-composting of oil sludge contaminated soil from a local refinery plant was studied using dry yard waste (CI) and nonrecyclable paper (CII) as bulking agents. Initially 16 L cubic composters were made using plexiglass. Composters were opened at the top and had number of holes at the bottom and sides. The soil was spiked with petroleum refinery sludge (20%, dry weight basis) and the ratio of contaminated soil to bulking agents and seeding materials was 1:1 (v/v) and 1:0.5 (w/w), respectively. The seeding materials as source of microorganisms was brought from the same refinery plant wastewater treatment facility. The total volume of each mixture was approximately 4.3 kg. The composters were cultivated weekly and water was added occasionally to maintain moisture content. Results show the temperature profile for both composters were built up after initial weeks. Moisture content reached to steady conditions (50% to 60%) in second week and was maintained within the range till the end of experiments. pH showed more fluctuation in CII compared to CI. The maximum reduction of total petroleum hydrocarbon (TPH) was 55% and 56% for CI and CII, respectively over the 14-week study duration. The composting degradation rate kinetics indicates that the TPH concentrations will reach less than 100 mg/kg after 23 weeks of degradation.
    Business Engineering and Industrial Applications Colloquium (BEIAC), 2013 IEEE; 01/2013
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    • "It increased again to reach 7.5 by 21 d of incubation, and then declined to an average of 6.8 from day 28 until day 35. Similar observations were reported by Aislabie et al. (2006) and Marin et al. (2006) and attributed this to the formation of low molecular weight organic acids during the degradation of the carbon compounds. Braddock et al. (1999) reported that the addition of nutrients lowered the pH of coarse sand from 7.4 to 6.8. "
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    ABSTRACT: A microcosm study was constructed to investigate the effect of complex co-substrate (corn steep liquor, CSL) addition on indigenous bacterial community, rate and extent of petroleum hydrocarbons (PH) degradation in an oily soil with total petroleum hydrocarbons (TPH) content of 63353 mg kg−1. TPH degradation was found to be characterized by a rapid phase of degradation during the first three weeks where 76% removal of TPH occurred, followed by a slower degradation phase, where further 7% of the initial TPH was removed by the end of incubation period, 35 d. Branched alkanes are more resistant to microbial degradation than n-alkanes. Furthermore, the unresolved complex mixtures (UCM) of hydrocarbons are less degradable than n- and iso-alkanes. Pristane (Pr) was the most recalcitrant aliphatic compound studied in this work. These results in addition to the extensive bacterial growth observed (from 107 to 1010 CFU g−1 soil) give strong support that the addition of CSL resulted in increased degradation rates. The indigenous bacteria grew exponentially during the incubation period of 35 d with a growth rate of 0.26 d−1. Kinetic modeling was performed to estimate the rates of biodegradation of each hydrocarbon type component in the studied system. Five different error functions were used in this study to evaluate the fitness of the model equation to the obtained experimental data. This showed that the degradation of ∑nC20-nC24, ∑nC35-nC42 and nC18 can be better represented by a second order model, whereas the TPH, total resolvable peaks (TRP), nC17, UCM, ∑nC10-nC14, ∑nC15-nC19, ∑nC25-nC29, ∑nC30-nC34, ∑nCn, and ∑isoCn and isoprenoids Pr and phytane (Ph) were similarly following the first order model.
    Soil and Sediment Contamination 05/2011; 20(4-4):432-446. DOI:10.1080/15320383.2011.571525 · 1.04 Impact Factor
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