Wastewater Treatment Techniques Research Articles

Activation of sodium percarbonate by micro amounts of copper for highly efficient degradation of acid orange 7

In recent years, activation of sodium percarbonate (SPC) has been regarded as very appealing technologies in the elimination of organic pollutants. In this work, the activation of SPC using micro amounts of Cu(II) (at μM level) towards acid orange 7 (AO7) degradation was explored. Experimental results displayed that nearly 97.5% of AO7 could be removed within 15 min using 20 µM Cu(II) and 0.4 mM SPC. Effects of Cu(II) concentration, SPC concentration, pH value and coexisting anions were investigated. Compared with conventional Fenton oxidation, which could only work under acidic pH conditions, Cu(II)-catalyzed SPC (Cu(II) /SPC) system could work under near-neutral or alkaline solutions. Furthermore, AO7 decomposition was barely impacted by Cl−, SO42− and NO3−, while 5 mM HCO3− inhibited the degradation of AO7. Electron paramagnetic resonance analysis confirmed the existence of multiple reactive oxygen species in the reaction (HO•, O2•–, 1O2). However, free radical scavenging experiments demonstrated that the degradation of AO7 was mainly due to the carbonate radicals (CO3•−) and singlet oxygen (1O2). The interaction between Cu(I) and Cu(II) was confirmed and the production of Cu(III) was proved to act as a degradation agent for AO7. The degradation of AO7 could be divided into two pathways. The study suggests a simple, economic and efficient technique for dye wastewater treatment using SPC triggered by micro-amount Cu(II).

Exploring the resilience of constructed wetlands to harmful algal blooms disturbances: A study on microbial response mechanisms

Constructed wetlands (CWs) have emerged as a promising environmentally sustainable technique for wastewater treatment. However, the susceptibility of CWs to disturbances caused by harmful algal blooms (HABs) raises concerns. This study aimed to investigate the impact of HABs on the pollutants’ removal performance of CWs and the response of rhizosphere microbial community. Results revealed that CWs possessed an adaptive capacity that enabled them to recover caused by HABs. The rhizosphere was found to stimulate the occurrence of Acinetobacter, which played a critical role to help resist HABs disturbance. This study also observed an increased dissimilatory nitrate reduction metabolic pathway which promoted denitrification and enhanced the nitrogen removal efficiency of CWs. Additionally, the structural equation model further suggested that dissolved oxygen exerted a significant influence on the microbial activities and then affected the pollutants removal performance. Overall, our findings shed light on the mechanism for CW stability maintenance during HABs disturbance.

Removal of Copper, Chromium, and Nickel Ions from aqueous solution by using different pre-treated orange peel

In Malaysia, water pollution due to the various heavy metal contaminants has become a serious issue that needs to be concerned. Among various water treatment methods, the adsorption method has been considered one of the most efficient wastewater treatment techniques. This study was done to find out the adsorption capacity of orange peel (OP) by different pre-treatment in removing copper, chromium, and nickel ion from aqueous. OP powder was divided into three portions, which were untreated OP, pretreated with sodium hydroxide (NaOH) OP, and detergent OP respectively. Each chemical solution that contains copper, chromium and nickel respectively was tested by these three adsorbents. From the experiment, NaOH pretreated OP was found highest performance in removing 85.67% of nickel and 81.55% of copper. While the untreated OP was good in removing 91.2% of chromium. The untreated OP for nickel ions and copper ions, Detergent treated OP for nickel ions and chromium ions were best fitted to Langmuir Isotherm, while untreated OP for chromium ions, detergent treated OP for copper ions and NaOH treated OP for all selected metal ions were best fitted to Freundlich Isotherm. In short, OP can be considered a very good adsorbent choice due to its good adsorption capacity, environment-friendly nature and low-cost characteristics.

Investigating the Performance of Single Chamber Microbial Fuel Cell (SCMFC) as Sustainable- Innovative Technique for Electricity Generation and Wastewater Treatment

Microbial fuel cells (MFCs) are considered as an economical and sustainable technology for various applications. This study has designed four single-chamber SCMFCs that composed of graphite plates as electrodes and used wastewater as a substrate for microorganisms. In order to evaluate the performance of SCMFC, the experiments were executed in a batch mode over 18 days at various types of salt bridge. Four salt bridges are used namely (KCl, NaCl, KNO3, and Cotton Rope). It was found that KCl generated a maximum voltage of 989 mv. The following results were obtained for wastewater investigated parameters: COD = 94%, PO4 = 88.4%, NO3 = 88%, TSS = 80%, and Fe = 76%, respectively at 1 M KCl. The experiment was then carried out using different values of KCl (1, 1.5, 2, 3 M). It was found that at a molar concentration of 1.5, 1422 mv of maximum voltage has been generated. Results for wastewater treatment demonstrated that COD of 81%, PO4 of 78.2%, NO3 of 79%, TSS of 80%, and Fe of 84%.

Adsorption Study on Waste Water Characteristics by using Natural Bio-Adsorbents

Abstract: Wastewater generation and treatment is an ever-increasing concern in the current century due to increased urbanization and industrialization. Hazardous contamination of water is a major hurdle in the provision of usable and drinkable water to the world. Innovative, economic, renewable and environment friendly technologies are need of the hour for wastewater treatment. Numerous wastewater treatment techniques, including physical, chemical, and biological (primary to tertiary treatment) approaches, are used to address the issue of growing environmental hazards. Various treatment techniques being used have the risks of producing secondary pollutants. The most promising technique is the use of different materials as adsorbents that have a higher efficacy in treating wastewater, with a minimal production of secondary pollutants. Adsorption Technology is used for Grey water treatment.

High-Flux lamellar MoSe2 membranes for efficient dye/salt separation

Membrane-based technology is emerging as an efficient technique for wastewater treatment in recent years. Membranes made up of two-dimensional materials provide high selectivity and water flux compared to conventional polymeric membranes. Herein, we report the synthesis and use of MoSe2 membrane for dye and drug separation in wastewater, mainly from textile and pharmaceutical industries. The as-prepared MoSe2 membrane shows ∼ 100% rejection for organic dyes and ciprofloxacin drug with a water flux reaching up to ∼ 900 Lm-2h-1bar-1. Further, the MoSe2 membrane shows lower NaCl rejection of ∼ 1.9% for the dye/salt mixture. The interlayer spacing in the MoSe2 membrane allows the water molecules and ions from the salt to pass through freely but restricts the movement of large contaminants. The membrane is stable against the bovine albumin serum fouling with a flux recovery rate of 96%. It also shows good performance even in harsh environments (pH 3–10). To the best of our knowledge, the MoSe2 membranes were fabricated for the first time for wastewater treatment application. The dye/salt separation performance of the MoSe2 membrane is significantly better than several other membranes. This work highlights the promising potential for using two-dimensional materials for textile and pharmaceutical wastewater treatment.

A Comparative Study of Vetiver Grass and Lemon Grass Using Phytoremediation Technique for Waste Water Treatment

The increase in population led to a scarcity of water. There are lots of diseases and problems that are affecting the environment and human life. This is increasing day by day. This causes lots of hazards in our world. To treat wastewater, we have lots of methods. In spite of this, it is very expensive, not affordable to the masses, and also not properly treated; therefore, we use natural methods to treat the wastewater in a way that does not harm our environment. To avoid this situation, there is a solution: using vetiver grass and lemon grass to treat wastewater. As a result of this method, we are able to determine a number of parameters, such as pH, turbidity, conductivity, alkalinity, DO, BOD, COD, and T.T. The coliforms are analyzed to identify changes before and after treatment. With the rapid growth of urbanization and industrialization, there is a high intake of water and a great generation of wastewater. This study aims to find the most cost-effective method for wastewater treatment and compare it to the conventional method of wastewater treatment. The conventional method is not suitable in rural areas as it is highly expensive. The foundation and improvement of a healthy life through water are two of the most important fundamentals. Using vetiver and lemon grass for wastewater treatment has been proven to be a sustainable and cost-effective alternative to conventional wastewater treatment technologies. In this study, an attempt is made to find the effectiveness of vetiver grass and lemon grass in a laboratory for pollutant removal from wastewater. Various characteristics of wastewater before and after treatment have been checked to study the comparative effectiveness of these two plants. Removal efficiencies of parameters like pH, conductivity, chemical oxygen demand, biological oxygen demand, dissolved oxygen, total coliform, turbidity, and E. coli are analysed.

Sustainable application of nanoparticles in wastewater treatment: Fate, current trend & paradigm shift

Existing water and wastewater treatment techniques are becoming increasingly difficult to employ due to the discovery of new toxins, the rapid development of population and industrial activities, and the limited quantity of water resources. Treatment of wastewater is a critical need in modern civilization due to a scarcity of water resources and rising industrial activity. Some of the techniques utilized include adsorption, flocculation, filtration, and others, although they are only used for primary wastewater treatment. However, the development and deployment of modern wastewater management with high efficiency and low capitalization are critical in terms of mitigating the environmental consequences of waste. The employment of different nanomaterials in the treatment of wastewater has opened up a world of possibilities for heavy metal and pesticide removal, as well as the treatment of microbes and organic contaminants in wastewater. Nanotechnology is a rapidly evolving technology because of certain nanoparticle's outstanding physiochemical and biological capabilities as contrasted to bulk counterparts. Secondly, it has been established that this is a cost-effective treatment strategy with significant potential in wastewater management, transcending the limitations imposed by currently existing technology. Advances in nanotechnology to reduce water contamination have been presented in this review, including the use of various nanomaterials such as nanocatalysts, nanoadsorbents, and nanomembranes in the treatment of wastewater containing organic contaminants, hazardous metals, and virulent pathogens.

Current status and future perspective in electro-Fenton techniques for wastewater treatment: a bibliometric review

Current status and future perspective in electro-Fenton techniques for wastewater treatment: a bibliometric review

MnNx-Carbon-Silica-Framework for highly efficient heterogeneous catalytic ozonation of electron-rich organics through nonradical pathway

Heterogeneous catalytic ozonation (HCO) is considered as a powerful technique for wastewater treatment, whose pathway of removing organics could be adjusted by tuning the active sites of catalysts. The traditional hydroxyl radical pathway could be affected by wastewater matrices. In comparison, nonradical pathways such as 1O2 pathway and intra-electron–transfer pathway provide a promising solution to electron-rich organics degradation avoiding the impact of matrices. In this study, we proposed MnNx loaded Carbon-Silica-Framework (MnNx-CSF) as an efficient catalyst with stable mechanical strength to selectively remove electron-rich organics through HCO. The TOC removal for p-HBA was up to 81% in MnNx -CSF HCO process within 30 min, while only 44% and 22% of TOC were removed in the Mn-SiO2 HCO process and ozonation process, respectively. The N species were confirmed to be related to the catalytic efficiency. Specifically, the pyridine N and graphitic N were the relevant active N species in MnNx-CSF. The pyridine N could coordinate with Mn atoms to form the active site MnN4, demonstrating a high tendency to adsorb O3 and decompose it into 1O2. The graphitic N could further enhance the electron transfer pathway to degrade organics. Modulating N species to coordinate with metal is considered to be a possible strategy for regulating the catalysts to achieve the catalytic ozonation process through a nonradical way. With a combination of experiments and theoretical calculations, the study provides a new insight for catalytic ozonation of electron-rich organics through 1O2 pathway and intra-electron-transfer pathway.

Investigation of Different Pre-Treatment Techniques and 3D Printed Turbulence Promoter to Mitigate Membrane Fouling in Dairy Wastewater Module.

This study investigates the enhancement of dairy wastewater treatment using chemical and physical pre-treatments coupled with membrane separation techniques to reduce membrane fouling. Two mathematical models, namely the Hermia and resistance-in-series module, were utilized to comprehend the mechanisms of ultrafiltration (UF) membrane fouling. The predominant fouling mechanism was identified by fitting experimental data into four models. The study calculated and compared permeate flux, membrane rejection, and membrane reversible and irreversible resistance values. The gas formation was also evaluated as a post-treatment. The results showed that the pre-treatments improved UF efficiency for flux, retention, and resistance values compared to the control. Chemical pre-treatment was identified as the most effective approach to improve filtration efficiency. Physical treatments after microfiltration (MF) and UF showed better fluxes, retention, and resistance results than ultrasonic pre-treatment followed by UF. The efficacy of a three-dimensionally printed (3DP) turbulence promoter was also examined to mitigate membrane fouling. The integration of the 3DP turbulence promoter enhanced hydrodynamic conditions and increased the shear rate on the membrane surface, shortening filtration time and increasing permeate flux values. This study provides valuable insights into optimizing dairy wastewater treatment and membrane separation techniques, which can have significant implications for sustainable water resource management. The present outcomes clearly recommend the application of hybrid pre-, main- and post-treatments coupled with module-integrated turbulence promoters in dairy wastewater ultrafiltration membrane modules to increase membrane separation efficiencies.

Influence of Light Color on Power Generation and Microalgae Growth in Photosynthetic Microbial Fuel Cell with Chlorella Vulgaris Microalgae as Bio-Cathode

Photosynthetic microbial fuel cell (PMFC) is an environmentally friendly sustainable technique for simultaneous wastewater treatment and power recovery. PMFC utilizes the microalgae to generate oxygen by photosynthesis process in the biocathode. Light sources and intensities have direct effect on chlorophyll pigment formation, photosynthesis processes and microalgae growth. In this study, Chlorella vulgaris was utilized as biocathode in PMFC fed with actual slaughterhouse wastewater. The biocathode was illuminated with florescent light as well as yellow, red and blue LED lights with light intensities of 67.46, 47.03, 26.18 and 4.70µmol/m.s, respectively. Power output and microalgae growth were considered in evaluating the PMFC performance. Results demonstrated that the highest power output was 217.04 mW/m2 generated under florescent light compared to 28.41, 171.08, and 21.65 mW/m2 observed under yellow, red and blue LEDs, respectively. Additionally, statistical analysis was performed using fifth-degree polynomial model which fitted well the experimental data with a determination coefficient (R2) > 0.97. The results reflected a high confidence level in depicting the growth mechanism of Chlorella vulgaris under lighting sources with different light colors and intensities.

Batik Effluent Treatment and Decolorization—A Review

Batik is a piece of woven cloth decorated with beautiful patterns and designs and has become a signature product of the Malay Archipelago, including Malaysia and Indonesia. Batik industry consumes a large volume of water and produces a large amount of wastewater during the boiling process and dyeing process, both for hand-drawn (batik lukis) and block-printed (batik cap) batik. The release of colored effluents that contain a large number of dyes and chemicals can harm the environment and become a human health concern, particularly in south east Asian countries. Therefore, treatments of batik effluent are very crucial and have caught a lot of attention from researchers. The color removal is a major challenge, especially from this industry, as up until now there is no single and cost-effective treatment that can effectively decolorize as well as treat the dye effluent. Since batik is part of the textile industry, most treatment methods have been adapted from textile effluent treatment. Here, we review a variety of textile wastewater treatment techniques to make a good consideration of selecting the most appropriate method to be applied in batik wastewater. First, we briefly review the batik process, including the potential dyes that are mostly used in batik processing. Secondly, we describe all possible techniques and their performance to reduce dye concentration and decolorization. Finally, we review all advantages and disadvantages of these techniques for domestic and industrial applications.

Degradation performance and potential protection mechanism of the anammox consortia in response to capecitabine

The potential risks of anti–cancer drugs such as capecitabine have attracted considerable attention due to their continuous release. Understanding the response of removal performance and protective mechanism to the presence of emerging contaminants is crucial for the application of anammox techniques in wastewater treatment. Capecitabine affected the nitrogen removal performance slightly in the activity experiment. Due to bio–adsorption and biodegradation, up to 64–70% of the capecitabine can be removed effectively. However, 10 mg/L of capecitabine significantly decreased the removal efficiency of capecitabine and total nitrogen at repeated load of capecitabine. Metabolomic analysis revealed the metabolites 5′–deoxy–5–fluorocytidine and alpha–fluoro–beta–alanine, while metagenomic analysis confirmed the biodegradation pathway and underlying gene distribution. The potentially protective mechanisms of the system against capecitabine were the increased heterotrophic bacteria and secretion of sialic acid. Blast analysis confirmed the presence of potential genes involved in the complete biosynthesis pathway of sialic acid in anammox bacteria, some of which are also found in Nitrosomonas, Thauera, and Candidatus Promineofilum.

A comparative study for the removal of reactive red 49 (RR49) and reactive yellow 15 (RY15) using a novel electrode by electrocoagulation technique

The present work deals with the investigation of the efficiency of the electrocoagulation (EC) technique in the removal of two different reactive dyes as a simple, durable, and cost-effective technique for wastewater treatment. The difference in structure between Reactive Red 49 (RR49) and Reactive Yellow 15 (RY15) is explored during the treatment process through the use of a novel design of electrodes. The optimum conditions obtained were 80 and 60 mg/L of initial dye concentrations, pH of 5.9 and 4 for RR49 and RY15, respectively, 0.5 g of NaCl electrolyte, and 900 and 500 rpm of stirring rate for RR49 and RY17 dyes respectively, which led to the highest percent removal (98.5%) for both dyes. The suitable temperatures were 20 and 30 °C for RR49 and RY15, respectively. The thermodynamic parameters were designated, and it was a spontaneous process for both dyes. The removal process was designated to pseudo- second-order for the RR49 dye and pseudo- first-order for the RY15 dye and fitted to the Langmuir model. Analysis of Variance (ANOVA) was presented to assess the variation of the outcomes attained from each factor.

Photo-Fenton system Fe3O4/NiCu2S4 QDs towards bromoxynil and cefixime degradation: A realistic approach

The contamination of natural water bodies with toxic pollutants are alarmingly increasing in recent decades. The development of advanced wastewater treatment techniques and their utilization is sought for the effective removal of pollutants especially pharmaceutical and pesticide compounds (PPCs). The present study focused on the green synthesis of a novel heterojunction NiCu2S4 QDs@Fe3O4 nanocomposite (NCs) using Dunica erecta plant extract for the photo-Fenton catalytic degradation of bromoxynil (BRX) and cefixime (CEF). The morphological, structural, and physiochemical properties of the fabricated nanomaterial were analysed via SEM, TEM, XRD, FTIR, Raman, UV–Vis DRS, BET, PL, EIS, and ESR spectroscopy techniques. The NiCu2S4 QDs@30% Fe3O4 showed 97.5 and 81% degradation of BRX and CEF within 200 and 180 min of visible light irradiation, respectively. The excellent photocatalytic efficiency of NCs was attributed to high visible light harvesting ability, efficient charge carriers’ separation, and migration across the heterostructure interface. Various initial parameters including nanomaterial dosage, pollutant concentration, pH, and ions were optimized. A possible photodegradation pathway was predicted based on the intermediates identified from GC-MS/MS analysis, and their non-toxic nature on daphnia, green algae, and fishes was determined by the ECOSAR program. The fabricated NiCu2S4 QDs@Fe3O4 NCs have shown excellent reusability efficiency of 98.7%. The reusability and structural stability were confirmed by six-cycle experiments, XRD, and XPS analysis. In addition, the photocatalyst exhibited 99% of degradation of industrial effluent. The prepared NiCu2S4 QDs@Fe3O4 NCs with superior photocatalytic performance can be used as a promising photocatalyst for the treatment of industrial effluents.

Extraction of diclofenac sodium from water using N-benzylethanolamine based ionic liquids: Computational and experimental approach

Despite the existence of numerous conventional wastewater treatment techniques, an efficient method for removing micropollutants remains elusive. Micropollutants (MPs)are chemicals that occur in trace amounts in the aquatic environment, which include pharmaceuticals, food additives, cosmetics, and dyes. The need to develop sustainable and cost-effective alternatives to eliminate these toxins has become a pressing issue. Recently, ionic liquids (ILs) have emerged as a potential candidate for wastewater treatment because of the ease in structure tunability and other unique chemical properties. This study aims to develop four N-benzylethanolamine based ionic liquids to eliminate diclofenac sodium, one of the top priority pharmaceutical micropollutants, from the aquatic environment. The ILs chosen were optimised with B3LYP theory and 6-311++G(d, p) basis set in Gaussian 16. Using integral equation formalism polar continuum model (IEFPCM) solvation as an aid, the interactions between the ILs and diclofenac medium were investigated. For the experimental studies, the liquid-liquid extraction (LLE) method was used, and parameters affecting extraction efficiencies (EE) such as IL concentration, rotation time, rotation speed, temperature, and equilibration time were optimised. The reusability of the best-performed IL was explored. Hydrophobicity, hydrogen bonding and π-π interactions were found to have a significant impact on the extraction efficiency of ILs.

Recent Developments of Light-Harvesting Excitation, Macroscope Transfer and Multi-Stage Utilization of Photogenerated Electrons in Rotating Disk Photocatalytic Reactor

The rotating disk photocatalytic reactor is a kind of photocatalytic wastewater treatment technique with a high application potential, but the light energy utilization rate and photo quantum efficiency still need to be improved. Taking photogenerated electrons as the starting point, the following contents are reviewed in this work: (1) Light-harvesting excitation of photogenerated electrons. Based on the rotating disk thin solution film photocatalytic reactor, the photoanodes with light capture structures are reviewed from the macro perspective, and the research progress of light capture structure catalysts based on BiOCl is also reviewed from the micro perspective. (2) Macroscope transfer of photogenerated electrons. The research progress of photo fuel cell based on rotating disk reactors is reviewed. The system can effectively convert the chemical energy in organic pollutants into electrical energy through the macroscopic transfer of photogenerated electrons. (3) Multi-level utilization of photogenerated electrons. The photogenerated electrons transferred to the cathode can also generate H2O2 with oxygen or H2 with H+, and the reduction products can also be further utilized to deeply mineralize organic pollutants or reduce the nitrate in water. This short review will provide theoretical guidance for the further application of photocatalytic techniques in wastewater treatment.

Use of Nano-Sized Adsorbents for Wastewater Treatment: A Review

There is an increased demand for high-quality drinking water, which requires the removal of hazardous contaminants emerging from municipal, agricultural, and industrial effluents. An approach towards safe drinking water requires the implementation of various treatment processes for water emerging from natural resources as well as coming in the form of industrial wastewater. Pollutants in water bodies may be present in multiple states, including large suspended particles, dissolved chemical substances, in the form of microorganisms or suspended solids. Over the last few years, researchers have concentrated on developing a practical methodology for extracting pollutants from wastewater. During the course of time, although many advanced and complex wastewater treatment processes have evolved, yet adsorption has its own importance. Owing to its simple operation process, low cost, and less sludge formation, adsorption is being considered the most promising technique for wastewater treatment. In this regard, nanomaterial adsorbents have become a topic of great interest owing to their exceptional properties such as high adsorption strength, greater surface area, and chemical stability. Keeping in view, key features of nanoparticles, researchers have explored the applications of various adsorbents at the nanoscale in addressing wastewater treatment issues. The present review focuses on the use of nano-adsorbents in treating various industrial effluents and also provides a comparative assay in terms of the advantages and drawbacks of these nano-adsorbents, employed in removing hazardous contaminants from industrial effluents.

An application of advanced oxidation process on industrial crude oily wastewater treatment

Advanced oxidation process, via photo-catalytic oxidation process was demonstrated in this study as one of the promising techniques of simulated oily wastewater treatment. Several effective factors such as initial oil concentration, catalyst dose, stirring speed (rpm), pH value and hydrogen peroxide (H2O2) dose influencing on the photo-catalytic degradation rate of oily wastewater were investigated. The catalyst used in this work was titanium dioxide (TiO2). The solubility of oil in water was increased using emulsifier. Results indicated that the photo-catalytic oxidation process has a good removal percentage of oil from oily wastewater reached to 98.43% at optimum operating parameters of 1 g/L initial oil concentration, 850 rpm, 8 pH, 3 mL H2O2 and 1.5 g/L of TiO2 after 40 min of irradiation time. The degradation reaction follows a first order kinetics with a correlation coefficient (R2) of 93.7%. Ultimately, the application of photo-catalytic oxidation processes at these optimum operating parameters on an industrial oily wastewater collected from an effluent stream of Ras Shukair at Red See supplied by Asuit Petrochemical Company was done in Egypt. The results showed that the best oil removal (99%) was achieved after adding 3 mL of H2O2 in a reaction time of 40 min compared to without adding H2O2.