Bioremediation Process Research Articles

SUSTAINABLE WASTE MANAGEMENT APPROACHES THROUGHNANOMATERIALS AND NANOBIOREMEDIATION:A REVIEW

Environmental pollution resulting from the release of various pollutants into ecosystems is a growing concern worldwide. Traditional bioremediation methods have demonstrated effectiveness in detoxifying contaminated environments, yet their efficiency is often limited by the complex nature of pollutants and the dynamics of environmental matrices. In recent years, the convergence of nanotechnology and bioremediation has emerged as a promising approach to address these limitations. Researchers and scientists in various fields of environmental sciences, particularly in bioremediation, have paid close attention to nanomaterials because they possess distinctive physical and chemical features. The improvement in living standards brought about by science and technology also has an impact either directly or indirectly on the rise in toxic waste. Therefore, removing poisons from the environment with current technology does not adequately and efficiently clean it up. The use of nanomaterials for bioremediation would not only have a less negative impact on microorganisms but will increase the microbial activity of the specific waste and toxic material, lowering the overall time consumption and the overall cost. The objective of nanotechnology functional side is to improve material performance andreduce the quantity of materials needed to complete the cleanup process. Nano-bio remediation uses ex-situ or in-situ nanomaterials to treat contaminated materials. Therefore, using nanomaterials to remove environmental pollution could be an efficient, effective method that is sustainable. This review paper presents an overview of the recent advancements and future prospects of nano bioremediation, highlighting the potential of nanomaterials in enhancing the efficiency and specificity of bioremediation processes.

Effect of heavy metals on the antioxidant system of the acid-tolerant microalga Coccomyxa onubensis

Coccomyxa onubensis (C. onubensis) is an acid-tolerant microalga whose ecosystem (Tinto River, Huelva, Spain) contains high amounts of different heavy metals. However, the potential of this microalga to remove these pollutants from the environment has still not been studied. Thus, this work evaluates the tolerance and physiological response of this microalga in the presence of three heavy metals, copper, cadmium, and mercury, and the metalloids As (III) and As (V). The results demonstrated that C. onubensis is able to improve its growth parameters with the presence of copper in the culture medium until concentrations of 2 mM Cu2+ and also shows high tolerance to other heavy metals and metalloids tested, such as Cd2+, As(III), As(V) or Hg2+. Moreover, this microalga seems to be a high arsenic accumulator organism, showing its high potential for arsenic bioremediation processes. Finally, the characterization of three antioxidant enzymes and their evaluation under heavy metal stress was performed. The results showed that ascorbate peroxidase (APX, EC:1.11.1.11), catalase (CAT, EC:1.11.1.6), and glutathione reductase (GR, EC:1.6.4.2) were upregulated to different degrees when C. onubensis was cultivated under heavy metal stress.

Production and characterization of a biosurfactant produced by Bacillus amyloliquefaciens C11 for enhancing the solubility of pesticides

The production and characterization of lipopeptide biosurfactant obtained from a novel bacterial strain Bacillus amyloliquefaciens C11 isolated from a biopurification system, to enhance the solubility of three pesticides of environmental concern was investigated. Biosurfactant production by B. amyloliquefaciens C11 was evaluated in a 2-L reactor and characterized by chromatographic and spectroscopic methods. Biosurfactant production was associated with bacterial growth and glucose consumption. The produced biosurfactant decreased the surface tension of water from 72 to 28 mN m−1 at 24 h of incubation, with critical micelle concentration (CMC) of 51.5 mg L−1. The polymerase chain reaction for determining the presence of srfAA gene in B. amyloliquefaciens C11 was carried out. The strain exhibited the presence of srfAA gene with amplification at 201 bp, which is specific to surfactin homologues. The production of surfactin was corroborated by high performance liquid chromatography (HPLC) and matrix-assisted laser desorption/ionization time-of flight mass spectrometry (MALDI-TOF-MS) analyses. The HPLC analysis showed six isoforms of surfactin, being the isoform D found in mayor percentage (41%). Thermal gravimetric analysis (TGA) revealed the thermostability of the biosurfactant. The obtained biosurfactant maintained its properties during exposure to temperatures in range of 30–80 °C and pH values in range of 5–9. The surfactin produced by B. amyloliquefaciens C11 increased the solubility in water of chlorpyrifos, iprodione and atrazine by 7.5-fold, 1.3-fold, and 1.4-fold, respectively. Our results show that the biosurfactant produced by B. amyloliquefaciens C11 improves the bioavailability of pesticides and consequently could improves the efficiency of bioremediation processes.

ANALYSIS OF Pseudomonas aeruginosa AND Bacillus subtilis BACTERIA GROWTH IN KNO3 FERTILIZER MEDIA AS NITROGEN BIOREMEDIATION AGENT

Increased population growth is the main cause of increased waste in the environment, especially in water. Increased population growth is the main cause of increased waste in the environment, especially in water. Ammonia, nitrite, and nitrate are forms of inorganic nitrogen, which if they exceed water quality standards, can pollute the environment and are toxic to aquatic biota. However, the toxicity of nitrogen compounds in water can be controlled by microorganisms through nitrification and denitrification processes. In this study, two types of bacteria were used as biological agents in the bioremediation process, Pseudomonas aeruginosa and Bacillus subtilis, which grown anaerobically in media that has been added by KNO3 as a pollutant for 8 days. The results obtained showed that B. subtilis survived for 7 days before entering the cell death phase on the 8th day, while Pseudomonas aeruginosa survived for 5 days and entered the cell death phase on the 6th day. Meanwhile, based on its ability to reduce nitrate, B. subtilis can reduce it up to 99.42%, while P. aeruginosa can reduce it up to 98.26% in 8 days.

A full-scale bioremediation study of diesel fuel-contaminated soil: the effect of plant species and soil amendments

This article presents a comprehensive on-site bioremediation of an excavated diesel fuel-contaminated soil aided by various soil amendments and plant species. In the first 125 days, the excavated soil was placed in a land treatment unit, mixed with compost, and seeded with white clover (Trifolium repens). In the next 155 days, the land treatment unit was re-established and divided into four experimental plots. Experimental plots 2 and 3 were seeded with a mixture of plant seeds (Trifolium alexandrinum, Fagopyrum esculentum Moench, Trifolium incarnatum, Phacelia tanacetifolia, Sinapis alba, Trifolium repens), while experimental plots 1 and 4 were left without seeded vegetation. Moreover, a zeolite and an Ascophyllum nodosum-based biostimulant were added to experimental plots 3 and 4. The objectives were to select the most beneficial plant species for the plant-based bioremediation process, to evaluate applicability of different soil amendments for an enhanced hydrocarbon biodegradation, and to study their effects on the microbial community in soil. Our results showed an overall reduction in hydrocarbon pollution by more than 95% within 280 days. The rates of hydrocarbon degradation and changes in the microbial population were not affected by the presence of the zeolite and the biostimulant. In addition, the use of different plant species did not have a statistically significant effect on hydrocarbon degradation but affected microbial population dynamics, confirming stabile and diverse indigenous hydrocarbon-degrading microbial community in the native soil.

Genomic dissection of Niallia sp. for potential application in lignocellulose hydrolysis and bioremediation.

Genus Niallia has recently been separated taxonomic group from the Bacillus based on conserved signature indels in the genome. Unlike bioremediation, its role in plant biomass hydrolysis has not garnered considerable attention. The present study investigates the genomic potential of a novel Niallia sp. CRN 25 for applications in lignocellulose hydrolysis, significant enzyme production, and bioremediation. The CRN 25 strain exhibits xylosidase, cellobiosidase, α-arabinosidase, and α-D-galactosidase activity as 0.03U/ml whereas β-D-glucosidase and glucuronidase as 0.06 U/ml and 0.01U/ml, respectively. Further genome sequencing reveals nine copies of GH43 gene coding for hemicellulose-specific xylanase enzyme attached to the CBM 6 domain for increased processivity. The presence of β-glucosidase and β-galactosidase indicates the possible application of CRN 25 in facilitating the valorization of plant biomass into value-added products. Apart from this, genes of FMN-dependent NADH-azoreductase, cytochrome P450, and nitrate reductase, playing a crucial role in bioremediation processes, were annotated. Biosynthetic gene clusters (BGCs), responsible for synthesizing specialized metabolites of terpenes and lasso peptides, were also found in the genome. Conclusively genomic sketch of Niallia sp. CRN 25 reveals versatile metabolic potential for diverse environmental applications.

Enzymase Activity of Gut Microbes Isolated from the Rugose Spiraling Whitefly Aleurodicus rugioperculatus

This study investigated the enzymatic diversity among various bacterial isolates of Rugose Spiraling Whitefly (Aleurodicus rugioperculatus), shedding light on their potential industrial applications. Notably, Bacillus cereus (MRSW01) exhibited remarkable amylase and lipase activities, aligning with its reputation as a prominent amylase producer. These enzymes are crucial in the food industry, particularly in starch and lipid degradation processes. Pseudomonas helleri (CHRSW028) demonstrated substantial cellulase activity, essential for breaking down cellulose in plant materials, suggesting its relevance in biofuel production and waste management. Pseudomonas psychrophila (CRSW024) stood out with the highest pectinase and significant lipase activities, both of which find applications in the food and textile industries and the hydrolysis of fats and oils, respectively. Proteus vulgaris strains MRSW05 and CHRSW02 displayed significant amylase, cellulase, and protease activities, making them versatile candidates for various industrial applications, including detergent formulations and bioremediation processes. Conversely, Hafnia paralvei exhibited comparatively lower enzymatic activities, indicating limited industrial potential. The rich enzymatic diversity within these bacterial isolates and highlight their potential contributions to various industrial sectors, ranging from food and textiles to biofuel production and waste management. Such insights can inform the development of biotechnological applications and processes, ultimately benefitting both industrial and environmental domains.

Effect of Lyoprotective Agents on the Preservation of Survival of a Bacillus cereus Strain PBG in the Freeze-Drying Process.

Lyophilization is a widely employed long-term preservation method in which the bacterial survival rate largely depends on the cryoprotectant used. Bacillus cereus strain PBC was selected for its ability to thrive in environments contaminated with arsenic, lead, and cadmium, tolerate 500 ppm of free cyanide, and the presence of genes such as ars, cad, ppa, dap, among others, associated with the bioremediation of toxic compounds and enterotoxins (nheA, nheB, nheC). Following lyophilization, the survival rates for Mannitol 2.5%, Mannitol 10%, and Glucose 1% were 98.02%, 97.12%, and 96.30%, respectively, with the rates being lower than 95% for other sugars. However, during storage, for the same sugars, the survival rates were 78.71%, 97.12%, and 99.97%, respectively. In the cake morphology, it was found that the lyophilized morphology showed no relationship with bacterial survival rate. The best cryoprotectant for the PBC strain was 1% glucose since it maintained constant and elevated bacterial growth rates during storage, ensuring that the unique characteristics of the bacterium were preserved over time. These findings hold significant implications for research as they report a new Bacillus cereus strain with the potential to be utilized in bioremediation processes.

Submerged arc plasma treatment of landfill leachate with a high proportion of refractory organics: Degradation performance and biodegradability enhancement

Efficient treatment of landfill leachate remains a challenge because of the load and highly stable recalcitrant organics. Herein, pre-treatment of real stabilized leachate was realized in a submerged arc plasma (SAP) reactor to which microbubbles with different carrier gases (air, N2, and O2) were introduced to preserve the subsequent biological process. We performed a detailed parametric analysis (applied voltage, electrode material, carrier gas, and initial pH) to determine the optimum operational conditions of organics degradation and leachate biodegradability improvement. Besides, degradation kinetics, reaction mechanism, and electrical energy consumption were studied during the SAP process. Ion exchange resin was initially used to effectively reduce the ionic strength of the bulk solution to allow expanding the plasma discharge area. The biodegradability of leachate was outstandingly enhanced, as reflected by an increase in BOD5/COD ratio from 0.08 to 0.68 in O2 discharge within 120 min. Meanwhile, stainless-steel as a grounded electrode outperformed aluminum, brass, and copper. The SAP also exhibited excellent performance for organics decomposition, which was found to follow second-order and approximately pseudo-second-order kinetics. Meanwhile, the possible mechanism of organics destruction was proposed based on COD measurements and reactive species trapping experiments, demonstrating the prevailing contribution of H2O2 and 1O2, among others. Nonetheless, the SAP process of leachate treatment required relatively high energy consumption (18,400 kWh/m3). The study demonstrated an effective and robust pre-treatment process for the subsequent bioremediation of landfill leachate containing chemically stable and recalcitrant organics not treatable by conventional techniques.

The use of effective microorganisms changed the soil microbiota of canals in Maricá city, Brazil

The objective of this study was to evaluate the effect of bioremediation, through the application of two different strategies of effective microorganisms as treatment of effluents in the parameters of water quality and in the bacteriological profile of the soil of ‘Canal da Cidade’ - Maricá, Rio de Janeiro, Brazil. The metagenomic analyzes indicated that the abundance and richness of microorganisms in the substrate increased significantly after the bioremediation strategy used in this study. Because of bioremediation, 31 bacterial species disappeared from the environment when comparing the initial and final bacterial profiles of the soil, where 94% of these 31 species were anaerobic. Furthermore, 61 new aerobic or facultative aerobic species appeared in the channel substrate after bioremediation. As a consequence of bioremediation, the dissolved oxygen concentration and pH values increased significantly throughout the bioremediation process, indicating that the changes found in the microbiological profile of the soil contributed to the improvement of water quality parameters, helping the environment to move from anaerobic to aerobic characteristics. Thus, it is possible to state that the use of effective microorganisms directly affected the physical-chemical parameters of water quality and the microbial profile of the soil community of ‘Canal da Cidade’.

Microbial Strategies for Heavy Metal Removal from Industrial Wastewater

The contamination of industrial wastewater with heavy metals poses a severe environmental and public health concern. Traditional methods of heavy metal removal often prove costly and environmentally unsustainable. In this context, microbial strategies have emerged as a promising and eco-friendly approach for effective heavy metal remediation from industrial wastewater. Microorganisms, including bacteria, fungi, and algae, have developed various mechanisms to withstand and sequester heavy metals from their surroundings. This review explores the diverse microbial strategies employed in heavy metal removal, encompassing biosorption, bioaccumulation, bioprecipitation, and bioleaching. These strategies exploit microbial cell surfaces, extracellular polymeric substances, and intracellular compartments to immobilize, transform, or release heavy metals. Moreover, recent advancements in genetic engineering and biotechnology have enabled the development of tailored microbial strains with enhanced metal-removal capabilities. The application of these engineered microbes, as well as naturally occurring strains, in bioremediation processes is discussed. This review also delves into the factors influencing microbial metal removal efficiency, such as pH, temperature, metal concentration, and co-existing contaminants. Additionally, the potential drawbacks and limitations of microbial strategies, including biomass disposal and long-term performance, are addressed. As heavy metal pollution continues to be a pressing global issue, understanding and harnessing microbial strategies for heavy metal removal from industrial wastewater holds significant promise for sustainable and cost-effective remediation practices. Integrating microbial processes into existing treatment methods can offer innovative solutions to mitigate the environmental impact of heavy metal contamination, thereby safeguarding ecosystems and public health

Transformation of Benzene Derivatives in Acidic Conditions by the Fungus Hormoconis Resinae – Reductive, Oxidative, or Both?

Hormoconis resinae (or Cladosporium resinae), colloquially known as the kerosene fungus, is predominantly found in fuel tanks (Rafin and Veignie 2018). Its occurrence in fuel tanks was first reported in early 1960s. Since then, it has been considered as a serious threat by the petroleum industry for bio-deteriorating fuel quality, corroding storage tanks, and clogging pumps and filters (Sheridan et al. 1971). This fungus flourishes well in the presence of water and can thrive at a wider pH range (2-10), than most commonly studied bacteria, with optimum towards the acidic end (Rafin and Veignie 2018). As a biosafety level 1 organism (ATCC 2021) with wide natural prevalence, H. resinae is both safe to study and apply in the field. Thus, it can be utilized for developing bioremediation processes suitable for petroleum-contaminated sites. Contamination of groundwater sources by fuel pollutants has been an important public health concern for decades (Mitra and Roy 2011). Several components of fuel are known to be toxic even at low concentrations with deleterious health effects including teratogenicity and carcinogenicity (ATSDR 1995). Past research has mainly focussed on the degradation of n-alkanes, a major component of fuel, by H. resinae which used the n-alkanes as sole carbon and energy sources (Rafin and Veignie 2018). Benzene derivatives like toluene, benzaldehyde, benzoic acid are also often found as fuel pollutants. Though some studies have investigated the effects of benzene derivatives on the survival and growth of H. resinae (Cofone et al. 1973, Oh et al. 2001, Qi et al. 2002), not much work has been done on their biodegradation (Kato et al. 1990). Previous study showed a reductive transformation of benzoate to benzaldehyde, benzyl alcohol, and 1-phenyl-l,2-propanediol (Kato et al. 1990). More work was needed to study the further transformation of these products. Thus, the current study focussed on the transformation of benzaldehyde and benzyl alcohol in acidic conditions by H. resinae ATCC 34066. The main objectives were to study the effects of: culture media, glucose, and oxygen enrichment on the fungal growth in the presence of these benzene derivatives and their biodegradation kinetics and pathways. culture media, glucose, and oxygen enrichment on the fungal growth in the presence of these benzene derivatives and their biodegradation kinetics and pathways. Some experiments were also conducted with toluene as the contaminant. H. resinae was not able to transform toluene (1-200 ppm) at all, though it was able to grow on it in the presence of 1% glucose. The fungus was able to transform benzaldehyde (≤550 ppm) to benzyl alcohol (reductive) and benzoic acid (oxidative). Many monoaromatics such as catechol, resorcinol, hydroxybenzoic acids and aliphatic compounds such as fumaric acid, levulinic acid were also detected as the oxidation products of benzaldehyde by high-resolution liquid chromatography-mass spectrometry. The presence of glucose slowed down benzaldehyde transformation but increased the benzyl alcohol formation relative to benzoic acid, probably due to the further slower transformation of benzyl alcohol. Oxygen enrichment enhanced the benzaldehyde transformation. Glucose was a preferred culturing media as fungus grown on potato dextrose agar (PDA) showed a 5-week lag phase for benzaldehyde transformation. However, this PDA-cultured fungus, after growing on benzaldehyde, did not exhibit a lag phase and started benzaldehyde transformation immediately. Transformation of benzyl alcohol, as target contaminant, was slower and incomplete in the presence of glucose. Benzyl alcohol was transformed mainly to benzoic acid via an oxidative pathway. In summary, this study has shown that H. resinae can transform the benzene derivatives via both oxidative and reductive pathways. Moreover, H. resinae can use these compounds as sole carbon and energy sources.

Application of <i>Nannochloris</i> sp. for Landfill Leachate Biotreatment and Lipids Production

The sparse treatment of highly toxic leachates produced in landfills due to the excessive generation of urban solid waste is a common problem worldwide. For this reason, this research aims to show the convenience of the use of algal biotechnology in leachate bioremediation processes. Nannochloris sp. species was used in this research. It was isolated and cultured for bioassays. The leachate was diluted to 5 and 10% in the microalgae cultures during a period of 8 d in which the growth of the species. Then removal of nutrients (phosphate and nitrate) and the production of lipids by the microalgae were measured. Nannochloris sp. removed more than 70% of the phosphates and 60% of the nitrates from samples. This result shows the benefits of using these microalgae to treat landfill leachate at low cost and also with the potential to obtain bio-lipids that may be useful for biodiesel production.

Effects of zero-valent iron (ZVI) on nitrogen conversion, transformation of sulfamethoxazole (SMX) and abundance of antibiotic resistance genes (ARGs) in aerobic granular sludge process

Even after pre-treatment, livestock and poultry wastewater still contain high concentrations of ammonia and residual antibiotics. These could be removed economically using the aerobic granular sludge (AGS) process with zero-valent iron (ZVI). The interaction of antibiotics and nitrogen in this process needs to be clarified and controlled, however, to achieve good removal performance. Otherwise, antibiotics might generate transformation products (TPs) with higher toxicity and lead to the emergence of antibiotic-resistant bacteria carrying antibiotic resistance genes (ARGs), which could cause persistent toxicity and the risk of disease transmission to the ecological environment. This study investigated the impact of ZVI on AGS for nitrogen and sulfamethoxazole (SMX) removal. The results show that AGS could maintain good ammonia removal performance and that the existence of SMX had a negative impact on ammonia oxidation activities. ZVI contributed to an increase in the abundance of nitrite oxidation bacteria, denitrifying bacteria and the functional genes of nitrogen removal. This led to better total nitrogen removal and a decrease in N2O emission. Accompanied by biological nitrogen transformation, SMX could be transformed into 14 TPs through five pathways. ZVI has the potential to enhance transformation pathways with TPs of lower ecotoxicity, thereby reducing the acute and chronic toxicity of the effluent. Unfortunately, ZVI might enhance the abundance of sul1, sul2, and sul3 in AGS, which increases the risk of sulfonamide antibiotic resistance. In AGS, Opitutaceae, Xanthomonas, Spartobacteria and Mesorhizobium were potential hosts for ARGs. This study provides theoretical references for the interaction of typical antibiotics and nitrogen in the biological treatment process of wastewater and bioremediation of natural water bodies.

Bioremediation of an industrial soil contaminated by hydrocarbons in microcosm system, involving bioprocesses utilizing co-products and agro-industrial wastes.

The present study describes practical implication of bioaugmentation and biostimulation processes for bioremediation of an industrial soil chronically contaminated by hydrocarbons. For this purpose, biomass production of six autochthonous hydrocarbon-degrading bacteria were evaluated as inoculum of bioaugmentation strategy, by testing carbon and nitrogen sources included co-products and agro-industrial waste as sustainable and low-cost components of the growth medium. Otherwise, biostimulation was approached by the addition of optimized concentration of nitrogen and phosphorus. Microcosm assays showed that total hydrocarbons (TH) were significantly removed from chronically contaminated soil undergoing bioremediation treatment. Systems Mix (bioaugmentation); N,P (biostimulation) and Mix + N,P (bioaugmentation and biostimulation) reached higher TH removal, being 89.85%, 91.00%, 93.04%, respectively, comparing to 77.83% of system C (natural attenuation) at 90days. The increased heterotrophic aerobic bacteria and hydrocarbon degrading bacteria counts were according to TH biodegrading process during the experiments. Our results showed that biostimulation with nutrients represent a valuable alternative tool to treat a chronically hydrocarbon-contaminated industrial soil, while bioaugmentation with a consortium of hydrocarbon degrading bacteria would be justified when the soil has a low amount of endogenous degrading microorganisms. Furthermore, the production of inoculum for application in bioaugmentation using low-cost substrates, such as industrial waste, would lead to the development of an environmentally friendly and attractive process in terms of cost-benefit.

Biodegradation of Malathion in Amended Soil by Indigenous Novel Bacterial Consortia and Analysis of Degradation Pathway

The capabilities of pure bacterial strains and their consortia isolated from agricultural soil were evaluated during a bioremediation process of the organophosphate pesticide malathion. The pure bacterial strains efficiently degraded 50.16–68.47% of the pesticide within 15 days of incubation, and metabolites were observed to accumulate in the soil. The consortia of three bacterial species [Micrococcus aloeverae (MAGK3) + Bacillus cereus (AGB3) + Bacillus paramycoides (AGM5)] degraded the malathion more effectively, and complete malathion removal was observed by the 15th day in soils inoculated with that consortium. In contrast, the combined activity of any two of these strains was lower than the mixed consortium of all of the strains. Individual mixed consortia of Micrococcus aloeverae (MAGK3) + Bacillus cereus (AGB3); Micrococcus aloeverae (MAGK3) + Bacillus paramycoides (AGM5); and Bacillus cereus (AGB3) + Bacillus paramycoides (AGM5) caused 76.58%, 70.95%, and 88.61% malathion degradation in soil, respectively. Several intermediate metabolites like malaoxon, malathion monocarboxylic acid, diethyl fumarate, and trimethyl thiophosphate were found to accumulate and be successively degraded during the bioremediation process via GC–MS detection. Thus, inoculating with a highly potent bacterial consortium isolated from in situ soil may result in the most effective pesticide degradation to significantly relieve soils from pesticide residues, and could be considered a prospective approach for the degradation and detoxification of environments contaminated with malathion and other organophosphate pesticides. This study reports the use of a mixed culture of Indigenous bacterial species for successful malathion degradation.

Bacterial Biodegradation of Perfluorooctanoic Acid (PFOA) and Perfluorosulfonic Acid (PFOS) Using Pure Pseudomonas Strains

The principal objective of the present research involved the achievement of high biodegradation degrees of perfluorooctanoic acid (PFOA) and perfluorosulfonic acid (PFOS) using pure individual bacterial strains. The use of such microorganisms can contribute to the improvement of the wastewater treatment process in sewage treatment plants through bioaugmentation or other bioremediation processes. Thus, in this study, we investigated the biodegradation potential of PFOA and PFOS. Bacterial strains tested in this study were from the Pseudomonas genus, namely: Pseudomonas aeruginosa and Pseudomonas putida, due to their known capacity to degrade xenobiotic compounds. The results indicated that Pseudomonas aeruginosa was able to transform 27.9% of PFOA and 47.3% of PFOS in 96 h, while Pseudomonas putida managed to transform 19.0% of PFOA and 46.9% of PFOS in the same time frame. During the biodegradation tests, PFHxA was recognized as the principal biotransformation product of PFOA in the presence of Pseudomonas aeruginosa, and PFPeA, PFPxA and PFHpA were recognized as the biotransformation products in the presence of Pseudomonas putida. For PFOS, only two biotransformation products (PHHxA and PFHpA) were observed as a consequence of biodegradation by both bacterial strains.

Microfiltration, ultrafiltration and nanofiltration as a post-treatment of biological treatment process with references to oil field produced water of Moran oilfield of Assam

The selection of an apt technology for the treatment of Oilfield Produced Water (OFPW) depends mainly on the quality of OFPW and methods of pre-and post-treatment processes. The most challenging part of the OFPW treatment process is the removal of Suspended Solid (SS), Oil & Grease (O&G) and dissolved organics. SS and O&G pose an acute problem to the membrane filtration system by fouling the membrane surface which increases operation & maintenance costs and decreases the life of the membrane. Fouling of the membrane surface is mainly attributed to the presence of low molecular weight aromatic compounds and naphthenic acids in the suspended and dissolved organic compounds. Thus, the removal of these suspended and dissolved organic compounds before membrane filtration proffers a challenge to the researchers. In this research, bioremediation process has been applied to remove the organic compounds and the performance and fouling behaviour of hollow fibre Microfiltration (MF), Ultrafiltration (UF) and Nanofiltration (NF) membranes after the bioremediation process has been analyzed in detail. The level of toxicity was determined by comparing the pollutants with the safe discharge limit for disposal into the environment set by Central Pollution Control Board (CPCB), India. The research presents its novelty by using a hydrocarbon-degrading bacteria, Pseudomonas aeruginosa for the Reduction of Organic Loads (ROL) from OFPW of Moran oil field of Upper Assam as a pre-treatment to membrane filtration. The Total Sum Corrected Area (TSCA) method through chromatographic analyses was used for this. The organic loads removal from OFPW by the TSCA method was found to be 67–100%, 100% and 100% after 7, 14 and 21 days of bioremediation respectively. The major parameters in feed OFPW of Moran oil field were found to be pH (7.5–9.3), Total Dissolved Solid (TDS) (1.79–4.75) ppt, O&G (1.78–2.8) ppt, Salinity (2.94–6.98) ppt, Chloride (Cl−) (1.6–3.86) ppt, Bicarbonate (HCO3−) (2.89–4.03) ppt. It was observed that the ranges of pollutants removal by NF was highest such as TDS (26–86%), salinity (81–86%), turbidity (78–94%), hardness (67–75%), O&G (96–99%), Cl− (80–89%) and HCO3− (95–97%).

A Review on In-Situ Denitrification Technology for Consideration in Jaffna Peninsula Aquifer Remediation

A Review on In-Situ Denitrification Technology for Consideration in Jaffna Peninsula Aquifer Remediation

Isolation, screening and characterization of hydrocarbon-degrading bacteria isolated from oil contaminated soil in Wasit province / Iraq

Eleven soil samples were collected from one of the oil sites in Wasit Governorate.65 bacterial isolates were isolated from soil samples by using BHM with 1% crude oil as carbon source. In primary and secondary screening (10) isolates of bacteria can remediate crude oil. Among the ten isolates, bacterial isolate named HD2 was most effective in bioremediation process. The results of biomass, optical density, and percentage of hydrocarbon remediation of HD2 were (0.63, 1.080 and 67 %) respectively. The results of morphological and biochemical tests showed that the bacterial isolate named HD2 belongs to the species Pseudomonas putida.