Bioremediation of Unconventional Oil Contaminated Ecosystems under Natural and Assisted Conditions: A Review.

It is a general understanding that unconventional oil is petroleum-extracted and processed into petroleum products using unconventional means. The recent growth in the United States shale oil production and the lack of refineries in Canada built for heavy crude processes have resulted in a significant increase in U.S imports of unconventional oil since 2018. This has increased the risk of incidents and catastrophic emergencies during the transportation of unconventional oils using transmission pipelines and train rails. A great deal of effort has been made to address the remediation of contaminated soil/sediment following the traditional oil spills. However, spill response and cleanup techniques (e.g., oil recuperation, soil-sediment-water treatments) showed slow and inefficient performance when it came to unconventional oil, bringing larger associated environmental impacts in need of investigation. To the best of our knowledge, there is no coherent review available on the biodegradability of unconventional oil, including Dilbit and Bakken oil. Hence, in view of the insufficient information and contrasting results obtained on the remediation of petroleum, this review is an attempt to fill the gap by presenting the collective understanding and critical analysis of the literature on bioremediation of products from the oil sand and shale (e.g., Dilbit and Bakken oil). This can help evaluate the different aspects of hydrocarbon biodegradation and identify the knowledge gaps in the literature.

Dataset of breakthrough time for various modified sand materials using Rhodamine-B as an adsorbate.

Removal of synthetic dyes from wastewater generated by the textile industries is important. Rhodamine-B is widely used colorant and is medically proven to lead to tissue borne sarcoma, reproductive and neurotoxicity issues in humans, if still present in the treated drinking water. Herein, this dataset provides information on different forms of sand materials for their effective utilization as an adsorbent material for Rhodamine-B. The effectiveness of the media was measured in terms of breakthrough time obtained. One of the 27 presented data set is a part of a research article [1] explaining the breakthrough time of these filter media under specific experimental condition. All these data is a combination of three variables that were studied: a) concentration of Rhodamine-B (1 mg/L, 5 mg/L and 10 mg/L), b) flow velocity of Rhodamine-B spiked water (2 mL/min, 5 mL/min and 10 mL/min) and c) bed height (7.5 cm, 10 cm, and 12.5 cm). At any bed height, the breakthrough time of graphitized sand (brewery sugar coated, GS1) was found to be 3-4 times higher than the second best adsorbent, i.e., manganese dioxide coated on GS1.

Agro-industrial residues as a unique support in a sand filter to enhance the bioactivity to remove microcystin-Leucine aRginine and organics.

In the past, the versatility of a biosand filter has been successfully checked to counter suspended solids, metals, dissolved organic carbon (DOC), coliforms and other water quality parameters (WQPs) from the drinking water sources. In this study, cyanotoxin in the form of microcystin-LR (MC-LR) along with above-mentioned WQPs including nitrate, nitrite, and ammonia are analyzed for their removal using agro-residue based biosand filters (ARSFs) for 49 days (7 cycles). Three different agro-residue materials (ARMs) viz. deinking sludge (DSF), hemp fiber (HFF) and paper-pulp dry sludge (PPF) were used as the support material (top 5 cm) along with sand (49 cm) as the primary filter media to enhance the overall bioactivity. This enhancement in bioactivity is hypothesized to remove more MC-LR, DOC, coliform along with efficient nitrification/denitrification. Native bacterial community isolated from the filtration unit of a drinking water treatment plant (Chryseobacterium sp. and Pseudomonas fragi = X) along with the MC-LR-degrader: Arthrobacter ramosus (which was screened as the best biofilm-former among two other MC-LR-degraders tested) were used to inoculate the filters (all three ARSFs). Overall, DSF performed the best among all the ARSFs when compared to the sand filter (SFI) inoculated with the same bacterial strains (A + X). An increase in the bioactivity for ARSFs, particularly DSF was evident from the DOC removal (44 ±â€¯11%, 15% more than SFI), coliform removal (92.7 ±â€¯12.8%, 24% more than SFI), MC-LR removal (87 ±â€¯14%, 13% more than SFI) and an effective nitrification/denitrification, reducing ammonia, nitrate and nitrite level to below guideline values. Toxic assessment using bioindicator (Rhizobium meliloti) revealed safe filter water only in case of DSF.

Biodegradation of microcystin-LR using acclimatized bacteria isolated from different units of the drinking water treatment plant.

Bacterial community isolated from different units of a Drinking Water Treatment Plant (DWTP) including pre-ozonation unit (POU), the effluent-sludge mixture of the sedimentation unit (ESSU) and top-sand layer water sample from the filtration unit (TSFU) were acclimatized separately in the microcystin-leucine arginine (MC-LR)-rich environment to evaluate MC-LR biodegradation. Maximum biodegradation efficiency of 97.2 ±â€¯8.7% was achieved by the acclimatized-TSFU bacterial community followed by 72.1 ±â€¯6.4% and 86.2 ±â€¯7.3% by acclimatized-POU and acclimatized-ESSU bacterial community, respectively. Likewise, the non-acclimatized bacterial community showed similar biodegradation efficiency of 71.1 ±â€¯7.37%, 86.7 ±â€¯3.19% and 94.35 ±â€¯10.63% for TSFU, ESSU and POU, respectively, when compared to the acclimatized ones. However, the biodegradation rate increased 1.5-folds for acclimatized versus non-acclimatized conditions. The mass spectrometry studies on MC-LR degradation depicted hydrolytic linearization of cyclic MC-LR along with the formation of small peptide fragments including Adda molecule that is linked to the reduced toxicity (qualitative toxicity analysis). This was further confirmed quantitatively by using Rhizobium meliloti as a bioindicator. The acclimatized-TSFU bacterial community comprised of novel MC-LR degrading strains, Chryseobacterium sp. and Pseudomonas fragi as confirmed by 16S rRNA sequencing.

Microwave-assisted one-pot conversion of agro-industrial wastes into levulinic acid: An alternate approach.

Brewery liquid waste (BLW), brewery spent grain (BSG), apple pomace solid wastes (APS), apple pomace ultrafiltration sludge (APUS) and starch industry waste (SIW) were evaluated as alternative feedstocks for levulinic acid (LA) production via microwave-assisted acid-catalyzed thermal hydrolysis. LA production of 204, 160, 66, 49 and 12 g/kg was observed for BLW, BSG, APS, APUS, and SIW, respectively, at 140 °C, 40 g/L substrate concentration (SC), 60 min and 2 N HCl (acid concentration). Based on the screening studies, BLW and BSG were selected for optimization studies using response surface methodology. Maximum LA production of 409 and 341 g/kg for BLW and BSG, respectively were obtained at 160 °C, 4.5 M HCl, 85 g/L SC and 27.5 min. Results demonstrated the possibility of using brewery wastes as promising substrates for economical and higher yield production of LA, a renewable platform chemical and versatile precursor for fuels and chemicals.

Phytodesalinization potential of Typha angustifolia, Juncus maritimus, and Eleocharis palustris for removal of de-icing salts from runoff water.

Typha angustifolia, Juncus maritimus, and Eleocharis palustris were evaluated for de-icing salt removal from runoff water. Plants were exposed to a range of de-icing salt levels (0.2, 0.7, 4, 8, and 13 dS m(-1)) in laboratory-scale subsurface constructed wetlands (CWs) for 2 months under greenhouse conditions. Effluent characteristics, plant height, biomass, and Cl and Na removal rates and uptake were monitored. More water volume was retained in CWs of T. angustifolia (∼60 %) than of J. maritimus and E. palustris (∼37.5 %), which accounted for the electrical conductivity increase in effluents (1.3-1.9-fold). Based on the NaCl removal rate, T. angustifolia showed the greatest phytodesalinization ability (31-60 %) with the highest removal at the lowest salt levels (0.2-0.7 dS m(-1)), followed by J. maritimus (22-36 %) without differences in removal among levels, and E. palustris (3-26 %) presenting a removal rate highly decreased with increasing salt levels. Plant height and biomass were stimulated at low de-icing salt levels, but, at higher levels, T. angustifolia and E. palustris growth was inhibited (tolerance index ∼67 and 10 %, respectively, in the worst cases). Salt amounts in aboveground biomass in g m(-2) differed among levels and ranged as follows: 13.6-29.1 (Cl), 4.2-9.3 (Na; T. angustifolia); 7.0-12.0 (Cl), 2.7-6.4 (Na; J. maritimus); and 0.9-7.6 (Cl), 0.3-1.6 (Na; E. palustris). Chloride and Na translocation decreased with de-icing salt increase in T. angustifolia, while no significant differences were found in J. maritimus, which is interesting for harvesting purposes.

Performance and microbial diversity of aerated trickling biofilter used for treating cheese industry wastewater.

Wastewater discharged from cheese industries is often characterized by high values of organic pollutants, solids, and nutrients. An aerated trickling biofilter using peat and perlite as filter media was employed in a pilot-scale level in order to evaluate the performance of biofilter for removal of pollutants from cheese industry wastewater. The biofilter was operated for a period of 33 days under laboratory conditions, and several parameters were monitored. The results showed a significant improvement in the quality of treated effluent. The maximum removal efficiencies of chemical oxygen demand and biological oxygen demand were 99.2 and 99.9 %, respectively. Significant reduction in total suspended solids (>96 %) was also achieved. A stable ammoniacal-nitrogen (NH(4)-N) removal was accompanied by biofilter. On an average, NH(4)-N and total nitrogen decreased by 98.7 and 72 %, respectively, with a significant portion of NH(4)-N being converted to nitrate-nitrogen (NO(3)-N). Also, a molecular approach based on 16S rDNA was employed to analyze the bacterial community composition present in the biofilter. A comparative sequence analysis of excised denaturing gradient gel electrophoresis bands revealed the presence of diverse groups of bacteria belonging to α- and ß-Proteobacteria and Bacteroidetes phylum. We conclude from the results that the use of trickling biofilter is highly effective and a potential treatment method for polishing cheese industry wastewater before being discharged into the local environment.

An evaluation of several in-lake restoration techniques to improve the water quality problem (eutrophication) of Saint-Augustin Lake, Quebec, Canada.

Increasing phosphorus (P) content and decreasing water quality of Saint-Augustin Lake, Quebec City, Canada, has led to implementation of an Integrated Watershed Management Plan to restore the lake. As a part of the plan, the effects of different restoration techniques on lake water quality and biological community (i.e., biological compatibility) were assessed during an isolated water enclosure study and laboratory microcosm assay, respectively. The restoration techniques include: (i) coagulation of P by alum only (20 mg L(-1)), (ii) active capping of sediments using a calcite layer of 10 cm, and (iii) a complete method involving both alum coagulation and calcite capping. The results showed that the total P (TP) was greatly decreased (76-95 %) by alum + calcite, followed by calcite only (59-84 %). Secchi depth was 106 % greater and chlorophyll a concentrations were declined by 19-78 % in the enclosure which received both alum and calcite. Results of the biological compatibility test showed that total phytoplankton biomass declined by 31 % in microcosms composed of alum + calcite. No significant (P > 0.05) toxic effect was found on the survival of Daphnia magna and Hyalella azteca in both alum only and alum + calcite microcosms. Although the alum + calcite technique impaired the survival of Chironomus riparius, the midge emergence was much higher compared to alum only and control. Overall, the alum + calcite application was effective in controlling P release from sediment and lowering water column P concentrations, and thus improving the water quality and aquatic life of Saint-Augustin Lake. However, the TP concentrations are still higher than the critical limit (20 µg L(-1)) for aquatic life and the water column remained in the eutrophic state even after treatment. Increased TP concentrations, to higher than ambient levels of the lake, in the water column of all four enclosures, due to bioturbation artefact triggered by the platform installation, likely cause insufficient dosages of alum and/or calcite applied and reduced their effectiveness.

Concomitant Zn-Cd and Pb retention in a carbonated fluvio-glacial deposit under both static and dynamic conditions.

The chemical and physical processes involved in the retention of 10(-2)M Zn, Pb and Cd in a calcareous medium were studied under saturated dynamic (column) and static (batch) conditions. Retention in columns decreased in order: Pb>>Cd approximately Zn. In the batch experiments, the same order was observed for a contact time of less than 40h and over, Pb>>Cd>Zn. Stronger Pb retention is in accordance with the lower solubility of Pb carbonates. However, the equality of retained Zn and Cd does not fit the solubility constants of carbonated solids. SEM analysis revealed that heavy metals and calcareous particles are associated. Pb precipitated as individualized Zn-Cd-Ca- free carbonated crystallites. All the heavy metals were also found to be associated with calcareous particles, without any change in their porosity, pointing to a surface/lattice diffusion-controlled substitution process. Zn and Cd were always found in concomitancy, though Pb fixed separately at the particle circumferences. The Phreeqc 2.12 interactive code was used to model experimental data on the following basis: flow fractionation in the columns, precipitation of Pb as cerrusite linked to kinetically controlled calcite dissolution, and heavy metal sorption onto proton exchanging sites (presumably surface complexation onto a calcite surface). This model simulates exchanges of metals with surface protons, pH buffering and the prevention of early Zn and Cd precipitation. Both modeling and SEM analysis show a probable significant decrease of calcite dissolution along with its contamination with metals.

Bioremediation of metal contamination.

A study was initiated to evaluate the use of the fungus Aspergillus niger for bioleaching and then to determine the effect of process steps, the tailings concentration and type of substrate. An oxidized mining tailing containing mainly copper (7240 mg kg(-1) tailings) was studied. A sucrose and mineral salts medium was initially used to produce citric and gluconic acids by A. niger at various concentrations of tailings ( 1, 5, 7, 10 and 15% w/v). Maximal removal of up to 60% of the copper was obtained for the 5% tailings when the organic acid supernatant was added to the tailings. In a single step process, A. niger was then grown in the presence of mining tailings at various concentrations. Maximum copper solubilization (63%) occurred with 10% mining tailings using sucrose as the substrate. Other substrates were then evaluated including molasses, corn cobs and brewery waste (10% mining tailings). Sucrose gave the best results for copper removal, followed by molasses, corn cobs and brewery waste. Other experiments using ultrasound as a pretreatment showed that 80% removal of the copper could be obtained for a 5% tailings concentration. In conclusion, leaching of copper from mining tailings is technically feasible using A. niger but further research will be required to increase the economic feasibility of the process.