Haiying Tang, Guohong Xiang, Wen Xiao et al.

Frontiers in Plant Science • 2024

Heavy metal pollution has become a serious concern across the globe due to their persistent nature, higher toxicity, and recalcitrance. These toxic metals threaten the stability of the environment and the health of all living beings. Heavy metals also enter the human food chain by eating contaminated foods and cause toxic effects on human health. Thus, remediation of HMs polluted soils is mandatory and it needs to be addressed at higher priority. The use of microbes is considered as a promising approach to combat the adverse impacts of HMs. Microbes aided in the restoration of deteriorated environments to their natural condition, with long-term environmental effects. Microbial remediation prevents the leaching and mobilization of HMs and they also make the extraction of HMs simple. Therefore, in this context recent technological advancement allowed to use of bioremediation as an imperative approach to remediate polluted soils. Microbes use different mechanisms including bio-sorption, bioaccumulation, bioleaching, bio-transformation, bio-volatilization and bio-mineralization to mitigate toxic the effects of HMs. Thus, keeping in the view toxic HMs here in this review explores the role of bacteria, fungi and algae in bioremediation of polluted soils. This review also discusses the various approaches that can be used to improve the efficiency of microbes to remediate HMs polluted soils. It also highlights different research gaps that must be solved in future study programs to improve bioremediation efficency.

Shuai Zhao, Xue-Tao Yuan, Xiao-Hong Wang et al.

Sustainability • 2024

Microbial remediation has become a prominent focus in soil pollution control due to its environmental friendliness, cost-effectiveness, and high efficiency. The effectiveness of microbial remediation is rooted in the interactions between microbial metabolic activities and the soil environment. Various microorganisms employ distinct mechanisms for pollutant treatment, including surface adsorption, intracellular accumulation, and biomineralization. Using the Web of Science Core Collection database, tools such as CiteSpace 6.1.R6, VOSviewer 1.6.20, and HistCite Pro were employed to conduct a quantitative analysis of several key aspects: the volume and thematic distribution of research papers on microbial remediation of soils, the cooperative networks between countries and institutions, the leading journals, major research hotspots, and emerging trends. The analysis reveals that utilizing microbial regulatory mechanisms and functions to remediate inorganic pollutants, such as heavy metals, and organic pollutants, such as PAHs, is becoming a significant frontier in future research. This study provides a valuable reference for scholars aiming to understand the current status of microbial research in soil remediation, both domestically and internationally. It also offers guidance for developing efficient, sustainable, and safe remediation strategies while identifying directions for future innovative research. The specific results are as follows: (1) China, the USA, India, and other countries have a high frequency of citations in this field, and the research is more in-depth. (2) More and more attention has been paid to the use of microbial remediation of contaminated soil in the world, mainly in Environmental Sciences. (3) Major publications include Chemosphere, Journal of Hazardous Materials, and Science of The Total Environment. In the key literature, the use of microorganisms to restore the soil environment and the combination of microorganisms and plants to repair soil contaminated by heavy metals occupy a high proportion. (4) The key areas of focus include the application of microorganisms in soil inorganic pollution remediation, the application of microorganisms in remediation of soil organic pollution (crude oil and polycyclic aromatic hydrocarbons (PAHs)), and the contribution of microorganisms to soil pollutant degradation and toxicity assessment systems. The research and development of combined microbial remediation technology is the current research hotspot in the field of soil remediation, focusing on the symbiosis between mycorrhizal fungi and plant roots, the enhancement in the ability of microorganisms to absorb and degrade pollutants and their tolerance, and the interaction mechanism between indigenous microorganisms and plants.

Wu‐Juan Sun, Qian Li, Bo-Yun Luo et al.

Environmental Geochemistry and Health • 2024

Soil contamination by petroleum, including crude oil from various sources, is increasingly becoming a pressing global environmental concern, necessitating the exploration of innovative and sustainable remediation strategies. The present field-scale study developed a simple, cost-effective microbial remediation process for treating petroleum-contaminated soil. The soil treatment involves adding microbial activators to stimulate indigenous petroleum-degrading microorganisms, thereby enhancing the total petroleum hydrocarbons (TPH) degradation rate. The formulated microbial activator provided a growth-enhancing complex of nitrogen and phosphorus, trace elements, growth factors, biosurfactants, and soil pH regulators. The field trials, involving two 500 m3 soil samples with the initial TPH content of 5.01% and 2.15%, were reduced to 0.41% and 0.02% in 50 days, respectively, reaching the national standard for cultivated land category II. The treatment period was notably shorter than the commonly used composting and bioaugmentation methods (typically from 8 to 12 weeks). The results indicated that the activator could stimulate the functional microorganisms in the soil and reduce the phytotoxicity of the contaminated soil. After 40 days of treatment, the germination rate of rye seeds increased from 20 to 90%, indicating that the microbial activator could be effectively used for rapid on-site remediation of oil-contaminated soils.

Jatinder Singh Randhawa

Bulletin of the National Research Centre • 2024

Abstract Background Neonicotinoids are a group of synthetic insecticides that are highly effective and have a wide range of insecticidal activities. This group includes acetamiprid, dinotefuran, clothianidin, imidacloprid, sulfoxaflor, nitenpyram, thiamethoxam, and thiacloprid. They are extensively used worldwide, both in rural and urban environments. However, the widespread use of neonicotinoids has led to their accumulation and biomagnification in the environment due to their long half-life. This has resulted in the emergence of toxicological and hazardous pollutants, posing significant risks to humans and non-target animals. Neonicotinoids are a type of insecticides that bind to neuronal nicotinic acetylcholine receptors (nAChRs). This mechanism allows them to effectively activate insect nAChRs while having minimal impact on vertebrate nAChRs. This reduces the risk of toxicity and makes them safer for non-target species. However, the presence of neonicotinoids in the environment can still increase the risk of toxicity and exposure. Although they have low affinity for mammalian nAChRs, concerns arise due to the abundance, diversity, and widespread presence of these receptors, as well as their various functions. These factors raise concerns about the potential impact of these pesticides on unintended species. Therefore, it is crucial to remove neonicotinoids from the environment in a sustainable and methodical manner. Main body of the abstract Various techniques can be employed to eliminate neonicotinoid residues in soil and aquatic habitats. These techniques include physiochemical remediation methods such as advanced oxidation processes, adsorption, oxidation, Fenton technology, photocatalysis, and activated persulfate-based oxidation. Additionally, microbial remediation techniques involving bacteria, fungi, and microalgae can also be utilized. This review aims to focus on the scientific foundation, advancements, and key topics related to microbial remediation technologies for neonicotinoids. Proper implementation of bioremediation techniques can significantly reduce the harmful effects of neonicotinoids on the environment and human health. Short conclusion The main focus of this review is the new studies on the bioremediation of neonicotinoids by bacteria, fungi, and microalgae, and the role of their enzymes. This topic is gaining importance as pesticide bioremediation techniques become increasingly significant.

Narcís Pous, Maria Dolors Balaguer, Jesús Colprim et al.

Microbial Biotechnology • 2018

Summary Groundwater pollution is a serious worldwide concern. Aromatic compounds, chlorinated hydrocarbons, metals and nutrients among others can be widely found in different aquifers all over the world. However, there is a lack of sustainable technologies able to treat these kinds of compounds. Microbial electro‐remediation, by the means of microbial electrochemical technologies ( MET ), can become a promising alternative in the near future. MET can be applied for groundwater treatment in situ or ex situ , as well as for monitoring the chemical state or the microbiological activity. This document reviews the current knowledge achieved on microbial electro‐remediation of groundwater and its applications.

Umair Riaz, Laila Shahzad, Wajiha Anum et al.

Advances in Environmental Engineering and Green Technologies • 2021

Beneficial microbes are used as the best alternative against the synthetic fertilizers and pesticides. The beneficial microbes not only help with plant growth, nutrition uptake, nitrogen fixation, but also help in acquiring the ions, not freely available to plants to uptake; these microbes also guard the plants by secreting toxic chemicals by inducing defense systems against pathogens. These microbes can provide best choice to look forward to sustainable agriculture and sustainable ecosystem. The addition of soil inoculants in the form of microorganisms or bio stimulants promise more environmentally friendly approaches for augmenting crop yields. The crop becomes less reliant on chemical fungicides and herbicides as many strains of microorganism have abilities of controlling pests. In this chapter, the interaction of beneficial plant bacteria, bio stimulants, effects on native microbial communities, and bacteria influencing economically important crops are discussed.

Mathew P Watts, John W Moreau

Microbiology Australia • 2018

Thiocyanate (SCN–) forms in the reaction between cyanide (CN–) and reduced sulfur species, e.g. in gold ore processing and coal-coking wastewater streams, where it is present at millimolar (mM) concentrations1. Thiocyanate is also present naturally at nM to µM concentrations in uncontaminated aquatic environments2. Although less toxic than its precursor CN–, SCN– can harm plants and animals at higher concentrations3, and thus needs to be removed from wastewater streams prior to disposal or reuse. Fortunately, SCN– can be biodegraded by microorganisms as a supply of reduced sulfur and nitrogen for energy sources, in addition to nutrients for growth4. Research into how we can best harness the ability of microbes to degrade SCN– may offer newer, more cost-effective and environmentally sustainable treatment solutions5. By studying biodegradation pathways of SCN– in laboratory and field treatment bioreactor systems, we can also gain fundamental insights into connections across the natural biogeochemical cycles of carbon, sulfur and nitrogen6.

Leena Merlin Biju, Veena Gayathri Krishnaswamy

Advances in Environmental Engineering and Green Technologies • 2021

Industrialization led to the release of synthetic and toxic compounds. Partial or improper treatment increases environmental pollution. Conventional methods possess more disadvantages, such as increased duration of degradation and release of secondary pollutants. The drawbacks paved the way for the significant bioremediation perspective. The ubiquitous nature of microbes enables it to utilize toxic compounds, which attracted the focus of treatment towards the biological and eco-friendly methods. The recent decade has shown interest in the application of indigenous microbes in the polluted environment. Apart from the microbial application, phytoremediation is an emerging tool for treating soil contaminated with hazardous pollutants. Technological advancement in biotechnology ensures a safe and healthy environment for a better future.

Asha Laxman Giriyan, Vikrant B. Berde, Elroy J. Pereira et al.

Advances in Environmental Engineering and Green Technologies • 2021

Heavy metals are found naturally. Anthropogenic activities and rapid industrialization have led to their unprecedented release into the environment. Being non-biodegradable in nature, they persist in the environment. Prolonged exposure and accumulation of these metals poses a serious threat to the ecosystem. Conventional treatment of contaminated material whether soil or water involves expensive chemical or physical methods which are arduous, energy demanding, and carry the risk of secondary contamination. It is thus necessary to adopt a sustainable remediation process to mitigate this problem. Biological remediation processes are preferable as they are environmentally safe, techno-economically feasible, and do not generate toxic byproducts. Microbial bioremediation is particularly attractive as it allows remediation processes by tapping naturally occurring catabolic capacities to transform, accumulate, and adsorb metals for detoxification. It is a comparatively low-cost technology. Therefore, microbial bioremediation is promising as an alternative to physico-chemical methods.

Lirong Zhong, M. R. Islam

SPE Annual Technical Conference and Exhibition • 1995

Abstract Microbial mineral precipitation occurs constantly over the geological time. This process induces natural cementation or plugging in sediments or rock formations. Petroleum microbiologists employed the process as a reservoir selective plugging method to enhance the production of hydrocarbon resources. Mineral precipitation is induced as a result of microbial activities. Bacteria can deposit minerals directly from the medium through their metabolic activities. They can also precipitate minerals indirectly from the medium by changing regional geological environmental conditions. Mineral precipitations and the dead bacteria bodies can persist as a part of the environment and result in plugging or cementing in pores in that environment. The process is optimized with bacteria Bacillus Pasteurii to precipitate CaCO3 so that the bacteriogenic cementation occurs in hours rather than in years. It is suggested that the process be used to plug fractures in water-producing zones to prevent excessive water production during oil recovery. The same technique can be used to consolidate sands in an unconsolidated fractures. A series of experiments was conducted to investigate the possibility of using microbial plugging process to remediate fractures and to test factors affecting that process. The effects of pH, temperature and medium on mineral precipitation and bacteria growth are studied in detail. Also, the effect of fracture width and fracture fillings is studied. It is found that the microbial mineral plugging technique is effective in plugging fractures.

Chioma Blaise Chikere, Memory Tekere, Rasheed Adeleke

• 2020

Abstract Background: The frequency of crude oil pollution has been on the increase following increased exploration, exploitation and production of energy from fossil fuel. Bioremediation has been shown to be eco-friendly and cost-effective method of oil spill remediation. In the Niger Delta, Landfarming has been the most used technique. The aim of this research was to employ metagenomic techniques to understand microbial dynamics during field-scale remediation in the Niger Delta in order to improve and reduce the time of remediation. Results: The surface (0.0 – 0.5m) sample had an extractable TPH value of 6231 mg/kg. The subsurface samples from 1m, 1.5m and 2.0m depths had extractable TPH concentration of 4836 mg/kg, 9112 mg/kg and 7273 mk/kg respectively. Proteobacteria dominated the soil microbial profile in all the samples studied as it made up at least 50% of each sample and mostly comprised of the class Alphaproteobacteria with variation only on day 18 and 36 which was mostly dominated by the class Gammaproteobacteria and Betaproteobacteria. Alpha diversity analysis revealed the presence of crude oil in the soil reduced microbial diversity. Principal coordinate analysis showed the microbial structure continually changed following changes in the chemical composition of the soil. Mycobacterium , Burkholderia , Rhodoplanes , Methylobacterium and Bacillus were the core OTUs detected during the period of remediation. Significant variation in pathway abundance particularly pathways for propanoate degradation, benzoate degradation, naphthalene degradation, fatty acid metabolism, polycyclic aromatic hydrocarbon degradation and degradation of xenobiotics were observed when the unpolluted soil was compared to the samples obtained during remediation. Conclusions: The findings from this study will greatly advance an already preferred landfarming oil spill recovery technique in the Niger Delta.

R. J. Portier, D. L. Sattler, D. G. Hoover et al.

Remediation Journal • 1998

Abstract Well‐recovery networks coupled to immobilized microbe bioreactors (IMBRs) were installed at a 172‐acre former wood preserving facility for the bioremediation of organic wood preservatives present in site groundwater. Free‐phase creosote from the hardpan and soluble preservative fractions contained in subsurface groundwater were pumped separately to different holding tanks. Trace creosote fractions contained in the subsurface groundwater were further gravity separated in the holding tank. Immobilized microbial isolates evaluated in earlier laboratory and field pilot tests were established into two 40, 000‐liter bioreactors for the biodegradation of all targeted consitituents. Microbial growth, dissolved oxygen, pH, nutrients, flow rate, and temperature were monitored in this in situ/ex situ bioremediation system. The process was used to remove the polycyclic aromatic hydrocarbon (PAH) and phenolic components of creosote and pentachlorophenol from contaminated groundwater. Data generated during the past 2 1/2 years indicate that 26 target compounds consistently are reduced to levels acceptable for discharge. Currently operating in Baldwin, Florida, this full‐scale prototype is remediating the former wood preserving facility and is being used as a model system for the design and construction of new bioreactor systems needed at similar industrial sites in the United States and abroad.

Sayali S. Patil, Eric M. Adetutu, Jacqueline Rochow et al.

Microbial Biotechnology • 2014

Summary Microbial electric systems ( MESs ) hold significant promise for the sustainable remediation of chlorinated solvents such as tetrachlorethene (perchloroethylene, PCE ). Although the bio‐electrochemical potential of some specific bacterial species such as D ehalcoccoides and G eobacteraceae have been exploited, this ability in other undefined microorganisms has not been extensively assessed. Hence, the focus of this study was to investigate indigenous and potentially bio‐electrochemically active microorganisms in PCE ‐contaminated groundwater. Lab‐scale MESs were fed with acetate and carbon electrode/ PCE as electron donors and acceptors, respectively, under biostimulation ( BS ) and BS ‐bioaugmentation ( BS‐BA ) regimes. Molecular analysis of the indigenous groundwater community identified mainly S pirochaetes , F irmicutes , B acteroidetes , and γ and δ ‐ P roteobacteria . Environmental scanning electron photomicrographs of the anode surfaces showed extensive indigenous microbial colonization under both regimes. This colonization and BS resulted in 100% dechlorination in both treatments with complete dechlorination occurring 4 weeks earlier in BS‐BA samples and up to 11.5 μ A of current being generated. The indigenous non‐ D ehalococcoides community was found to contribute significantly to electron transfer with ∼61% of the current generated due to their activities. This study therefore shows the potential of the indigenous non‐ D ehalococcoides bacterial community in bio‐electrochemically reducing PCE that could prove to be a cost‐effective and sustainable bioremediation practice.

Ann Azadpour‐Keeley, Lynn A. Wood, Tony R. Lee et al.

Remediation Journal • 2004

Abstract The evaluation of microbial responses to three in situ source removal remedial technologies—permanganate‐based in situ chemical oxidation (ISCO), six‐phase heating (SPH), and steam injection (SI)—was performed at Cape Canaveral Air Station in Florida. The investigation stemmed from concerns that treatment processes could have a variety of effects on the indigenous biological activity, including reduced biodegradation rates and a long‐term disruption of community structure with respect to the stimulation of TCE (trichloroethylene) degraders. The investigation focused on the quantity of phospholipid fatty acids (PLFAs) and its distribution to determine the immediate effect of each remedial technology on microbial abundance and community structure, and to establish how rapidly the microbial communities recovered. Comprehensive spatial and temporal PLFA screening data suggested that the technology applications did not significantly alter the site's microbial community structure. The ISCO was the only technology found to stimulate microbial abundance; however, the biomass returned to predemonstration values shortly after treatment ended. In general, no significant change in the microbial community composition was observed in the SPH or SI treatment areas, and even small changes returned to near initial conditions after the demonstrations. © 2004 Wiley Periodicals, Inc.

Xin Sui, Xuemei Wang, Yuhuan Li et al.

Sustainability • 2021

The petroleum industry’s development has been supported by the demand for petroleum and its by-products. During extraction and transportation, however, oil will leak into the soil, destroying the structure and quality of the soil and even harming the health of plants and humans. Scientists are researching and developing remediation techniques to repair and re-control the afflicted environment due to the health risks and social implications of petroleum hydrocarbon contamination. Remediation of soil contamination produced by petroleum hydrocarbons, on the other hand, is a difficult and time-consuming job. Microbial remediation is a focus for soil remediation because of its convenience of use, lack of secondary contamination, and low cost. This review lists the types and capacities of microorganisms that have been investigated to degrade petroleum hydrocarbons. However, investigations have revealed that a single microbial remediation faces difficulties, such as inconsistent remediation effects and substantial environmental consequences. It is necessary to understand the composition and source of pollutants, the metabolic genes and pathways of microbial degradation of petroleum pollutants, and the internal and external aspects that influence remediation in order to select the optimal remediation treatment strategy. This review compares the degradation abilities of microbial–physical, chemical, and other combination remediation methods, and highlights the degradation capabilities and processes of the greatest microbe-biochar, microbe–nutrition, and microbe–plant technologies. This helps in evaluating and forecasting the chemical behavior of contaminants with both short- and long-term consequences. Although there are integrated remediation strategies for the removal of petroleum hydrocarbons, practical remediation remains difficult. The sources and quantities of petroleum pollutants, as well as their impacts on soil, plants, and humans, are discussed in this article. Following that, the focus shifted to the microbiological technique of degrading petroleum pollutants and the mechanism of the combined microbial method. Finally, the limitations of existing integrated microbiological techniques are highlighted.

Turlough F. Guerin

Remediation Journal • 1999

Abstract The current study describes an improved method for estimating the abundance of polycyclic aramatic hydrocarbon (PAH) degraders in contaminated soil and groundwater. Since the method is a simple incremental improvement to a commonly used approach, it can be easily introduced into the remediation practitioner's testing protocols by simply changing growth indicator dyes. The procedure described is relatively easy to conduct and provides an important addition to laboratories that are using conventional, nonmolecular techniques for microbial enumeration in their bioremediation programs. © 1999 John Wiley & Sons, Inc.

Hina Jabeen, Akhtar Rasool

Pakistan Journal of Biochemistry and Biotechnology • 2021

Extensive dependence of textile and other industries on the synthetic dyes have made these chemicals a necessary evil nowadays. Among all classes of dyes, triphenylmethane dyes (TPMs) are most common and unfortunately most hazardous. The wastewater originated from various industries is usually found to contain a major portion of TPMs along-with other synthetic dyes, inorganic and organic contaminant which lead to serious environmental consequences. In this regard, microbial remediation of such synthetic chemicals seems to be a very robust, cost effective and environment friendly strategy. Microbial remediation exploits the enzymatic capabilities of microorganisms (bacteria, fungi or microalgae) to cope with recalcitrant synthetic dyes and other chemicals. The remediation of TPMs can occur either by the phenomenon of adsorption onto the microbial systems or through the degradation by the enzymatic or metabolic mechanisms of the microbe under optimized conditions. Both of the two ways convert the toxic chemicals to harmless and friendly products. Biodegradation or bioremediation of pollutants can be achieved through various living organisms such as plants and algae. But the current review only focuses on the remediation of TPMs by microbes such as bacteria, yeast and fungi. The factors such as pH, temperature, inoculum size, dye concentration etc. which have profound effect on optimization of degradation of TPMs, can never be neglected and hence they are discussed in detail in the present study. In this way we claim that the present article will provide deep insights into the current consequences of TPMs and related toxicants being added to our environment. Further, an emphasis on the implementation of bioremediation to get rid of such chemicals from our waters would be helpful to enhance the interest of researchers and scientists already working on the same theme.

Priti Panwar, Pooja Mahajan, Jyotsna Kaushal

Remediation Journal • 2023

Abstract Azo dyes, which are the most commonly used dyes in the textile industry, are aromatic compounds with N═N– groups. The treatment of these pollutants has been receiving considerable attention due to their persistence and release of dyes into the environment. The existing treatment approaches are not only expensive but also result in the production of concentrated sludge, which creates a secondary disposal issue. Under particular ecological conditions, a variety of microbes, including bacteria, fungi, algae, and yeasts, can not only decolorize numerous dyes but can also degrade them. In this respect, microbial degradation is a successful, cost‐effective, biologically friendly, and ecologically sustainable treatment strategy. This review paper discusses research articles identified in the ScienceDirect bibliographic database for the last 10 years (from January 1, 2010 to June 29, 2022). Only the most appropriate research articles were included in the review process which was identified by searches with keyword phrases Azo‐dye degradation with bacteria, fungi, algae, yeast, and microbial consortia. The review paper also emphasizes the constraints that persist and the future scope for the degradation of dyes via genetic engineering.

PREETI CHAURASIA, Nakuleshwar Dut Jasuja, Sanjeev Kumar

Research Square • 2022

Abstract Man-made pollution and pollutants are increasing day by day which has prompted alarming health issues and a declining availability of clean drinking water. Xenobiotic compounds from the waste of industries aggregate in agricultural soils and penetrates in the food chain. Thus, imposes a negative influence on the natural ecosystem and eventually impacts on human. The limitations of conventional methods used in remediation to get rid of the contaminants have given rise to trial nanotechnological aids for environmental clean-up by various researchers. The use of nanoparticles produced by microorganisms with the aid of nano biotechnology is known as nano bioremediation. This substitute for developing nanoparticles is an eco-compatible, environment-affable and cost-efficient method to eliminate the contaminants. Nanoparticles have shown their effectiveness over bulk materials as they confer easy handling, large surface area, economic viability, higher reactivity, and hence better performance. Microorganisms like bacteria, fungi, yeast, actinomycetes, and algae are exploited as a “biofactory” for the nanoparticle’s synthesis such as cadmium sulfide iron, silver, gold, platinum, titanium, titanium dioxide, palladium, magnetite, etc for the conversion and detoxification of the contaminants. Microbes have secured remarkable attentiveness as they possess the potency to synthesize nanoparticles in varying sizes, shapes and compositions with distinct physicochemical features for the elimination of heavy metals, organic, inorganic contaminants, organochlorines, dyes in soil and water treatment. Developments withinside the subject of nanoparticle biosynthesis will raise the commercial economic system through producing inexperienced energy. This manuscript emphasizes the importance and mechanism of environmental remediation of pollutants by microbe-driven nanoparticles.

Saleha Husain

Remediation Journal • 2008

Abstract High molecular weight polycyclic aromatic hydrocarbons (HMW PAHs) increase in hydrophobicity with increases in their molecular weight and ring angularity. Microbial strategies to deal with PAH hydrophobicity include biofilm formation, enzyme induction, and biosurfactants, the effect of which is variable on PAH metabolism depending on the surfactant type and concentration, substrate, and microbial strain(s). Aerobic HMW PAH metabolism proceeds via mineralization, partial degradation, and cometabolic transformations. Generally, bacteria and nonlignolytic fungi metabolize PAHs via initial PAH ring oxidation by dioxygenases to form cis ‐dihydrodiols, which are transformed to catechol compounds by dehydrogenases and other mono‐ and dioxygenases to substituted catechol and noncatechol compounds, all ortho‐ or metacleaved and further oxidized to simpler compounds. However, lignolytic fungi form quinones and acids to CO 2 . This review discusses the pathways for HMW PAH microbial metabolism. © 2008 Wiley Periodicals, Inc.

A. Rüdiger, I. Rüdiger, L. Jurisevic

Water Science and Technology • 2007

An innovative technology for industrial wastewater treatment has been developed. The main focus of the new system is a transformation of persistent organic compounds (biorecalcitrant COD) into a biodegradable fraction, followed by high efficient biological elimination using specialised bacteria's. To fulfill these targets the Aqua-Biomant® process integrates two treatment steps: an aerated biological upflow filter and a electrochemical oxidation technique using boron doped-diamond electrodes. The advantages of the process are high efficient COD removal with reduced energy consumption combined with low total residence time.

Chengyu Zhang, Zhisheng Yu, Xiangyang Wang

Frontiers in Chemistry • 2022

Antibiotics widely exist in medical wastewater, which seriously endanger human health. With the spread of the COVID-19 and monkeypox around the world, a large number of antibiotics have been abused and discharged. How to realize the green and efficient treatment of medical wastewater has become a hot research topic. As a common electrochemical water treatment technology, electrochemical oxidation technology (EOT) could effectively achieve advanced treatment of medical wastewater. Since entering the 21st century, electrochemical oxidation water treatment technology has received more and more attention due to its green, efficient, and easy-to-operate advantages. In this study, the research progress of EOT for the treatment of medical wastewater was reviewed, including the exploration of reaction mechanism, the preparation of functional electrode materials, combining multiple technologies, and the design of high-efficiency reactors. The conclusion and outlook of EOT for medical wastewater treatment were proposed. It is expected that the review could provide prospects and guidance for EOT to treat medical wastewater.

Josiel Martins Costa

International Journal of Environmental Research and Public Health • 2023

Water scarcity and pollution are global issues caused by factors, such as population growth, industrialization, and the utilization of water resources [...]

Jian Gong Wang, Xue Min Li

Advanced Materials Research • 2011

The electrochemical treatment of wastewater containing 2, 4, 6-trichlorophenol has been carried out experimentally with synthetic boron-doped diamond (BDD) thin film electrodes. Removal rate of COD, instant current efficiency (ICE) and energy consumption were investigated under different current density. The influence of supporting media is reported, which plays an important role in determining the global oxidation rate. The oxidative chloride is stronger than peroxodisulphate. The electrochemical characteristics of boron-doped diamond electrodes were investigated in comparison with active coating Ti substrate anode (ACT). The experimental results show that BDD is markedly superior to ACT due to its different absorption properties.

Chun Hong Nie, Bao Hui Wang

Advanced Materials Research • 2014

The electrochemical oxidation of o-Aminophenol in the presence o f NaCl for wastewater treatment was studied on Ti/IrO 2 -Ta 2 O 5 , Ti/IrO 2 -Ta 2 O 5- SnO 2 and Ti/IrO 2 anodes. The experimental results have shown that the presence of NaCl catalyses the anodic oxidation of o-Aminophenol due to the participation of electrogenerated ClO - in the oxidation. Analysis of the oxidation products has shown that initially organo chlorinated compounds are formed in the electrolyte.

Neetesh Kumar Dehariya, Sonal Rajoria, Vikas Kumar Sangal

Journal of The Electrochemical Society • 2024

Doxycycline (DOXY), a widely used antibiotic during COVID-19, was overused, leading to concerns about contamination of aquatic environments and environmental problems. The present study used the Ti/TiO 2 -RuO 2 -IrO 2 electrode for DOXY’s electrochemical oxidation (EO) in batch and once-through continuous mode operations. Process parameters were optimized using a response surface methodology (RSM)-Box-Behnken Design (BBD) model. The impact of key input parameters, including time (t), current density (j) (mA cm −2 ), and pH, on the percentage of DOXY degradation and energy consumption was systematically investigated. Under optimal conditions pH = 3, t = 73 min, and j = 11.63 mA cm −2 , DOXY degradation achieved 91% with an energy consumption of 5.283 kWh m −3 . In the once-through continuous mode EO process, optimal conditions reached 91% DOXY degradation with an energy consumption of 13.98 kWh m −3 , achieved at a residence time (R t ) of 139 min, elapsed (E t ) time of 100 min and at j = 20.40 mA cm −2 . The EO process utilizing Ti/TiO 2 -RuO 2 -IrO 2 electrodes demonstrates significant potential for the degradation of DOXY, primarily due to its enhanced degradation efficiency. This method’s superior performance highlights its viability as a highly effective approach for the treatment of DOXY-contaminated wastewater.

Hai Dong Wang, Kang Le Gao, Bo Te Lu

Advanced Materials Research • 2013

Coking wastewater RO brine is considered to be refractory, toxic, mutagenic and carcinogenic. Electrochemical oxidation has attracted wide attention in wastewater treatment because of its strong oxidation performance and ease of control. In this paper, the electrochemical degradation of NH 3 -N and COD were investigated at different anodes materials and current densities .The electrochemical oxidation using Ti/RuO 2 IrO 2 anode was effective and promising for advanced treatment of coking wastewater RO brine. COD and NH 3 -N concentration degraded 86% and 100% in 80min at the current density of 5 mA cm -2 . Current density is the most important factor of organic degradation and energy consumption. When the current density was 10mA cm -2 , the COD removal ratio quickly increased to 52.94% in 20min reaction time, but under high current density, the life of the electrode will be reduced. When the current density is too low, the electrolytic reaction time to reach standard needs to be 2h or more, which will perpetuate the equipment bulky, increase the cost of the equipment. The optimal current density is 5.0 ~ 7.5 mA cm -2 . Unit per COD energy consumption is 114.4 kWh kgCOD -1 , and unit per cubic meter wastewater energy consumption is 5.9 kWh m -3 at the current density of 5 mA cm -2 .

S. Mahesh, K. S. Shivaprasad, Mahesh Sanjana

Water Science and Technology • 2022

Abstract The goal of this research was to remove COD, oil and grease (O&G) and color from raw ayurvedic hospital wastewater (AHWW) using a novel electrochemical coagulation (ECC) process. Cell voltage was initially optimized using iron electrodes in bipolar mode for both raw AHWW and ayurvedic hospital therapy room wastewater (AH-TRWW) for a pre-optimized electrolysis time (ET) of 60 min. O&G, COD and color removals for AHWW at 8 V optimized cell voltage were 96, 61 and 96% respectively. Different electrode materials, copper, aluminum, graphite, were used to evaluate relative performances at 8 V. Iron electrodes showed maximum pollutant removal from raw AHWW. The sludge obtained after the ECC process showed good settling and filterability properties compared to graphite and aluminum electrodes. The low SVI value of 146 mL/g was obtained exercising absolute control on sludge volume. Solids flux values showed assurances of compact settling tank design with least spatial footprint. EDX analysis for ECC sludge of AHWW using iron showed gross elements 40.19% C, 48.63% O and 7.92% Fe redefining the fate of sludge. The XRD pattern of the ECC sludge showed an amorphous nature. Post-ECC filtration effluent showed clear water reclamation of 80–82%, proving the effectiveness of the novel ECC treatment process.

Faidzul Hakim Adnan, Marie‐Noëlle Pons, Emmanuel Mousset

Electrochemical Science Advances • 2023

Abstract The use of microfluidic electrochemical reactors has been introduced several decades ago, but their application in the field of wastewater treatment is more recent (2010). The parallel development of electrochemical advanced oxidation processes (EAOPs) as promising technologies for effluent treatment make them good candidates to be implemented as thin film cells. This allows favoring the mass transfer, which is particularly interesting for heterogenous electro‐oxidation. Moreover, the energy requirement is reduced, while there is possibility to treat low‐conductivity solutions. This review intends to provide instructions on the main operating parameters to be optimized during the EAOPs treatment. Directions on engineering aspects have been given to overcome the main drawbacks of microreactors, such as fouling, scaling, and low treatment capacity, based on recent encouraging results given in literature. The promising development of hybrid processes that combine electroseparation with electroconversion would also benefit from such reactor designs.

Soumitra Nath

ChemBioEng Reviews • 2024

Abstract Electrochemical wastewater treatment technologies are gaining attraction as sustainable alternatives for industrial and municipal wastewater management. This study conducts a comprehensive life cycle assessment to assess the environmental and economic sustainability of electrochemical methods such as electrocoagulation, electrooxidation, and electroreduction. By analyzing key stages, from raw material extraction to end‐of‐life disposal, the review aims to provide insight into their overall sustainability performance. The study also delves into environmental impact categories and utilization of methods used in quantifying the environmental implications. Moreover, a cost structure analysis and cost‐effectiveness evaluation offer insights into the economic viability of these technologies. Despite facing challenges like high initial costs and regulatory constraints, electrochemical technologies demonstrate competitive advantages in treatment efficiency and energy savings. Collaborative efforts and supportive policy frameworks are deemed crucial for overcoming barriers and fostering the widespread adoption of electrochemical technologies, thereby advancing sustainable wastewater management practices.

Mohammad Saleh Najafinejad, Simeone Chianese, Angelo Fenti et al.

Preprints.org • 2023

In recent years, the discharge of various emerging pollutants, chemicals and dyes in water and wastewater has represented one of the prominent human problems. Since water pollution is directly related to human health, highly resistant and emerging compounds in aquatic environments will pose many potential risks to the health of all living. Therefore, water pollution is a very acute problem that has constantly increased in recent years with the expansion of various industries. Consequently, choosing efficient and innovative wastewater treatment methods to remove contaminants is crucial. Among advanced oxidation processes, electrochemical oxidation (EO) is the most common and effective method for removing persistent pollutants from municipal and industrial wastewater. However, there are still many gaps despite the great progress in using EO to treat real wastewater. This is due to the lack of comprehensive information on the operating parameters which affect the process and its operating costs. In this paper, among various scientific articles, the impact of operational parameters on the EO performances, a comparison between different electrochemical reactor configurations, and a report on general mechanisms of electrochemical oxidation of organic pollutants have been reported. Moreover, an evaluation of cost analysis and energy consumption requirements have also been discussed. Finally, the combination process between EO and another important advanced oxidation technology, PEC, called photoelectrocatalysis (PEC), has shortly been discussed and reviewed. This article showed that there is a direct relationship between important operating parameters with the amount of costs and the final removal efficiency of emerging pollutants. Optimal operating conditions can be achieved by paying special attention to reactor design, which can lead to higher efficiency and more efficient treatment. The rapid development of EO for removing emerging pollutants from impacted water and its combination with other green methods can result in more efficient approaches to face the pressing water pollution challenge.

Su Ryu, Michael Hoffmann

Catalysts • 2016

A procedure for the preparation of semiconductor anodes using mixed-metal oxides bound together and protected with a TiO2 nanoglue has been developed and tested in terms of the relative efficiencies of the oxygen evolution (OER), the reactive chlorine species evolution (RCS), and the hydrogen evolution (HER) reactions. The composition of the first anode is a Ti metal substrate coated with IrTaOx and overcoated with TiO2 (P25) that was mixed with TiO2 nanogel, while the second anode consists of a Ti metal substrate coated with IrTaOx and an over-coating layer of La-doped sodium tantalate, NaTaO3:La. The experimental efficiencies for water splitting ranged from 62.4% to 67.5% for H2 evolution and 40.6% to 60.0% for O2 evolution. The corresponding over-potentials for the Ti/IrTa-TiO2 and Ti/IrTa-NaTaO3:La anodes coupled with stainless steel cathodes of the same dimensions were determined to be 437 mV and 367 mV for the OER, respectively, and 239 mV and 205 mV for RCS, respectively. The preparation procedure described herein should allow for easier production of large-surface area anodes at lower costs than standard methods.

Gulizar Kurtoglu Akkaya

Environmental Research and Technology • 2020

In this paper, the treatment of real hospital wastewater (HWW) by electrocoagulation process (EC), which is one of the electrochemical treatment methods, has been evaluated. In the EC process, aluminum (Al) and iron (Fe) plates as anode and cathode are used. Experimental studies were conducted at 5, 10, 20, 30 voltage (V) and 5, 10, 20, 30, 45 minutes (min) exposure times. pH, temperature, and conductivity were monitored. COD and phenol removal were evaluated. As a result of experimental studies, Al and Fe electrodes were effective in the treatment of HWW with EC. The highest COD removal efficiency was 93% at 30V 10 min and 95% at 30V 5 min for Al and Fe electrode, respectively. The highest phenol removal efficiency is 97% at 10V 10 min and 97% at 10V 5 min for Al and Fe electrode. When all parameters are evaluated, optimum electro kinetic conditions for treatment of HWW was obtained for 10V 5 min by the Fe electrode.

J. Naumczyk, L. Szpyrkowicz, F. Zilio-Grandi

Water Science and Technology • 1996

The treatment of textile wastewater, containing a high concentration of Cl- ion, by an electrochemical method using Ti/RuO2, Ti/Pt and Ti/Pt/Ir electrodes is investigated. All three anodes proved to be very effective in direct or indirect oxidation of organics present in the wastewater. After 60 min of electrolysis at 6 A/dm2, COD was reduced by 85-92% and DOC by about 85%. Of the three electrodes tested, the efficiency of organics removal followed the order: Ti/RuO2 > Ti/Pt > Ti/Pt/Ir. The electrochemical treatment of textile wastewater resulted in the production of many chloroorganics in high concentration. GC-MS analysis showed the presence of the following major products: 1,1-dichlorocyclopentene, 2,3-dichloro-2-methylbutane, chloromethylsilane, 2,3-dichloro-2-methyl butanoic acid, 2,3-dichloro-2-methyl propanol, 2,3-dimethyl-2, 3-butanediol and 2-butylphenol.

Yevhen Makarov, Volodymyr Andronov, Yuliya Danchenko

Key Engineering Materials • 2022

Researches of chemical-technological parameters of electrochemical production of aluminum-based coagulants for electrocoagulation wastewater treatment of milk processing enterprises have been carried out. The impact of pH and the timing of the electrocoagulation process was studied in two cases of the implementation of the technological process: with the addition of an alkaline additive before and after the electrocoagulation treatment. The mechanism of the coagulation action of aluminum compounds formed as a result of electrocoagulation has been studied. It has been established that the addition of an alkaline additive after electrocoagulation is more effective. At the same time, the degree of wastewater treatment remains quite high. This will ensure energy savings and will positively affect the environmental and economic assessment of the technology.

Siming Lei, Yonghui Song

Frontiers in Chemistry • 2021

The electrochemical treatment of wastewater is widely used for cleaning due to its efficiency. In this paper, two-dimensional (2D) and three-dimensional (3D) electrochemical systems were used to treat cyanide wastewater. The effect of the applied voltage and the material of the main electrode on the removal of various ions and the characteristics of chemical reactions were mainly studied. The results show that the applied voltage was the key effect of the electrochemical treatment process. The removal of ions from the wastewater at 2 V is mainly due to the effect of electro adsorption and enrichment precipitation, while at 4 V, it is mainly due to anodization and cathodic deposition. The treatment effect of the 3D electrode system was significantly better than the 2D system. The 3D electrode system by used granular activated carbon as the particle electrode, with the carbon filled stainless mesh (CM) and coal based electrode (CB) as the main electrode, the treatment effect were better than main electrode of stainless steel mesh (M). The 3D system with CB as the main electrode had an applied voltage of 4 V, a treatment time of 5 h, plate spacing of 10 mm, and the dosage of activated carbon particles was 2 g. The removal rates of CN T , Cu, Zn, CN − , and SCN − were 94.14, 94.53, 98.14, 98.55, and 93.13%, respectively. The main reaction in anode was the electroly oxidation of CN − and SCN − , while the electrolytic deposition of Cu, Zn, and other metal ions in the cathode surface. There were not only adsorption and electric adsorption of various ions, but also an electrolytic deposition reaction of Cu, Zn, and other metal ions on the surface of the activated carbon particle electrode. During the electrochemical reaction, the concentration of hydrogen ions near the anode increases locally, which produces the precipitation of CuSCN, Cu 2 Fe(CN) 6 , and Zn 2 Fe(CN) 6 , etc. in the solution, which are helpful for the removal of cyanide and heavy metal ions in cyanide wastewater.

Sadia A. Jame, Zhi Zhou

Nanotechnology Reviews • 2016

Abstract Electrochemically active carbon nanotube (CNT) filters have been developed as a highly efficient technology for water and wastewater treatment during the last few years. CNT filters have been widely used to adsorb chemical and biological contaminants due to their high stability, great flexibility, and large specific surface area. Electrochemically active CNT filters provide additional electrooxidation of the adsorbed contaminants and have been proven to be a highly effective treatment technology in a few recent lab-scale studies. The working principles, impacting factors, and some of the latest development of electrochemically active CNT filters are reviewed in this paper. The existing challenges and future perspectives are also discussed.

L Mendia

Water Science and Technology • 1982

Many electrochemical processes for watewater treatment have been developed over the years. In the field of sewage purification attention has focused on clarification, disinfection and phosphate removal with the aim of reducing costs compared to traditional processes. The on-site production of necessary chemicals is a step towards reducing operating costs. Electrochemical treatment is very efficient and reduces process detention times thereby allowing smaller plants. Sea water or brine is mixed with the screened sewage in an appropriate ratio, then passed through an electrolysis cell rather similar to that used for hypochlorite production. Depending on the material of the electrodes, their arrangement (vertical or horizontal) and the applied potential difference, the reactions which occur produce the chemicals required for the purification processes. Downstream the electrolysis, the mixture flows into a clarification basin which acts as a contact tank for disinfection. The detention time of this process depends on the type of basin used. I report results of electrochemical treatment performed on a semiindustrial scale, using horizontal electrodes: anode of graphite or silicon-iron and stretch-iron cathodes; followed by a sludge recirculation clarification basin. The removal of suspended solids and the abatement of B.O.D. and phosphates were much better than those reached by traditional physical-chemical treatment. The energy consumption is approximately 0.5 kWh/m of raw sewage.

Dilek Gümüş

Research Square • 2022

Abstract Various types of dyes and other hazardous pollutants used in the textile industry are one of the leading pollutants of surface water. In this study, real textile wastewater was electrochemically treated with two different electrode combinations (graphite/graphite and iron/graphite) by changing the anode electrode type. Then, comparison studies were carried out by adding Fe 2+ or H 2 O 2 to these combinations to improve Chemical Oxygen Demand (COD) removal. Current density (5, 7.5, 10 mA cm − 2 ), initial pH (2.5–8), and electrochemical (EC) oxidation time (0-120 min) were investigated to determine the optimum electrooxidation conditions. The results showed that in the electro-oxidation (EO) process, 100% colour removal, and 75.39% COD degradation efficiencies were achieved at pH 5.5, current density (I) 7.5 mA cm − 2 , and electrolysis time (t) 40 min. In the peroxi-coagulation (PC) process, 89.41% colour removal, and 74.28% COD degradation efficiencies were achieved at pH 3, current density 7.5 mA cm − 2 , and electrolysis time 120 min. In the EO + Fe + 2 and PC + H 2 O 2 processes, 99.9% colour removal efficiencies, 96.38 and 90.63% COD degradation efficiencies were reached at pH 3, current density 7.5 mA cm − 2 , and electrolysis time 40 min., respectively. In systems using EO, PC, EO + Fe 2+ and PC + H 2 O 2 , energy consumption, and operating cost were estimated as 2.85, 2.34, 0.54, 0.62 kWh m − 3, and 0.304, 0.249, 0.199, 3.466 US$ m − 3 , respectively. Among all processes applied in the study, the most efficient one in terms of COD removal performance, energy, and cost is the (EO + Fe 2+ ) system.

Saravanathamizhan Ramanujam, Kaavya Muthumanickam

Journal of Electrochemical Science and Engineering • 2021

Removal of dye from wastewater has been investigated using the electrocoagulation method. Batch experiment has been conducted to remove the color from synthetically prepared acid red 87dye wastewater. Stainless steel and nickel foam sheets are used as cathode and anode, respectively. The effect of some operating parameters, such as current density, initial dye concentration and supporting electrolyte concentration, on color removal has been studied. It can be observed from the present investigations that the nickel foam electrode effectively removes color from the wastewater. Nickel hydroxyl species formed during the operation and also, nickel (II) hydroxide flocs formed in a subsequent stage, trap colloidal precipitates and make solid-liquid separation easier during the flotation stage. These stages of electrocoagulation must be optimized to design an economically feasible process.