Wastewater Treatment Techniques Research Articles

Co-bioaugmentation with microalgae and probiotic bacteria: Sustainable solutions for upcycling of aquaculture wastewater and agricultural residues into microbial-rice bran complexes

Aquaculture farming generates a significant amount of wastewater, which has prompted the development of creative bioprocesses to improve wastewater treatment and bioresource recovery. One promising method of achieving these aims is to directly recycle pollutants into microbe-rice bran complexes, which is an economical and efficient technique for wastewater treatment that uses synergetic interactions between algae and bacteria. This study explores novel bioaugmentation as a promising strategy for efficiently forming microbial-rice bran complexes in unsterilized aquaculture wastewater enriched with agricultural residues (molasses and rice bran). Results found that rice bran serves a dual role, acting as both an alternative nutrient source and a biomass support for microalgae and bacteria. Co-bioaugmentation, involving the addition of probiotic bacteria (Bacillus syntrophic consortia) and microalgae consortiums (Tetradesmus dimorphus and Chlorella sp.) to an existing microbial community, led to a remarkable 5-fold increase in microbial-rice bran complex yields compared to the non-bioaugmentation approach. This method provided the most compact biofloc structure (0.50 g/L) and a large particle diameter (404 μm). Co-bioaugmentation significantly boosts the synthesis of extracellular polymeric substances, comprising proteins at 6.5 g/L and polysaccharides at 0.28 g/L. Chlorophyta, comprising 80% of the total algal phylum, and Proteobacteria, comprising 51% of the total bacterial phylum, are emerging as dominant species. These microorganisms play a crucial role in waste and wastewater treatment, as well as in the formation of microbial-rice bran complexes that could serve as an alternative aquaculture feed. This approach prompted changes in both microbial community structure and nutrient cycling processes, as well as water quality. These findings provide valuable insights into the transformative effects of bioaugmentation on the development of microbial-rice bran complexes, offering potential applications in bioprocesses for waste and wastewater management.

Comprehensive review of industrial wastewater treatment techniques.

Water is an indispensable resource for human activity and the environment. Industrial activities generate vast quantities of wastewater that may be heavily polluted or contain toxic contaminants, posing environmental and public health challenges. Different industries generate wastewater with widely varying characteristics, such as the quantity generated, concentration, and pollutant type. It is essential to understand these characteristics to select available treatment techniques for implementation in wastewater treatment facilities to promote sustainable water usage. This review article provides an overview of wastewaters generated by various industries and commonly applied treatment techniques. The characteristics, advantages, and disadvantages of physical, chemical, and biological treatment methods are presented.

The anti-fouling and mechanism of Fe3O4@PVDF catalytic membrane in-situ coupling Fenton oxidation for organic pollutants removal

Polyvinylidene fluoride (PVDF) membrane is a promising technique for deep treatment of organic wastewater. However, the unavoidable membrane contamination greatly restrictions its field of application. Herein, we successfully prepared Fe3O4@PVDF membrane with excellent anti-fouling and catalytic ability by non-solvent induced phase inversion method. Meanwhile, Fe3O4@PVDF membrane was characterized by SEM, XRD, FTIR, Water contact Angle and membrane aperture analyzer. The properties of separation and anti-fouling were also evaluated by cross flow filtration of humic acid (HA). Compare with pristine membrane, the pure water flux, rejection rate and FRR respectively increase from 556.81 L m-2 h−1, 65.42 %, 68.26 % to 656.96 L m-2 h−1, 99.64 %, 90.17 % under in-situ Fenton reaction condition. In addition, further mechanistic insights by XDLVO theory, 3D-EEM and EPR verified that high anti-fouling mainly attribute to excellent hydrophilicity of Fe3O4@PVDF and in-situ degradation of HA by OH and 1O2· This work provides insights for improving the separation properties and anti-fouling properties of PVDF membrane in the field of treatment organic wastewater.

Emerging pollutants in waste water: Challenges and advancements in treatment technology

Abstract Microplastics, per- and polyfluoroalkyl substances (PFAS), pharmaceuticals and personal care products (PPCPs), and other emerging contaminants in wastewater have all caused serious environmental and public health issues. The effectiveness of conventional wastewater treatment techniques to remove these pollutants, such as activated sludge, membrane bioreactors, and coagulation-flocculation, is often insufficient. The difficulties and improvements in treatment technology for eliminating developing contaminants from wastewater are examined in this thorough review study. The review gives a general overview of the most important subcategories of emerging pollutants, the shortcomings of traditional wastewater treatment techniques, and the developments in treatment technologies, including advanced oxidation processes (AOPs), adsorption-based methods, and novel biological treatment approaches. The obstacles mentioned include the need for sustainable and energy-efficient solutions, regulatory and monitoring concerns, and technological and economic hurdles. A number of suggestions are made as a response to these difficulties, such as boosting oversight and regulating procedures, fostering cooperation and information sharing, encouraging industry participation, and supporting research and development. These suggestions may be put into practice in order to reduce the hazards posed by developing contaminants in wastewater and safeguard our water resources and the ecosystem over the long run. The article emphasizes the value of using a multidisciplinary and cooperative approach to solving the problems caused by new contaminants. In order to create original solutions, advance best practices, and build suitable regulatory frameworks, it underlines the necessity for ongoing research, policy development, and stakeholder collaboration. The ultimate goal of this analysis is to provide academics, decision-makers, industry stakeholders, and the general public with a useful resource in their quest to comprehend and resolve the complicated problem of developing contaminants in wastewater.

Effective removal of toxic mixed azo dyes and Cr (VI) ions from wastewater using an integrated approach

The textile industry generates a significant amount of wastewater, including hazardous dyes, pigments, and heavy metals. The integrated approach of isolated bacterial strain and the bacterially synthesized ZnO nanoparticles was used in the removal of mixed azo dyes and Cr(VI) in a lab-scale bioreactor. It resulted in 77.19 % bromocresol purple (4th day), 50.11 % on bromocresol blue (3rd day), and 50.59 % bromocresol green (4th day) removal. Mixed azo dyes and Cr(VI) were removed using bacterial strain, which showed the maximum removal of Cr(VI) was 73.6 % at 25 ppm (3rd day) and mixed azo dyes removal was a maximum of 49.01 % at 75 ppm. A lab-scale reactor study using bacterial strain resulted in 45.89 % (5th day) of mixed azo dye and Cr(VI) removal. However, when the reactor was employed with synthetic wastewater and bacterially synthesized ZnO nanoparticles, achieved a maximum removal of 53.84 % at 120 min. Also, a phytotoxicity study on the Cicer arietinum plant with different concentrations of mixed azo dyes and chromium concentrations showed a maximum length of 5.5 cm at 100 ppm (3rd day). The bacterial strain and synthesized ZnO nanoparticles integrated technique providing an economically viable and scale-up solution for wastewater treatment techniques.

Ultrasonic destruction of surfactants

This study investigates the effectiveness of ultrasonic (US) treatment in removing and mineralizing surfactants in wastewater. It examines the complex mechanisms and variables (acoustic conditions, solution temperature, initial dose, etc.) that affect sonolytic processes. The effect of water matrix components (such as salts and the presence of secondary pollutants) on process performance is thoroughly investigated. Various treatments are analyzed through a detailed comparison of synergistic hybridization processes. The study also provides a comprehensive review of current environmental applications and explores potential directions for surfactant degradation using ultrasound. Insightful information is presented to advance sustainable wastewater treatment techniques. The literature review clearly reveals the promising future of sonotreatment for degrading various surfactants under different conditions. The use of multifrequency mechanisms and the integration of other advanced oxidation processes (AOPs) with the US process have significantly enhanced the energy efficiency of the sonochemical system. Additionally, the results highlight the need to focus on developing new sonoreactor designs, identifying degradation intermediates, and hybridizing the sonochemical system under innovative operating conditions

Synthesis and Characterization of Composite WO3 Fibers/g-C3N4 Photocatalysts for the Removal of the Insecticide Clothianidin in Aquatic Media.

Photocatalysis is a prominent alternative wastewater treatment technique that has the potential to completely degrade pesticides as well as other persistent organic pollutants, leading to detoxification of wastewater and thus paving the way for its efficient reuse. In addition to the more conventional photocatalysts (e.g., TiO2, ZnO, etc.) that utilize only UV light for activation, the interest of the scientific community has recently focused on the development and application of visible light-activated photocatalysts like g-C3N4. However, some disadvantages of g-C3N4, such as the high recombination rate of photogenerated charges, limit its utility. In this light, the present study focuses on the synthesis of WO3 fibers/g-C3N4 Z-scheme heterojunctions to improve the efficiency of g-C3N4 towards the photocatalytic removal of the widely used insecticide clothianidin. The effect of two different g-C3N4 precursors (urea and thiourea) and of WO3 fiber content on the properties of the synthesized composite materials was also investigated. All aforementioned materials were characterized by a number of techniques (XRD, SEM-EDS, ATR-FTIR, Raman spectroscopy, DRS, etc.). According to the results, mixing 6.5% W/W WO3 fibers with either urea or thiourea derived g-C3N4 significantly increased the photocatalytic activity of the resulting composites compared to the precursor materials. In order to further elucidate the effect of the most efficient composite photocatalyst in the degradation of clothianidin, the generated transformation products were tentatively identified through UHPLC tandem high-resolution mass spectroscopy. Finally, the detoxification effect of the most efficient process was also assessed by combining the results of an in-vitro methodology and the predictions of two in-silico tools.

Advanced Photocatalytic Degradation of Cytarabine from Pharmaceutical Wastewaters.

The need to develop advanced wastewater treatment techniques and their use has become a priority, the main goal being the efficient removal of pollutants, especially those of organic origin. This study presents the photo-degradation of a pharmaceutical wastewater containing Kabi cytarabine, using ultraviolet (UV) radiation, and a synthesized catalyst, a composite based on bismuth and iron oxides (BFO). The size of the bandgap was determined by UV spectroscopy, having a value of 2.27 eV. The specific surface was determined using the BET method, having a value of 0.7 m2 g-1. The material studied for the photo-degradation of cytarabine presents a remarkable photo-degradation efficiency of 97.9% for an initial concentration 0f 10 mg/L cytarabine Kabi when 0.15 g of material was used, during 120 min of interaction with UV radiation at 3 cm from the irradiation source. The material withstands five photo-degradation cycles with good results. At the same time, through this study, it was possible to establish that pyrimidine derivatives could be able to combat infections caused by Escherichia coli and Candida parapsilosis.

Artificial intelligence integration in conventional wastewater treatment techniques: techno-economic evaluation, recent progress and its future direction

Artificial intelligence integration in conventional wastewater treatment techniques: techno-economic evaluation, recent progress and its future direction

Advances in Nanoparticles and Nanocomposites for Water and Wastewater Treatment: A Review

Addressing water scarcity and pollution is imperative in tackling global environmental challenges, prompting the exploration of innovative techniques for effective water and wastewater treatment. Nanotechnology presents promising solutions through the customization of nanoparticles and nanocomposites specifically designed for water purification applications. This review delves into recent advancements in nanoparticle-based technologies for water treatment, with a particular focus on their synthesis methodologies, intrinsic properties, and versatile applications. A wide range of nanoparticles, ranging from metal nanoparticles to carbon-based nanomaterials, along with hybrid nanocomposites such as metal/metal oxide-based nanocomposites, polymer-based nanocomposites, and others, were emphasized for eliminating contaminants from water and wastewater matrices. Furthermore, this review elucidates the underlying mechanisms governing pollutant removal processes, encompassing adsorption, catalysis, and membrane filtration, facilitated by nanoparticles. Additionally, it explores the environmental implications and challenges associated with the widespread deployment of nanoparticle-based water-treatment technologies. By amalgamating existing research findings, this review provides valuable insights into the potential of nanoparticles and nanocomposites in mitigating water-related challenges and presents recommendations for future research trajectories and technological advancements in this domain.

Artificial intelligence and machine learning for the optimization of pharmaceutical wastewater treatment systems: a review

AbstractThe access to clean and drinkable water is becoming one of the major health issues because most natural waters are now polluted in the context of rapid industrialization and urbanization. Moreover, most pollutants such as antibiotics escape conventional wastewater treatments and are thus discharged in ecosystems, requiring advanced techniques for wastewater treatment. Here we review the use of artificial intelligence and machine learning to optimize pharmaceutical wastewater treatment systems, with focus on water quality, disinfection, renewable energy, biological treatment, blockchain technology, machine learning algorithms, big data, cyber-physical systems, and automated smart grid power distribution networks. Artificial intelligence allows for monitoring contaminants, facilitating data analysis, diagnosing water quality, easing autonomous decision-making, and predicting process parameters. We discuss advances in technical reliability, energy resources and wastewater management, cyber-resilience, security functionalities, and robust multidimensional performance of automated platform and distributed consortium, and stabilization of abnormal fluctuations in water quality parameters.

Ultrafiltration of anaerobically digested sludge centrate as key process for a further nitrogen recovery process

In a wastewater treatment plant, the centrate generated in the dehydration process of the anaerobically digested sludge has a high potential for nutrients recovery because of its high nutrients concentration (specifically nitrogen and phosphorous). However, the high organic matter and solids content may make difficult its management. Membrane fouling is the most significant challenge limiting the application of membrane techniques for wastewater treatment. Results in this article highlight the potential of conventional filtration followed by ultrafiltration as pretreatment for further nutrients recovery using emerging membrane technologies (as membrane contactor, membrane distillation or forward osmosis). Thus, a conventional filtration (with 1, 5 and 60 μm filters) followed by an ultrafiltration process were tested. The UF membranes studied were two PES membranes (5 kDa and 0.01 μm) and one PVDF membranes (100 kDa). Results demonstrated that a conventional filtration with a cartridge filter of 60 μm and a subsequent UF process with a 0.01 μm RAY100 membrane (Orelis, France) achieved the best results in terms of the maximum organic matter (66% COD removal) and solids (over 97% suspended solids removal) separation, hardly varying nutrients concentration (13% NH4+ removal). Concerning membrane fouling, FESEM-EDX confirmed salt precipitation on the membrane surface, which has to be controlled to avoid loss of performance.

Investigation of the removal of diclofop methyl herbicide by peroxy electrocoagulation process and kinetic and cost analysis

Pesticides containing chlorine, which are released during agricultural activities, are chemical substances that mix with surface and underground waters and have toxic, carcinogenic, and mutagenic effects on the entire living ecosystem. Due to their chemically stable structure, conventional water and wastewater treatment techniques such as coagulation, flocculation, and biological oxidation do not entirely remove these chemical substances. Therefore, before releasing them into the environmental receptor, these chemical substances must be transformed into harmless products or mineralized through advanced oxidation processes. When we look at the literature, there are not many studies on methods of removing diclofop methyl from aquatic media. Our study on the removal of diclofop methyl herbicide from aquatic media using the peroxy electrocoagulation method will provide the first information on this subject in the literature. In addition, this treatment method will contribute significantly to filling an important gap in the literature as an innovative approach for diclofop methyl removal. Moreover, peroxy electrocoagulation, which produces less sludge, provides treatment in a short time, and is economical, has been determined to be an advantageous process. The effects of conductivity, pH, H2O2 concentration, current, and time parameters on the removal of diclofop methyl were investigated using a GC–MS instrument. Kinetics, energy consumption, and cost calculations were also made. Under the optimum conditions determined (pH = 5, H2O2 = 500 mg/L, NaCl = 0.75 g/L, current density = 2.66 mA/cm2), the peroxydic electrocoagulation process resulted in a diclofop methyl removal efficiency of 79.2% after a 25-min reaction. When the experimental results were analyzed, it was found that the results fitted the pseudo-second-order kinetic model.

Investigation on pulsed-electrocoagulation process for the treatment of wet coffee processing wastewater using an aluminum electrode

The use of conventional direct current-electrocoagulation in wastewater treatment is limited by its drawbacks, which include electrode passivation, high energy consumption, and significant sludge generation. Therefore, to address these issues, pulsed-electrocoagulation (PECP) has been developed. The PECP is an advanced wastewater treatment technique that uses intermittent electrical pulses to target and break down organic compounds in wastewater. It offers several benefits, including enhanced removal of organic compounds, reduced chemical consumption, energy efficiency, treatment of complex wastewater composition, pathogen inactivation, environmental compliance, and potential for water reuse. In this research, removal efficiency of % Chemical Oxygen Demand (COD), % Color, % Turbidity, % phosphate, and %nitrate was investigated for the wet coffee processing wastewater by using PECP and the obtained results as the COD-98.75%, color-99.92%, turbidity-99.00%, phosphate-99.02%, and nitrate-98.83%, respectively. Independent variables were the major significant factors and the optimum value was investigated and obtained at pH of 7, electrolyte dosage of 0.75 g L−1, electrolysis time of 45 min, and current of 0.45 Amp. As a result, PECP with NaCl and CaCl2 as an electrolyte is an effective treatment technique for pollutant removal from wastewater. As a consequence, the specific benefits may vary depending on the system design, operational parameters, and wastewater characteristics. The pilot-scale studies and optimization are essential for assessing PECP feasibility and performance.

Comparative study of wastewater treatment efficiency: ozone vs. atmospheric oxygen with a manganese dioxide catalyst

Abstract This study aims to validate the wastewater treatment technique and compare the effectiveness of applying an ozone mixture and atmospheric oxygen in the presence of a catalyst (manganese dioxide) with various dosages. A total of 540 replicates were performed, corresponding to different levels of manganese dioxide concentrations during oxygen and ozone delivery (270 repetitions for each of the experiments). The research was carried out using an experimental setup developed by the authors. The maximum efficiency of oxidation processes was observed within 15–30 min after the start of the treatment cycle. The decrease in the level of chemical oxygen demand within the first quarter-hour during ozone treatment was significantly greater compared to atmospheric oxygen treatment (p ≤ 0.05). The method's efficiency increased to 53% for ozone and 41% for oxygen after 30 min of purification (p ≤ 0.05). Lower catalyst consumption was observed when using an ozone mixture. The tested technology can be recommended for wastewater treatment with high hydrocarbon concentrations. The findings of the study indicated the potential application of ozone treatment with a manganese catalyst for treating wastewater with high hydrocarbon content, thereby fostering the development of more effective water purification methods in the industrial sector.

Pharmaceuticals in the Water: Emerging Concerns and Innovative Remediation Solutions

Abstract: Pharmaceutical contamination, resulting from the discharge of active pharmaceutical ingredients (APIs) and other related compounds into the water, has become a growing concern due to its potential adverse effects on ecosystems and human health. This review article aims to examine the many facets of pharmaceutical contamination and highlight the most recent developments in its remediation. The effects of pharmaceuticals, sources, and pathways of pharmaceutical contamination, as well as the difficulties in detecting and evaluating its toxicities, have been included in the present manuscript. Nowadays various remediation strategies are employed to mitigate pharmaceutical contamination in water. Conventional wastewater treatment techniques, including activated sludge processes and membrane filtration, are effective in removing a portion of the pharmaceutical compounds. However, advanced oxidation processes such as ozonation and photocatalysis have shown promising results in enhancing the degradation of recalcitrant APIs. Nanotechnology-based approaches, such as the use of nanoparticles for adsorption and degradation, and bioremediation methods utilizing microbial degradation, enzymatic processes, and phytoremediation, offer potential future directions for efficient and sustainable remediation. This review describes the most recent developments, current status, and potential research directions with the future prospects of pharmaceutical pollutants.

Optimizing Cr(VI) Reduction in Plastic Chromium Plating Wastewater: Particle Size, Irradiation, Titanium Dose

The preservation of the aquatic environment and water systems has been a fundamental objective that has led great scientists and researchers to seek new alternatives or techniques that allow the decontamination of water sources. The plastic chromium plating industries have been identified as important sources of contamination since their residues are characterized by having considerable amounts of hexavalent chromium Cr (VI), which alters the stability of water resources and can affect effluents on the surface and the subsoil. Given this problem, the need to improve the usual methods and techniques for wastewater treatment with more effective solutions, such as photocatalysis, which presents significant advantages over the inefficiency of traditional methods, is recognized. However, given the limited availability of research in the country that addresses the removal of hexavalent chromium from the wastewater of these industries, this work focuses on optimizing the process by varying conditions of variables such as particle size, catalyst dose, and irradiation time. The optimization of the photocatalysis process was evaluated using the Box-Behnken experimental design. The results show that contaminant removal occurred when the particle size was 0.177 mm. This particle size showed the highest photocatalytic activity, with 100% removal at 45 minutes. These findings represent a significant step towards solving the problem of contamination in this business sector by this pollutant and contribute to preserving our water resources. Doi: 10.28991/ESJ-2024-08-01-02 Full Text: PDF

Photodegradation of cationic and anionic dyes by ZnO and S/ZnO biosynthesized nano‐photocatalysts

Photocatalysis is considered a promising and efficient oxidation technique for wastewater treatment. Developing more environmentally biocompatible, simple, effective, and inexpensive photocatalysts enables photocatalysis technology to be at the forefront of wastewater treatments. As an alternative to harmful chemicals, this work focused on the biosynthesis of a variety of ZnO and doped ZnO based on the extract of the brown alga Cystoseira crinite. X‐ray diffraction (XRD), scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy (EDX), Fourier transform‐infrared (FTIR) spectroscopy, and ultraviolet–visible (UV–vis) spectroscopy were used to characterize the structure, phase, morphology, and UV–vis properties of the biosynthesized samples. XRD showed the crystalline structure of ZnO and S‐doped ZnO. SEM analysis revealed agglomerated spherical particles of the prepared samples. EDX analysis confirmed the formation of S‐doped ZnO. FTIR spectra exhibited that phenolic compounds and protein molecules are present in the Cystoseira crinite extract. The photocatalytic efficiency of biosynthesized materials was examined by monitoring the degradation of crystal violet (CV) and methyl orange (MO) dyes, which serve as cationic and anionic dye models, respectively. The various factors that influence the efficacy of the photodegradation process were investigated. In total, 5% S‐doped ZnO decomposed 97.40% and 89.18% of CV and MO dyes, respectively. The dye degradation was most efficient in samples calcined at 500 °C. The photodegradation of CV dye was enhanced at high pH, while the highest photocatalytic activity of MO dye was observed at low pH values. The kinetic study confirmed that the photodegradation follows the first‐order reaction.

Degradation of direct red 23 dye in a plug flow reactor with adjustable angle baffles using nano-Fe3O4: modelling and optimisation

ABSTRACT Photocatalytic degradation is a key technique in wastewater treatment, particularly for toxic dye removal, yet challenges related to poor hydrodynamics and mass transfer limitations persist. This study addresses these challenges by innovatively employing an adjustable-angle baffle in a plug flow reactor (PFR) to enhance dye removal efficiency. A lab-scale PFR with an adjustable baffle was utilised to assess the impact of various factors, including baffle angle, catalyst concentration, hydraulic retention time (HRT), pH, and initial dye concentration, on the removal of direct red 23 dye. The experimental design employed a central composite design (CCD), with subsequent data analysis using response surface methodology (RSM) and artificial neural network (ANN) models. The findings demonstrate that the adjustable baffle significantly impacts dye removal, achieving maximum efficiency at an optimal angle of 77.5 degrees. The ANN model outperformed the RSM model, with a higher determination coefficient (R 2) of 0.994 compared to 0.928. Furthermore, RSM and genetic algorithms yielded closely aligned optimal conditions, validating their accuracy. The optimised conditions achieved a dye removal efficiency of 89.47%. Significantly, the study also identified degradation as the dominant mechanism over adsorption and highlighted the impressive stability of nano-Fe3O4 during the recycling process. Mineralisation analysis revealed the presence of lightweight organic residual molecules post-treatment. These outcomes demonstrate the effectiveness of adjustable baffles in PFRs, marking a significant advancement in wastewater treatment technologies and underscoring the critical role of baffle orientation and catalyst concentration in optimising dye removal processes.

Critical evaluation of electroactive wetlands: traditional and modern advances.

In the field of sustainable wastewater management, electroactive wetlands (EW), or constructed wetland-microbial fuel cells (CW-MFC), are an emerging technology. With the growing problem of untreated wastewater, the emphasis must shift to decentralisation of wastewater treatment infrastructure, and CW-MFC can be an excellent choice. This review provides a chronologically organized account of the design and configuration of CW-MFCs developed between 2010 and 2023. The research on CW-MFC has mainly focused on material, positioning and number of electrodes; use of electroconductive media and filler materials; flow regime; algal-based CW-MFC and multistage setups. Compared to traditional constructed wetlands (CW) and microbial fuel cells (MFC), CW-MFCs have a number of advantages, including better treatment efficiency, faster organic matter utilisation, lower capital and land requirements and a smaller carbon footprint. However, there are some limitations as well, such as upscaling and viable electricity generation, which are covered in more detail in the article. Moreover, the economics of this technology is also evaluated. The microbiology of a CW-MFC and its influence on its performance are also elaborated. Recent advancements in this field in terms of design, configuration and performance are discussed. Finally, the knowledge gaps that must be addressed before this technique can be successfully implemented on a large scale are highlighted, along with specific recommendations. This article aims to advocate for EWs as an ideal decentralised wastewater treatment technique, while also shedding light on the areas that still need to be worked on.