Showing papers on "Wastewater published in 2019"
TL;DR: In this article, the authors present a critical review of the currently available literature regarding typical and real characteristics of the textile effluents, and also constituents including chemicals used for preparing simulated textile wastewater containing dye, as well as the treatments applied for treating the prepared wastewater.
Abstract: Textile industries are responsible for one of the major environmental pollution problems in the world, because they release undesirable dye effluents. Textile wastewater contains dyes mixed with various contaminants at a variety of ranges. Therefore, environmental legislation commonly obligates textile factories to treat these effluents before discharge into the receiving watercourses. The treatment efficiency of any pilot-scale study can be examined by feeding the system either with real textile effluents or with artificial wastewater having characteristics, which match typical textile factory discharges. This paper presents a critical review of the currently available literature regarding typical and real characteristics of the textile effluents, and also constituents including chemicals used for preparing simulated textile wastewater containing dye, as well as the treatments applied for treating the prepared effluents. This review collects the scattered information relating to artificial textile wastewater constituents and organises it to help researchers who are required to prepare synthetic wastewater. These ingredients are also evaluated based on the typical characteristics of textile wastewater, and special constituents to simulate these characteristics are recommended. The processes carried out during textile manufacturing and the chemicals corresponding to each process are also discussed.
963 citations
TL;DR: The results indicate that microplastic counts increase over time where successive sludge applications are performed, and stress the relevance of sludge as a driver of soil microplastics contamination.
667 citations
TL;DR: An overview of liquid-solid adsorption processes using conventional and non-conventional adsorbents for pollutant removal can be found in this article, where a classification for adsorbent materials is proposed.
Abstract: The removal of contaminants from wastewaters is a major challenge in the field of water pollution. Among numerous techniques available for contaminant removal, adsorption using solid materials, named adsorbents, is a simple, useful and effective process. The adsorbent matter can be mineral, organic or biological. Activated carbon is the preferred, conventional material at the industrial scale. Activated carbon is extensively used not only for removing pollutants from wastewater streams, but also for adsorbing contaminants from drinking water sources, e.g., groundwater, rivers, lakes and reservoirs. However, the widespread use of activated carbon is restricted due to a high cost. In the last three decades, numerous approaches using non-conventional adsorbents have been studied for the development of cheaper and more effective adsorbents to eliminate pollutants at trace levels. This review gives an overview of liquid-solid adsorption processes using conventional and non-conventional adsorbents for pollutant removal. The manuscript outlines the principles of adsorption and proposes a classification for adsorbent materials. Finally, the various mechanisms involved in the adsorption phenomena are discussed.
543 citations
TL;DR: In this paper, the authors present a comprehensive and fundamental assessment of the photocatalytic activity for the removal of organic dyes and phenolic compounds from textile wastewater, which has been widely studied and is being commercialized in many developing countries in the world.
Abstract: Treatment of textile wastewater using titanium dioxide (TiO2) photocatalysis has been started from the last decade and reached attention to the researchers because of its versatile application. The variety of applications of TiO2 as a photocatalyst has been taken place because of low operating temperature, biologically inert nature, low energy consumption, water insolubility, ease availability and photoactivity, less toxicity, high chemical stability, suitable flat band potential, narrow band gap and environmentally benign. The successful and efficient application of photocatalysis depends on quality of photocatalyst, nature of pollutants, and source of light, which should be in close contact with each other. The TiO2 photocatalyst is used for the effluent treatment of textile wastewater in the presence of ultraviolet (UV) irradiation. Heterogeneous UV-TiO2 photocatalysis is capable to remove organic pollutants from textile wastewater, which has been widely studied and the technology also being commercialized in many developing countries in the world. This review focuses on the mechanism of UV-TiO2 photocatalysis, modification of TiO2 photocatalyst, and application of doping and co-doping in order to improve the photocatalytic activity in wastewater treatment. In addition, the review conveys comprehensive and fundamental assessments of the photocatalytic activity for the removal of organic dyes and phenolic compounds from textile wastewater.
490 citations
TL;DR: In this paper, an in-situ Fe-doped g-C3N4 catalyst was synthesized by thermal shrinkage polymerization, which exhibited excellent and recyclable removal performance for refractory contaminants such as: phenol, bisphenol A, 2, 4-dichlorophenol and coking wastewater, which was due to the formation of σ-π bonds via Fe and N element in the triazine ring skeleton of Fe-g-C 3N4.
Abstract: In this work, an in-situ Fe-doped g-C3N4 catalyst was synthesized by thermal shrinkage polymerization. A heterogeneous photocatalysis-Fenton system was formed with the addition of H2O2 under visible irradiation and exhibited excellent and recyclable removal performance for refractory contaminants such as: phenol, bisphenol A, 2, 4-dichlorophenol and coking wastewater, which was due to the formation of σ-π bonds via Fe and N element in the triazine ring skeleton of Fe-g-C3N4. The electrons generated can be quickly transferred to Fe3+ to form Fe2+ under the interaction of the chemical bond. The efficiency of photoelectron separation was accelerated, and OH radicals were quickly generated with the reaction between Fe2+ and H2O2. Specifically, the recycling of Fe can be achieved in the heterogeneous system, which avoids the problems for the recycling and secondary pollution of Fe ions in homogeneous Fenton reaction. Parameters such as Fe doping amount, hydrogen peroxide concentration, pH value, catalyst concentration, and complex wastewater (coking wastewater) were optimized. The degradation of coking wastewater were also performed, and the chemical oxygen demand (COD) and total organic carbon (TOC) values for 300 ml coking wastewater could be reduced from 64.6 and 25.3 mg/L to 22.8 and 12.3 mg/L in 60 min, respectively. These results demonstrate photocatalysis-Fenton reaction with Fe-g-C3N4 catalyst is promising for environmental remediation.
367 citations
TL;DR: In this article, the authors present the recent developments in Advanced Oxidation Processes (AOPs), biological processes and their combinations for industrial textile wastewater, focusing on the comparison of cost effectiveness of wastewater treatment processes.
365 citations
TL;DR: An overview of microalgae strains commonly used for wastewater treatment, physical and chemical properties of various wastewaters and their suitability for algae cultivation, factors affecting algae growth, nutrient assimilation/removal and biomass productivity are provided.
365 citations
TL;DR: This review emphasizes the importance of costs in industrial-scale treatment of dye wastewater and provides a way to assess the cost-based feasibility of bio-adsorption technologies and discusses the major factors affecting adsorption and desorption performance based on basic chemical and physical structures ofBio-adsorbents available in literatures.
353 citations
TL;DR: In this paper, the potential use of wood-based biochar (WB) for the removal of potentially toxic elements (PTEs) from water and wastewater has been discussed, and a review demonstrates the overarching scientific opportunities for a comprehensive understanding of using WB as an emerging biosorbent and a promising low-cost and effective material for the remediation of contaminated water.
Abstract: Recently, biochar has received significant attention, especially for the removal of potentially toxic elements (PTEs) from water and wastewater. No review has been focused on the potential use of wood-based biochar (WB) for the removal of PTEs in water and wastewater. Here, we have critically reviewed the (i) preparation and characterisation of WB; (ii) removal efficiency of WB for PTEs in water with respect to its physicochemical characteristics, biochar/water ratio, pH, and sorption system; (iii) removal mechanisms of PTEs by WB; (iv) fate of the sorbed PTEs onto WB; and (v) recovery of the sorbed PTEs from the resultant sludge of WB. We also discussed the removal of PTEs by engineered/designer WB as compared to pristine WB. This review demonstrates the overarching scientific opportunities for a comprehensive understanding of using WB as an emerging biosorbent and a promising low-cost and effective material for the remediation of PTEs contaminated water.
350 citations
TL;DR: A brine treatment technology framework is introduced to outline the Zero Liquid Discharge (ZLD) approach through high freshwater recovery and wastewater volume minimization, which results in the reduction of environmental pollution, minimization of waste volume and production of freshwater with high recovery.
348 citations
TL;DR: In this paper, a novel design involving controlled water transport, edge-preferential crystallization and gravity-assisted salt harvesting was proposed to achieve continuous steam generation and salt harvesting in over 600 hours of non-stop operation.
Abstract: As a low-cost green technology, solar steam generation using nanostructured photothermal materials has been drawing increasing attention in various applications, e.g. seawater desalination, and zero liquid discharge of industrial wastewater. However, the crystallisation of salts on the surface of photothermal materials during steam generation leads to a gradual decline in the water evaporation rate. Herein, this challenge was overcome by a novel design involving controlled water transport, edge-preferential crystallisation and gravity-assisted salt harvesting. The crystallisation sites of the salt were spatially isolated from the water evaporation surface, achieving continuous steam generation and salt harvesting in over 600 hours of non-stop operation. The study provides new insights into the design of solar steam generators and advances their applications in sustainable seawater desalination and wastewater management.
TL;DR: This critical analysis offers new strategies to limit the number of nano/microplastics in water and wastewater to keep water quality up to the required standards and reduce threats on the authors' ecosystems.
TL;DR: In this article, a review of recent technologies for the removal of dyes from wastewater are discussed briefly, including coagulation, membrane treatment, advanced oxidation process, biological treatment and adsorption, their performance, features, advantages and disadvantages have been highlighted.
TL;DR: The present paper is focused on the remediation of noxious wastes from wastewater using graphene based materials as adsorbents, and it contains all the details on materials - i.e., from their synthesis to application in the field of wastewater treatment (removal of hazardous contaminants of different chemical nature - heavy and rare-earth metal ions, and organic compounds - from wastewater effluents).
TL;DR: It is highlighted that WWTPs could represent a potential source of MPs also to agroecosystems and the possible re-use of WWTP sludge in fertilizers for agriculture is highlighted.
TL;DR: Technological solutions including conventional activated sludge, membrane bioreactors, moving bed biofilm reactors, and nature-based solutions such as constructed wetlands are compared for the achievable removal efficiencies of the selected CEC and their potential of acting as reservoirs of ARB&ARGs.
TL;DR: With the capabilities of stable and high-rate evaporation out of high-salinity brine and the effective separation of solute from water, it is expected that this technology can have direct implications in various fields such as wastewater treatment, sea-salt production, and metal recycling.
Abstract: In recent years, interfacial solar vapor generation has shown great potential in realizing desalination and wastewater treatment with high energy conversion efficiency. However, high evaporation rate cannot be maintained because of the seemingly unavoidable fouling or salt accumulation on the solar absorbers. The degradation accelerates as the solute concentration increases. Here, we demonstrate a water lily–inspired hierarchical structure that enables efficient evaporation (~80% solar-to-vapor efficiency) out of high-salinity brine [10 weight % (wt %)] and wastewater containing heavy metal ions (30 wt %). More notably, neither decrease in evaporation rate nor fouling on absorbers was observed during the entire evaporation process until water and solute were completely separated. With the capabilities of stable and high-rate evaporation out of high-salinity brine and the effective separation of solute from water, it is expected that this technology can have direct implications in various fields such as wastewater treatment, sea-salt production, and metal recycling.
TL;DR: In this article, a review of the current research in heavy metal adsorption by clay minerals such as halloysite, bentonite, montmorillonite, vermiculite and attapulgite is presented.
Abstract: Heavy metal pollution such as water contamination by Pb, Hg, Cu, Cd and Cr ions is induced by rapid urbanization and industrialization and is a major threat to human health. One of the most efficient processes to clean contaminated water is adsorption. Adsorbents such as clay minerals and modified clays are efficient for the removal of metal ions from wastewater. This manuscript reviews current research in heavy metal adsorption by clay minerals such as halloysite, bentonite, montmorillonite, vermiculite and attapulgite, from 2013 to 2017, and highlights the main adsorption mechanisms. The structure, composition and synthesis of various clay minerals and modified clays are presented.
TL;DR: Chromium (Cr) is a potentially toxic metal originating from natural processes and anthropogenic activities such as the iron-steel, electroplating, and leather industries.
Abstract: Chromium (Cr) is a potentially toxic metal originating from natural processes and anthropogenic activities such as the iron-steel, electroplating, and leather industries, which is carcinogen to liv...
TL;DR: Of these methods, membrane-based separation processes (MBSPs) are effective over the conventional techniques for providing clean water from wastewater streams at an affordable cost with minimum energy requirement.
TL;DR: FA can be leveraged to substantially enhance the biodegradability of secondary sludge, which would further improve biological nutrient removal and enhance renewable energy production.
TL;DR: In this paper, the authors describe the different methods used by the dairy industry to treat wastes, highlighting their effects on quality and efficiency removal of the pollution, focusing on biotechnological alternatives to utilize the dairy wastes.
Abstract: Background Demand of dairy products is increasing in different countries, which results in the development of the dairy industry and increases in the generation of wastes. The main wastes generated are whey, dairy sludges and wastewater (processing, cleaning and sanitary). They have high nutrient concentration, biological oxygen demand (BOD), chemical oxygen demand (COD) and organic and inorganic contents. Furthermore, they can contain different sterilizing agents and a wide range of acid and alkaline detergents. Pollution due to dairy industry affects the air, soil and water quality. Scope and approach This review aims to describe the different methods used by the dairy industry to treat wastes, highlighting their effects on quality and efficiency removal of the pollution. Especially, it focusses on biotechnological alternatives to utilize the dairy wastes. Key findings and conclusions Physico-chemical, biological, and biotechnological methods can be used for treatment of dairy wastewaters. The physico-chemical treatment is used for reduction of milk fat and protein colloids, but it has the disadvantages of the high cost of the reagents and limited removal of COD. Biological treatments are used to remove organic material from dairy waste, however, the formation of sludge during aerobic biodegradation is a disadvantage. Aerobic and anaerobic process treatments can be used together in order to reach the effluents discharge limits for dairy wastewater. Biotechnological processes are the most recent alternatives, and can result in important products to the industries, such as whey-derived products, bioplastics, biofuels, bioenergy, organic acids, bioactive peptides, enzymes, among others.
TL;DR: The field is reviewed from the rather fundamental research on biofilm morphology and microbial community analysis to the impact of feedwater composition, process parameters and organic removal performance and the application potential is highlighted in comparison to conventional ultrafiltration.
TL;DR: In this paper, a comparative study of the efficiency of different coagulants in textile wastewater treatment was carried out, and the results showed that the use of natural coagulate instead of synthetic ones has demonstrated significant advantages since it provides a low cost and environmentally friendly technology for removing dyes.
TL;DR: In this paper, a sludge-derived biochar (SBC) was prepared, characterized and applied to activate peroxymonosulfate (PMS) for the degradation of triclosan (TCS) in water and wastewater.
TL;DR: Significant greater stability and enhanced nitrogen removal efficiency have been demonstrated in the novel integrations of PD and anammox process, indicating a broad perspective in dealing with the mainstream municipal sewage, ammonia-rich streams, and industrial NO3--N contained wastewater.
TL;DR: Wang et al. as mentioned in this paper revisited the development history of China's municipal wastewater management and identified the remaining challenges, highlighting the future needs of sustainable development and exploring China's own wastewater management path, and outlook the future from several aspects including targets of wastewater management, policies and technologies, especially the new concept WWTP.
Abstract: China has the world’s largest and still growing wastewater sector and water market, thus its future development will have profound influence on the world. The high-speed development of China’s wastewater sector over the past 40 years has forged its global leading treatment capacity and innovation ability. However, many problems were left behind, including underdeveloped sewers and sludge disposal facilities, low sustainability of the treatment processes, questionable wastewater treatment plant (WWTP) effluent discharge standards, and lacking global thinking on harmonious development between wastewater management, human society and the nature. Addressing these challenges calls for fundamental changes in target design, policy and technologies. In this mini-review, we revisit the development history of China’s municipal wastewater management and identify the remaining challenges. Also, we highlight the future needs of sustainable development and exploring China’s own wastewater management path, and outlook the future from several aspects including targets of wastewater management, policies and technologies, especially the new concept WWTP. Furthermore, we envisage the establishment of new-generation WWTPs with the vision of turning WWTP from a site of pollutant removal into a plant of energy, water and fertilizer recovery and an integrated part urban ecology in China.
TL;DR: This paper presents comprehensive information for the adsorption of heavy metal ions from water and waste water using various nanostructured adsorbents such as different clay minerals, carbon nanotube and nanocomposites, hence protecting water bodies from high pollution load.
TL;DR: In this paper, a magnetic nitrogen doped biochar-supported CoFe2O4 composite (MNBC) was synthesized by using rice straw, an abundant agricultural waste as the precursor.
Abstract: Conversion of agricultural biomass waste to value-added biochar based catalysts receives tremendous interests because it falls into the scope of resource recycle concept. In this work, a magnetic nitrogen doped biochar-supported CoFe2O4 composite (MNBC) was synthesized by using rice straw, an abundant agricultural waste as the precursor. The prepared catalyst exhibited excellent performance in catalytic degradation of metolachlor (MET), a broad-spectrum chloroacetanilide herbicide, by coupling with peroxymonosulfate (PMS). The pyrolysis temperature played a significant role in the activity of the resultant catalysts. Among others, MNBC800 catalyst performed the best stability and reusability. In-situ (EPR) analysis revealed that SO4•−, •OH and 1O2 participated into the degradation process and the SO4•− was the major contributor. The degradation was promoted at neutral and weak basic conditions, whilst significantly inhibited at strong basic condition (pH = 11). Eleven degradation intermediates were successfully identified through liquid chromatography – quadrupole time-of-flight – mass spectrometer (LC-Q-TOF-MS). The degradation mainly occurred via hydroxylation, dechlorination, and dealkylation reactions. Additionally, though the degradation was greatly inhibited in real wastewater, it was not remarkably influenced in river and groundwater, implying its applicability in river/groundwater remediation. Eventually, the easy separation and low toxicity make the catalyst promising for the degradation of MET from several aquatic systems. This study would pave the way to the catalytic degradations of organic pollutants by low-cost biochar based catalysts.
TL;DR: In this paper, the authors present a review on the detoxification aspects of AOPs with special emphasis on arsenic toxicity with different bioassays employing bacteria, invertebrates, algae, plants, and fish.