Wastewater Treatment Technologies Research Articles

Cutting edge technology for wastewater treatment using smart nanomaterials: recent trends and futuristic advancements.

Water is a vital component of our existence. Many human activities, such as improper waste disposal from households, industries, hospitals, and synthetic processes, are major contributors to the contamination of water streams. It is the responsibility of every individual to safeguard water resources and reduce pollution. Among the various available wastewater treatment (WWT) methods, smart nanomaterials stand out for their effectiveness in pollutant removal through absorption and adsorption. This paper examines the application of valuable smart nanomaterials in treating wastewater. Various nanomaterials, including cellulose nanocrystals (CNC), cellulose nanofibrils (CNF), nanoadsorbents, nanometals, nanofilters, nanocatalysts, carbon nanotubes (CNTs), nanosilver, nanotitanium dioxide, magnetic nanoparticles, nanozero-valent metallic nanoparticles, nanocomposites, nanofibers, and quantum dots, are identified as promising candidates for WWT. These smart nanomaterials efficiently eliminate toxic substances, microplastics, nanoplastics, and polythene particulates from wastewater. Additionally, the paper discusses comparative studies on the purification efficiency of nanoscience technology versus conventional methods.

Life-Cycle Analysis of Natural Treatment Systems for Wastewater (NTSW) Applied to Municipal Effluents

The objective of the described activity is to develop technologies or proposals that can be implemented within the cycle to enhance the relationship between climate change, water, energy, and food. The focus is on analyzing natural treatment systems for wastewater (NTSW) within the context of Macaronesia, considering factors such as life-cycle assessment (LCA), carbon footprint, impacts, and mitigation capacity. The analysis of real case data from the Canary Islands and Cape Verde will inform the development of appropriate technologies tailored to different areas and scales within Macaronesia. This work includes a comprehensive life-cycle analysis of the Santa Catarina (Cape Verde) NTSW. This analysis encompasses: (a) Inventory analysis of the construction phase: This involves the assessment of inputs and outputs associated with the construction of the NTSW, including materials, energy consumption, transportation, and waste generation. The maintenance and operation phases are then evaluated, with a focus on the ongoing maintenance and operation activities required for the NTSW, including energy consumption, water usage, chemical inputs (if any), labor, and equipment maintenance. (b) Finally, the impacts of the NTSW are evaluated. The environmental, social, and economic impacts generated by the NTSW are assessed. This includes an analysis of factors such as carbon emissions, water usage, land use, ecosystem impacts, human health effects, and economic costs. By conducting a comprehensive analysis of the Santa Catarina NTSW, the document aims to provide insights into the environmental performance and sustainability of the system. This information can then be used as a tool and experience of educational innovation for final-year undergraduate students to identify areas for improvement, develop mitigation strategies in the water sector, and inform decision-making processes regarding wastewater treatment technologies in Macaronesia. Furthermore, lessons learned from real case studies in the Canary Islands and Cape Verde can be applied to similar regions within the Macaronesia archipelago (IDIWATER project).

Pollutants Analysis and Life Cycle Assessment of a Photovoltaic Powered Textile Electro-Fenton Wastewater Treatment System.

Textile wastewater poses a substantial environmental challenge due to the persistence of organic dyes. This study introduces a novel approach using photovoltaic (PV) powered electro-Fenton (EF) technology for effective treatment of textile wastewater. Acid orange 7 (AO7), methylene blue (MB), and malachite green (MG) were selected as representative organic dyes to validate the method under varying experimental conditions. Analysis of variance (ANOVA) highlighted the significant influence of pollutant type, pH levels, and current density on the degradation efficiency of the system, with optimal conditions observed at pH = 3 and high current density. To underscore the environmental benefits, a comprehensive life cycle assessment (LCA) was conducted. The PV-powered EF system, when implemented in a textile mill, exhibited an energy payback time (EPBT) of 9.53 years, a greenhouse gas payback time (GPBT) of 4.45 years, and a life cycle cost (LCC) of 1.9 × 105 RMB. Comparative analysis with conventional Fenton and EF processes revealed substantial energy savings, with carbon emissions reduced by 95% and 78%, and energy consumption reduced by 87% and 52%, respectively.

Phytosorbents in Wastewater Treatment Technologies: Review

Turning to green technologies in wastewater treatment is a well-known global trend. The use of natural sorbents of plant origin or phytosorbents in order to purify water from various types of pollutants is becoming more and more popular. This solves several important problems at once: the use of harmless natural materials, reducing the cost of processing, and waste disposal. Moreover, there is a global increase in waste in the agricultural, food, woodworking, and other industries. This review presents data on the modern use of natural materials, mainly vegetable waste, as sorbents in wastewater treatment technologies. Natural materials remove ion metals, dyes, crude oil and petroleum products, and other organic and non-organic contaminants. The techniques of obtaining phytosorbents from plant raw materials are considered. The methods for activation and modification of the various phytosorbents, which provide greater sorption efficiency, are presented. The adsorption mechanisms for various water contaminants are examined, and model descriptions are shown. It has been revealed that the effectiveness of sorption interaction mainly depends on the presence of functional groups. Studies over the past twenty years have shown good prospects for the use of such materials and technologies in practice.

Technological Advancements and Prospects for Near-Zero-Discharge Treatment of Semi-Coking Wastewater

This review examines the technological bottlenecks, potential solutions, and future development directions in the treatment and resource utilization of semi-coking wastewater (SCOW) in China. By comprehensively investigating the semi-coking industry and analyzing wastewater treatment research hotspots and existing projects, this study systematically explores the current status and challenges of each treatment unit, emphasizing the necessity for innovative wastewater treatment technologies that offer high efficiency, engineering feasibility, environmental friendliness, and effective resource recovery. This review highlights prospects and recommendations, including the development of novel extractants for phenol and ammonia recovery, a deeper understanding of biological enhancement mechanisms, exogenous bio-enhancement materials, and the creation of cost-effective advanced oxidation process (AOP)-based combined processes. Additionally, it underscores the potential for repurposing SCOW as a valuable resource through appropriate treatment, whether recycling for production or other applications.

Scaling and wetting resistant silica nanoparticle grafted multi-scale corrugated omniphobic membranes for membrane distillation

Membrane distillation (MD) is a promising technology for wastewater treatment, but often faces significant challenges of scaling and wetting. Development of advanced omniphobic membranes has been the core research for mitigating scaling and wetting in MD. In this study, a novel fluorinated multi-scale silicon nanoparticle grafted corrugated (FSiC-PVDF) membrane (water contact angle 179.5 ± 0.3°) was prepared and explored for enhancement of anti-scaling performance by calcium sulfate and anti-wetting performance by sodium dodecylsulfate (SDS). Silica nanoparticles (SiNPs) were synthesized and covalently bonded to the surface of the corrugated membrane and the surface energy was further reduced via chemical fluorination. Flat-sheet membrane (F-PVDF) and corrugated membrane (C-PVDF) were compared. Results showed that compared to the previous study of grafting SiNPs on flat membranes directly, FSiC-PVDF exhibited superior flux (21.1 kg/(m2·h)), and it can consistently demonstrate stable water flux and quality even at high calcium sulfate and SDS concentrations. The F-PVDF experienced significant declines in performance, and the C-PVDF showed limited improvement in scaling and wetting resistance. Corrugation pattern contributed to a larger evaporation area and higher velocity near the membrane surface, thus reducing crystal deposition and heterogeneous nucleation on the surface. The combination of corrugation and SiNPs resulted in a stable Cassie-Baxter wetting state, reduced solid-liquid interface areas, and created slippage conditions that minimized the impact of contaminants on MD performance. These findings indicated that FSiC-PVDF membranes offer significant advantages for MD processes, enhancing operational stability and efficiency.

Gels for Water Remediation: Current Research and Perspectives.

The development of cost-effective and high-performance technologies for wastewater treatment is essential for achieving a sustainable economy. Among the various methods available for water remediation, adsorption is widely recognized as an effective and straightforward approach for removing a range of pollutants. Gel materials, particularly hydrogels and aerogels, have attracted significant research interest due to their unique properties. Hydrogels, for instance, are noted for their ability to be regenerated and reused, ease of separation and handling, and suitability for large-scale applications. Additionally, their low cost, high water absorption capacity, and contribution to environmental protection are important advantages. Aerogels, on the other hand, are distinguished by their low thermal conductivity, transparency, flexibility, high porosity, mechanical strength, light weight, large surface area, and ultralow dielectric constant. This review provides a comprehensive analysis of the current literature, highlighting gaps in knowledge regarding the classification, preparation, characterization, and key properties of these materials. The potential application of hydrogels and aerogels in water remediation, particularly in removing contaminants such as dyes, heavy metals, and various organic and inorganic pollutants, is also discussed.

Effect of Thiophene-Hydrazinyl-Thiazole derivative as an efficient dye sensitizer and performance enhancer of TiO2 toward rhodamine B photodegradation

Visible-light-driven photocatalysis is an eco-friendly technology for wastewater treatment, where TiO2-based photocatalysts displayed outstanding performance in this regard. Dye sensitization is a promising approach for overcoming the common drawbacks of TiO2via improving its photocatalytic performance and extending its activity to visible light. Herein, we demonstrate the synthesis of the Thiophene-Hydrazinyl-Thiazole (THT) derivative as a novel organic dye sensitizer to be employed as a visible-light antenna for TiO2 nanoparticles. The physicochemical characteristics of the as-synthesized TiO2-based nanoparticles are examined by different techniques, which revealed the successful fabrication of the proposed THT-TiO2 heterojunction. The incorporation of THT molecules on the TiO2 surface led to slight disorders and deformation in the crystal lattice of TiO2, a remarkable improvement of its absorption in the visible light as a perfect visible-light antenna in the whole visible region, and significant enhancement in the charge transfer. Rhodamine B (RhB) is used as an organic dye model to assess the photocatalytic efficiency of the as-fabricated THT-TiO2 photocatalyst which achieved almost complete degradation (>95% in 150 min) with an observed rate constant (kobs) of 0.0164 min−1; total organic carbon (TOC) measurements suggested ∼75% mineralization. THT-TiO2 achieved 2.1-fold enhancement in photodegradation% and 4.1-fold enhancement in kobs compared to the bare TiO2. THT showed good activity under visible-light irradiation (RhB degradation% was >66% in 150 min and kobs = 0.0085 min−1). The influence of the initial pH of the solution was investigated and pH 4 was the optimum pH value for suitable interaction between RhB and the surface of THT-TiO2. Radical quenching experiments were conducted to assess the crucial reactive species where the ∙OH and O2.− were the most reactive species. THT-TiO2 showed promising stability over three successive cycles. Finally, the improvement mechanism of the photocatalytic activity of THT-TiO2 was attributed to the electron injection from the excited THT (the dye sensitizer) to TiO2 and enhanced charge separation.

Machine learning to guide the use of plasma technology for antibiotic degradation

Antibiotics are misused and discharged into environmental water, posing a constant potential threat to the ecosystem. Utilising plasma’s physical and chemical effects to remove antibiotics has emerged as a promising wastewater treatment technology. However, the complexity and high cost of reactor configurations represent significant limitations to the practical application of this technology. Furthermore, evaluating the degradation efficiency of antibiotics necessitates using costly and sophisticated testing instruments, coupled with time-consuming and labour-intensive experiments. The present study developed a generalised model using machine learning algorithms to predict the removal efficiency of antibiotics by a plasma system. Of the eight machine learning algorithms constructed, the ensemble model XGBoost exhibited the highest prediction accuracy, as indicated by a Pearson correlation coefficient of 0.943. This correlation indicates a strong relationship between the predicted removal rates and the experimental values. Moreover, the accuracy of the prediction was enhanced through the utilisation of a multi-model stacking approach. A further quantitative assessment of the key factors affecting the efficiency of the plasma process, and their synergistic effects, is provided by the interpretable analysis of the model’s behaviour. It is anticipated that the results will facilitate the design of efficient plasma systems, reduce the need for extensive experimental screening, and improve practical applications in the removal of antibiotic contamination. This provides an informative view of the applications of plasma technology, opening the way for new environmental research questions.

Prevalence of Congenital Anomalies Before and After Implementation of a Novel Wastewater Treatment Technology in Texas: An Augmented Synthetic Control Method Analysis Utilizing Data from a Population-Based Birth Defects Registry

Objective and ApproachDirect potable reuse (DPR) involves adding purified wastewater that has not passed through an environmental buffer into a water distribution system. This technology may address growing demand for water in many population centers, but there are no studies of health outcomes in populations receiving DPR-treated drinking water. Our objective was to determine whether the prevalence of congenital anomalies increased in the period following introduction of DPR-treated water to certain public water systems in Texas. We obtained data on all cases with congenital anomalies regardless of pregnancy outcome during 2003-2017 from the population-based Texas Birth Defects Registry. Maternal demographic and residential data were obtained and a reference population of all livebirths in Texas was identified by linkage to birth and fetal death records. The augmented synthetic control method was used to model county-level changes in prevalence of congenital anomalies (expressed per 10,000 livebirths) after the adoption of DPR by four Texas counties in mid-2013. County-level data on maternal age, education, ethnicity, and rural-urban status were included as covariates. Results: We observed increased prevalence of all congenital anomalies collectively (average treatment effect in the treated [ATT] = 53.6) and congenital heart disease (ATT = 287.3) during the years 2014-2017. Neural tube defects prevalence was unchanged. ConclusionsWe found evidence that the prevalence of congenital anomalies overall and congenital heart disease specifically increased during the years 2014-2017. ImplicationsAdditional research into reproductive and developmental outcomes among people in areas supplied with DPR-treated water is warranted to inform water policy decisions.

Trace the evolution path of pharmaceutical wastewater treatment technology based on a patent perspective

ABSTRACT This paper discusses the research hotspots and future development trends of pharmaceutical wastewater treatment technology, in order to provide valuable reference and guidance to promote the development of technology. First, the search path counting (SPC) algorithm is utilized to identify the global main path to perform a preliminary analysis of the technology evolution path from a macro perspective. Second, according to the life cycle, S-curve divides the time windows of the temporal themes and uses the Latent Dirichlet Allocation (LDA) modeling to identify the themes under each time window. Then, a visualized Sankey diagram is generated to determine the evolutionary relationship, which can be supplemented with the paths of technological evolution from the micro point of view. Finally, six research hotspots of pharmaceutical wastewater treatment technology were found, which are compounding agents, advanced oxidation technology, nanomaterials, artificial intelligence (AI) technology, membrane pollution prevention, and various combinations of wastewater treatment technology. The study also predicted its future development direction.

Phosphomolybdic acid functionalized nano silica for enhanced anti-biofouling effect in polymer electrolyte membranes for microbial fuel cell application

Microbial fuel cells (MFCs) represent a promising technology for simultaneous electricity generation and wastewater treatment. In this study, a single-chambered MFC was fabricated utilizing a novel polymer electrolyte membrane synthesized from sulfonated polyether ether ketone grafted with styrene sulfonic acid (SPEEK/SSA) as the base polymer, and silica decorated with phosphomolybdic acid (SPMA) as a functionalized nanofiller. Various concentrations of SPMA (2.5 %, 5 %, 7.5 %, and 10 %) were incorporated into the SPEEK/SSA membranes and characterized physicochemically. The SPEEK/SSA membrane with 5 wt% SPMA demonstrated the highest proton conductivity (3.75×10−2 S cm−1) and ion exchange capacity (1.68 meq g−1). This PEM also exhibited superior tensile strength (20 MPa) and excellent chemical durability, as evidenced by Fenton's reagent test. Performance evaluation revealed that this membrane achieved a maximum power density of 196.6 mW m−2 at a maximum of 180 mA m−2 current density. Additionally, antibiofouling tests indicated that the 5 % SPMA-incorporated membrane possessed significant antibacterial properties against both gram-positive and gram-negative bacteria and exhibited high biofilm inhibition. The wastewater treatment efficacy of the MFC with the 5 % SPMA membrane was confirmed by a chemical oxygen demand (COD) removal efficiency of 81.49 %, indicating its potential for effective wastewater treatment. Phylogenetic analysis through 16S rRNA sequencing identified major bacterial phyla including Proteobacteria, Bacteroidetes, Chloroflexi, and Firmicutes, with predominant genera such as Pseudomonas and Acidovorax. This study emphasises the potential of nanocomposite membranes to enhance the performance and durability of MFCs while mitigating biofouling, thereby paving the way for future research and development in this field.

Life Cycle Impact Assessment (LCIA), A Decision Making Approach in Waste Water Treatment Plant: A Case Study

Environmental foot print of a waste water treatment plant is an important criterion to assess the performance of treatment unit. The novel waste water treatment technology was used to clean waste water up to a certain limit. Therefore, in whole process, beginning from electricity production to final disposal of water these treatment technologies can affect our environment. This environmental foot print can be determined by using CML 2000 guideline. In final performance of a waste water treatment plant environmental ill effects should also be incorporated instead of only using treatment efficiency, CML 2000 gives environmental performance. In this study four waste water treatment technologies namely Activated Sludge Process, up flow Anaerobic Sludge Blanket, Membrane Biofilm Bioreactor, Fluidized Aerobic Bed were taken. The environmental performance of all these novel technologies was assessed on the basis of eutrophication, global warming potential and removal efficiency, characterization factors are normalized by using CML 2000 guideline. The maximum and minimum results of Acidification was obtained as 0.2215 & 0.0569 in UASB and FAB respectively. The maximum and minimum results of Eutrophication was attained as 0.564 & 0.055 in MBBR and ASP respectively.

Potential for nutrients reuse, carbon sequestration, and CO2 emissions reduction in the practice of domestic and industrial wastewater recycling into agricultural soils: A review

This review assesses the feasibility of reusing treated wastewater for irrigation in agricultural soils as a strategy for nutrients recycling and mitigation of CO2 emissions. Through a literature review, it was examined wastewater sources enriched with carbon and nutrients, including municipal wastewater and associated sludge, vinasse, swine wastewater, as well as wastewater from the food industry and paper and pulp production. The review also explores the dynamics of organic matter within the soil, discussing the aspects related to its potential conversion to CO2 or long-term storage. It was found that industrial wastewaters, owing to their higher organic matter and recalcitrance, exhibit greater potential for carbon storage. However, the presence of pollutants in wastewater necessitates careful consideration, particularly concerning their impact on soil quality. Toxic metals, microplastics, and organic compounds emerged as significant contaminants that could accumulate in the soil, posing risks to ecosystem health. To mitigate the environmental impacts, it was evaluated various wastewater treatment technologies and their associated carbon emissions. While advanced treatments may effectively reduce the contaminant load and mitigate soil impacts, their adoption is often associated with an increase in CO2 emissions. Membrane bioreactors, microfiltration, ultrafiltration, and up-flow anaerobic sludge blanket reactors were identified as promising technologies with lower carbon footprints. Looking ahead, future research should aim to enhance the understanding of carbon dynamics in soil and validate the environmental impacts of treated wastewater disposal. Despite remaining uncertainties, the literature indicates a positive outlook for wastewater recycling in soil, offering a viable strategy for carbon storage and mitigation of greenhouse gas emissions.

Semi-IPN polysaccharide-based hydrogels for effective removal of heavy metal ions and dyes from wastewater: a comprehensive investigation of performance and adsorption mechanism.

The escalating issue of environmental pollutants necessitates efficient, sustainable, and innovative wastewater treatment technologies. This review comprehensively analyzes the mechanisms and isotherms underlying the adsorption processes of semi-interpenetrating polymer network (semi-IPN) polysaccharide-based hydrogels to remove heavy metal ions and dyes from wastewater. Polysaccharides are extensively utilized in hydrogel synthesis due to their biocompatibility, cost-effectiveness, and non-toxic nature. The synthesis of these hydrogels as semi-IPNs enhances their mechanical and structural robustness and adsorption capacity. This review explores the key parameters affecting adsorption performance, including pH, temperature, contact time, and adsorbent dosage. Findings highlight that semi-IPN polysaccharide-based hydrogels exhibit remarkable adsorption capabilities through electrostatic interactions, ion exchange, and surface complexation. Furthermore, this review highlights the distinct advantages of semi-IPNs over other polymer networks. Semi-IPNs offer improved mechanical stability, higher adsorption efficiencies, and better reusability, making them a promising solution for wastewater treatment. Detailed isotherm models, including Langmuir and Freundlich isotherms, were studied to understand these hydrogels' adsorption behavior and capacity for different pollutants. This study highlights the potential of semi-IPN polysaccharide-based hydrogels as effective adsorbents forheavy metals and dyes and as a promising solution for mitigating environmental pollution. The insights provided herein contribute to developing advanced materials forenvironmental remediation, aligning with global sustainability goals, and advancing wastewater treatment technology.

Insights into the role of electrochemical stimulation on sulfur-driven biodegradation of antibiotics in wastewater treatment

The presence of antibiotics in wastewater poses significant threat to our ecosystems and health. Traditional biological wastewater treatment technologies have several limitations in treating antibiotic-contaminated wastewaters, such as low removal efficiency and poor process resilience. Here, a novel electrochemical-coupled sulfur-mediated biological system was developed for treating wastewater co-contaminated with several antibiotics (e.g., ciprofloxacin (CIP), sulfamethoxazole (SMX), chloramphenicol (CAP)). Superior removal of CIP, SMX, and CAP with efficiencies ranging from 40.6 ± 2.6 % to 98.4 ± 1.6 % was achieved at high concentrations of 1000 μg/L in the electrochemical-coupled sulfur-mediated biological system, whereas the efficiencies ranged from 30.4 ± 2.3 % to 98.2 ± 1.4 % in the control system (without electrochemical stimulation). The biodegradation rates of CIP, SMX, and CAP increased by 1.5∼1.9-folds under electrochemical stimulation compared to the control. The insights into the role of electrochemical stimulation for multiple antibiotics biodegradation enhancement was elucidated through a combination of metagenomic and electrochemical analyses. Results showed that sustained electrochemical stimulation significantly enriched the sulfate-reducing and electroactive bacteria (e.g., Desulfobulbus, Longilinea, and Lentimicrobiumin on biocathode and Geobactor on bioanode), and boosted the secretion of electron transport mediators (e.g., cytochrome c and extracellular polymeric substances), which facilitated the microbial extracellular electron transfer processes and subsequent antibiotics removal in the sulfur-mediated biological system. Furthermore, under electrochemical stimulation, functional genes associated with sulfur and carbon metabolism and electron transfer were more abundant, and the microbial metabolic processes were enhanced, contributing to antibiotics biodegradation. Our study for the first time demonstrated that the synergistic effects of electrochemical-coupled sulfur-mediated biological system was capable of overcoming the limitations of conventional biological treatment processes. This study shed light on the mechanism of enhanced antibiotics biodegradation via electrochemical stimulation, which could be employed in sulfur-mediated bioprocess for treating antibiotic-contaminated wastewaters.

Efficient treatment of polyacrylamide wastewater by cascade heterogeneous Fenton and magnetic flocculation process

A large quantity of polyacrylamide containing wastewater is generated during polymer flooding every year and it poses great threats to the environment. As highly efficient technology for polyacrylamide wastewater treatment with potential for engineering application is rare, magnetic flocculation represents a promising alternative. It usually takes minutes for complete sedimentation to occur. However, we found in experiments that viscosity reduction in advance was essential to improve the performance of magnetic flocculation. So, a cascade of heterogeneous Fenton and magnetic flocculation process was proposed. Effect of Fe3O4 dosage, flocculants type and dosage, flocculation pH, stirring conditions and flocculation methods on the removal efficiency of PAM was investigated. The cascade process turned out to be one of the most efficient technologies and achieved 92% PAM removal rate in the shortest time (45 min) for 500 mg/L of PAM when Fe3O4 dosage was 1.5 g/L, AlCl3 dosage was 100 mg/L and flocculation pH was 8.0 under optimized stirring conditions. Nano-Fe3O4 exhibited good stability after at least 3 successive runs. The water quality of polymer flooding wastewater from Nanyang Oilfield reached the required standards for reinjection after treatment by the cascade process. The study provides a new and highly efficient technology for PAM wastewater treatment with promising potential for engineering application.

Construction of heterojunction superparamagnetic Cd0.5Ag0.5Fe2O4 nanocomposite photocatalyst for simulated textile effluent oxidation

Abstract Significant attempts have been recently made regarding nanomaterials due to their several environmental applications especially in wastewater treatment technologies. Among the available nanoparticles, ferrite based substances are gaining a special interest since their superior characteristics such as their magnetic nature, high adsorption capacity and large specific surface area. In this regard, Cd0.5Ag0.5Fe2O4 was prepared using the green simple co-precipitation route. Then, the sample is characterized via Scanning Electron Microscopy (SEM) that proved the produced material’s surface morphology. The substance is then employed as a catalyst source for Fenton reaction to oxidize textile effluent solution containing Rhodamine B (Rh-B 6G) dye. The oxidation experiment conducted under ultraviolet (UV) light with the ferrite-based Fenton catalyst supplemented with hydrogen peroxide showed an exceptional removal rate of up to 94% removals. Notably, the oxidation system is significantly impacted by the operational variables. The oxidation efficiency of the dye was maximized at pH 3.0 and 50 mg/L and 1600 mg/L for ferrite-based Fenton catalyst and H2O2, respectively. The impacts of the operational factors, i.e. initial pH value, initial dye concentration, catalyst, and H2O2 concentrations were also investigated. This perspective introduces the role of a superparamagnetic material to be a recyclable sustained catalyst.

Electro-nitrification coupled with biological denitrification achieves efficient nitrogen removal from rare earth mine ammonia-nitrate wastewater

Nowadays, ammonia-nitrate wastewater has been posed serious environmental hazards. Electrochemical ammonia oxidation (AOR) technology with environmentally friendly and easy-to-operate features has attracted much attention. In this work, a novel anode catalytic electrode (Ni1Cu1Fe0.5-S/Ti) is prepared by a one-step electrodeposition method for electro-nitrification, and coupled a biological denitrification device for the treatment of real ammonia-nitrate wastewater. The unique three-dimensional layered spherical structure of Ni1Cu1Fe0.5-S/Ti electrode has been verified through physical characterization, and electrochemical tests demonstrated that Ni1Cu1Fe0.5-S/Ti electrode gained an excellent current density of 54.48 mA·cm−2 toward to AOR at 0.65 V vs. Hg/HgO as well as good stability for four times repeated electro-nitrification experiments. The optimal experimental operating conditions were obtained by changing electrode spacing, initial NH4+-N concentration, current density and flow rate. Consequently, 97.7 % total nitrogen (TN) removal efficiency of real wastewater is achieved through electro-nitrification coupled with biological denitrification, providing a new perspective technology for ammonia-nitrate wastewater treatment.

Performance Evaluation of Advanced Wastewater Treatment Technologies in Herbal Processing and Extraction Industry

"Due to enormous quantities with hazards and complexity in nature is a big challenge for effective treatment of wastewater from pharmaceutical processes including herbal extraction through conventional methods of distillation. The situation is further aggravated in countries facing high rising population, urbanization, and industrialization resulting in the generation of industrial wastes. The study has been carried out in the herbal extraction industry by conducting stage-wise sampling of ETP based on the conventional method and further coupled with ozonation as an advanced treatment to comply with regulatory standards. Additionally, the same process was studied that implementing the best available technology (BAT) by providing ETP with advanced technology modules such as MBR (membrane bioreactor) + RO + O3 has not only resulted in compliance with standards but also reuse of treated wastewater into the process and utilities has been proved to be techno-economically a viable and sustainable option. Modifying existing aeration tanks and advanced oxidation through ozone injection post-biological treatment has resulted in COD and BOD reduction of 96.42% and 99.0% respectively. Whereas in the case of MBR + RO + O3, the values of pH, BOD, COD, TSS, and sulfide have been observed as 8.32, 2.0 mg.L-1, 14.0 mg.L-1, 1.0 mg.L-1 and 0.0 mg.L-1 respectively and 98% recovery of treated effluent, thus saving 44 KL.day-1 of freshwater resulting into significant financial benefits of Rupees 12.59 acs annually, which otherwise was outsourced through tankers."