Academic literature on the topic 'Bioreactors Bioremediation. Soils'

This work investigated the possibility of using vinasse as an amendment in ex-situ bioremediation processes. Groundwater and soil samples were collected at petrol stations. The soil bioremediation was simulated in Bartha biometer flasks, used to measure the microbial CO2 production, during 48 days, where vinasse was added at a concentration of 33 mL.Kg-1of soil. Biodegradation efficiency was also measured by quantifying the total petroleum hydrocarbons (TPH) by gas chromatography. The groundwater bioremediation was carried out in laboratory experiments simulating aerated (bioreactors) and not aerated (BOD flasks) conditions. In both the cases, the concentration of vinasse was 5 % (v/v) and different physicochemical parameters were evaluated during 20 days. Although an increase in the soil fertility and microbial population were obtained with the vinasse, it demonstrated not to be adequate to enhance the bioremediation efficiency of diesel oil contaminated soils. The addition of the vinasse in the contaminated groundwaters had negative effects on the biodegradation of the hydrocarbons, since vinasse, as a labile carbon source, was preferentially consumed.

Abstract Previous tests using a growth medium and olive mill wastewater (OMWW) have shown that it supplies carbon and electron donors suitable for sulphate reducing bacteria (SRB). We assessed the co-treatment of acid mine drainage (AMD) and OMWW using SRB-enriched bioreactors and identified the most abundant bacterial populations present under optimized conditions. The process requires a neutralizing agent to create optimal pH conditions for successful removal of the AMD’s main contaminants. Concentrations of SO42−, Al, Fe, Cu, Zn, and Mn decreased to below Portugal’s maximum admissible values for irrigation waters, and all but Mn were reduced to less than Portugal’s emission limit values (ELVs) for wastewater discharges. Phenol concentrations—the main pollutants in OMWW—dropped to values between 1/10 and 1/5 their initial concentrations in batch tests using mixtures of AMD and OMWW, and to 1/2 their initial concentrations in flow-through tests. The final total phenol concentrations were still above the ELV for wastewater discharges, but phenols are not regulated in irrigation waters, and OMWW is used by some producers to irrigate soils. Six main SRB groups were identified as likely having a fundamental role in the bioremediation process: the genera Desulfovibrio, Sulfurospirillum, and Acetobacter and the families Sphingomonadaceae, Prevotellaceae, and Deferribacteraceae.

Nitrogen cycle microorganisms are essential in agricultural soils and may be affected by mercury pollution. The aims of this study are to evaluate the bioremediation of mercury-polluted agricultural soil using Cupriavidus metallidurans MSR33 in a rotary drum bioreactor (RDB) and to characterize the effects of mercury pollution and bioremediation on nitrogen cycle microorganisms. An agricultural soil was contaminated with mercury (II) (20–30 ppm) and subjected to bioremediation using strain MSR33 in a custom-made RDB. The effects of mercury and bioremediation on nitrogen cycle microorganisms were studied by qPCR. Bioremediation in the RDB removed 82% mercury. MSR33 cell concentrations, thioglycolate, and mercury concentrations influence mercury removal. Mercury pollution strongly decreased nitrogen-fixing and nitrifying bacterial communities in agricultural soils. Notably, after soil bioremediation process nitrogen-fixing and nitrifying bacteria significantly increased. Diverse mercury-tolerant strains were isolated from the bioremediated soil. The isolates Glutamicibacter sp. SB1a, Brevundimonas sp. SB3b, and Ochrobactrum sp. SB4b possessed the merG gene associated with the plasmid pTP6, suggesting the horizontal transfer of this plasmid to native gram-positive and gram-negative bacteria. Bioremediation by strain MSR33 in an RDB is an attractive and innovative technology for the clean-up of mercury-polluted agricultural soils and the recovery of nitrogen cycle microbial communities.

Field and laboratory studies were used to study the influence of temperature and O2on the bioremediation of diesel-fuel contaminated soil. Field data were obtained from a landfarm located in Northern Ontario, whereas laboratory experiments were conducted using bioreactors containing diesel-spiked soil and contaminated soil from the field site. Laboratory and field degradation rates were quantified based on changes in the total petroleum hydrocarbons concentration and some individual components, as well as by monitoring O2consumption and CO2evolution. A degradation rate correlation was developed from the laboratory data. Based on comparison with the laboratory data, the slow rate observed in the field was likely due to low O2concentrations at the site.Key words: bioremediation, diesel fuel, unsaturated soil, cold climate, degradation rate.

The aim of the present work was to evaluate the biodegradation of petroleum hydrocarbons in clay soil a 45-days experiment. The experiment was conducted using an aerobic fixed bed reactor, containing 300g of contaminated soil at room temperature with an air rate of 6 L/h. The growth medium was supplemented with 2.5% (w/w) (NH4)2SO4 and 0.035% (w/w) KH2PO4. Biodegradation of the crude oil in the contaminated clay soil was monitored by measuring CO2 production and removal of organic matter (OM), oil and grease (OandG), and total petroleum hydrocarbons (TPH), measured before and after the 45-days experiment, together with total heterotrophic and hydrocarbon-degrading bacterial count. The best removals of OM (50%), OandG (37%) and TPH (45%) were obtained in the bioreactors in which the highest CO2 production was achieved.

Central composite design (CCD) and response surface methodology (RSM) were employed to optimize four important variables, i.e. amounts of oil, bacterial inoculum, nitrogen and phosphorus, for the removal of selected n-alkanes during bioremediation of weathered crude oil in coastal sediments using laboratory bioreactors over a 60 day experimentation period. The reactors contained 1 kg soil with different oil, microorganisms and nutrients concentrations. The F Value of 26.89 and the probability value (P < 0.0001) demonstrated significance of the regression model. For crude oil concentration of 2, 16 and 30 g per kg sediments and under optimized conditions, n-alkanes removal was 97.38, 93.14 and 90.21% respectively. Natural attenuation removed 30.07, 25.92 and 23.09% n-alkanes from 2, 16 and 30 g oil/kg sediments respectively. Excessive nutrients addition was found to inhibit bioremediation.

Thesis (MTech (Chemical Engineering))--Peninsula Technikon, 2001
Certain fungi have been shown to excrete extracellular enzymes, including peroxidases, laccases, etc. These enzymes are useful for bioremediation of aromatic pollutants present in industrial effluents (Leukes, 1999; Navotny et aI, 1999). Leukes (1999) made recent significant development in the form of a capillary membrane gradostat (fungal) bioreactor that offers optimal conditions for the production of these enzymes in high concentrations. This system also offers the possibility for the polluted effluent to be treated directly in the bioreactor. Some operating problems relating to continuous production of the enzymes and scale-up of the capillary modules, were, however, indentified. In an attempt to solve the above-mentioned identified problems the research group at Peninsula Technikon considered a number of alternative bioreactor configurations. A pulsed packed bed bioreactor concept suggested by Moreira et at. (1997) was selected for further study. Their reactor used polyurethane pellets as the support medium for the fungal biofilm and relied upon pulsing of the oxygen supply and recycle of nutrient solution in order to control biomass accumulation. These authors reported accumulation due to the recycle of proteases that were believed to destroy the desired ligninases. We experimented with a similar concept without recycle to avoid backrnixing and thereby overcome protease accumulation. In our work, a maximum enzyme productivity of 456 Units.L1day·1 was attained. Since this was significantly greater than the maximum reported by Moreira et aI, 1997 (202 Units.L-1day-I) it appeared that the elimination of recycle had significant benefits. In addition to eliminating recycle we also used a length / diameter (L / D) ratio of 14: 1 (compared with 2.5: 1 used by Moreira et aI, 1997) in order to further reduce backrnixing. Residence time distributions were investigated to gain insight into mechanisms of dispersion in the reactor. It was found that the pulsed packed bed concept presented problems with regard to blockage by excess biomass. This led us to consider the advantages of a fluidized bed using resin beads. Accordingly, growth of fungi on resin beads in shake flasks was investigated with favorable results. An experimental program is proposed to further investigate the fluidized bed concept with a view to extending the operation time of the bioreactor. From our literature survey to date, packed bed fungal bioreactors are still the best reactor configuration for continuous production ofligninolytic enzymes. An interesting study of the application of laccases to the degradation of naphthalene and MTBE is described in an addendum to this thesis.

The Savannah River Site (SRS), a Department of Energy facility, generated non-hazardous petroleum and radiological co-contaminated soils that did not have a disposal pathway. The purpose of this project was to generate treatment data and test the hypothesis that an engineered biological process could safely and efficiently remove petroleum co-contamination from radiological contaminated soil. Demonstration of the treatment would allow the soils to be disposed as low-level radiological materials. Although radiation and radiological contamination may, depending on the type and level, impact microbial activity and growth, the impact of low levels of radiation were not expected to impact the biodegradation of petroleum contaminated soils. Important parameters identified for successful biological treatment included oxygen mass transfer, bioavailability, temperature, microbiological capabilities, nutrients, and moisture. System design was based on a bioventing approach to control the supply of oxygen (air) based on petroleum contamination levels and type of soil being treated. Before bioremediation began, a bioreactor system was permitted, designed, constructed, and tested. An operating permit was obtained from SCDHEC, as were approvals required by the SRS. The design was based on bioventing principles and used a modified prefabricated skid-pan, which was constructed by SRNL. System operation included formulating a test plan, developing and using system sampling and monitoring methods, loading the system, starting up operations, obtaining results, modifying operation, and final disposal of the soil after the bioremediation goal was achieved. The PRCS bioreactor operated for 22 months in various configurations treating the contaminated soil to a final TPH concentration of 45 mg/kg. During operation, degradation of over 20,000 mg/kg of waste was accounted for through monitoring of carbon dioxide levels in the effluent. System operation worked best when soil temperatures were above 15 ?nd the pumps were operated continuously. The low level radiological contaminated soil was disposed in an engineered trench at SRS that accepts this type of waste. The project demonstrated that co-contaminated soils could be treated biologically to remove petroleum contamination to levels below 100 mg/kg while protecting workers and the environment from radiological contamination.

An engineered bioreactor system was designed and constructed to bioremediate approximately 1,800 m$\sp3$ of petroleum-contaminated soil at CFB Petawawa, Petawawa, Ontario. The bioremediation facility operated between May-November 1993. The facility consists of four above ground bioreactors each incorporating aeration piping and a water/nutrient delivery system. The aeration piping is connected to a central vacuum pump which draws air through the bioreactor leachate collection system enables the leachate to be amended. The bioreactors are covered with an opaque vapour barrier. Monitoring involved the collection of soil, water and air samples on a weekly and bi-weekly basis and various field measurements. A detailed microbial monitoring program was also implemented. Total petroleum hydrocarbon concentrations in the bioreactor soils were found to have been reduced by 97%. Temperature had an effect on the rate of petroleum biodegradation. Little or no evidence suggested that the continuous addition of nutrients to the soil had a significant effect on the rate of biodegradation. The estimated treatment cost for this project was 70-$90 per tonne. This facility however, is reusable and hence the potential exists to lower the net treatment cost to 20--\$40 per tonne. This project has shown that diesel contaminated soil can be efficiently and effectively treated to meet the most stringent federal and/or provincial criteria in a cost effective manner over a typical Canadian summer. (Abstract shortened by UMI.)

L'objectif de cette thèse a été de développer une technologie pour l'assainissement des sols / sédiments sélénifères et d’étudier la réduction microbienne des oxy-anions de sélénium dans différentes conditions de respiration et de configurations du bioréacteur.Le sol sélénifère prélevé, dans les terres agricoles cultivées de blé au Pendjab (Inde), a été caractérisé et son lavage a été optimisé en faisant varier les paramètres tels que le temps de réaction, la température, le pH et le rapport liquide / solide. Afin de maximiser l'élimination et la récupération du sélénium à partir de ce sol, l'effet des ions compétiteurs et les composés oxydants comme les agents d'extraction pour le lavage du sol, ont également été étudiés. Bien que les agents oxydants aient montré une efficacité maximale d'élimination du sélénium (39%), la présence d'agents oxydants dans le lixiviat et le sol agricole peut augmenter le coût de leur post-traitement. Les plantes aquatiques, Lemma minor et Egeria densa ont été utilisées pour étudier la phyto-remédiation du lixiviat du sol contenant des agents oxydants. Cependant, l'efficacité d'élimination du sélénium par les plantes aquatiques a été significativement affectée par les fortes concentrations de ces agents oxydants dans le lixiviat du sol.Le rinçage du sol sélénifère a révélé un motif de migration du sélénium à travers la colonne du sol. La migration de la fraction de sélénium soluble de la couche supérieure vers la couche inférieure et sa réduction et son accumulation subséquentes dans les couches inférieures de la colonne de sol, ont été observées pendant le rinçage du sol. L'efficacité d'élimination du sélénium par la méthode de rinçage du sol a diminué avec une augmentation de la hauteur de la colonne. De plus, le lixiviat contenant des oxy-anions de sélénium obtenus à partir du lavage du sol, a été traité dans un réacteur UASB en faisant varier l'alimentation organique. Des effluents contenant moins de 5 μg de sélénium L-1 ont été obtenus, ce qui est conforme aux normes de l'USEPA pour la limite de rejet de sélénium dans les eaux usées.De plus, la bio-remédiation ex situ des oxy-anions de sélénium a été étudiée dans des conditions variables. Une bactérie aérobie (Delftia lacustris) capable de transformer le sélénate et le sélénite en sélénium élémentaire, mais aussi en composés d'ester de sélénium solubles jusque-là inconnus, a été isolée et caractérisée de manière fortuite. Alternativement, la bio-réduction anaérobie du sélénate couplé au méthane en tant que donneur d'électrons, a été étudiée dans des bouteilles de sérum et un filtre percolateur en utilisant des sédiments marins comme inoculum. Enfin, l'effet de la contamination d'autres oxy-anions chalcogènes, en plus du sélénium, a été étudié. La réduction simultanée de la sélénite et de la tellurite par un consortium microbien mixte ainsi que la rétention des nanostructures de Se et de Te biogènes dans l'EPS, ont été réalisées durant une opération de 120 jours dans un bioréacteur UASB
The aim of this Ph.D. was to develop a technology for the remediation of seleniferous soils/sediments and to explore microbial reduction of selenium oxyanions under different respiration conditions and bioreactor configurations.Seleniferous soil collected from the wheat-grown agricultural land in Punjab (India) was characterized and its soil washing was optimized by varying parameters such as reaction time, temperature, pH and liquid to solid ratio. In order to maximize selenium removal and recovery from this soil, effect of competing ions and oxidizing agents as chemical extractants for soil washing were also studied. Although oxidizing agents showed a maximum selenium removal efficiency (39%), the presence of oxidizing agents in the leachate and the agricultural soil may increase the cost of their post-treatment. Aquatic plants, Lemma minor and Egeria densa were used to study phytoremediation of the soil leachate containing oxidizing agents. However, the selenium removal efficiency by aquatic weeds was significantly affected by the high concentrations of these oxidizing agents in the soil leachate.Seleniferous soil flushing revealed the selenium migration pattern across the soil column. Migration of soluble selenium fraction from the upper to the lower layers and its subsequent reduction and accumulation in the lower layers of the soil column was observed during soil flushing. The selenium removal efficiency by the soil flushing method decreased with an increase in the column height. Furthermore, the soil leachate containing selenium oxyanions obtained from soil washing was treated in a UASB reactor by varying the organic feed. Effluent containing less than 5 μg L-1 selenium was achieved, which is in accordance with the USEPA guidelines for selenium wastewater discharge limit.Moreover, ex situ bioremediation of selenium oxyanions was studied under variable conditions. An aerobic bacterium (Delftia lacustris) capable of transforming selenate and selenite to elemental selenium, but also to hitherto unknown soluble selenium ester compounds was serendipitously isolated and characterized. Alternatively, anaerobic bioreduction of selenate coupled to methane as electron donor was investigated in serum bottles and a biotrickling filter using marine sediment as inoculum. Finally, the effect of contamination of other chalcogen oxyanions in addition to selenium was studied. Simultaneous reduction of selenite and tellurite by a mixed microbial consortium along with the retention of biogenic Se and Te nanostructures in the EPS was achieved during a 120-day UASB bioreactor operation

碩士
國立成功大學
環境工程學系
88
The objective of this study was to promote the biodegradation of refinery CPI oil separator sludge and soil containing fuel oil with slurry bioreactor. The study was conducted in 250ml slurry bioreactors under aerobic conditions. The dry oil sludge and fuel oil-contaminated soil containing 17-21% oil and grease are treated from 2 weeks to 2 months. The factors that were varied in the bioremediation test of oil sludge were aeration, inoculation and amount of surfactant (Tween80) added. The factors that were varied in the bioremediation test of fuel oil-contaminated soil were carbon source, oil/soil ratio and amount of Tween80 added. Evaluated measures of the experimental results were remained percentage of oil and grease in the solid phase and NAH ( nonaromatic hydrocarbons ), AH ( aromatic hydrocarbons ), PC ( polar compounds ), SP ( spot point materials ) content in the oil and grease. Low biodegradable compounds were made qualitative analysis by GC/MS, and pH, dissolved oxygen (DO) were the environmental change index. During 2 months operation period , indigenous microorganisms degraded 47.63% oil and grease in refinery CPI oil separator sludge under the conditions of 1 L/min/L-liquid air flow rate and no Tween80 added. When choosing 0.1L/min/L-liquid aeration, the removal efficiency of the oil and grease can reach 44.23%. The removal efficiency of NAH, PC and AH in oil and grease were 70.27, 69.78 and 61.37%, but SP did not exhibit any significant concentration changes. When amount of Tween80 added >0.1%, it had not any help for removing oil and grease during 2 months operation period. The results of the bioremediation test of fuel oil-contaminated soil indicates that inorganic salts solution added increased the bioavailability of fuel oil more than organic compost; the lower contaminant degree of soil, the higher removal efficiency of fuel oil; Tween80 added did not also help for removing fuel oil. When oil/soil ratio is 1/10, we get 54.2% removal efficiency of fuel oil with adding the mixture of compost and inorganic salts solution, vibrating 120 rpm and 30±2℃ temp during 60days operation period. The removal efficiency of NAH, AH and PC in fuel oil were 52.12, 59.5 and 42.2%, respectively. Keywords : slurry bioreactor, CPI oil sludge, fuel oil-contaminated soil oil and grease

Extraction of bitumen from Alberta oil sands produces 2 to 4 barrels of aqueous tailings per barrel of crude oil. Oil sands process water (OSPW) contains naphthenic acids (NAs), a complex mixture of carboxylic acids of the form CnH2n+ZOx that are persistent and toxic to aquatic organisms. Previous studies have demonstrated that aerobic biodegradation reduces NA concentrations and OSPW toxicity; however, treatment times are long. The objective of this study was to evaluate the feasibility of an immobilized soil bioreactor (ISBR) for treatment of NAs in OSPW and to determine the role of ammonium and ammonium oxidizing bacteria (AOB) in NA removal. ISBRs have been used to successfully remediate water contaminated with pollutants such as pentachlorophenol and petroleum hydrocarbons. A system of two ISBRs was operated continuously for over 2 years with OSPW as the sole source of carbon. Removal levels of 30-40% were consistently achieved at a residence time of 7 days, a significant improvement compared to half-lives of 44 to 240 days reported in the literature. However, similar to biodegradation experiments in the literature, a significant portion (~60%) of the NAs was not degraded. The role of AOB in NA removal was investigated by decreasing ammonium concentration and inhibiting AOB activity with allylthiourea, neither of which significantly affected removal, indicating that AOB did not enhance NA removal. Furthermore, high AOB populations actually inhibited the removal of a simple NA surrogate. Therefore, a moderate ammonium concentration of 0.3 g/L is recommended. NA degradation occurred with nitrate as the sole nitrogen source, however, removal levels were lower than those achieved with ammonium. Exploratory studies involving ozonation or biostimulation were conducted with the aim of increasing NA removal. Ozonation decreased NA concentration by 94% and total organic carbon (TOC) by 6%. Subsequent ISBR treatment removed ~30% of the remaining TOC. Addition of a NA surrogate increased heterotrophic NA-degrading populations due to the increase in available carbon, resulting in a significant increase in NA removal levels. However, use of a surrogate may result in a population that is only adapted to degradation of the NA surrogate.
Thesis (Master, Chemical Engineering) -- Queen's University, 2013-06-20 14:53:47.498