Effluent Treatment Research Articles

Investigating the application of novel filling materials in Vertical Subsurface Flow Constructed Wetlands for the treatment of anaerobic effluents originating from domestic wastewater.

Vertical subsurface flow constructed wetlands (VSSF CWs) were employed to investigate the use of biochar that could be produced with local agricultural biomass through pyrolysis, recycled glass from local recycling companies and gel beads with decreased packing volume and shipping cost as substrate alternatives to sand. The materials were assessed in terms of granulometry, porosity, adsorption capacity and hydraulic conductivity and were used for the treatment of an upflow anaerobic sludge blanket (UASB) reactor, treating domestic wastewater, effluent. Granulometry was a major factor impacting TSS removal that ranged from 81%±10% to 97%±2%. The COD removal was affected by granulometry, porosity and the active biofilm formation, since biochar removal was slightly higher (up to 93%±3%) than that of sand and recycled glass (up to 86%±4% and 85%±5%, respectively) and significantly higher than that of gel beads (up to 68%±8%). The higher porosity of biochar affected NH4-N removal in which adsorption had a greater and longer effect. The overall NH4-N removal ranged between 84%±11% and 99%±1% for all materials. Sand, biochar and glass achieved an 80% average removal of selected contaminants of emerging concern (CECs), including ibuprofen (IBU), naproxen (NPX), triclosan (TCS), bisphenol A (BPA), diclofenac (DCF) and ketoprofen (KFN). The biochar and recycled glass are effective in treating UASB effluent and enable the treated wastewater reuse, since, high compliance rates with the EU Regulation 2020/741 - Class A were achieved (>98% for TSS, >88% for BOD5 and 100% for turbidity).

Transformation of eucalyptus ash into alkalizing agents for dairy effluent treatment

Transformation of eucalyptus ash into alkalizing agents for dairy effluent treatment

Biobased Strategies for E-Waste Metal Recovery: A Critical Overview of Recent Advances

The increasing e-waste volumes represent a great challenge in the current waste management landscape, primarily due to the massive production and turnover of electronic devices and the complexity of their components and constituents. Traditional strategies for e-waste treatment focus on metal recovery through costly, energetically intensive, and environmentally hazardous processes, such as pyrometallurgical and hydrometallurgical approaches, often neglecting other e-waste constituents. As efforts are directed towards creating a more sustainable and circular economic model, biobased alternative approaches to these traditional techniques have been increasingly investigated. This critical review focuses on recent advances towards sustainable e-waste treatment, exclusively considering studies using e-waste sources. It addresses, from a critical perspective, approaches using inactive biomass, live biomass, and biogenic compounds, showcasing the diversity of strategies and discussing reaction parameters, advantages and disadvantages, challenges, and potential for valorization of generated by-products. While ongoing research focuses on optimizing operational times and metal recovery efficiencies, bioprocessing approaches still offer significant potential for metal recovery from e-waste. These approaches include lower environmental impact by reducing energy consumption and effluent treatments and the ability to recover metals from complex e-waste streams, paving the way for a more circular economy in the electronics industry.

Reverse Osmosis Coupled with Ozonation for Clean Water Recovery from an Industrial Effluent: Technical and Economic Analyses.

Technical and economic criteria were used to evaluate the feasibility of the treatment of an industrial effluent (10 m3/h) for water recovery and reuse. The treatment evaluation included the following: (1) effluent characteristic determination; (2) selection and evaluation of the effluent treatment at lab scale, establishing operating conditions and process efficiency; (3) scaling up the treatment process to the industrial level; (4) treatment plant design and commercial availability analysis of the required equipment; and (5) the costs of the inversion and operation of the plant treatment, cost/m3 for water recovery, and time of investment recovery. The physicochemical characteristics of the effluent exposed the polluted wastewater with sodium chloride salts and colourants, predominating a mixture of tartrazine, Red 40, and brilliant blue from the synthesis of food additives. Other contributions of organic compounds and salts could be in minor content. According to the effluent conditions, a coupled process, integrated with ozonation and reverse osmosis, was indicated to be a treatment for water recovery. Scaling up the plant treatment design resulted in 130 m2 of area, producing 7.7 m3/h of clean water. The cost of the effluent treatment was 1.4 USD/m3, with an inversion return of 3.4 years and cost investment of USD 860,407. The treatment process resulted a viable project for water recovery.

Parameter optimization of the chloride mediator-based electrochemical advanced oxidation process for the treatment of commercial azo dyes and actual dyeing effluent

This work focused on the development of an electrochemical system for direct and indirect electrochemical advanced oxidation process (EAOP) with a chloride mediator by electrogenerated active species for the degradation of unused toxic azo dye molecules of textile wastewater and the connection between cathodic and anodic processes. The experiments were carried out in a batch electrochemical cell for the degradation of Direct Red 1 (DR 1) and Reactive Orange 14 (RO 14) dyes. Eight different combinations of iron (Fe), stainless steel (Ss), copper (Cu), and graphite (Gr) electrodes were utilized as the cathode and anode. The influences of effluent initial concentration, pH, supporting electrolyte concentration, temperature, inter-electrode distance, current density, agitation rate, retention time, and radical scavengers on dye degradation have been critically examined. The optimum conditions were obtained at the monopolar-parallel (MP-P) connected electrodes (Gr- Ss) with 7.0 pH, 7.25 V voltage, 0.4 A current, 353 A/m2 current density, 1 g/L NaCl, and a distance of 3 cm between the electrodes. Under these conditions, the removal efficiency reached 95.6% within 60 min of operation. Additionally, a multiple regression analysis was performed to assess how operating conditions affected the effectiveness of dye removal. The actual textile wastewater was examined as well, and the results revealed significant decolorization. Finally, due to its great capacity, the EAOP system is a promising large-scale technique for treating dye-contaminated effluents.Graphical

Recent advances in electrochemical sensing and remediation technologies for ciprofloxacin.

Ciprofloxacin (CIP) is an extensively used broad-spectrum, fluoroquinolone antibiotic used for treating diverse bacterial infections. Effluent treatment plants (ETPs) worldwide lack technologies to detect or remediate antibiotics. CIP reaches the aquatic phase primarily due to inappropriate disposal practices, lack of point-of-use sensing, and preloaded activated charcoal filter at ETPs. The co-existence of bacteria and CIP in such aqueous pools has promoted fluoroquinolone resistance in bacteria and should be minimized. The worldwide accepted standard detection methodologies for the detection of CIP are high-performance liquid chromatography and mass spectrometry, which are lab-based, require state-of-the-art equipment, and are expensive. Hence, it is difficult to integrate them for on-site monitoring. Further, the current remediation technologies like conventional sludge-treatment techniques fail to remove antibiotics such as CIP. Several point-of-use technologies for the detection of CIP are being investigated. These typically involve the development of electrochemical sensors where substrates, modifiers, biorecognition elements, and their chemistries are designed and optimized to enable robust, point-of-use detection of CIP. Similarly, remediation techniques like adsorption, membrane filtration, ion exchange, photocatalysis, ozonation, oxidation by Fenton's reagent, and bioremediation are explored, but their onsite use is limited. The use of these sensing and remediation technologies in tandem is possibly the only way the issues related to antimicrobial resistance may be effectively tackled. This article provides a focused critical review on the recent advances in the development of such technologies, laying out the prospects and perspectives of their synergistic use to curb the menace of AMR and preserve antibiotics.

Exploring Ionic Liquid-based Liquid-Liquid Extraction as Benign Alternative for Sustainable Wastewater Treatment

The uncontrolled release of industrial effluents containing micropollutants (MPs), dyes, and heavy metal ions contaminates natural water bodies posing threats to health and the environment. Conventional treatment methods often struggle with challenges such as prolonged processing time, low specificity, and risk of producing secondary pollutants. Liquid-liquid extraction (LLE) technique utilizing ionic liquids (ILs) has emerged as a viable alternative for the elimination of contaminants from wastewater. ILs, characterized by minimal volatility and tunable physicochemical properties, facilitate the precise elimination of contaminants from industrial effluent. IL-LLE streamlines the experimental setup, lowers energy consumption, promotes recyclability for reuse, enhances mechanistic understanding, and hence provides a sustainable alternative to industrial effluent treatment. This review provides a comprehensive analysis of IL-LLE approaches for wastewater treatment, commencing with an overview of the historical evolution of ILs, tracing their progression from initial research to contemporary and advanced applications. The article primarily examines the practical applications of IL-LLE, demonstrating how these approaches are employed to efficiently remove diverse contaminants from both simulated and actual industrial wastewater samples. As a whole, the review consolidates the versatility and efficiency of IL-based LLE in addressing various challenges in wastewater treatment.

Effectively eliminating lead and cadmium from industrial wastewater using a biowaste-based sorbent

Toxic heavy metals, such as Pb(II) and Cd(II), pose serious environmental and health risks, stressing the urgent demand for innovative and sustainable techniques to reduce their adverse effects. This study investigates the use of sugar beet biowaste as an eco-friendly biosorbent for the removal of Pb(II) and Cd(II) from aqueous solutions, in both laboratory and industrial effluents. Characterization through scanning electron microscopy, X-ray diffraction, thermogravimetric analysis, Fourier-transform infrared spectroscopy, and energy-dispersive X-ray spectroscopy revealed the formation of stable hydrocerussite and otavite, confirming chemisorption. Approximately 95% of the employed biowaste is composed of calcium (Ca), carbon (C), and oxygen (O). The zeta potential was measured at − 17.5 mV with a point of zero charge at pH 8.0, and the total surface area of the biosorbent was approximately 7.72 m2 g−1, with a Langmuir surface area of 11.563 m2 g−1 and a pore volume of 0.028 cm3 g−1. Various parameters, such as the metal concentration, biosorbent dosage, pH, temperature, and contact time, were optimized, achieving maximum removal of Pb(II) and Cd(II) within 60 min at pH 12 and 328 K. Sorption followed a pseudo-second-order kinetic model (R2 = 0.99) and the Freundlich isotherm (R2 = 0.98), with high sorption capacities of 466.5 mg g−1 for Pb(II) and 505.6 mg g−1 for Cd(II). Thermodynamic analysis indicated that the sorption process is spontaneous, thermodynamically favorable, and endothermic. The biowaste effectively removed heavy metals and demonstrated removal efficiencies exceeding 85% for most heavy metals in industrial effluent samples from Alexandria and Ain Sokhna. Sorption capacity ratio values close to 1 indicate effective Pb(II) and Cd(II) uptake with minimal interference, even in the presence of methylene blue dye. Comparative analysis revealed that the untreated biosorbent was more efficient than typical biosorbents, and an economic cost evaluation revealed that processing the biosorbent costs 1.05 USD/kg, highlighting its potential as a sustainable and economically viable option for industrial effluent treatment and supporting broader environmental goals.

Evaluation of the aerobic process performance for treating tannery effluent in the fungicide presence and ammoniacal nitrogen high concentration

Leather processing is characterized by the generation of effluents with a high concentration of ammonia nitrogen (N-NH4+) and the presence of fungicides. This study evaluated the interference of these two constituents on the removal of chemical oxygen demand (COD) and N-NH4+. To this end, an aerated reactor operating in a batch system was used. The effects of cycle time, fungicide volume, and initial N-NH4+ concentration on COD and N-NH4+ removal was evaluated using a Centralized Rotational Composite Design. The highest COD removal (45.45%) occurred under the conditions of 72 h, 0.55 mL of fungicide, and 62.5 mg L-1 of N-NH4+, and the lowest removal (8.24%) occurred under the conditions of 24 h, 0.28 mL of fungicide and 84.8 mg L-1 of N-NH4+. The highest removal of N-NH4+ (38.49%) occurred under the conditions of 42 h, 0.55 mL of fungicide, and 62.5 mg L-1 of N-NH4+, and the lowest removal (4.26%) occurred under the conditions of 24.1 h, 0.82 mL of fungicide and 84.8 mg L-1 of N-NH4+. Through statistical analysis, it was possible to obtain mathematical models for the two response variables, which satisfactorily described the removal efficiency of COD and N-NH4+, and through the desirability analysis, it was possible to optimize the treatment process operation with a cycle time of 58.15h, with the addition of 0.62 mL of fungicide and 57.91 mg L-1 of ammoniacal nitrogen. Although the removal of N-NH4+ via nitrification is an efficient technique in industrial effluent treatment, the results obtained in this work indicate that the removal of N-NH4+ was significantly affected by the presence of the fungicide. Keywords: biological treatment, chemical oxygen demand, DCCR, TCMTB.

Biochar from orange waste as a filter medium for domestic effluent treatment aimed at agricultural reuse

Brazil is the world's leading orange grower, and this agro-industrial sector produces a sizable amount of by-products. Because biochar has the potential to be used as a filtering medium in wastewater treatment systems, it can be advantageous to produce biochar from orange trash as an efficient way to use these resources. The purpose of this study was to assess how temperature affects the synthesis of biochar and to describe the adsorptive qualities of the material for use in filtration systems for agricultural reuse. The produced material was examined for its chemical composition, crystalline structure, morphological changes brought about by the conversion of biomass into biochar, surface area, and average pore size. The pyrolysis temperatures used to produce biochar ranged from 350 to 650°C for 60 minutes. Based on the advantageous physicochemical characteristics for usage as an adsorbent, 550°C was determined to be the ideal temperature. The orange biochar system outperformed the gravel system in terms of macronutrient removal, according to the filtration results using septic tank effluent. The elimination of magnesium (62.09%) and total phosphorus (31.58%) was noteworthy. These findings indicate a promising and long-term wastewater treatment option by indicating that the treated effluent may be suitable for use in some crops. Keywords: biochar, horizontal flow, sewage treatment, wastewater.

Electrocoagulation and Anodic Oxidation for the Treatment of Commercial Dyes and Real Textile Effluent: Meta-analysis for Optimal Operating Conditions

Electrocoagulation and Anodic Oxidation for the Treatment of Commercial Dyes and Real Textile Effluent: Meta-analysis for Optimal Operating Conditions

Assessing immobilization matrices for nuclear effluent treatment: Cs case study

Assessing immobilization matrices for nuclear effluent treatment: Cs case study

Relationship between Biological and Qualitative Indices in Surface Waters Receiving the Effluent of Fish Farms in the Northwest of Iran.

Water quality is usually measured using various indicators based on physical, chemical and biological parameters. By using the biological index that is based on the identification of the arthropod families, it is possible to make a logical judgment about the ecosystem condition. The aim of this study was measuring correlation coefficients between qualitative and biological Indices. Water samples were collected 27 samples in northwest of Iran and aquatic insects' samples 54 in 2019. The NSFWQI and IRWQISC as the most important indices of physical and chemical quality of water ranged from 54.45-76.21 and from 41.32 to 77.40, respectively. A total of 2,953 aquatic insects were collected, and biological Index ranged from 6.26 to 3.38. It can be stated that increasing in the concentration of pollutants in the source and end of the river could lead to a sharp decrease in biological index. IRWQISC index, the effluent stations of fish farms can fit into 'fairly bad quality' and 'moderate quality' categories. The linear regression analysis revealed a significant relationship between the Hilsenhoff biological Index and the physiochemical parameters of pH, DO (Dissolved Oxygen) and total dissolved solids. The activity of fish farms and discharging their effluents into water sources, can change the physical, chemical and biological parameters of receiving waters, therefore it is recommended that the location of these units be reviewed and also the appropriate treatment for such effluents should be considered, so that the health risks caused by them can be effectively reduced.

Municipal anaerobic filter effluent treatment using advanced oxidation processes for potential use in unrestricted crop production

To meet wastewater treatment quality standards for reuse, integrating advanced oxidation processes (AOPs) with Decentralized Wastewater Treatment Systems (DEWATS) is promising. This study aimed to optimize AOPs (ozonolysis, UV photolysis, TiO2 photocatalysis) for polishing anaerobic filter (AF) effluent from DEWATS, as an alternative to constructed wetlands. Metrics included pathogen reduction efficiency, post-disinfection regrowth, and effects on physical parameters (pH, EC, turbidity), organic matter (soluble COD, BOD, DOC, humic), and nutrient concentration (ammonium, nitrates, ortho-P). Ozonolysis and TiO2 photocatalysis achieved a 6.4-log pathogen reduction, while UV photolysis achieved a 6-log. No pathogen regrowth occurred with ozonolysis, but TiO2 photocatalysis showed E. coli and Total coliforms regrowth of 2.5-log and 2.7-log, respectively. UV photolysis showed 0.5-log and 2.2-log regrowth for E. coli and Total coliforms, respectively. TiO2 photocatalysis significantly reduced BOD, soluble COD, humic substances, ortho-P, turbidity, and nitrates, while increasing pH, EC, ammonium, and DOC. Ozonolysis significantly lowered BOD, soluble COD, humics, and turbidity, but increased ortho-P, nitrates, pH, EC, ammonium, and DOC. UV-photolysis showed marginal reductions in BOD, nitrates, and turbidity, with increased EC, pH, ammonium, DOC, ortho-P, and humic levels. Ozonolysis emerged as the best AOP, demonstrating efficient effluent treatment with no pathogen regrowth.

Studies on the Use of Snail Shells in the Treatment of Wastewater Effluent

Studies on the Use of Snail Shells in the Treatment of Wastewater Effluent

Detoxification of dairy industry effluent from toxic metal ions: Preparation and characterization of a magnetized adsorbent derived from agricultural residues

This study investigated the potential of a mixture of agricultural wastes for the preparation of an adsorbent and evaluated its efficiency in removing Co(II) and Cu(II) ions. Brunauer-Emmett-Teller analysis revealed a surface area of 89.57 m2/g, a total pore volume of 4.92 cm³/g, and an average pore diameter of 43.26 nm. Scanning electron microscopy and energy-dispersive X-ray spectroscopy confirmed a layered structure, uniform pore distribution, and successful adsorption of cobalt and copper ions. Vibrating sample magnetometry analysis demonstrated superparamagnetic behavior, with a saturation magnetization of 52.8 emu/g. Fourier-transform infrared spectroscopy identified oxygen-containing functional groups formed during activation, which significantly enhanced the adsorbent’s adsorption capacity. Equilibrium data for pollutant adsorption were well-described by the Freundlich isotherm, with maximum adsorption capacities of 91.7 mg/g for Co(II) and 89.9 mg/g for Cu(II). At 50 °C, the correlation coefficients (R2) were determined to be 0.969 for Co(II) and 0.960 for Cu(II). Under optimal conditions, 75 mg of adsorbent at 50 °C, pH 6.5, and 30 min, the adsorbent achieved 92–93% removal of pollutants from real dairy effluent and 95–96% from synthetic effluent. The process highlights its potential as a sustainable solution for dairy effluent treatment and agricultural waste management, with scalability for industrial applications.

Treatment of effluent from municipal wastewater treatment plants using electrochemically produced Caro's acid.

This work describes the application of electrochemically produced Caro's acid in a divided electrochemical flow cell for the removal of fourteen CECs from real effluent at a municipal wastewater treatment plant in Ciudad Real, Spain. The results are compared with direct dosing of the reagent (with an ionic/molecular oxidant) and radical-assisted oxidation (activated sulfate radical via photochemical oxidation or hydrogen peroxide-induced radical oxidation). This study sheds light on the underlying mechanisms of these processes. As well, the effect of these three technologies on effluent disinfection is evaluated. The results demonstrate that this treatment alternative efficiently destroys all monitored pollutants, reaching the detection limits of the analytical equipment.

“Catch-and-feed”: Janus catalytic flow-through membrane enables highly efficient removal of micropollutants in water

Micropollutants, due to their low concentrations, exceptional chemical stability, and profound toxicity, present a significant challenge in water treatment. While electrocatalysis and photocatalysis have shown promise as potential water purification techniques, their inherent limitations in mass transfer often result in elevated energy requirements and suboptimal efficiency. In this study, a Janus catalytic flow-through membrane (JCFM) was utilized to successfully remove two notorious micropollutants dichlorvos (DDVP) and azoxystrobin (AZX) from water based on the "catch-and-feed" strategy. This membrane adopts a "sandwich" configuration, comprising platinum-modified reduced titanium (Pt@rTO) as the electrocatalytic layer, porous titanium (Ti) as the current collector, and rTO as the photocatalytic layer. The JCFM exhibited remarkable performance, maintaining an •OH energy conversion efficiency of up to 20.12 nM and displaying catalytic activity (kJCFM=6.97 × 10–4 s–1) in degrading AZX far superior to that of photocatalysis (kPC=9.51 × 10–5 s–1) or electrocatalysis (kEC=9.89 × 10–5 s–1) alone. It is evidenced that the Pt@rTO layer efficiently generates reactive oxygen species (ROS), which, along with the micropollutants, flow through the JCFM (“feed”), which strengthens mass transfer and facilitates efficient reactions within the confined space (“catch”). The ROSs then seep through the rTO layer, where they are reactivated by UV light radiation. The mechanism and the alternative reaction pathway of DDVP and AZX has also been proposed. In sequential testing, the JCFM achieved continuous and energy-efficient removal of micropollutants, exceeding 97.5% over 200 h. The scale-up application of this technology has proven effective in the treatment of secondary biochemical effluent from municipal sewage, coking wastewater, and landfill leachate, achieving the concurrent degradation of various micropollutants.

Anchorage of ZnO quantum dots and CuO on graphene for sonophotocatalytic treatment of pharmaceutical effluent: From experimental data and prediction by advanced machine learning algorithms

Quantum dots (QDs) have recently received much attention as photocatalysts due to their unique properties. Despite the advantages reported for QDs as photocatalysts in literature, their sonophotocatalytic/photocatalytic activity is still hindered by a series of barriers, which limit them to operate after several successive cycles efficiently. The main aim of this work is to fabricate an efficient and recyclable sonophotocatalyst/photocatalyst using ZnO quantum dots (ZQDs), tenorite (CuO), and graphene (G). In this regard, different amounts of ZQDs (ZQDs(x)/G, x= 10, 20, 30, 40, and 50mg) were immobilized on graphene by hydrothermal method and various weight percent of CuO was impregnated on ZQDs(40)/G. The PXRD patterns and Raman spectra confirmed the wurtzite and monoclinic crystal structure for ZQDs and CuO, respectively. Also, FESEM, AFM, and PXRD showed that the mean crystal size of ZQDs increased after immobilization on graphene and impregnation by CuO. PL and Mott–Schottky analyses showed that the presence of GO and CuO in CuO(0.5)/ZQDs(40)/G reduced the recombination of excitons and formed p-n heterogeneous junctions between CuO and ZnO. The VB and CB potential and bandgap energy were obtained using DRS and Mott–Schottky analyses, and the mechanism of tetracycline (TC) degradation was proposed according to active species trapping and H2O2 paper testes. The apparent rate constant (kapp) was 0.030 and 0.060min-1 for photocatalytic and sonophotocatalytic degradation of TC in the presence of CuO(0.5)/ZQDs(40)/G, respectively. The treated effluent of TC showed acceptable performance in growing wheat seeds. The electricity cost estimation showed that (CuO(0.5)/ZQDs(40)/G) consumed less electricity in sonophotocatalytic/photocatalytic TC degradation and could also be used in several successive cycles. Finally, two RF and AdaBoost models based on ML algorithms were developed to predict photocatalytic/sonophotocatalytic degradation. The results showed that the values of statistical metrics, including SAE, MAE, MSE, and RMSE, for the AdaBoost model were relatively lower than those for the RF model, indicating better prediction performance in train and test datasets.

Hydrous ferric arsenate transformation coupled with As, Fe, and S environmental cycling in sulfidic systems under anoxic and circumneutral conditions.

Despite many studies on the environmental cycling of As, Fe, and S, sulfide (S(-II))-induced hydrous ferric arsenate (HFA) transformation remains to be elucidated. Herein, we investigated the anaerobic reaction of HFA with S(-II) at three environmental concentrations (1, 10, and 50mM) at pH48. Changes in solid-phase As, Fe, and S speciation were investigated by XRD, FTIR, Raman, XPS, synchrotron XANES, SEM, and TEM. The results demonstrated that 1mMS(-II) induced significant As mobilization from HFA, and secondary goethite formed only at pH8. Greater S(-II) addition caused rapid reductions in As(V) and Fe(III) and generated substantial amounts of elemental sulfur, S2O32, SO32, and SO42, subsequently decreasing As mobilization through secondary As-bearing phase formation. Solid characterization revealed that 10mMS(-II) produced a scorodite‑sulfur mixture at pH4, while schwertmannite, goethite, hematite, and tooeleite formed at pH8. At pH4 and 6, 50mMS(-II) produced secondary semicrystalline symplesite, lepidocrocite, and tooeleite; in contrast, a substantial fraction of FeSam plus minor amounts of hematite and goethite were generated at pH8. These results deepen our understanding of the geochemical cycling of As, Fe, and S and will help establish an effective As fixation method for effluent treatment.