In this work, a moving bed biofilm reactor (MBBR) was equipped for simultaneous biodegradation of CS2 and H2S. MBBR was started up and operated with different inlet concentrations and retention time; ...results indicated that approximately 81.9% CS2 and 93.9% H2S could be degraded, and the maximum elimination capacities of 209.3 g/(m3·h) and 138.5 g/(m3·h) were achieved for CS2 and H2S, respectively. The biodegradation mechanisms, including mass transfer, kinetics, and electron transfer, were then investigated. The mass transfer fraction and the maximum degradation rate per unit filter volume were calculated for evaluating the characteristics of mass transfer in MBBR. The variations of extracellular polymeric substances secretion, electron transport system activity and ATP enzyme activity showed that MBBR had an excellent performance for waste gas purification. Subsequently, the recovery of sulfur was explored via morphology, crystal structure, and generation kinetics, indicating that a modified Gompertz model could precisely describe the kinetics of sulfur recovery, and the product selectivity of 51.7% was achieved for sulfur. The microbial community analysis suggested that the dominant genera for biodegradation and sulfur recovery were Acidithiobacillus and Mycobacterium. Finally, MBBR system was validated for treatment of actual waste gas; results indicated that maximum elimination capacities of 134.1 g/(m3·h) and 117.1 g/(m3·h) were obtained for CS2 and H2S, respectively, suggesting that MBBR had the potential for application.
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•MBBR system was conducted for simultaneous removal of CS2 and H2S.•The maximum elimination capacities of 209.3 g/(m3·h) and 138.5 g/(m3·h) were achieved for CS2 and H2S, respectively.•Sulfur was successfully recycled with a product selectivity of 51.7% during the biodegradation process.•MBBR had a potential for treatment of actual waste gas.
Plastics have become ubiquitous in both their adoption as materials and as environmental contaminants. Widespread pollution of these versatile, man‐made and largely petroleum‐derived polymers has ...resulted from their long‐term mass production, inappropriate disposal and inadequate end of life management. Polyethylene (PE) is at the forefront of this problem, accounting for one‐third of plastic demand in Europe in part due to its extensive use in packaging. Current recycling and incineration processes do not represent sustainable solutions to tackle plastic waste, especially once it becomes littered, and the development of new waste‐management and remediation technologies are needed. Mycoremediation (fungal‐based biodegradation) of PE has been the topic of several studies over the last two decades. The utility of these studies is limited by an inconclusive definition of biodegradation and a lack of knowledge regarding the biological systems responsible. This review highlights relevant features of fungi as potential bioremediation agents, before discussing the evidence for fungal biodegradation of both high‐ and low‐density PE. An up‐to‐date perspective on mycoremediation as a future solution to PE waste is provided.
Understanding human health risk associated with the rapidly emerging graphene‐based nanomaterials represents a great challenge because of the diversity of applications and the wide range of possible ...ways of exposure to this type of materials. Herein, the biodegradation of graphene oxide (GO) sheets is reported by using myeloperoxidase (hMPO) derived from human neutrophils in the presence of a low concentration of hydrogen peroxide. The degradation capability of the enzyme on three different GO samples containing different degree of oxidation on their graphenic lattice, leading to a variable dispersibility in aqueous media is compared. hMPO fails in degrading the most aggregated GO, but succeeds to completely metabolize highly dispersed GO samples. The spectroscopy and microscopy analyses provide unambiguous evidence for the key roles played by hydrophilicity, negative surface charge, and colloidal stability of the aqueous GO in their biodegradation by hMPO catalysis.
The dispersibility dependent biodegradation of graphene oxide (GO) is demonstrated by using oxidative catalysis of myeloperoxidase (hMPO) derived from human neutrophils in the presence of a low concentration of hydrogen peroxide. hMPO can completely degrade the most dispersible GO but failed in degrading the least dispersed (aggregated) sample. The surface charge as well as aqueous dispersiblity of the GO samples are a playing crucial role in the biodegradation by hMPO.
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•The effect of microalage on the removal of emerging contaminants has been evaluated.•Volatilization was relevant for compounds with a moderate Henry’s law constant.•Biodegradation ...was the main factor for the removal of caffeine and ibuprofen.•Ibuprofen enantioselective biodegradation was observed.•CA-ibuprofen and OH-ibuprofen followed the concentration decline of ibuprofen.
Aerated batch reactors (2.5L) fed either with urban or synthetic wastewater were inoculated with microalgae (dominated by Chlorella sp. and Scenedesmus sp.) to remove caffeine, ibuprofen, galaxolide, tributyl phosphate, 4-octylphenol, tris(2-chloroethyl) phosphate and carbamazepine for 10 incubation days. Non-aerated and darkness reactors were used as controls. Microalgae grew at a rate of 0.25d−1 with the complete removal of N-NH4 during the course of the experiment. After 10 incubation days, up to 99% of the microcontaminants with a Henry’s law constant higher than 3 10−1Pam3mol−1 (i.e., 4-octylphenol, galaxolide, and tributyl phosphate) were removed by volatilization due to the effect of air stripping. Whereas biodegradation was effective for removing ibuprofen and caffeine, carbamazepine and tris(2-chloroethyl) phosphate behaved as recalcitrant compounds. The use of microalgae was proved to be relevant for increasing the biodegradation removal efficiency of ibuprofen by 40% and reducing the lag phase of caffeine by 3 days. Moreover, the enantioselective biodegradation of S-ibuprofen suggested a biotic prevalent removal process, which was supported by the identification of carboxy-ibuprofen and hydroxy-ibuprofen. The results from microalgae reactors fed with synthetic wastewater showed no clear evidences of microalgae uptake of any of the studied microcontaminants.
The atrazine (ATR) is extensively used in dryland crops like corn and sorghum in black soil region of Northeast China, posing ecological risks due to toxic metabolites. Vermicompost are known for ...soil organic pollution remediation but their role in pesticide degradation in black soil remains understudied. The influence of vermicompost on the microbial degradation pathway of atrazine was assessed in this study. Although vermicompost didn't significantly boost atrazine removal, they notably aided in primary metabolite degradation, hydroxyatrazine (HYA), deisopropylatrazine (DIA), and deethylatrazine (DEA), reducing their content by 38.67 %. They also altered the soil microbial community structure, favoring atrazine-degrading bacteria like Proteobacteria, Firmicutes, and Actinobacteria. Five secondary degradation products were identified in vermicompost treatments. Atrazine degradation occurred via dechlorination, dealkylation, and deamination pathways mainly by Nocardioidacea, Streptomycetaceae, Bacillaceae, Sphingomonadaceae, Comamonadaceae and Nitrososphaeraceae. pH and available nitrogen (AN) influenced microbial community structure and atrazine degradation, correlating with vermicompost application rates. Future black soil remediation should optimize application rates based on atrazine content and soil properties.
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•Vermicompost improved deep degradation of atrazine in black soil.•IaaA, PncC, and PncA were key genes in atrazine primary metabolites degradation.•pH and AN were closely related with microbial metabolism process of atrazine.
Ozonation is an efficient treatment system to reduce the concentration of trace organic compounds (TrOCs) from technical aquatic systems such as drinking water, wastewater and industrial water, etc. ...Although it is well established that ozonation generally improves the removal of organic matter in biological post-treatment, little is known about the biodegradability of individual transformation products resulting from ozonation of TrOCs. This publication provides a qualified assessment of the persistence of ozone-induced transformation products based on a review of published product studies and an evaluation of the biodegradability of transformation products with the biodegradability probability program (BIOWIN) and the University of Minnesota Pathway Prediction System (UM-PPS). The oxidation of TrOCs containing the four major ozone-reactive sites (olefins, amines, aromatics and sulfur-containing compounds) follows well described reaction pathways leading to characteristic transformation products. Assessment of biodegradability revealed a high sensitivity to the formed products and hence the ozone-reactive site present in the target compound. Based on BIOWIN, efficient removal can be expected for products from cleavage of olefin groups and aromatic rings. In contrast, estimations and literature indicate that hydroxylamines and N-oxides, the major products from ozonation of secondary and tertiary amines are not necessarily better removed in biological post-treatment. According to UM-PPS, degradation of these products might even occur via reformation of the corresponding amine. Some product studies with sulfide-containing TrOCs showed a stoichiometric formation of sulfoxides from oxygen transfer reactions. However, conclusions on the fate of transformation products in biological post-treatment cannot be drawn based on BIOWIN and UM-PPS.
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•Review of product studies from the reaction of ozone with trace organic compounds.•Evaluation of the biodegradability of transformation products with different tools.•Results suggest enhanced removal by cleavage of olefin groups and aromatic rings.•Major products from ozonation of amines are not necessarily better biodegradable.
Management of growing volumes of fluid fine tailings (FFT) is a significant challenge for oil sands industry. A potential alternative non-aqueous solvent extraction (NAE) process uses cycloalkane ...solvent such as cyclohexane or cyclopentane with very little water and generates smaller volumes of ‘dry’ solids (NAES) with residual solvent. Here we investigate remediation of NAES in a simulated bench-scale upland reclamation scenario. In the first study, microcosms with nutrient medium plus FFT as inoculum were amended with cyclohexane and incubated for ∼1 year, monitoring for cyclohexane biodegradation under aerobic conditions. Biodegradation of cyclohexane occurred under aerobic conditions with no metabolic intermediates detected. A second study using NAES mixed with FFT spiked with cyclohexane and cyclopentane, with or without additional nutrients (nitrogen and phosphorus), showed complete and rapid aerobic biodegradation of both cycloalkanes in NAES inoculated with FFT and supplemented with nutrients. 16S rRNA gene sequencing revealed dominance of Rhodoferax and members of Burkholderiaceae during aerobic cyclohexane biodegradation in FFT, and Hydrogenophaga, Acidovorax, Defluviimonas and members of Porticoccaceae during aerobic biodegradation of cyclohexane and cyclopentane in NAES inoculated with FFT and supplemented with nutrients. The findings indicate that biodegradation of cycloalkanes from NAES is possible under aerobic condition, which will contribute to the successful reclamation of oil sands tailings for land closure.
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•Cycloalkanes were biodegraded under aerobic conditions in “dry” oil sands tailings.•Anaerobic fluid fine tailings used as inoculum provided microbes for aerobic biodegradation.•Higher abundance of Rhodoferax and Hydrogenophaga suggested their involvement in cycloalkane biodegradation.•Results suggest bioremediation of cycloalkane-contaminated wastes under upland reclamation.
Accidental oil spills can result in catastrophic ecological insults and therefore require rapid intervention to mitigate the potential impacts to aquatic ecosystems. One of the largest oil spills, ...known as the Deepwater Horizon oil spill, occurred in the Spring of 2010 near the coast of Louisiana (USA) due to an explosion during oil drilling activities. Millions of gallons of oil were released into the Gulf of Mexico, impacting thousands of ocean miles and coastal areas linked to the gulf. Among the actions taken during the remediation efforts was the unprecedented large use of Corexit dispersants, including at the subsurface to prevent oil from reaching the surface. While there is evidence that dispersants can accelerate the biodegradation of oil, reports on their potential toxicity to aquatic biota and to microbial functions have also been documented. In this review, we will examine the most recent literature on the impact of dispersants on microbial communities implicated in oil degradation and overall ecological networks. The primary focus will be on studies using Corexit but other dispersants will be discussed if data are available. We will share the literature gaps identified and discuss future work that is needed to reconcile some of the discrepancies found on the effectiveness of dispersants on oil degradation and their potential toxicity.
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Chemical dispersants have been applied as a chemical response measure for oil spills
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The effects of chemical dispersants on microbial communities have been the subject of substantial research
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This work seeks to review recent work on the impact of chemical dispersants on oil biodegradation, microbial communities, and ecosystems
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