A feasibility study on the bioremediation of hydrocarbon-contaminated soil from an Alpine former military site: Effects of temperature and biostimulation (original) (raw)
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Laboratory-scale bioremediation experiments on hydrocarbon-contaminated soils
International Biodeterioration & Biodegradation, 2004
Successful application of bioremediation technology to contaminated soil requires knowledge of the characteristics of the site and the parameters that a ect the microbial biodegradation of pollutants. Here, we propose a simple protocol for biotreatability assays in two phases. In the ÿrst phase of the assays we examined the type and metabolic activity of the indigenous microorganisms at the site, and the presence of possible inhibitors. The biodegradability of contaminants in soil slurries under optimal conditions was also tested. In the second phase several parameters, such as the in uence of nutrients and the addition of surfactant and specialized inocula, were evaluated in microcosms with 2:5 kg soil. The application of this protocol to two hydrocarbon-contaminated soils is described. In the ÿrst phase of the protocol, the results obtained with the ÿrst soil indicated high metabolic activity of indigenous microbial populations and a total petroleum hydrocarbon (TPH) decrease of 46%. Assays of the second soil indicated low indigenous microbial metabolic activity and limited biodegradation of TPH. In the second phase of the protocol, which lasted 360 days, assay of microcosms showed that the ÿrst soil responded to several treatments with a large decrease in TPH, while none of the treatments applied to the second soil showed a reduction in TPH. The information obtained from the results in the ÿrst phase of the protocol indicates whether a biological treatment of contaminated soil is appropriate. In the second phase of the protocol, we attempted to identify the most appropriate treatment through the evaluation of various conditions and additives.
Bioremediation of hydrocarbon-contaminated polar soils
Extremophiles, 2006
Bioremediation is increasingly viewed as an appropriate remediation technology for hydrocarboncontaminated polar soils. As for all soils, the successful application of bioremediation depends on appropriate biodegradative microbes and environmental conditions in situ. Laboratory studies have confirmed that hydrocarbon-degrading bacteria typically assigned to the genera Rhodococcus, Sphingomonas or Pseudomonas are present in contaminated polar soils. However, as indicated by the persistence of spilled hydrocarbons, environmental conditions in situ are suboptimal for biodegradation in polar soils. Therefore, it is likely that ex situ bioremediation will be the method of choice for ameliorating and controlling the factors limiting microbial activity, i.e. low and fluctuating soil temperatures, low levels of nutrients, and possible alkalinity and low moisture. Care must be taken when adding nutrients to the coarse-textured, low-moisture soils prevalent in continental Antarctica and the high Arctic because excess levels can inhibit hydrocarbon biodegradation by decreasing soil water potentials. Bioremediation experiments conducted on site in the Arctic indicate that land farming and biopiles may be useful approaches for bioremediation of polar soils.
Journal of Bioscience and Applied Research
Soil contamination by petroleum hydrocarbons is a widespread and global environmental contamination concern that needs to be carefully treated and controlled. This research investigates, compare, and analyse the viability of bioremediation technologies for the ex situ remediation of hydrocarbon polluted soils. It also outlines the most appropriate bioremediation technique. Results showed one of the important advantages of necrophytoremediation as a remediation protocol. The degradation amount of oil in different treatments follows this sequence: pea straw (PS) > combination of pea straw and Bacillus consortium (BAPS) > Bacillus consortium (BA) > natural attenuation (NA). The same amount of "bacteria" was added into treatment BAPS and BA. Necrophytoremediation using pea straw has a positive effect on the degradation of TPH by 96% during 12 weeks of treatment; the same pattern was followed for the combination of necrophytoremediation and bioaugmentation (pea straw and Bacillus consortium) with 95% total petroleum hydrocarbons (TPH) reduction. Natural attenuation and bioaugmentation microcosms modified with Bacillus were the least practical with TPH reduction of 79% and 76% respectively. The findings from this study recommend researching the possibility of relying on in situ necrophytoremediation as valuable, economical and invulnerable method for enhancing the bioremediation efficiency of oil contaminated soils.
Soil and Sediment Contamination: An International Journal, 2018
The bioremediation of petroleum hydrocarbons (PHCs)-polluted soils was studied by an ex-situ, lab-scale, biopile experiment with different parameters: aeration rate (1 h day −1 and 2 h day −1), soil moisture (44% and 60%), and microorganisms consortia addition (320 and 640 mL). The trial was conducted using eight treatment cells, each having different parameters, and one control cell for 18 weeks on soil containing 7600 ± 400 mg kg −1 total PHCs, taken from a former petroleum product warehouse in Sfantu Gheorghe, Covasna County (Romania). The microorganisms used for bioremediation were isolated from the native microflora of the polluted soil and grown in laboratory on culture media. A bioremediation yield up to 76% was obtained in the test cells, while in the control cell the reduction of PHCs content by 16% was attributed to natural attenuation. The results indicated that by addition of microorganisms the bioremediation is much more effective than natural attenuation. The results also revealed an accentuated decrease in PHC concentrations after 4 weeks of treatment, irrespective of the treatment conditions.
Effective bioremediation requires an extensive understanding of the soil parameters and microbial community diversity. Long term contamination of petroleum hydrocarbon soils in arid areas present unique opportunities to study the response of the impacted microbial community to bioremediation efforts. Two bioremediation treatments viz., biopile and bioslurry, were applied to assess the efficacy of different bioremediation methods in long term petroleum hydrocarbon contaminated soils. The bioslurry treatment was markedly more effective at treating the long term petroleum hydrocarbon contaminated soils in a short period of time. First order rates of hydrocarbon degradation in the bioslurry treatment were between 0.066 and 0.073 d1 compared with the biopile treatment where the rates ranged from 0.011 to 0.03 d1, depending on the level and nature of the hydrocarbon fractions present in the soils. Bioslurry treatment of the long term contaminated soils exhibited a shift in the microbial community composition. Alpha-proteobacteria dominated the microbial community present in the hydrocarbon contaminated soils but bioslurry treatment of the contaminated soils led to a clear shift in the microbial community present in the soils, with Gamma-proteobacteria dominating the remediation environment along with microbial sequences associated with the TM7 phylum and a subsequent reduction in hydrocarbon concentration in the soils.
Effectiveness of bioremediation process in hydrocarbon-contaminated subantarctic soils
2004
An accidental contamination by diesel fuel occurred in the subantarctic Crozet Island between July and November 1997 near the "Alfred Faure" scientific station (51° 51'E -46° 25'S). In order to determine the best bioremediation approach for such hydrocarbons contaminated subantarctic soils, a controlled field study was initiated in December 2000 in soils of a neighbor island with better research facilities (Grande Terre, Kerguelen Archipelago). Two soils were selected, one supporting an abundant vegetal cover while the second one was completely dry and desert. A series of 6 experimental plots (0.75 x 0.75 m) were firmly settled in place. Each plot received 500 mL of diesel fuel or Arabian light crude oil and some of them were treated with the slow release fertilizer Inipol EAP-22 (Elf Atochem). All plots were sampled on a regular basis over a one-year period. All samples were analyzed for total bacteria, heterotrophic viable assemblages and hydrocarbon microflora, hydrocarbons distribution by GC/MS and toxicity of residues by Microtox SP ®.
Bioremediation and Biodegradation of Hydrocarbon Contaminated Soils: A Review
2015
Bioremediation is environment friendly process that utilised a range of communities of microorganisms in combination with series of techniques to decontaminate polluted sites. This has however remained in pilot scale and pot experiment studies and as far as the application of these techniques in field realities are concerned, there is need for compilation of research on the subject. This review found that the application of BS and BA techniques should be done only after a pilot study confirmed the feasibility of using either techniques or both. Otherwise, the remediation may incur unnecessary and avoidable cost due to the use of these techniques while they are not important.Selection of suitable and cost-effective amendments and more efficient hydrocarbon degraders or a consortium of hydrocarbon degraders are very critical to the success of biological remediation of hydrocarbon contaminated sites. Biostimulation using organic substances such the poultry manure, cow dung, biochar and food waste are more effective in optimising the process of bioremediation. Aerobic degradation process is the most viable technique for field application of bioremediation of soils.
IOSR Journals , 2019
This study appraised the capability of indigenous microorganisms in a location with no history of hydrocarbon contamination. The experiment was conducted using microcosms and particle size of the soil was manipulated to arrive at about 9 different types of soils using the soil textural triangle. For operational convenience, nine types of soil were considered, and an undisturbed soil was considered a control experiment. Samples were artificially spiked with 3.4% (w/w) diesel and all nine samples were stimulated with 4% (w/w) NPK fertilizer. These treatments were prepared in three replicates and samples were drawn for extraction and microbial monitoring every 14 days and the study lasted for 56 days. Extraction was done using Soxhlet Extractor and analysis was performed with gas chromatography installed with mass spectrometry. The result of the diesel degradation is significant at the p = 0.05 levelwith little variation in microbial activities except in clay where the organisms experienced excessive stress leading to complete mortality of the degraders at the end of the experiment. Highest bioremediation rate was noted in silt with 75% diesel removal while the lowest bioremediation efficiency was in clay with about 18% and is significantly lower than control with 35% diesel removal. It has been concluded that clay soil bioremediation will require textural amendment to minimize effects of adsorption of nutrients making it unavailable for degraders and, its textural disadvantage for aerobic degradation of contaminants. There is high probability of increasing bioremediation rates as the texture moves away from clayand in this experiment;biostimulation wasthe most significant factor that improves remediation efficiency.
Bioremediation of diesel-oil-contaminated alpine soils at low temperatures
Applied Microbiology and Biotechnology, 1997
Bioremediation of two diesel-oil-contaminated alpine subsoils, diering in soil type and bedrock, was investigated in laboratory experiments at 10°C after supplementation with an inorganic fertilizer. Initial diesel oil contamination of 4000 mg kg)1 soil dry matter (dm) was reduced to 380±400 mg kg)1 dm after 155 days of incubation. In both soils, about 30 % of the diesel oil contamination (1200 mg kg)1 dm) was eliminated by abiotic processes. The residual decontamination (60 %± 65 %) could be attributed to microbial degradation activities. In both soils, the addition of a cold-adapted diesel-oil-degrading inoculum enhanced biodegradation rates only slightly and temporarily. From C/N and N/P ratios (determined by measuring the contents of total hydrocarbons, NH 4 N, NO À 3 N and PO 3À 4 P) of soils it could be deduced that there was no nutrient de®ciency during the whole incubation period. Soil biological activities (basal respiration and dehydrogenase activity) corresponded to the course of biodegradation activities in the soils.
Transformation of a petroleum pollutant during soil bioremediation experiments
Journal of the Serbian Chemical Society, 2008
The experiment of ex situ soil bioremediation was performed at the locality of the Oil Refinery in Pančevo (alluvial formation of the Danube River, Serbia) polluted with an oil type pollutant. The experiments of biostimulation, bioventilation and reinoculation of an autochthonous microbial consortium were performed during the six-month period (May-November 2006). The changes in the quantity and composition of the pollutant, or the bioremediation effect, were monitored by analysis of the samples of the polluted soil taken in time spans of two weeks. In this way, from the beginning until the end of the experiment, 12 samples were collected and marked as P 1 -P 12 (Pančevo 1-Pančevo 12). The results obtained showed that more significant changes in the composition of the oil pollutant occurred only during the last phases of the experiment (P 8 -P 12 ). The activity of microorganisms was reflected in the increase of the quantity of polar oil fractions, mainly fatty acid fractions. In this way, the quantity of total eluate increased, and the quantity of the insoluble residue was reduced to a minimum, whereby the oil pollutant was transformed to a form that could be removed more efficiently and more completely from the soil, as a segment of the environment.