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

Microbial Biotechnology • 2014

<jats:title>Summary</jats:title><jats:p>Microbial electric systems (<jats:styled-content style="fixed-case">MESs</jats:styled-content>) hold significant promise for the sustainable remediation of chlorinated solvents such as tetrachlorethene (perchloroethylene, <jats:styled-content style="fixed-case">PCE</jats:styled-content>). Although the bio‐electrochemical potential of some specific bacterial species such as <jats:styled-content style="fixed-case">D</jats:styled-content>ehalcoccoides and <jats:styled-content style="fixed-case">G</jats:styled-content>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 <jats:styled-content style="fixed-case">PCE</jats:styled-content>‐contaminated groundwater. Lab‐scale <jats:styled-content style="fixed-case">MESs</jats:styled-content> were fed with acetate and carbon electrode/<jats:styled-content style="fixed-case">PCE</jats:styled-content> as electron donors and acceptors, respectively, under biostimulation (<jats:styled-content style="fixed-case">BS</jats:styled-content>) and <jats:styled-content style="fixed-case">BS</jats:styled-content>‐bioaugmentation (<jats:styled-content style="fixed-case">BS‐BA</jats:styled-content>) regimes. Molecular analysis of the indigenous groundwater community identified mainly <jats:italic><jats:styled-content style="fixed-case">S</jats:styled-content>pirochaetes</jats:italic>, <jats:italic><jats:styled-content style="fixed-case">F</jats:styled-content>irmicutes</jats:italic>, <jats:italic><jats:styled-content style="fixed-case">B</jats:styled-content>acteroidetes</jats:italic>, and γ and δ<jats:italic>‐<jats:styled-content style="fixed-case">P</jats:styled-content>roteobacteria</jats:italic>. Environmental scanning electron photomicrographs of the anode surfaces showed extensive indigenous microbial colonization under both regimes. This colonization and <jats:styled-content style="fixed-case">BS</jats:styled-content> resulted in 100% dechlorination in both treatments with complete dechlorination occurring 4 weeks earlier in <jats:styled-content style="fixed-case">BS‐BA</jats:styled-content> samples and up to 11.5 μ<jats:styled-content style="fixed-case">A</jats:styled-content> of current being generated. The indigenous non‐<jats:italic><jats:styled-content style="fixed-case">D</jats:styled-content>ehalococcoides</jats:italic> 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‐<jats:italic><jats:styled-content style="fixed-case">D</jats:styled-content>ehalococcoides</jats:italic> bacterial community in bio‐electrochemically reducing <jats:styled-content style="fixed-case">PCE</jats:styled-content> that could prove to be a cost‐effective and sustainable bioremediation practice.</jats:p>

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

Remediation Journal • 2004

<jats:title>Abstract</jats:title><jats:p>The evaluation of microbial responses to three <jats:italic>in situ</jats:italic> source removal remedial technologies—permanganate‐based <jats:italic>in situ</jats:italic> 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.</jats:p>

Xin Sui, Xuemei Wang, Yuhuan Li et al.

Sustainability • 0

<jats:p>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.</jats:p>

Turlough F. Guerin

Remediation Journal • 1999

<jats:title>Abstract</jats:title><jats:p>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 &amp; Sons, Inc.</jats:p>

Hina Jabeen, Akhtar Rasool

Pakistan Journal of Biochemistry and Biotechnology • 0

<jats:p>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. </jats:p>

Priti Panwar, Pooja Mahajan, Jyotsna Kaushal

Remediation Journal • 2023

<jats:title>Abstract</jats:title><jats:p>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.</jats:p>

PREETI CHAURASIA, Nakuleshwar Dut Jasuja, Sanjeev Kumar

• 0

<title>Abstract</title> <p>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.</p>

Saleha Husain

Remediation Journal • 2008

<jats:title>Abstract</jats:title><jats:p>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 <jats:italic>cis</jats:italic>‐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<jats:sub>2</jats:sub>. This review discusses the pathways for HMW PAH microbial metabolism. © 2008 Wiley Periodicals, Inc.</jats:p>

A. Rüdiger, I. Rüdiger, L. Jurisevic

Water Science and Technology • 2007

<jats:p>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.</jats:p>

Chengyu Zhang, Zhisheng Yu, Xiangyang Wang

Frontiers in Chemistry • 0

<jats:p>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.</jats:p>

Josiel Martins Costa

International Journal of Environmental Research and Public Health • 0

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

Jian Gong Wang, Xue Min Li

Advanced Materials Research • 0

<jats:p>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.</jats:p>

Chun Hong Nie, Bao Hui Wang

Advanced Materials Research • 0

<jats:p>The electrochemical oxidation of o-Aminophenol in the presence o f NaCl for wastewater treatment was studied on Ti/IrO<jats:sub>2</jats:sub>-Ta<jats:sub>2</jats:sub>O<jats:sub>5</jats:sub> , Ti/IrO<jats:sub>2</jats:sub>-Ta<jats:sub>2</jats:sub>O<jats:sub>5-</jats:sub>SnO<jats:sub>2</jats:sub> and Ti/IrO<jats:sub>2</jats:sub> 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<jats:sup>-</jats:sup> in the oxidation. Analysis of the oxidation products has shown that initially organo chlorinated compounds are formed in the electrolyte.</jats:p>

Neetesh Kumar Dehariya, Sonal Rajoria, Vikas Kumar Sangal

Journal of The Electrochemical Society • 2024

<jats:p>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<jats:sub>2</jats:sub>-RuO<jats:sub>2</jats:sub>-IrO<jats:sub>2</jats:sub> 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<jats:sup>−2</jats:sup>), 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<jats:sup>−2</jats:sup>, DOXY degradation achieved 91% with an energy consumption of 5.283 kWh m<jats:sup>−3</jats:sup>. In the once-through continuous mode EO process, optimal conditions reached 91% DOXY degradation with an energy consumption of 13.98 kWh m<jats:sup>−3</jats:sup>, achieved at a residence time (R<jats:sub>t</jats:sub>) of 139 min, elapsed (E<jats:sub>t</jats:sub>) time of 100 min and at j = 20.40 mA cm<jats:sup>−2</jats:sup>. The EO process utilizing Ti/TiO<jats:sub>2</jats:sub>-RuO<jats:sub>2</jats:sub>-IrO<jats:sub>2</jats:sub> 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.</jats:p>

Hai Dong Wang, Kang Le Gao, Bo Te Lu

Advanced Materials Research • 0

<jats:p>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<jats:sub>3</jats:sub>-N and COD were investigated at different anodes materials and current densities .The electrochemical oxidation using Ti/RuO<jats:sub>2</jats:sub>IrO<jats:sub>2</jats:sub>anode was effective and promising for advanced treatment of coking wastewater RO brine. COD and NH<jats:sub>3</jats:sub>-N concentration degraded 86% and 100% in 80min at the current density of 5 mA cm<jats:sup>-2</jats:sup>. Current density is the most important factor of organic degradation and energy consumption. When the current density was 10mA cm<jats:sup>-2</jats:sup>, 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<jats:sup>-2</jats:sup>. Unit per COD energy consumption is 114.4 kWh kgCOD<jats:sup>-1</jats:sup>, and unit per cubic meter wastewater energy consumption is 5.9 kWh m<jats:sup>-3</jats:sup>at the current density of 5 mA cm<jats:sup>-2</jats:sup>.</jats:p>

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

Water Science and Technology • 2022

<jats:title>Abstract</jats:title> <jats:p>The goal of this research was to remove COD, oil and grease (O&amp;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&amp;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.</jats:p>

Faidzul Hakim Adnan, Marie‐Noëlle Pons, Emmanuel Mousset

Electrochemical Science Advances • 2023

<jats:title>Abstract</jats:title><jats:p>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.</jats:p>

Soumitra Nath

ChemBioEng Reviews • 2024

<jats:title>Abstract</jats:title><jats:p>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.</jats:p>

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

• 0

<jats:p>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.</jats:p>

Su Ryu, Michael Hoffmann

Catalysts • 0

<jats:p>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.</jats:p>

Gulizar Kurtoglu Akkaya

Environmental Research and Technology • 0

<jats:p xml:lang="en">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.</jats:p>

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

Water Science and Technology • 1996

<jats:p>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.</jats:p> <jats:p>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 &amp;gt; Ti/Pt &amp;gt; 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.</jats:p>

Yevhen Makarov, Volodymyr Andronov, Yuliya Danchenko

Key Engineering Materials • 0

<jats:p>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.</jats:p>

Siming Lei, Yonghui Song

Frontiers in Chemistry • 0

<jats:p>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<jats:sub>T</jats:sub>, Cu, Zn, CN<jats:sup>−</jats:sup>, and SCN<jats:sup>−</jats:sup> were 94.14, 94.53, 98.14, 98.55, and 93.13%, respectively. The main reaction in anode was the electroly oxidation of CN<jats:sup>−</jats:sup> and SCN<jats:sup>−</jats:sup>, 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<jats:sub>2</jats:sub>Fe(CN)<jats:sub>6</jats:sub>, and Zn<jats:sub>2</jats:sub>Fe(CN)<jats:sub>6</jats:sub>, etc. in the solution, which are helpful for the removal of cyanide and heavy metal ions in cyanide wastewater.</jats:p>

Sadia A. Jame, Zhi Zhou

Nanotechnology Reviews • 2016

<jats:title>Abstract</jats:title><jats:p>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.</jats:p>

L Mendia

Water Science and Technology • 1982

<jats:p>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.</jats:p> <jats:p>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.</jats:p> <jats:p>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.</jats:p> <jats:p>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.</jats:p>

Dilek Gümüş

• 0

<jats:title>Abstract</jats:title> <jats:p>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<jats:sup>2+</jats:sup> or H<jats:sub>2</jats:sub>O<jats:sub>2</jats:sub> to these combinations to improve Chemical Oxygen Demand (COD) removal. Current density (5, 7.5, 10 mA cm<jats:sup>− 2</jats:sup>), 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 <jats:sup>− 2</jats:sup>, 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 <jats:sup>− 2</jats:sup>, and electrolysis time 120 min. In the EO + Fe<jats:sup>+ 2</jats:sup> and PC + H<jats:sub>2</jats:sub>O<jats:sub>2</jats:sub> 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 <jats:sup>− 2</jats:sup>, and electrolysis time 40 min., respectively. In systems using EO, PC, EO + Fe<jats:sup>2+</jats:sup>and PC + H<jats:sub>2</jats:sub>O<jats:sub>2</jats:sub>, energy consumption, and operating cost were estimated as 2.85, 2.34, 0.54, 0.62 kWh m<jats:sup>− 3,</jats:sup> and 0.304, 0.249, 0.199, 3.466 US$ m<jats:sup>− 3</jats:sup>, 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<jats:sup>2+</jats:sup>) system.</jats:p>

Saravanathamizhan Ramanujam, Kaavya Muthumanickam

Journal of Electrochemical Science and Engineering • 0

<jats:p>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.</jats:p>

Afaf Abdel Razik Mohamed, Ali El-Dissouky Ali, Mohamed Salah El-Din Hassouna et al.

Applied Water Science • 2025

<jats:title>Abstract</jats:title> <jats:p>Ammonia presence in water has many negative impacts including eutrophication. So, the major objective of this research was to evaluate the efficiency of microbial fuel cell (MFC) and electrochemical (ECS) systems for their removal and/or recovery from wastewater at different levels of ammonia (500 ppm, 1000 ppm, and 1500 ppm). Additionally, a novel approach was tested by using nanomaterial prepared from pomegranate peel as a coating material for the electrodes as it is abundant in many countries. Two systems were tested: Group (A) with a non-coated graphite plate anode (MFC1 and ECS1) and Group (B) which was coated with nano-graphene oxide made from pomegranate peels (MFC2 and ECS2). Results revealed that MFC1 gave the best ammonia removal efficiency reaching 96.2% when the initial concentration was 500 ppm after 13 days, and MFC2 gave maximum removal efficiency of 94.4% and 99.4% for 1000 and 1500 ppm after 19 and 25 days, respectively. COD results coincided with the removal efficiency. Electrochemical ammonia removal was carried out using two external electrical currents, 40 and 80 mA. Results showed that ECS2 gave the highest ammonia removal efficiency of 95.08% at 80 mA in case of 500 ppm, and the maximum for recovery was 80% when 1000 ppm was tested at 80 mA along with an increase in pH in the cathode chamber. Furthermore, ECS2 consumed less energy than ECS1 for ammonia recovery. ECS2 efficiently treated slaughterhouse wastewater reaching almost 100% ammonia removal; however, the maximum recovery of 44.7% occurred after 6 h, but consuming less energy than ECS1. It was evidenced that using an anode coated with nanographene oxide provided dual benefits of quickness and effective ammonia removal and/or recovery and provisioning energy requirements.</jats:p>

Efthalia Chatzisymeon

Water • 0

<jats:p>Existing wastewater treatment plants (WWTPs) face huge challenges that can impede the achievement of sustainable development goals for clean water and sanitation (SDG 6) and clean energy (SDG 7), amongst others [...]</jats:p>

Cristina Quintelas, Daniela Mesquita, Eugénio Campos Ferreira

Biological Treatment of Industrial Wastewater • 2021

<jats:p>The discharge of industrial wastewater into the environment is an issue of particular concern especially in developing countries. In some cases, these industrial wastewater effluents are untreated or inadequately treated before being discharged and represent a threat to the environment and human health. This chapter highlights the scientific literature published in the last decade on issues related to the discharge of polluted industrial wastewater, including a review of general environmental pollutants, both chemical and microbial, as well as the ecological implications of industrial wastewater discharge for the environment, in water, soil and air ecosystems. Finally, the health impacts of these pollutants is summarized. The authors are aware that regular monitoring and appropriate legislation is necessary to avoid or minimize this problem and, in this context, the challenges and future perspectives related to the discharge of industrial wastewaters are presented.</jats:p>

Komal Agrawal, Pradeep Verma

Biological Treatment of Industrial Wastewater • 2021

<jats:p>The membrane bioreactor system due to its advantages such as improved effluent quality, disinfection, better nitrification, smaller footprint and production of sludge has paved its way in the treatment of wastewater over conventional purification methods. This technology has been effective in removing organic, inorganic and microorganisms from both municipal and certain industrial wastewater systems. In the membrane bioreactor system, the membrane system allows physical separation whereas the bioreactor enables the biodegradation of the pollutant. There are various types of bioreactors, such as the plug-flow reactor, sequencing batch reactor, upflow anaerobic sludge blanket etc. Various parameters such as hydrodynamic conditions, biomass concentration, pH and temperature affect the pollutant removal potential of the bioreactor. Thus, the present chapter deals with process description and configuration, the effect of MBRs on microorganisms, the quality of water after treatment along with the cost associated with MBR technology. The limitations, advantages and technological advances are also elaborated in the chapter.</jats:p>

Rajneesh Kumar, Gurvinder Kaur Saini, Mohammad Jawed

Biological Treatment of Industrial Wastewater • 2021

<jats:p>Industrial wastewater varies in quality and quantity depending on the industry type and may contain various toxic compounds. In a biological process, organic substances in the wastewater are used as food by bacteria and other microorganisms. Several biological reactors conventionally used for industrial wastewater treatment are briefly discussed in this chapter. Biological reactors are categorized as aerobic, anaerobic, and a combination of both based on their oxygen requirement. The suspended and attached growth processes are a further subdivision of aerobic and anaerobic processes. Advanced biological reactors such as membrane bioreactors and granular sludge technologies are primarily used in industry. Industrial wastewater contains various organic and inorganic pollutants. The occurrence of toxic compounds imparts toxic or inhibitory effects on microorganisms and may lead to failure of the biological units. Thus, the impact of several industrial wastewaters on various biological reactors are also discussed in this chapter.</jats:p>

Cecilia Oluseyi Osunmakinde, R. Selvarajan, B. Mamba et al.

Microorganisms • 2019

Next-generation sequencing provides new insights into the diversity and structure of bacterial communities, as well as the fate of pathogens in wastewater treatment systems. In this study, the bacterial community structure and the presence of pathogenic bacteria in three wastewater treatment plants across Gauteng province in South Africa were studied. The physicochemical results indicated that the quality of wastewater varies considerably from one plant to the others. Proteobacteria, Actinobacteria, Firmicutes, and Chloroflexi were the dominant phyla across the three wastewater treatment plants, while Alphaproteobacteria, Actinobacteria, Bacilli, and Clostridia were the dominant classes. The dominant bacterial functions were highly associated with carbohydrate, energy, and amino acid metabolism. In addition, potential pathogenic bacterial members identified from the influent/effluent samples included Roseomonas, Bacillus, Pseudomonas, Clostridium, Mycobacterium, Methylobacterium, and Aeromonas. The results of linear discriminant analysis (LDA) effect size analysis also confirmed that these bacterial pathogens were significantly abundant in the wastewater treatment systems. Further, the results of this study highlighted that the presence of bacterial pathogens in treated effluent pose a potential contamination risk, transmitted through soil, agriculture, water, or sediments. There is thus a need for continuous monitoring of potential pathogens in wastewater treatment plants (WWTPs) in order to minimize public health risk.

Hamed Gholami Derami, Qisheng Jiang, Deoukchen Ghim et al.

ACS Applied Nano Materials • 2019

Toxic heavy metal ions and organic pollutants are significant concerns in wastewater treatment. Here, we demonstrate a novel membrane composed of polydopamine (PDA) particles and bacterial nanocellulose (BNC), which can efficiently remove a variety of metal ions and organic dyes from contaminated water. The biocompatible and biodegradable PDA/BNC membrane is synthesized by in situ incorporation of PDA particles into BNC matrix during its bacteria-mediated growth. We show that the PDA/BNC membrane can effectively remove heavy metal ions such as lead and cadmium, and organic dyes as surrogate markers of organic pollutants such as rhodamine 6G (R6G), methylene blue (MB), and methyl orange (MO). The removal efficiencies of contaminants were tested separately or simultaneously via simple filtration at pH values ranging from 4 to 7. Furthermore, after simple washing with regeneration agents, the membrane can be reused multiple times without compromising its contaminant sorption ability and mechanical integrity....

Lin Shi, Naiyuan Liu, Gang Liu et al.

Microorganisms • 2021

Chemicals of emerging concern (CEC) in pig farm breeding wastewater, such as antibiotics, will soon pose a serious threat to public health. It is therefore essential to consider improving the treatment efficiency of piggery wastewater in terms of microorganisms. In order to optimize the overall piggery wastewater treatment system from the perspective of the bacterial community structure and its response to environmental factors, five samples were randomly taken from each area of a piggery’s wastewater treatment system using a random sampling method. The bacterial communities’ composition and their correlation with wastewater quality were then analyzed using Illumina MiSeq high-throughput sequencing. The results showed that the bacterial community composition of each treatment unit was similar. However, differences in abundance were significant, and the bacterial community structure gradually changed with the process. Proteobacteria showed more adaptability to an anaerobic environment than Firmicutes, and the abundance of Tissierella in anaerobic zones was low. The abundance of Clostridial (39.02%) and Bacteroides (20.6%) in the inlet was significantly higher than it was in the aerobic zone and the anoxic zone (p < 0.05). Rhodocyclaceae is a key functional microbial group in a wastewater treatment system, and it is a dominant microbial group in activated sludge. Redundancy analysis (RDA) showed that chemical oxygen demand (COD) had the greatest impact on bacterial community structure. Total phosphorus (TP), total nitrogen (TN), PH and COD contents were significantly negatively correlated with Sphingobacteriia, Betaproteobacteria and Gammaproteobacteria, and significantly positively correlated with Bacteroidia and Clostridia. These results offer basic data and theoretical support for optimizing livestock wastewater treatment systems using bacterial community structures.

F. Qi, Y. Jia, R. Mu et al.

Scientific Reports • 2021

Microalgal-bacterial consortium is an effective way to meet increasingly stringent standards in wastewater treatment. However, the mechanism of wastewater removal effect has not been properly explained in community structure by phycosphere. And little is known about that the concept of macroecology was introduced into phycosphere to explain the phenomenon. In the study, the algal–bacterial consortia with different ratios of algae and sludge were cultured in same aerobic wastewater within 48 h in photobioreactors (PSBRs). Community structure at start and end was texted by metagenomic analysis. Bray–Curtis similarities analysis based on microbial community showed that there was obvious convergent succession in all consortia, which is well known as “convergence” in macroecology. The result showed that Bray–Curtis similarities at End (overall above 0.88) were higher than these at Start (almost less than 0.66). In terms of community structure, the consortium with 5:1 ratio at Start are the more similar with the consortia at End by which the maximum removal of total dissolved nitrogen (TDN, 73.69%), total dissolved phosphorus (TDP, 94.40%) and NH3-N (93.26%) in wastewater treatment process and biomass production (98.2%) higher than other consortia, according with climax community in macroecology with the highest resource utilization than other communities. Therefore, the macroecology can be introduced into phycosphere to explain the consortium for advanced wastewater treatment and optimization community structure. And the study revealed a novel insight into treatment effect and community structure of algal–bacterial consortia for advanced wastewater treatment, a new idea for to shortening the culture time of consortium and optimize predicting their ecological community structure and predicting ecological community.

Aditi Sharma, Upasana Bhardwaj, Devendra Jain et al.

ACS Omega • 2022

In the present work, ferroelectric sodium niobate (NaNbO3) nanorods are formulated to attain photopiezocatalysis for water pollutant degradation and bacterial disinfection. NaNbO3 nanorods, integrating the advantages of photocatalysis (generation of free charge carriers) and piezocatalysis (separation of these charge carriers), possess synergistic effects, which results in a higher catalytic activity than photocatalysis and piezocatalysis alone. Active species that are involved in the catalytic process are found to be •O2– < OH• < h+, indicating the significance of piezocatalysis and photocatalysis. The degradation efficiency of sodium niobate (NaNbO3) nanorods for Rhodamine B in the presence of both sunlight and ultrasonic vibration is 98.9% within 60 min (k = 7.6 × 10–2 min–1). The piezo potential generated by NaNbO3 nanorods was reported to be 16 V. The antibacterial activity of the produced sample was found to be effective against Escherichia coli. With inhibitory zones of 23 mm, sodium niobate has a greater antibacterial activity.

L. Senila, Alexandra Hoaghia, A. Moldovan et al.

Materials • 2022

The aim of this study was to investigate the use of natural zeolite as support for microbial community formation during wastewater treatment. Scanning electron microscopy (SEM), thermal decomposition and differential thermogravimetric curves (TGA/DGT) techniques were used for the physicochemical and structural characterization of zeolites. The chemical characterization of wastewater was performed before and after treatment, after 30 days of using stationary zeolite as support. The chemical composition of wastewater was evaluated in terms of the products of nitrification/denitrification processes. The greatest ammonium (NH4+) adsorption was obtained for wastewater contaminated with different concentrations of ammonium, nitrate and nitrite. The wastewater quality index (WWQI) was determined to assess the effluent quality and the efficiency of the treatment plant used, showing a maximum of 71% quality improvement, thus suggesting that the treated wastewater could be discharged into aquatic environments. After 30 days, NH4+ demonstrated a high removal efficiency (higher than 98%), while NO3+ and NO2+ had a removal efficiency of 70% and 54%, respectively. The removal efficiency for metals was observed as follows (%): Mn > Cd > Cr > Zn > Fe > Ni > Co > Cu > Ba > Pb > Sr. Analysis of the microbial diversity in the zeolite samples indicated that the bacteria are formed due to the existence of nutrients in wastewater which favor their formation. In addition, the zeolite was characterized by SEM and the results indicated that the zeolite acts as an adsorbent for the pollutants and, moreover, as a support material for microbial community formation under optimal conditions. Comparing the two studied zeolites, NZ1 (particle size 1–3 mm) was found to be more suitable for wastewater treatment. Overall, the natural zeolite demonstrated high potential for pollutant removal and biomass support for bacteria community growth in wastewater treatment.

Yaqiong Gu, Beiying Li, Xiang Zhong et al.

Water • 2022

Bacterial diversity and community composition are of great importance in wastewater treatment; however, little is known about the diversity and community structure of bacteria in tropical municipal wastewater treatment plants (WWTPs). Therefore, in this study, activated sludge samples were collected from the return sludge, anaerobic sludge, anoxic sludge, and aerobic sludge of an A2O WWTP in Haikou, China. Illumina MiSeq high-throughput sequencing was used to examine the 16S ribosomal RNA (rRNA) of bacteria in the samples. The microbial community diversity in this tropical WWTP was higher than in temperate, subtropical, and plateau WWTPs. Proteobacteria, Bacteroidota, Patescibacteria, and Chloroflexi were the dominant phyla. Nitrification bacteria Nitrosomonas, and Nitrospira were also detected. Tetrasphaera, instead of Candidatus Accumulibacter, were the dominant polyphosphate accumulating organisms (PAOs), while, glycogen accumulating organisms (GAOs), such as Candidatus Competibacter and Defluviicoccus were also detected. The bacterial community functions predicted by PICRUSt2 were related to metabolism, genetic information processing, and environmental information processing. This study provides a reference for the optimization of tropical municipal WWTPs.