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The remote villages in arid and semi-arid inland regions of Rajasthan state in India and many other countries are dependent on brackish groundwater for potable uses. Generally, community RO (Reverse Osmosis) plants are installed for brackish water treatment in rural agglomerations where the MLD (Minimal liquid discharge) scheme is followed which includes pre-treatment and pre-concentration technologies, that consumes relatively low energy than thermal technologies for ZLD (Zero liquid discharge). This paper discusses the application of hybrid processes involving MLD technologies such as IEX (Ion Exchange), NF (Nanofiltration), RO, FO (Forward Osmosis) and UF (Ultrafiltration). for brackish water treatment. The impact of feed water quality and operational parameters such as flux, feed flow rate and transmembrane pressure are discussed. Further, performance indicators such as salt rejection, recovery, energy consumption and scaling propensity are discussed to evaluate the feasibility of various configurations. The findings of this review indicate NF as impressive membrane technology for conjunction with IEX, RO and UF. Further, the use of FO or NF as a pre-treatment for RO has been found to reduce the scaling propensity of RO membranes; and the use of UF as a pre-treatment for NF has been found to reduce the propensity of organic fouling on NF membranes. Also, IEX as a pre-treatment can be coupled with low-pressure RO/NF to remove the scale-causing divalent ions and enhance recovery along with an option of reusing RO/NF reject water for regeneration of IEX column. [ABSTRACT FROM AUTHOR]

Purpose: The textile industry is one of the largest and most important industrial sectors in India. Because the textile industry consumes large quantities of water and produces highly polluted water discharge, its environmental impact is high. Water is expensive to use, treat and dispose of. Therefore, water conservation and reuse are critical necessity for the textile industry because decreasing water and wastewater treatment and recycling costs can be beneficial. Design/methodology/approach: This research neutralized the pH during dyeing industry wastewater treatment. The system should be robust to erroneous sensor measurements. A pH meter was developed and used to monitor the pH of wastewater hourly before and after HCl treatment. Findings: HCl was used to neutralize the pH of wastewater from 9 to 7.5. The amount of HCl was optimized depending on the wastewater. Three wastewater treatment methods were used, namely, HCl, wash water and reverse osmosis (RO) treatments. The HCl treatment was the most effective for decreasing the pH; the wash water treatment was the most effective for decreasing the total dissolved solids (TDS), total suspended solids (TSS) total hardness and chemical oxygen demand; and the RO treatment was the most effective for decreasing the biochemical oxygen demand, TDS, TSS, total hardness and Cl− concentration. Originality/value: The pH should be monitored during the textile dyeing because the addition of color to textile fabrics is the most effective at neutral pH. This study evaluated several parameters of wastewater, including pH, color, TSS and TDS. The fabricated digital pH meter provided superior results than conventional measuring devices. The goal was to maintain a neutral pH during dyeing and recycle wastewater to improve environmental sustainability. The newly developed digital pH meter was less expensive and more precise than traditional pH meters. Before reusing and recycling, wastewater underwent ultrafiltration and RO treatment. [ABSTRACT FROM AUTHOR]

Arsenic contamination in drinking water is a great concern in different regions of the world as well as in India. Several technologies have been investigated to remove arsenic from water, such as coagulation and co-precipitation, ion exchange, adsorption, and reverse osmosis. In the present research, electrocoagulation with iron electrodes has been assessed as a treatment technology for arsenic removal from groundwater to reach concentrations below 0.01 mg/L (WHO limit) and which is technically effective, affordable for the local area, and easy to operate and maintain. Electrochemically generated iron is converted to hydrated ferric oxide within the contaminated water, which takes up the arsenic from water. A downstream filtration unit (sand or activated alumina) is applied to remove ferric hydroxide flocs produced during the process. The laboratory experiments were conducted in a batch reactor using iron plates as electrodes with monopolar configuration to study the effects of initial pH and electro-charge loading (ECL) on arsenic removal. The optimum operating condition was observed for an electro-charge loading of 25–30 Coulombs/L at pH 7.0 and an initial arsenic concentration of 0.2 mg/L. Two field trials were implemented in West Bengal after suitably designing the electrocoagulation system. Arsenic removal was significant (75–80%) delivering safe water with arsenic below 0.01 mg/L (acceptable limit). Passivation of the electrodes occurred during the operation and calcium-based (including iron) deposition was observed on the cathodes. Passivation is avoidable after running regular polarity reversal of the electrodes. [ABSTRACT FROM AUTHOR]

Introduction: Excessive intake of fluorides can lead to the development of fluorosis, a serious public health issue in India. The objective of this study was to assess the impact of community defluoridation in preventing fluorosis in Kaiwara village. Methodology: This community interventional trial was conducted in Kaiwara village, Karnataka, after obtaining ethical clearance. The study included 903 participants; preintervention data were collected by recording the required parameters. The postinterventional study was carried out 2 years after installing the reverse osmosis plant. Data from pre- and post-intervention study were compared. Results: Dean's index showed no significant change in the pre- and post-intervention period for its various categories (P = 0.543). However, the mean urine fluoride levels were found to be decreased significantly (Wilcoxon Signed-Rank test, P < 0.001). Conclusion: This study demonstrates the importance of providing defluorinated water to the village population as a potential solution for fluorosis. [ABSTRACT FROM AUTHOR]

Background and objective: Reverse osmosis technique is an adequate method for treating ground water for reducing the burden of abnormal levels of fluorides. The method protects the general population from diseases associated with high fluoride levels in the body. The objective of the present study was to assess the suitability and sustainability of reverse osmosis technology for community de-fluoridation of water used for cooking and drinking purposes in Kaiwara village, Karnataka. Methodology: This interventional study was conducted between July 2012 and June 2014 at Kaiwara village, Karnataka using reverse osmosis technique for de-fluoridation of water used for drinking and cooking. Complete chemical analysis of water was done before intervention, and processed water supplying the village was tested every six months after intervention for about two years. The variation in chemical concentrations of various components were analysed. Results: The mean baseline level of fluoride in untreated water was 2.075 mg/dl (above the safety limit), which dropped to 0.08 mg/dl at the end of first six months following the intervention, 0.042 mg/dl in 12 months, 0.1 mg/dl at 18 months and 0.01 mg/dl at 24 months after intervention, which were all below the safety limits for India in the treated water. The mean total dissolved solids in the water was 542.25 mg/dl in the untreated water, which dropped to zero after the first six months, remained at zero in the next six months, rose to 120 mg/dl at 18 months and then dropped to 70 mg/dl at 24 months in the treated water. The observed values were reduced significantly. Discussion: The study concluded that it is possible to set up a community de-fluoridation plant using reverse osmosis technique at Kaiwara village, Karnataka which is economically sustainable and acceptable by local population. [ABSTRACT FROM AUTHOR]

The conventional treatment system adopted by Indian and Global Tanneries consist of (i) Segregation of Spent Chrome Stream and discharge of supernatant for combined treatment along with effluent from all sectional operations starting from soaking to finishing, (ii) Conventional physiochemical and biological treatment for reduction of Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), etc., (iii) Ultra-filtration and Reverse Osmosis (RO) system for recovery of water and Multiple Effect Evaporator (MEE) for the evaporation of RO reject stream and generation of mixed salt in case of Zero Liquid Discharge (ZLD) system and (iv) Storage of mixed salt recovered from the MEE system for which no viable disposal system is found. Establishment of treatment system for the mixed stream results in poor performance of biological treatment units, increases the O&M cost, and accumulation of recovered mixed salt in case of ZLD system. It is estimated that, more than 8-10 tons of mixed salt is generated during the treatment of 1.0 MLD effluent under ZLD system. To address this serious environmental problem, an innovative approach of segregation of saline streams such as soak liquor and chrome liquor are planned to be collected separately with the feasibility of recovering reusable quality salt and chromium in the form cake for regeneration and use in the form of Basic Chromium Sulphate (BCS) by the tanneries. This innovative treatment concept has been developed and is being implemented in many CETPs in India. This will become the first of its kind in Global Leather World. This developmental scheme is in accordance with the guidelines and recommendations of UNIDO in terms of sustainability of ZLD system for the leather sector. The technological developments on cleaner productions, centralized chrome recovery reuse system, segregation of saline soak water for separate treatment with recovery of water and quality salt are dealt in this technical paper. [ABSTRACT FROM AUTHOR]

Delivering the right amount of fluoride to drinking water protects the teeth from decay and reduces the risk of cavities. Nonetheless, fluorosis has been diagnosed as the result of excessive exposure of fluoride, which induces brain impairment, muscle disorders and hyperactivity. Fluoride ingestion during the formation of the tooth enamel is the main reason for fluorosis, which is characterized by hypomineralization. Dissolution of fluoride-containing rock minerals contributes to naturally occurring fluoride contamination in water. The intentional addition of fluoride to water in dental care is alarming in growing countries such as India. This article reviews the origin of fluoride, the analysis of fluoride derivatives and the technologies to remove fluoride from water. The manuscript presents adsorption techniques for fluoride removal, using different types of adsorbents. The adsorption capacities of adsorbents under various conditions, such as contaminant concentration, adsorbent dosage, time, pH and temperature, are presented. Adsorbent types include alumina, zeolites, organic waste, shell-based and carbon-based including graphite and carbon nanotubes. Defluoridation of water using clays and muds, modified activated alumina, chitosan derivatives and composites are also discussed. [ABSTRACT FROM AUTHOR]

Phenolic compounds are one of the main contributors to water source contamination worldwide. In this review, the data collected on Elsevier, Scopus, and Pubmed, considering papers published between 2000 and 2023, showed more than 60 different phenols have been identified in water matrix (<0.065–179,000,000 ng L−1). The highest concentration reported was in surface water canals in India. The most recurrent and studied compound was bisphenol A (n = 93) in concentrations ranging from 0.45 to 2,970,000 ng L−1. The solid phase extraction (HBL Oasis cartridge) and methanol as solvent was the method of pre-concentration most used followed by gas chromatography for the determination of phenols in water samples. The importance of drinking water guidelines incorporating more phenolic compounds was emphasized given the variety of these compounds quantified in water matrix. The human health risk assessment (HRA) was performed for the min-max concentrations of the pollutants reported in the literature. High HRA even at the lowest concentrations for 2-nitrophenol, 2,6-dichlorophenol, 3,4,5-trichlorophenol, 2,3,4,6-tetrachlorophenol, and 2,4-dinitrophenol was recognized. The cancer risk estimated was considered possible for 3-methylphenol, 2,4-dimethylphenol, 2,4,6-trichlorophenol, pentachlorophenol, and 2,4-dinitrophenol in the highest concentrations. The in-depth discussion of mechanisms, advantages, challenges, and carbon footprint of membrane technologies in water treatment and phenols retention demonstrated the great potential and trends for the production of safe drinking water, highlighting reverse osmosis, as a mature technology, and membrane distillation, as an emergent technology. [Display omitted] • More than 60 phenolic compounds were identified in water sources. • The highest concentration in surface water was reported as 1.79 E8 ng L−1 in India. • Water guidelines address, in general, only 14 phenols. • High risk to human health and the possibility of cancer were estimated. • Membrane technology can effectively remove phenols, especially reverse osmosis. [ABSTRACT FROM AUTHOR]

The presence of elevated fluoride levels in Bathinda City, Punjab, India, has been a major health concern for residents. Previous studies have primarily focused on groundwater but have neglected other drinking water sources. The primary aims of this investigation are to analyze fluoride levels in various drinking water sources in Bathinda City, establish their relationship with physicochemical parameters, and appraise the non-carcinogenic health hazards associated with fluoride exposure for various age categories. A total of 296 water samples were collected, including groundwater (GW), surface water (SW), public water supply (PWS), bottled water (BW), private reverse osmosis water (PROW), municipal reverse osmosis water (MROW) (pre-and post-monsoon), and rainwater (RW). Fluoride levels were determined using a photometer (model: HI97739; make: Hanna Instruments) employing the SPADNS colorimetric procedure. The mean fluoride levels in different water sources were as follows: GW (3.77 mg L−1), SW (0.76 mg L−1), PWS (1 mg L−1), BW (1.4 mg L−1), PROW (0.94 mg L−1), MROW (pre-monsoon) (1.62 mg L−1), MROW (post-monsoon) (1.29 mg L−1), and RW (0.63 mg L−1). A significant proportion of GW (78.4%), PWS (14.3%), BW (37.5%), PROW (25%), and MROW (72.1% in pre-monsoon and 27.9% in post-monsoon) samples surpassed the World Health Organization guideline value. The study findings highlight the high fluoride levels in GW, BW, PROW, and MROW, making them hazardous for consumption. Hazard quotient analysis suggests that children face the highest risk of non-carcinogenic health effects from fluoride exposure, followed by teenagers, adults, senior citizens, and infants. [Display omitted] • Fˉ levels were measured in various sources of drinking water in Punjab, India. • Most of the drinking water sources are unfit for human consumption. • Physicochemical parameters influence Fˉ levels in various drinking water sources. • Children and teenagers are more vulnerable to high fluoride exposure than adults. • The study found a potential risk of skeletal and dental fluorosis in the region. [ABSTRACT FROM AUTHOR]

Background: Punjab is becoming cancer capital of India due to increasing cancer rates especially in Malwa belt. Keeping in view the alarming increase in cancer incidence in this region, 1881 Reverse Osmosis plants have been installed in 16 districts of Punjab by the Government since 2010, but People are not utilizing this community RO water fully. Although 180 crores of rupees have been spent on installation of these RO plants by the government, but little attempts have been made to ascertain the extent of utilization of this water by the people and the Knowledge, Attitude and practices of the people residing in rural areas regarding community RO water. Aim of the study to assess the utilization and awareness of community RO water by the households in the study area. Results: There is only 50% utilization of community RO water as per this study. Most common responses elicited for not using community RO water was the unavailability of any family member for fetching this water (32%). Some other reasons observed were affordability (18%), accessibility due to distance of RO plant (15%) and dislike for taste of water (17%) though most of the households were aware of the risks of using contaminated water. Conclusions: though utilization of community RO water has increased as compared to past records still it is not as much as expected, since it has been 5 years since the installation of RO plants. Government heads to intensify its efforts in making people aware and solving the problems encountered in using community RO water. [ABSTRACT FROM AUTHOR]

Household water treatment systems play an important role in safe drinking water supply in India as safety barrier at point of use and contribute to improved public health on short and medium term. In this study, three household water purifiers that based on different principles were investigated in order to determine whether and under which conditions they can safeguard the microbial safety of drinking water. The water purifiers consisted of the following treatment trains: (i) activated carbon (AC), ultrafiltration (UF) and reverse osmosis, AC and UV irradiation; (ii) AC and UF, and (iii) AC, passive chlorine dosage and AC. They were examined in a two-phase challenge test using bacteria (Escherichia coli) and bacteriophages (MS2) in a laboratory environment. Under normal operation conditions filtering tap water, mean microbial reductions of 4–6 log10 and 0–3 log10 for E. coli and MS2 phages, respectively, were observed that therefore partly comply with WHO requirements. Reduction of protozoa (Cryptosporidium oocysts) was estimated based on size exclusion or chlorine exposure to be ≥2 log10 (membrane-based size exclusion) and <2 log10 (chlorine-based disinfection), respectively. To further determine their applicability for filtering water sources with higher pollution load, tap water with increased loads of organic and suspended matter simulating turbid river water (which is beyond the intended use of the systems) was studied. Only the multi-stage treatment was able to remove organics and turbidity to ≥89%. Both tested membrane-based systems suffered from rapid and severe irreversible fouling when challenged with high turbidity whereas the chlorine-based system maintained the production rate, however, at the expenses of a lower physicochemical quality. Hence, none of the tested systems was able to produce water of satisfying physicochemical and microbial quality at sufficient quantities from raw water with turbid river water quality. Therefore, it is suggested introducing mandatory standardized testing protocols and certification of household water purifiers specifying the usage conditions. [ABSTRACT FROM AUTHOR]

Arsenic contamination of groundwater is posing a serious challenge to drinking water supplies on a global scale. In India and Bangladesh, arsenic has caused the most serious public health issue in the world for nearly two decades. The aim of this work was to study an arsenic removal system based on reverse osmosis at pilot scale treating two different water sources from two different locations in the State of Bihar, India. For this purpose two villages, Bind Toli and Ramnagar in the Patna District were selected, both located very close to the river Ganga. The trials were conducted with aerated and non-aerated groundwater. It is the first time that the arsenic removal efficiency for aerated and non-aerated groundwater by reverse osmosis technology in combination with an energy-saving recovery system have been studied. As the principle of reverse osmosis requires a relatively high pressure, its energy demand is naturally high. By using an energy recovery system, this demand can be lowered, leading to an energy demand per liter permeate of 3–4 Wh/L only. Due to high iron levels in the groundwater and as a consequence the precipitation of ferric (hydr)oxides, it was necessary to develop a granular media filter for the trials under aeration in order to protect the membrane from clogging. Two different materials, first locally available sand, and second commercially available anthracite were tested in the granular media filter. For the trials with aerated groundwater, total arsenic removal efficiency at both locations was around 99% and the arsenic concentration in permeate was in compliance with the WHO and National Indian Standard of 10 μg/L. However, trials under anoxic conditions with non-aerated groundwater could not comply with this standard. Additionally a possible safe discharge of the reverse osmosis concentrate into an abandoned well was studied. It was observed that re-injection of reject water underground may offer a safe disposal option. However, long-term hydrogeological studies need to be conducted for confirmation. [ABSTRACT FROM AUTHOR]

Sea-water desalination has emerged as the key alternative to overcome demand–supply gap of potable water, worldwide. This paper aims to carry out a technology review of sea-water desalination, technologies in an integrated framework of economic, environmental and ecological analyses. The economic analysis here refers to a project/technology development effort analysis in the context of national economy. The cost per unit output from this perspective is the economic cost. In an environmental analysis, the higher specific energy consumption in a process vis-à-vis the best technology option in the project area is measured in terms of certified emission reduction. In ecosystem analysis, the accent is to find out whether the technology disrupts the existing eco-system. Such a disturbance entails a huge ecological cost. The cost quantified per unit output is arrived at as the reduction in GDP in the project affected area due to the direct and indirect effects of adverse ecological effects; these effects are deduced using specifically developed I–O tables 'with and without' technology options, for the project area. The choice of technology is the one with the minimum composite cost per unit output. The composite cost in the context is the sum of economic cost, the environmental cost and the ecological cost per unit output. The framework is applied in the technology review of low-temperature thermal desalination process and its impact on project areas of Lakshadweep islands and Thoothukodi district vis-à-vis the alternative RO process of sea-water desalination technology. [ABSTRACT FROM AUTHOR]

Abstract: Fresh water crisis is evident in many parts of India, varying in scale and intensity at different times of the year. About seven states are underlain by brackish ground water affecting 42million people. 25% population of India resides along the coast having easy access to seawater. Hence, these saline water resources can be exploited to meet their water requirements. Desalination technologies create new sources of fresh water from seawater or brackish water, but they do require energy. This paper addresses the socio-economic and technical feasibility of powering membrane desalination technologies with photovoltaic (PV) systems in regions which have mixed advantage of high solar potential and disadvantage of presence of saline water. A database of Indian population dependence on saline water, its regional solar potential and present state of desalination have been compiled. Technical aspects of reverse osmosis (RO) and electrodialysis (ED) membrane desalination processes powered by PV are addressed and desalinated water cost, obtained through PV-RO and PV-ED processes, are compared with diesel powered RO and ED processes respectively for a plant capacity of 50m3/day over a 20year working life of the plant. The technology will augment fresh water requirements of India and contribute to its sustainable development. [ABSTRACT FROM AUTHOR]

Chennai Seawater Desalination Plant (SWDP), with a production capacity of 100 MLD with a maximum extended capacity in future of up to 120 MLD, is located at Minjur (Chennai, India) and is being developed under a 25-year DBOOT contract. It will supply drinking water to the city of Chennai which currently experiences poor water quality, water shortages and restrictions. The Chennai SWDP is situated in close proximity to a river creek, an important port and an overpopulated urban area, resulting in a difficult to treat raw water source subject to very high suspended solids values, and a high level of pollutants. The different pilot plant treatment processes (gravity settling, flotation, gravity filtration and pressure filtration) can be connected in series or in parallel. Therefore, this paper describes the pilot plant studies performed to determine the feasibility, efficiency and best operation mode of the pre-treatment process designed for Chennai SWDP at the time of the publication as well as the main conclusions inferred from those studies. By applying the results of these studies to the full-scale design, the performance of the RO membranes will be kept optimal while reducing production and maintenance costs. It can be concluded that this pilot study has been important in developing the Chennai SWDP design, and provided valuable information for the plant start up and its operation later on. [ABSTRACT FROM AUTHOR]

Abstract: The aquatic environment around the textile industries in India was severely affected due to continuous discharge of effluents. In order to avoid further deterioration, the pollution control board of Tamil Nadu, India has enforced zero discharge concepts throughout the state. Consequently, most of the industries have opted membrane technology to recover water. The present study was aimed to find out the efficacy of electrochemical techniques as pretreatment methods to reverse osmosis (RO). The textile wastewater was initially treated by electrocoagulation to remove the suspended solids. After the electrocoagulation, the wastewater was further treated by electrooxidation for COD removal. Mild steel as anode was found to be effective for coagulation of suspended solids. For electrooxidation, graphite and RuO2/IrO2/TaO2 coated titanium were used as electrodes. The efficiency of these electrode materials was evaluated in terms of chemical oxygen demand (COD) removal, instantaneous current efficiency (ICE) and electrooxidation index (EOI). The COD was removed to the extent of 90–93% using graphite and 54% with RuO2/IrO2/TaO2 coated titanium electrodes. The current efficiency of 40% and 11% was achieved with graphite and RuO2/IrO2/TaO2 coated titanium respectively. The degradation of organics was followed using GC–MS and the reason for incomplete degradation of organics in the presence of RuO2/IrO2/TaO2 coated titanium was discussed. [Copyright &y& Elsevier]

Abstract: Arsenic poisoning in drinking water is a health issue in many Asian countries including Bangladesh, India, China and Vietnam. In areas where the drinking water supply contains unsafe levels of arsenic, technologies to remove arsenic are of prime importance. Many technologies have been developed for the removal of arsenic. Among those reverse osmosis (RO) and nanofiltration (NF) are very promising techniques because they have the advantage of removing dissolved arsenic along with other dissolved and particulate compounds. So far, however, this kind of membrane filtration has needed bulky and sophisticated units, which are not suitable for application in the rural areas of developing and newly industrializing countries. Therefore the purpose of this work was to test a small-scale, commercially available marine RO desalinator with three different membrane modules on arsenic removal. The experiments were conducted with arsenic-spiked local tap water, using As(III) and As(V) up to feed concentrations of 2400 μg/L. The As(V) rejection was generally much better than the retention of As(III). With two of the tested membranes As(V) rejection was so high, that the permeate water quality complied with the WHO recommended maximum contaminant level (MCL) of 10 μg/L even at a feed concentration of 2400 mg/L. In the case of As(III) only feed concentrations below 350 μg/L resulted in permeate concentration lower than the MCL. The experiments should provide a basis for field tests on the ground in Bangladesh using natural arsenic contaminated groundwater. These field tests are currently running. [Copyright &y& Elsevier]

In compliance with the protection of the drinking water source in one of the state capital of India, a cluster of small scale textile industries implemented membrane processes based on treatability studies for recovery of boiler feed water quality with recourse to effluent recycling/reuse. The paper addresses to a case study in one of the textile units on upgradation of a full scale effluent treatment plant comprising chemical, biological, tertiary and advanced treatment processes. Based on the adequacy assessment of chemical and biological processes, improvement in the performance of the unit processes were achieved through optimization of coagulant dosage for chemical coagulation and build-up of active biomass in the activated sludge system. In addition, application of membrane separation processes comprising ultrafiltration and reverse osmosis units are also highlighted including disposal of reverse osmosis (RO) rejects through evaporator leading to zero liquid effluent discharge. The treatment scheme implemented resulted in conservation of around 55% of fresh water demand for industry. [Copyright &y& Elsevier]

Abstract: Textile dyeing industries in Tirupur and Karur of Tamil Nadu (India) usually discharge effluents ranging between 80 and 200m3/t of production. Dyeing is performed either by conventional winch process or by advanced soft flow reactor process. Hypochlorite, the commonly used bleaching chemical is being gradually phased out by alkaline hydrogen peroxide solution that generates less effluent and fewer solids in the effluents. Coloring of yarn/cloth takes place in the presence of high concentration of sodium chloride or sodium sulphate (25–75kg/m3) in dye solutions. Dye bath wastewaters and wash waters are the process effluents of dyeing industry which are collected separately or together and follow the advanced treatment for maximum recycling of recovered waters. Dye bath water after treating by sand and nanofiltrations (NF), the permeate is used in process for dye bath preparation and the reject of about 20–30% is sent to multi effect evaporator (MEE)/solar evaporation pond (SEP). Wash waters treated using a sequence of physicochemical and biological unit processes are passed into two stages reverse osmosis (RO) membrane systems and then the permeate is reused in the processes. The rejects about 15–20% of the inlet volume is subject either to nanofiltration for salt recovery or sent to evaporators. The final rejects from nanofilter systems is directed to multi effect evaporator system where condensed waters are recovered. The removal of total dissolved solids (TDS), chemical oxygen demand (COD), chloride and sodium are in the range of 80–97%, 91–97%, 76–97% and 96%, respectively. Multiple effect evaporators out flows of about 2–3% of the effluent volume are allowed for solar evaporation and the solids are disposed off. The cost of operation of MEE is about INR 400/m3 of the rejects. The cost of water recovery is about INR 60–80/m3 including commissioning and maintenance whereas price of raw-water in Tirupur is about INR 100/m3. [Copyright &y& Elsevier]

DuPont Water Solutions, a business unit of DuPont Safety & Construction, is working with after-sales services company Onsitego, based in India, to sell FilmTecTM residential reverse osmosis (RO) elements on Amazon, making them available to households across the country. [ABSTRACT FROM AUTHOR]

Described herein is a case study of long-term reverse osmosis (RO) plant operation without applying chemical pretreatments to the feed water. This project was undertaken with the financial support from the Department of Bio-Technology, New Delhi, and the work was carried out by a research team from Central Salt and Marine Chemicals Research Institute (CSMCRI), Bhavnagar (Gujarat), India. A prototype plant with a 30,000 L/d capacity was designed, manufactured, installed and operated at the village of Mocha-Gorsar, located in the Porbandar district, to provide drinking water. The village was to be developed as a model Bio-Village where other projects related to village problems are also operated by other research institutes. Thin-film composite (TFC) membrane-based RO technology was indigenously developed by the institute for treatment of brackish water and waste water for the first time in India; it was used successfully in this plant, which gave a typical NaCl rejection of about 95%. This is a typical case study of RO plant installation where physical methods of pretreatment such as sand and micron cartridge filters were used; no chemical pretreatment of feed was employed for long-term brackish water desalination study. The idea was to avoid the usage of chemicals, which concentrate in the effluent water, might affect the environment and may not suit the village community. Plant performance during 24 months of continuous operation with respect to variable feed salinity, membrane cleaning and regenerations is discussed. [Copyright &y& Elsevier]

Fibre reinforced plastic (FRP) basin solar still is manufactured and marketed commercially in developing/underdeveloped nations. Unfortunately, these commercial units have not been widely adopted by the public due to its low water productivity. In the present investigation, an effort has been made to assess the performance and enviro-economic aspects of the commercial unit and its low-cost improved versions under Coimbatore climatic conditions through real-time experiments and mathematical models, respectively. The commercial unit has distillate productivity of about 2.76 L/d under cumulative solar radiation intensity of 24.37 MJ/m2d and it increased up to 6.03 L/d with the addition of black dye and thermocol insulation. Yearly average distillate production rate, thermal efficiency, and exergy efficiency of the improved version is about 4.36 L/d, 53.62%, and 6.89%, respectively. The greenhouse payback time of the commercial unit and insulated commercial unit with black dye is about 2.39 and 1.81 Years, respectively. Global warming potential, acidification potential and photochemical oxidant formation potential of the commercial unit decreased from 0.27 to 0.12 kg of carbon di-oxide eq/L of distillate, 2.40 to 1.05 g of sulphur di-oxide eq/L of distillate and 0.73 to 0.32 g of ethylene eq/L of distillate, respectively with the incorporation of low-cost improvement techniques. The sustainability index of the improved version is around 5.94% higher than the sustainability index of the commercial unit. The distillate production cost of improved version (1.32 INR/L) is closer to reverse osmosis (RO) water supplied to Indian houses (1.00 INR/L). The incorporation of low-cost improved techniques to the commercial unit makes it an attractive option for sustainable potable water production. However, proper marketing and awareness strategies must be adopted by stakeholders to make this improved version acceptable among the public. • Potable water productivity of commercial solar stills is low. • Insulating basin to enhance productivity increases environmental impacts. • Sustainability of improved version of improved unit is about 1.08 • Global warming potential, acidification potential and human toxicity potential is about 0.21 kg of CO 2 eq/L of distillate, 1.82 g of SO 2 eq/L of distillate and 2.15 g of DCB eq/L of distillate. • Distillate production cost ranges between 1.32 and 2.15 INR/L. [ABSTRACT FROM AUTHOR]

Water scarcity is increasing in most Indian cities, exemplified by the recent 2019 Chennai water crisis. Though there were measures initiated at both institutional and local levels, water scarcity has continued. One possible solution is to install energy-efficient renewable energy-powered desalination plants (REpDP) for Indian cities, especially those in favorable climatic zones. The modeling of REpDP combined with multi-criteria decision analysis (MCDA) is proposed to prioritize the optimal site and REpDP selection for providing low-cost freshwater. A standalone seawater reverse osmosis (SWRO) based REpDP that delivers water at a rate of 1.5 m3/h is modeled. Based on the SWRO operation; analytical modeling is carried out to optimize the hybrid energy configuration that combines solar, wind, hydrokinetic with backup energy facilities. The Fuzzy-TOPSIS MCDA with five attributes is performed to rank the modeled alternatives for selected coastal cities. The analysis identified Dwarka in the state of Gujarat, India, as the most suitable urban zone. The results also indicated that the electricity and freshwater production cost for the optimal configuration with an energy recovery scheme provide savings up to 10% and 36.4%, respectively. A comparison is made with EDAS and BWM methods. It provides consistency in results with the Fuzzy-TOPSIS. [Display omitted] • Integrated membrane solutions design tool for modelling desalination plant. • Use of energy recovery scheme in desalination plant provides up to 36.4% savings. • Optimal sizing of the renewable energy-powered desalination plants in India. • Techno-economic-environmental, social, and political attributes for desalination. • Multi-criteria evaluation methods to rank the alternatives. [ABSTRACT FROM AUTHOR]

Reverse osmosis desalination plants running with renewable energy-based microgrids are gaining importance. A new approach for the design of microgrid with a reverse osmosis desalination plant system called coordinated sizing is proposed in this manuscript. The proposed algorithm is a leader-follower structured optimization process. The desalination plant is segregated as units and each unit can be operated independently as required. A direct load control-demand side management is incorporated into the sizing process to determine the optimal flexible operation of the desalination plant and microgrid's power dispatch simultaneously. A conceptual microgrid powering desalination plant is considered to evaluate performance of the proposed coordinated sizing method. Different evolutionary algorithms are applied for solving the sizing problem and the results are analyzed. The proposed coordinated sizing method is compared with the conventional sizing method. With and without the flexible operation of desalination plant cases are considered to compare economy of the plant. The results demonstrate that the proposed coordinated sizing is cost-effective and provide better operational flexibility. • Coordinated sizing of a microgrid and an RO desalination plant • Optimization framework for solving the resulting MINLP problem • Exploiting operational flexibility of RO desalination plant • Direct load control based demand response for desalination • Case studies for Ashkelon City, Israel and Chennai City, India [ABSTRACT FROM AUTHOR]

• Rhombohedral crystalline structure of calcite evidenced as major foulant. • Outward-oriented aragonite needles fouled the tail end of membrane. • Consecutive combination of ions proposed for identification of probable deposition. • Commercial antiscalant found to be ineffective for sulfate scales. An extensive chemical analysis was conducted on water samples and fouled membranes of community Reverse Osmosis plants of Rajasthan, India facing accelerated scaling. Calcium carbonate was the major foulant as evidenced by the rhombohedral crystalline structure with sharp edges in SEM images of membranes of one of the plants while the other membrane had deposits of aragonite having outward-oriented needles. The reverse solubility of CaCO 3 with temperature was the major reason behind carbonate scaling as the area witnesses ambient temperatures of more than 40 °C for many months of the year. To further explain the scaling process, a detailed chemical analysis of five recently established plants was carried out and verified by ion balance. It was found that consecutive combination of Ca2+ and Mg2+ with F−, CO 3 2- and SO 4 2- would give the best quantification of scale formation. Extent of CaCO 3 scaling was also verified through Langelier Saturation Index and Ryznar Stability Index. The earlier part of this study resulted in promotion of the use of antiscalants in these plants, leading to sharp increase in the membrane life. Therefore, reject and raw samples were analyzed in presence and absence of antiscalant in the feed supply. The molar ratios of ions clearly revealed the inefficiency of antiscalant in arresting the growth of sulfate scales. As a result, many other inorganic deposits besides carbonates require further research inputs. [ABSTRACT FROM AUTHOR]

Separation processes that combine reverse osmosis elements with ion exchange resins from German speciality chemicals company Lanxess Deutschland GmbH are playing a key role in the treatment of effluent produced by companies operating in the textile industry in India, as this brief case study shows. [ABSTRACT FROM AUTHOR]

Development of coalbed methane (CBM) projects is critical to the achievement of climate change goals because it will help facilitate coal-to-gas transitions in Asia-Pacific countries with low conventional gas reserves. However, growth in CBM in these regions will necessitate strategic, sustainable approaches to produced water management. We posit that it may be possible to deliver synergistic water, energy, and health benefits by reusing CBM-produced waters as potable water supply in water-stressed coal-bearing regions. The goal of this study is to probabilistically evaluate life cycle costs and benefits of using reverse osmosis to treat CBM-produced water in the Damodar Valley coalfields in eastern India. Two treatment configurations are assessed, namely, centralized, and decentralized (i.e., in-home). We find that both configurations offer good cost-effectiveness based on two separately computed metrics to account for the value of health improvement benefits (i.e., disability-adjusted life years (DALYs) averted or monetized health benefits). We also observe that centralized systems are more cost-effective than decentralized, because they reduce capital cost and use-phase energy consumption per unit-volume treated. Average estimated values for the cost–benefit ratio are <0.5 and 1.0 for centralized and decentralized, respectively. Normalizing by anticipated health benefits, cost-effectiveness metrics are <$30/DALY for the centralized system versus <$200/DALY for the decentralized system. These results are highly sensitive to the value of statistical life and baseline water access. A related analysis taking into account both CBM-produced waters and mine waters revealed that deployment of reverse osmosis (RO) could provide drinking to approximately 3.5 million people over 20 years in the Damodar Valley region. These results have interesting implications not only for the study region but also for other CBM-producing countries experiencing chronic severe water stress. [ABSTRACT FROM AUTHOR]

In low concentration, fluoride is considered a necessary compound for human health. Exposure to high concentrations of fluoride is the reason for a serious disease called fluorosis. Fluorosis is categorized as Skeletal and Dental fluorosis. Several Asian countries, such as India, face contamination of water resources with fluoride. In this study, a comprehensive overview on fluoride contamination in Asian water resources has been presented. Since water contamination with fluoride in India is higher than other Asian countries, a separate section was dedicated to review published articles on fluoride contamination in this country. The status of health effects in Asian countries was another topic that was reviewed in this study. The effects of fluoride on human organs/systems such as urinary, renal, endocrine, gastrointestinal, cardiovascular, brain, and reproductive systems were another topic that was reviewed in this study. Different methods to remove fluoride from water such as reverse osmosis, electrocoagulation, nanofiltration, adsorption, ion-exchange and precipitation/coagulation were introduced in this study. Although several studies have been carried out on contamination of water resources with fluoride, the situation of water contamination with fluoride and newly developed technology to remove fluoride from water in Asian countries has not been reviewed. Therefore, this review is focused on these issues: 1) The status of fluoride contamination in Asian countries, 2) health effects of fluoride contamination in drinking water in Asia, and 3) the existing current technologies for defluoridation in Asia. Image 1 • The status of fluoride contamination in groundwater of Asian countries is reviewed. • India, Pakistan and China are critically affected by fluoride contamination. • Dental fluorosis is major adverse effect due to fluoride contamination in water. • Various defluoridation techniques have been discussed. • More research on fluoride decontamination is suggested. [ABSTRACT FROM AUTHOR]

The consumption of saline groundwater has contributed to a growing incidence of renal diseases, particularly in coastal communities of India. Although reverse osmosis (RO) is routinely used to remove salt from groundwater, conventional RO systems (i.e. centralized systems using spiral wound RO elements) have limited utility in these communities due to high capital and maintenances costs, and lack of infrastructure to distribute the water. Consequently, there is a need to develop an appropriate solution for groundwater treatment based on small-scale, mobile and community-led systems. In this work, we designed a mobile desalination system to provide a simple platform for water treatment and delivery of goods to rural communities. The system employs tubular RO membranes packed in a single, low-profile vessel which fits below the cargo space. The low-profile enables minimal intrusion on the space available for the transportation of goods. Pressure is delivered by a belt driven clutch pump, powered by the engine. Water is treated locally by connecting the intake to the village well while the vehicle idles. A combined numerical and experimental approach was used to optimise the module/system design, resulting in ∼20% permeate flux enhancement. Experimental results revealed that the system can produce 16 L per square meter of membrane area per hour (LMH) at a salinity level of 80 ppm from a ∼2000 ppm groundwater when it is feed at 1 m 3 /h at 8 bars. This indicates that a vehicle equipped with 12 m 2 of tubular RO membranes can deliver 1 m 3 of drinkable water by using ∼0.9 L of diesel. Assuming eight such systems could be implemented in a community to fulfil the water demands for a village with 2000 residents, a social business study revealed that a payback time of 2.5 years is achievable, even if the sale price of the water is relatively low, USD 0.18 (Rs 12, which is half of the lowest market price) per 20 L, including providing a goods transportation service at price of USD 5.25 (Rs 350) per 100 km., (Copyright © 2018 Elsevier Ltd. All rights reserved.)