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Abstract

Petroleum pollution is still one or crucial environmental problems. Bioaugmcntation is a popular technique used in soil remediation. The aim of soil inoculation is acceleration or decomposition processes or improving the degradation efficiency. Effectiveness of bioaugmentation processes depends on the number and activity of microorganisms adapted to pollutant degradation. Enhancement of microorganisms' activity can be reached by the use or plants. Roots or plants excrete organic substances that stimulate microorganisms' growth. Among different species or plants interesting arc papilionaceous plants because of their nitrogen fixation ability in symbiosis with bacteria. The effects or using papilionaceous plants (Trifolium pratense), multiplied autochthonous microorganisms and commercial biopreparation in aged-petroleumpolluted soil were studied. The samples of soil were taken from the refinery in Czechowice-Dziedzice (Poland) and classified as heavily degraded with a C/N-ratio or 100:0.7. Investigations were conducted for 14 weeks. Microbiological analysis included: total bacteria, fungi, Actinomycetes and Pscudonionas counts. Concentration or heavy fractions, TPH (total petroleum hydrocarbons) and PAHs (polycyclic aromatic hydrocarbons) were measured at the start and at the end of the experiment. Presence of pap il ionaceous plant (Trifolium pratensei enhanced the growth or microorganisms, nitrogen concentration and biodegradation processes (removal of 63% or TPH, 44% or heavy fractions, 9% or 4-6 aromatic PAHand 80% of 2-3 aromatic PAH) in polluted soil. An increasing number of Pseudomonas species was observed in samples in which pollution removal was more effective.
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Authors and Affiliations

Ewa Zabłocka-Godlewska
Wioletta Przystaś
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Abstract

Studies were conducted using a 10-chamber Micro-Oxymax (Columbus, OH, USA) respirometer to determine the effect of bioaugmentation, biostimulation and combination of them on enhancing intrinsic biodegradation of oil hydrocarbons in soil. Contaminated soil was collected from a former military airport in Kluczewo, Poland. Bioaugmentation was realized by addition of indigenous or exogenous bacteria to soil. Biostimulation was done by aerated water supply and surfactant addition. Bioaugmentation + addition of a surfactant was applied as the combined treatment. The intrinsic and enhanced hydrocarbons biodegradation rates were estimated from the slopes of linear regressions of cumulative curves of O2 uptake. Pertinent biodegradation rates were recalculated on the basis of the stoichiometric reaction (mass balance equation) and conversion equation. The results showed that combined treatment (indigenous bacteria bioaugmentation + addition of a surfactant) was the most effective method of biodegradation enhancement as the 20-fold increase of biodegradation rate was observed.

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Authors and Affiliations

Iwona Zawierucha
Grzegorz Malina
Wojciech Ciesielski
Piotr Rychter
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Abstract

Compounds present in oil sludge such as polycyclic aromatic hydrocarbons (PAHs) are known to be cytotoxic, mutagenic and potentially carcinogenic. Microorganisms including bacteria and fungi have been reported to degrade oil sludge components to innocuous compounds such as carbon dioxide, water and salts. In the present study, we isolated different bacteria with PAH-degrading capabilities from compost prepared from oil sludge and animal manures. These bacteria were isolated on a mineral base medium and mineral salt agar plates. A total of 31 morphologically distinct isolates were carefully selected from 5 different compost treatments for identification using polymerase chain reaction (PCR) of the 16S rRNA gene with specific primers (universal forward 16S-P1 PCR and reverse 16S-P2 PCR). The amplicons were sequenced and sequences were compared with the known nucleotides from the GenBank. The phylogenetic analyses of the isolates showed that they belong to 3 different clades; Firmicutes, Proteobacteria and Actinobacteria. These bacteria identified were closely related to the genera Bacillus, Arthrobacter, Staphylococcus, Brevibacterium, Variovorax, Paenibacillus, Ralstonia and Geobacillus. The results showed that Bacillus species were predominant in all composts. Based on the results of the degradation of the PAHs in the composts and results of previous studies on bacterial degradation of hydrocarbons in oil, the characteristics of these bacterial isolates suggests that they may be responsible for the breakdown of PAHs of different molecular weights in the composts. Thus, they may be potentially useful for bioremediation of oil sludge during compost bioremediation.

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Authors and Affiliations

Onyedikachi Ubani
Harrison Ifeanyichukwu Atagana
Mapitsi Silvester Thantsha
Adeleke Rasheed
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Abstract

Accidental oil spills at open sea is a common environmental problem. They lead to degradation of sea and shoreline life. In the last ten years there has been an increased interest in bioremediation using the enzymatic activity of the naturally occurring microorganisms. In this work the potential of mixed microbial cultures for biodegradation of crude oil in seawater and sand has been examined. Artificial seawater supplemented with nitrogen and phosphorus was inoculated with cultures isolated from refinery sludge. The same cultures were used for experiments in sand polluted by 5% (v/w) of crude oil. These experiments were performed in sterile and semi-natural (not sterile) conditions to see the degradation potential of isolated cultures, their growth characteristics and possible antagonisms between supplemented microorganisms and natural microflora. During the experiments the oxygen demand, number of bacteria (cfu) and optical density (OD660 ) were monitored. After 14 days of cultivation, the concentration of total petroleum hydrocarbons (TPH) in all samples was measured. All tested cultures had a potential for degradation of hydrocarbons in seawater and sand. After two weeks of experiment, loss of hydrocarbons in seawater polluted with crude oil was between 56.8% (A2 culture) and 64.4% (Al culture). The most effective culture for bioaugmentation of seawater does not have to be the best solution for bioaugmcntation of sand. In sand the best degraders in sterile and semi-natural conditions were found in the mixed cultures isolated from Corinth refinery sludge. For this culture concentration of hydrocarbons in sterile sand was 73.2% lower than in control sample and in non-sterile sand 70.5% lower than in control (sterile sand) without bioaugmentation. Finally, the addition of seawater and fertilizers to sand had also a positive influence on contaminants degradation by naturally occurring microorganisms (48%). Experiments performed with different environments (seawater and sand) and under different conditions (sterilized material and semi-natural conditions) confirmed that cultures should be tested in semi-natural conditions especially when indigenous microflora cans posse's high degradation potential. Allochtonie cultures, very active in sterile conditions, after inoculation to natural environment can even slow down the degradation.
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Authors and Affiliations

Wioletta Przystaś
Nikos Pasadakis
Nicolas Kalogerakis
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Abstract

The aim of this work is purification of contaminated soil from manufactured gas plants MGP, which arc not used. Prepared chromatographic methodologies, which allow qualitative identification and quantitative determination of individual aliphatic and aromatic (TAH, PAH) hydrocarbons in the soil from the selected MGP, arc presented. The results of the research on remediation of the soil polluted with petroleum hydrocarbons (TAH, PAHs) in semi-field conditions arc discussed. Application of basic biorcmcdiation and bioaugmcntation with indigenous microorganisms, enriched with PAH biodegradable fungi, resulted in reduction in amount of 5- and 6-polycyclic aromatic hydrocarbons. The research enables control of remediation progress, selection of optimal doses of biogenie compounds and determines the time of the process. The entire cycle of soil remediation was monitored with the use of gas chromatography (GC). Estimation ofbiodcgradation degree of individual aliphatic hydrocarbons (alkancs) was based on changes in their concentration in the soil and determined by biodegradation indicators: C,/pristanc and C,/phytanc ratios. Attention was paid particularly to biodcgradation of polycyclic aromatic hydrocarbons (PAH), which were observed in substantial concentrations in the polluted soil. The elaborated chromatographic methodology of PAH determination in the soil enabled estimation of a biodcgradation rate referring to individual compounds. Moreover, attempts to create a TAH biodcgradation model with the use of C30-l 7a(H),2 l l3(H)-hopanc were undertaken.
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Authors and Affiliations

Teresa Steliga

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