The continued use of ground/overhead storage infrastructures even after conversion from intermittent to a continuous water supply system can introduce microbial contamination into stored water, increase water losses and impose extra costs on consumers. A detailed study was conducted to understand the impact of such storage at the consumer end on quantity , microbial water quality and the associated hazards in Nagpur city, India. The study quantified the leakage losses through sumps, peak factor, physicochemical and microbial water quality parameters and coping costs for consumers in two zones of Nagpur city. Around 21% of the underground sumps in Zone-1 and 63% in Zone-2 were observed to be leaking and contaminated with faecal coliform and pathogens. The daily probability of infection was > 0.9/person/day. The study highlights the need to develop regulations supporting safe storage strategies and raising awareness concerning proper storage practices at the consumer end in a 24 & times; 7 water supply system.

The synergistic effects of increased anthropogenic activities and climate change have intensified the frequency of cyanobacterial blooms in surface water bodies. These blooms pose significant health risks to humans and animals due to the release of cyanotoxins into the water. Conventional drinking water treatment plants (DWTPs) are often ineffective in removing cyanobacterial cells due to challenges such as electrostatic repulsion, hydrophilicity, and buoyancy. While excessive pre-oxidation can remove cyanobacteria, it may cause cell lysis, increase cyanotoxin concentration, and surpass various regulatory guidelines, posing additional risks of forming disinfection by-products (DBPs). Moderate pre-oxidation presents a viable alternative by effectively removing intact cyanobacterial cells. This review comprehensively analyses the occurrence, toxicity, associated challenges faced by DWTPs, and treatment approaches for cyanobacteria. Various moderate pre-oxidation processes for enhancing coagulation efficiency while preserving cell integrity are systematically summarized and critically discussed. The review also highlights the importance of holistic multi-barrier approaches, including prevention, corrections measures and water intake management for managing cyanobacterial contamination in drinking water treatment. It underscores the need for intensive research to develop affordable and effective solutions to ensure sustainable and safe drinking water provision.

This study comprehensively evaluates handpump-attached defluoridation units installed across the Nuapada district, Odisha, where Groundwater sources are significantly affected by elevated fluoride concentrations. Evaluation conducted across three blocks, Nuapada, Sinapalli, and Boden, revealed that several locations had raw water fluoride levels exceeding the permissible limit of 1.5 mg/L, with maximum concentrations reaching up to 3.25 mg/L. The performance of three major defluoridation technologies, adsorption, ion exchange, and precipitation-based systems, was compared. While ion exchange and adsorption-based units demonstrated higher fluoride removal efficiency, they were also associated with elevated pH and TDS levels in treated water due to improper regeneration and maintenance. Precipitation-based systems were found to be less efficient in fluoride removal. The study found that no single technology proved universally superior, and highlights that long-term performance largely depended on regular operation and maintenance by trained personnel. Community involvement, routine monitoring, and context-specific technology selection emerged as critical factors for sustainability. Training programs, standardised maintenance protocols, regular audits and integration of simple indicators to detect system failure are highly recommended. The findings underscore the need for a holistic approach combining technical, managerial, and social strategies to ensure safe and sustainable drinking water access in fluoride-affected regions. • Field evaluation revealed inconsistent performance of hand-pump attachable defluoridation units in Nuapada district. • Field-specific constraints, such as lack of community engagement and inadequate post-installation support, emerged as critical barriers to sustained operation. • Comparative analysis showed that no defluoridation technology consistently worked under real field conditions.

This paper presents reclamation of greywater using "Green -wall treatment system". A Green -wall of capacity 100 L/d has been implemented with the aim of greywater reclamation from a bathing water facility. The treatment system comprised of a degreasing tank of size 0.9 m x 0.9 m x 0.3 m for oil & grease removal, followed by a Green -wall. Removal of oil & grease has been done along with commonly observed pollutants in greywater, to prevent clogging of filler material. In stage -I studies, Green -wall pots are filled with 4-10 mm & empty; inert filler material LECA and in stage -II, LECA is mixed with locally available coconut peat in equal proportion. Stage -I studies using LECA indicated that maximum achievable HRT is 12 h and the treated greywater with respect to BOD does not comply with USEPA (2012) norms for landscape irrigation. In stage -II, the optimized performance is observed at 16 &18 h HRT at hydraulic loading rate 67-70 L/m(2)/d, when compared with 14 and 12 h HRT. Treated greywater quality met the prescribed permissible limits with respect to BOD, TSS and FC and is observed to be innocuous in terms of the reuse options for agriculture and landscape irrigation. In stage -II, the BOD, COD, TSS and FC reduce from 48 to 10 mg/L, 58 to 18 mg/L, 96 to 10 mg/L and 400 CFU/ 100 mL to below detectable limits, respectively, at 18 h HRT.

Abstract The Shivpuri district of Madhya Pradesh in central India faces severe scarcity of water for drinking and other purposes during summer season. This situation prevailed due to compounded hydrogeological conditions with less precipitation and over exploitation of groundwater for irrigation needs. To address the water scarcity issue, a village water security plan (WSP) is prepared at a micro-watershed level for drought prone villages in Shivpuri tehsil of Shivpuri district in Madhya Pradesh. The plan entails about water sources and their utilization in a sustainable manner to cater the water requirements in the area. The study reveals that groundwater (GW) extraction excessively exceeds the groundwater recharge and it leads to depletion of groundwater level. Out of the total available groundwater, about 98% is used for irrigation and 2% for household purposes. The groundwater stage development above 100% indicates the over exploitation of groundwater, and the study area comes under critical category. The physico-chemical parameters of the groundwater are within the permissible limits as per BIS standards. The remote sensing data were used for thematic mapping to prepare a water security plan for augmentation of groundwater in the area. The study reveals that the organized scientific surveys facilitate in improvement of existing groundwater resources which can fulfill the requirements of local people.

Abstract Membrane-based PoU water treatment systems have proved to be a milestone in PoU water treatment eliminating various shortcomings of other water treatment technologies. The main driver of membrane-based PoU water treatment systems is that it works without the addition of chemicals, with relatively low energy usage, and easy and well-arranged process conductions. With improved technology, there is an inevitable need to understand the basic operational parameters, design and maintenance of membrane-based PoU water treatment systems to eliminate the repercussions of lack of knowledge. The book describes membrane-based PoU water treatment systems and is divided into eight chapters. Chapter 1 explains the sources and contaminants in drinking water and the importance of removing these contaminants. Chapter 2 describes different units, advantages and limitations of the conventional water treatment plants and various PoU water treatment technologies. Chapter 3 covers components of membrane-based PoU water treatment systems. Chapter 4 describes the effective designing of various components of the membrane-based water treatment systems to make them more economical and practical. Modelling, simulation, and process optimisation of membrane-based PoU water treatment systems are included in Chapter 5. Chapter 6 includes operation and maintenance aspects, including pre- and post-treatment units. Techno-economic aspects of membrane-based PoU water treatment systems are elucidated in Chapter 7. Chapter 8 elaborates on national and international protocols for certification and system evaluation. ISBN: 9781789062717 (paperback) ISBN: 9781789062724 (eBook) ISBN: 9781789062731 (ePub)

Lonar Lake is a highly saline inland water body created by a crater in Maharashtra, India. A rare occurrence of the colour change of lake water from green to brown and eventually to pinkish-red was observed in Lonar in June 2020. This phenomenon attracted the attention of researchers, academicians and interestingly legal fraternity to understand the causes of colour change. The literature studies coupled the phenomenon of colouration of water to three aspects: the presence of halophilic Halobacterium salinarum or an algal species of Dunaliella (Dunaliella salina) or oxidization of metals (Fe and Mn) present in water. A comprehensive study was done to understand and assess the change in the colour of Lonar Lake water. The green colour of the lake is primarily due to the dominance of chlorophyll-a pigment in the algae population. The stressed condition in June 2020 adversely affected the photosynthesis activity of Dunaliella sp. resulting in the red colouration of the species. This red colour of Dunaliella sp. is due to the formation of a pigment named carotenoid which is similar to that in halophilic bacteria. This pigment completely hides the green chloroplast, and water turns pinkish-red. This study describes detailed investigations of environmental and climatic parameters to determine possible causes of abiotic stress on the algae population of the lake. The major factors contributing to the stressed conditions are high dissolved solids, alkalinity and alkaline pH due to salts in the lake water due to evaporation losses and limited rainfall over the months. The study further verified whether the colour change is a cyclic event and predicted possible lake conditions for the event of colour change to occur in the future.

The reactions between natural organic matter, anthropogenic contaminants, ions, and disinfectants lead to the formation of disinfection by-products (DBPs) such as trihalomethanes (THMs) in drinking water. The formation of THMs is strongly related to the chlorination of water. The study’s central objective was to compare the concentration of THMs in twenty developed and developing countries and their disinfection techniques. The THM concentration in 11 developed and 9 developing countries ranged from 0.5 µg/L (Germany) to 215 µg/L (Russia) and 3 µg/L (China) to 439.2 µg/L (Bangladesh), respectively. The developed country has partially succeeded in reducing THM concentration in drinking water, whereas significant steps are needed in developing countries to reduce the existing high THM concentration. The concentration of THMs in water varies among these countries because of the different water sources, water quality, environmental conditions, and efficiency of water treatment technologies. A meaningful relationship has been observed between the properties of water and the THM formation. The use of chemical disinfectants will result in new forms of DBPs that are undesirable due to their carcinogenic and mutagenic effects on human health. The DBP guidelines by various national and international agencies have helped to control and manage the THM concentration in drinking water. However, these regulatory standards are not continuously monitored. Therefore, the formation of these compounds should be prevented either by removing THMs forming precursors or by using an integrated approach for controlling THM formation by implementing advanced water treatment technology. Extensive research is desirable in domains like THM minimization strategies which are easy to deploy, scalable, and cost-effective.

Desalination of groundwater and brackish water reverse osmosis is becoming more common worldwide as a means of supplementing and diversifying fresh water supply. However, a key impediment to extensive reverse osmosis desalination adoption, particularly at inland sites, is the lack of economic and ecologically viable reject management alternatives. The reverse osmosis concentrate can harm the ecosystem by causing pH fluctuations, eutrophication, and the proliferation of hazardous metals that can cause various issues in the aquatic ecosystem and subsurface habitat degradation. Several alternative technologies have been explored to enhance reverse osmosis water recovery, limit the reject volume that must be disposed, and eliminate contaminants prior to beneficial uses or discharge. This review examines reject management options and technologies, including disposal, treatment, and beneficial usage. A comparative study reviewing all the plausible methodologies practically employed to economically and feasibly treat varied types of reverse osmosis concentrate is currently unavailable. This review also examines the suitability of the different treatment technologies for different types of reverse osmosis concentrate. The review also identifies important hurdles to a larger usage of desalination procedures, especially for inland applications, by critically reviewing reject management systems, treatment technologies, and beneficial uses. At last, conclusion and future perspectives are provided for researchers working in this field.

The study was carried out on the drinking water supply status from source to consumer for Ashti town in Wardha District of Maharashtra in July 2020. The overall raw water quality mitigates standards for surface water. No serious water quality problem was observed as far as the water quality of Mamdapur reservoir is concerned. High turbidity in raw water is because of rains in catchment, which carry sediments from the catchment along with the overland flow. The coliform counts observed in raw water can be attributed to faecal contamination from the catchment. The Shannon Wiener Diversity Index (SWI) ranged between 1.8 and 1.9, and the Palmer Pollution Index (PPI) of 12 for raw water samples indicate that the water is slight to moderately polluted. The operation and maintenance of the water treatment plant are not up to the mark. The variability in bacterial contamination in treated water and water at consumer end was attributed to en-route contamination due to leakages in distribution pipelines. The proper operation and maintenance of water treatment plant, repairing and replacement of the distribution pipeline, good sanitary conditions around the public taps, appropriate water storage and the consumers’ hygienic habits are essential in achieving safe drinking water supply in the town.

Abstract Membrane-based PoU water treatment systems have proved to be a milestone in PoU water treatment eliminating various shortcomings of other water treatment technologies. The main driver of membrane-based PoU water treatment systems is that it works without the addition of chemicals, with relatively low energy usage, and easy and well-arranged process conductions. With improved technology, there is an inevitable need to understand the basic operational parameters, design and maintenance of membrane-based PoU water treatment systems to eliminate the repercussions of lack of knowledge. The book describes membrane-based PoU water treatment systems and is divided into eight chapters. Chapter 1 explains the sources and contaminants in drinking water and the importance of removing these contaminants. Chapter 2 describes different units, advantages and limitations of the conventional water treatment plants and various PoU water treatment technologies. Chapter 3 covers components of membrane-based PoU water treatment systems. Chapter 4 describes the effective designing of various components of the membrane-based water treatment systems to make them more economical and practical. Modelling, simulation, and process optimisation of membrane-based PoU water treatment systems are included in Chapter 5. Chapter 6 includes operation and maintenance aspects, including pre- and post-treatment units. Techno-economic aspects of membrane-based PoU water treatment systems are elucidated in Chapter 7. Chapter 8 elaborates on national and international protocols for certification and system evaluation. ISBN: 9781789062717 (paperback) ISBN: 9781789062724 (eBook) ISBN: 9781789062731 (ePub)

Textile wastewater poses a significant environmental threat, and its treatment is one of the most demanding and challenging problems. This study investigates the feasibility of vacuum membrane distillation (VMD) for colour removal from real textile industry wastewater. Hexagonal boron nitride (h-BN) nanosheets and Zinc oxide (ZnO) nanoflowers were synthesised using a facile single-step synthesis protocol. 1% w/v ZnO nanoflowers and a varied amount of h-BN nanosheets (0-2% w/v) were impregnated in a polyvinylidene fluoride (PVDF) matrix using the phase inversion technique. The h-BN nanosheets, ZnO nanoflowers and membranes were characterised using scanning electron microscopy (SEM), Fourier transform attenuated total reflectance (FT-ATR), thermogravimetric analysis (TGA), and X-ray diffraction (XRD). The XRD and FT-ATR spectra of the mixed matrix membranes confirmed the successful impregnation of h-BN nanosheets and ZnO nanoflowers in the PVDF matrix. The effect of various process parameters (feed temperature, feed flow rate, and degree of vacuum) on membranes' permeate flux and colour removal efficiency was studied. The M-BZ2 mixed matrix membrane having 18% PVDF+ 2% h-BN nanosheets+ 1% ZnO nanoflowers composition showed the highest flux of 12.98 kg m(-2) h(-1) and colour removal efficiency of > 98%. Incorporating ZnO nanoflowers in the membrane, matrix provided the membrane with a UV cleaning property. More than 95% of the initial flux was recovered after the UV treatment of the membrane surface. The SEM images confirmed successful photocatalytic degradation of dye and organic molecules from the membrane surface. The UV-treated membranes retained all characteristic bands with no significant alterations. This study established that the M-BZ2 is suitable for treating real textile wastewater with high flux and colour removal efficiency.

Polyaluminium chloride (PAC) with different basicity is used as a coagulant in most drinking water treatment plants (WTP). The aluminium concentration in PAC and its hydrolysis mechanism varied with the basicity of PAC. Incremental addition of PAC changes various physico-chemical properties and turbidity removal mechanisms in water. Water treatment plants use the PAC concentration beyond its optimum dose without considering other aspects, including residual aluminium concentration. In the present work, the effect of high and medium basicity of PAC on different physico-chemical properties like pH, zeta potential, and residual aluminium concentration of water was investigated. The pH of treated water decreases with the incremental addition of PAC, and an increase in zeta potential and residual aluminium concentration in treated water was evidenced. The change in pH after PAC addition is responsible for deciding the coagulation mechanism and efficiency of the coagulation process. pH reduction is comparatively more in high basicity PAC than medium basicity. PAC hydrolysis mechanism is controlled by the zeta potential of water and can be used as an alternative method to decide the optimum coagulant dose. The performance of clariflocculator and pulsator-based WTP was also evaluated for raw water from the same source. To reduce down the turbidity below the acceptable level, the coagulant requirement for clariflocculator based WTP is comparatively less than pulsator based WTP. The floc blanket in the pulsator gets disturbed with a slight change in the coagulant chemistry and quantity.

Highly porous adsorbent materials were developed from industrial waste lignin for denitrification of surface and groundwater. The effect of microwave treatment and zinc ion impregnation on denitrification capacities of the material was investigated. The denitrification efficiencies of prepared materials were investigated by performing batch and continuous column adsorption experiments. The effect of different experimental parameters, including initial nitrate ion concentration, solution pH, and contact time, was also investigated. Adsorption kinetic follows the pseudo-second-order kinetic mechanism. Adsorption isotherm follows the monomolecular adsorption and experimental data best fitted into the Langmuir isotherm model. Continuous column denitrification experiments were performed with granulated adsorbent at different experimental conditions to understand its applicability in the household water treatment unit. Thomas model breakthrough time and the nitrate removal efficiency increase with increasing bed depth, whereas it declines with flow rate and nitrate concentration. The economic viability and environmental friendliness were understood by conducting adsorption–desorption experiments with loaded materials. The performance of adsorbent did not alter significantly even after four consecutive adsorption–desorption cycles.

In this study, we synthesized recyclable Fe3O4-functionalized MIL101(Fe) chitosan composite beads for the removal of tetracycline (TC), doxycycline (DC) and ciprofloxacin (CFX) antibiotics from aqueous streams. More than 99% removal efficiency for each antibiotic was achieved at optimum pH, dosage, concentration and contact time. Langmuir adsorption isotherms and pseudo-second-ord er kinetic model were suitable with correlation coefficient values close to 1 for all the antibiotics. Adsorption capacities of 45.33, 33.20 and 31.30 mg g−1 for TC, DC and CFX, respectively, were reported by the synthesized Fe3O4-functionalized MIL101(Fe) chitosan composite beads. The Fe3O4-functionalized MIL101(Fe) chitosan composite beads were also tested for their regeneration ability, and a remarkable regeneration ability over up to 5 cycles was observed. The adsorption of TC, DC and CFX on the surface of Fe3O4-functionalized MIL101(Fe) chitosan composite beads was governed by the π-π interaction, H-bonding and electrostatic interaction between the antibiotics and adsorbent due to protonation, deprotonation and cation exchange in the aqueous solution. These results showed a good prospect for applying the reported beads towards removing antibiotics from pharmaceutical industry wastewater.

In this study, we developed a comprehensive two-dimensional computational fluid dynamics (CFD) model using COMSOL™ Multiphysics to describe and simulate heat transfer, mass transfer and fluid flow in the flat sheet vacuum membrane distillation (VMD) under laminar flow conditions. A combination of Knudsen and Poiseuille flow was applied to study mass transfer across the membrane. The effect of variation of Reynolds number, inlet feed temperature and degree of vacuum on different parameters (mass flux, temperature polarization coefficient- TPC, concentration polarisation, heat transfer coefficient) was studied. There was a positive impact of the Reynolds number (50–200) on mass flux (13.15%), heat transfer coefficient (2.64%) and TPC (1.42%), while CPC decreased by 56.63%. The increment in the heat transfer coefficient was due to fluid mixing on the feed side, while the increment in the TPC was due to a higher temperature gradient across the membrane surfaces. The increment in the feed temperature (323–343 K) resulted in an increase in mass flux by 132.9%, while TPC decreased from 0.98 to 0.90. The degree of vacuum (640–750 mm Hg) increased mass flux and heat transfer coefficient by 72.52 and 425.83%, respectively, while the TPC decreased by 8.81%. The feed temperature was the most sensitive parameter with respect to mass flux. The developed CFD model was validated with in-house experimental results with reasonable accuracy.

Common salt (NaCl) is one of the most important minerals for all living beings and an integral part of the history of humankind. The salt journey from one of the expensive trading commodities to the cheapest commodity has given enormous applications. This is a basic raw material for chlor-alkali and soda ash industries and is required for daily human consumption. The traditional method of harvesting salt relies on the rate of brine evaporation utilizing free solar energy. The demand for salt is steadily rising due to its various applications, including most industrial applications. To meet the rising demand for salt, increasing the rate of brine evaporation is one of the possible viable strategies to improve the yield of solar salt production. This paper summarizes numerous enhanced brine evaporation approaches, including experimental, theoretical, and modelling studies, to highlight the evolution of the approaches in this area of research. The various governing factors that influence brine evaporation, salt production and challenges are also highlighted. Finally, known experimental techniques to improve the rate of evaporation are compared.