Brackish Research Articles

Preparation of composite based on MXene-Ti3C2 and coconutshell-derived activated carbon for desalination of brackish water

Preparation of composite based on MXene-Ti₃C₂ and coconutshell-derived activated carbon for desalination of brackish water

Effect of Irrigation Water Quality and Soil Compost Treatment on Salinity Management to Improve Soil Health and Plant Yield

Increasing soil salinity and degraded irrigation water quality are major challenges for agriculture. This study investigated the effects of irrigation water quality and incorporating compost (3% dry mass in soil) on minimizing soil salinization and promoting sustainable cropping systems. A greenhouse study used brackish water (electrical conductivity of 2010 µS/cm) and agricultural water (792 µS/cm) to irrigate Dundale pea and clay loam soil. Compost treatment enhanced soil water retention with soil moisture content above 0.280 m3/m3, increased plant carbon assimilation by ~30%, improved plant growth by >50%, and reduced NO3− leaching from the soil by 16% and 23.5% for agricultural and brackish water irrigation, respectively. Compared to no compost treatment, the compost-incorporated soil irrigated with brackish water showed the highest plant growth by increasing plant fresh weight by 64%, dry weight by 50%, root length by 121%, and plant height by 16%. Compost treatment reduced soil sodicity during brackish water irrigation by promoting the leaching of Cl− and Na+ from the soil. Compost treatment provides an environmentally sustainable approach to managing soil salinity, remediating the impact of brackish water irrigation, improving soil organic matter, enhancing the availability of water and nutrients to plants, and increasing plant growth and carbon sequestration potential.

Evaluating the feasibility of direct contact membrane distillation and nanofiltration in ground water treatment through a techno-economic analysis

This study delves into the realm of water treatment by conducting a comprehensive techno-economic evaluation of direct contact membrane distillation (DCMD) and nanofiltration (NF) processes. While previous research has explored the technical aspects of membrane distillation (MD) and nanofiltration, there remains a notable gap in economic analyses. Our research aims to bridge this gap by assessing the financial feasibility of employing MD and NF technologies for water desalination. Specifically, we scrutinize the performance of hydrophobic microporous flat sheet membranes crafted from polytetrafluoroethylene (PTFE) supported by non-woven polypropylene (PP) in desalinating brackish water through DCMD and NF processes. By varying operating conditions such as flow rate and feed temperature, we evaluate the membrane's efficacy. Employing an analytical model based on heat and mass transfer equations, we predict process performance across diverse scenarios. Our model demonstrates a high level of accuracy, with flux predictions deviating by less than 10% when utilizing the Knudsen-molecular mechanism model. Furthermore, through a detailed design and economic analysis of industrial-scale units for both processes, we reveal that the cost of permeated water is lower with NF compared to DCMD. Specifically, our calculations indicate a water cost of 1.34 USD/m3 for DCMD at a feed temperature of 65 °C with an 80% recovery rate, positioning it as a competitive option among conventional desalination methods. Notably, our financial assessment highlights that steam cost constitutes the primary expense in DCMD operations, contingent upon heating value and fuel prices. Noteworthy findings suggest that natural gas emerges as the most cost-effective fuel for steam production in a DCMD plant. This study underscores the economic viability and potential cost efficiencies associated with NF over DCMD in water treatment applications.

Duckling survival increased with availability of flooded wetland habitat and decreased with salinity concentrations in a brackish marsh

Abstract Waterfowl population recruitment is sensitive to duckling survival. We quantified predator types and survival rates for Anas platyrhynchos (Mallard) and Mareca strepera (Gadwall) ducklings in one of the largest brackish water marshes in western North America (Suisun Marsh, California) using 556 radio-tagged ducklings from 284 broods tracked during the 2016 to 2019 breeding seasons. Overall, 78% of ducklings died and 84% of mortalities occurred <7 days after hatch. After hatching in upland fields, survival was greater for broods that hatched closer to flooded wetlands; broods had a ≥75% chance of surviving the move from the nest to water when nests were located ≤140 m from the nearest wetland and ≤50% chance of surviving when nests were located ≥970 m from the nearest wetland. Predation accounted for 91% of mortalities and was attributed to mammals (27.6%), birds (22.0%), snakes (4.4%), and unknown predators (46.0%). Anas platyrhynchos survival to fledging (54 days) was only 3.2% and 0.9% during two drier years and 11.7% and 16.7% during two wetter years. Mareca strepera survival to fledging was 9.4% to 11.2% among years. Daily survival rates for ducklings generally increased with the amount of flooded wetland within 0.5 km (A. platyrhynchos) and 1.0 km (M. strepera) of the nest at hatch. Additionally, survival rates increased with duckling age and body mass at hatch for both species and decreased with hatch date for A. platyrhynchos but not M. strepera, which may be partially due to the earlier onset of A. platyrhynchos nesting. For ducklings that survived the initial move to water, survival rates were negatively correlated with salinity and this effect was more pronounced for younger ducklings. Anas platyrhynchos survival to 7 days post hatch decreased by 9.1% (wetter year) to 31.4% (drier year) when ducklings were in 12 ppt water (99th quantile of cumulative salinity concentrations experienced by ducklings) versus 0.5 ppt water. Mareca strepera survival to 7 days decreased by 7.4% when ducklings were in 12 ppt versus 0.5 ppt water. Our results suggest that maintaining a network of low salinity wetlands within 1 km of upland nesting sites would likely improve duckling survival rates, especially during the critical 7-day period after hatch.

Matching field-based ranges in brackish water gradients with experimentally derived salinity tolerances of Conrad’s false mussel (Mytilopsis leucophaeata cochleata) and zebra mussel (Dreissena polymorpha)

The invasive alien false mussels Mytilopsis leucophaeata cochleata and Dreissena polymorpha (Dreissenidae) have established populations in the North Sea canal in the Netherlands that connects the harbours of Amsterdam with the North Sea. The favourable and unfavourable salinity ranges of both species were earlier studied in long-term outdoor mesocosm experiments. Their occurrence in salinity gradients in estuaries or canals connecting seaways to freshwater harbours provides information on their salinity tolerance under field conditions. By the combination of laboratory experiments and field data using the same source population a high predictability can be expected for establishment of the gradients facilitated by constructions. The reliability of experimentally derived salinity-tolerance limits for both dreissenid species was tested using data on their distribution in a salinity gradient of the littoral zone along the North Sea canal. The mussels used for the survival experiments in mesocosms were also collected from this canal. Favourable salinity ranges for adult survival in the mesocosms were 0.2 – 17.5 for M. leucophaeata cochleata and 0.2 – 6.0 for D. polymorpha. Unfavourable salinities were outside these ranges and led to high and fast mortality of these species. Mytilopsis leucophaeata cochleata was present over nearly the whole length of the North Sea canal with the highest densities close to the sea sluices where also the highest salinities and water temperatures were measured. Their densities in the canal decreased gradually at larger distances from the sea. Dreissena polymorpha co-exists with M. leucophaeata cochleata at the east end of the canal with low salinity due to the influence of freshwater of the river Rhine. The occurrence of D. polymorpha was restricted to a salinity below 4 and M. leucophaeata cochleata only occurred at a salinity above 1.5 (maximum value measured in the canal 9.2). Shorter salinity gradients with lower salinity ranges provided additional information on the co-existence of both species. Co-existence was observed at a salinity range of 1.5–3.3 (own data), 1.0–3.5 (Van Couwelaar and Van Dijk 1989), both in the North Sea canal, and 0.2–2.8, in the Canal through Voorne (Janssen and Janssen-Kruit 1967). These data correspond with studies of both species by Walton (1996) in the Hudson River (salinity range 0–3). Found salinity ranges in the North Sea canal for both species match with the tolerance results obtained by mesocosm experiments. A new invading dreissenid mussel Dreissena rostriformis bugensis and a mytilid Ischadium recurvum occur in the North Sea canal since 2006 and 2012, respectively. Competition between recent and earlier invaders is likely when salinity tolerances are similar. It has already been observed that D. rostriformis bugensis outcompetes D. polymorpha under freshwater conditions (Bij de Vaate et al. 2014; Matthews et al. 2014). Ischadium recurvum has the potential to colonize large parts of the canal and to be a strong competitor of M. leucophaeata cochleata (Goud et al. 2019). Since January 2022, the new ‘Zeesluis IJmuiden’ with the biggest locks in the world is in use, affecting the probability of population establishment of new introduced and invasive alien mussel species.

Estuary: A Natural Filter Emphasis on A Mathematical Model of Pollution in Mandovi River

An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it and with a free connection to the open sea. These freshwater estuaries also provide many of the ecosystem services and functions that brackish estuaries do, such as serving as natural filters for runoff and providing nursery grounds for many species of birds, fish, and other animals. Estuaries are among the most productive ecosystems in the world. Mandovi River in Goa is one such important Estuary. A mathematical model is presented to protect the Ecosystem

STRATEGI PEMBERDAYAAN EKONOMI MELALUI INOVASI TEKNOLOGI AIR BERSIH: STUDI KASUS PENERAPAN REVERSE OSMOSIS DAN PERINTISAN BISNIS

The helplessness of coastal communities in processing salt and brackish water into drinking water is a great irony of modern society, in the midst of technological advances and the industrial era 4.0. The problem in the coastal areas of Sungai Kakap subdistrict, Kubu Raya district, is the lack of availability of clean water and the absence of clean water infrastructure. Peat groundwater in coastal deltas cannot support the use of groundwater sources due to high levels of acid and organic substances. This can trigger problems of poor community sanitation and cause the community's inability to optimize the potential of villages that have abundant natural resources. This activity aims to empower and increase community participation in designing and processing brackish/salt water into drinking water using Reverse Osmosis (RO) technology to meet the need for hygienic ready-to-drink water. Small scale water treatment system design using ultrafiltration (UF) and reverse osmosis (RO) membranes. The raw water used comes from river surface water in coastal areas. The small-scale water treatment design consists of two FRP tubes containing filter media, three filter cartridges, and UF and RO membranes. Two thrust pumps, with a minimum pressure specification of 40 m, are used to provide pressure that exceeds osmosis pressure so that raw water can be filtered through the RO membrane. The results of the activity show that the implementation of the RO system has succeeded in increasing the availability of clean water in Sungai Itik Village, which previously experienced challenges in providing adequate water supply. In addition, the integration of local business startups with RO technology opens up new opportunities for local residents to participate in the local economy and increase family income. Key factors supporting the success of this economic empowerment strategy were identified, including active community involvement in planning and implementation, collaboration between local government and local stakeholders, and adoption of new technologies and skills by local communities. This activity provides an important contribution in understanding the role of clean water technology innovation as a catalyst for local economic transformation in coastal areas. The practical implications of these findings can help decision makers in designing sustainable and effective policies to improve the welfare of coastal communities through sustainable economic empowerment. The use of this technology can help increase the availability of clean water in areas that previously experienced difficulties in this regard.

Effects of Organic Fertilizer on Photosynthesis, Yield, and Quality of Pakchoi under Different Irrigation Conditions

Water scarcity and the overuse of chemical fertilizers present significant challenges to modern agriculture, critically affecting crop photosynthesis, yield, quality, and productivity sustainability. This research assesses the impact of organic fertilizer on the photosynthetic attributes, yield, and quality of pakchoi under varying irrigation water conditions, including fresh water and brackish water. Findings reveal that the modified rectangular hyperbolic model most accurately captures the photosynthetic reaction to organic fertilization, outperforming other evaluated models. The maximum net photosynthesis rate (Pnmax), yield, soluble sugar (SS), and soluble protein content (SP) all exhibited a downward-opening quadratic parabolic trend with increasing amounts of organic fertilizer application. Specifically, under fresh-water irrigation, the optimal Pnmax, yield, SS, and SP were obtained at organic fertilizer rates of 65.77, 74.63, 45.33, and 40.79 kg/ha, respectively, achieving peak values of 20.71 µmol/(m2·s), 50,832 kg/ha, 35.63 g/kg, and 6.25 g/kg. This investigation provides a foundational basis for further research into the intricate relationship between water salinity stress and nutrient management, with the goal of crafting more sophisticated and sustainable farming methodologies. The insights gained could significantly influence organic fertilizer practices, promoting not only higher yields but also superior quality in agricultural outputs.

Environment, intraspecific lineages and geographic range jointly shape the high morphological variability of Dikerogammarus villosus (Sowinsky, 1894) (Crustacea, Amphipoda): a successful aquatic invader across Europe

AbstractPhenotypic variability is a key factor promoting the establishment and spread of invasive populations in new environments. The Ponto-Caspian region contains a diverse endemic fauna known for its exceptional environmental plasticity, with many species invading European waters. However, the extent to which the environment shapes the phenotypic variability of these successful invaders remains poorly understood. We test to what extent the environment, intraspecific lineage affinity and geographic range interact and shape the variability of ecologically relevant functional morphological traits of the amphipod, Dikerogammarus villosus. Our results show the highest differentiation among environments, with an enhancement of predation-related traits in brackish waters relative to freshwaters. Differentiation among lineages and ranges (native/invaded) was smaller, occurring in traits related to locomotion and food processing. Although we uncovered an overall increase in variability outside the native range, the dynamics of morphological change were lineage-specific: the Western Lineage (invading via the River Danube) underwent a shift towards increased appendage length, while the Eastern Lineage (invading via the River Dnieper) underwent a significant overall morphospace expansion. We conclude that D. villosus exhibits a remarkable morphological variability across Europe that is influenced by the interplay between the environment as well as its evolutionary and invasion history.

Density estimation of the globally threatened fishing cat Prionailurus viverrinus through a participatory science approach in the Chilika lagoon, eastern India

The fishing cat Prionailurus viverrinus is an Indo-Malayan wetland-dependent felid which is listed as Vulnerable on the IUCN Red List. Its main prey, fish, has low energetic demands and is abundant in productive aquatic habitats. This facilitates high piscivore densities and potentially alters expected scaling patterns that link population density to the body mass of small cats. With local community participation, we estimated the density of the fishing cat in Chilika, Asia’s largest brackish water lagoon, located in the state of Odisha, eastern India, with community participation. The study was carried out in 2 phases in different habitats during 2021 and 2022: a homogeneous marshy habitat and its buffer (Northern Block), and a heterogeneous matrix of different land-use types (Southern Block). We deployed a total of 144 camera traps across 4380 trap nights. Using spatially explicit capture-recapture (SECR), we estimated mean (±SE) fishing cat density to be 0.69 ± 0.1 ind. km-2 in the Northern Block and 0.67 ± 0.33 ind. km-2 in the Southern Block. The population abundance estimates for the Northern and the Southern Blocks were 159 ± 23 and 185 ± 91 respectively. In the former, SECR modelling indicated an effect of anthropogenic habitat modification upon the species’ home range extent. Our density estimates are amongst the highest reported for the species outside protected areas. The results imply that Chilika holds an abundant population of the fishing cat, the continued persistence of which requires mitigation of local and external threats to fish populations. Furthermore, our study, with its inclusive approach, sets a precedent for the use of camera trapping for obtaining robust density estimates of species with uniquely marked individuals in wetland habitats.

Cost-effective moisture-induced electrical power generators for sustainable electrodialysis desalination

To establish a sustainable method for desalination, it is necessary to explore and use renewable energy sources that are cost-effective and unaffected by weather conditions. Therefore, in this study we propose a novel hybrid electrodialysis system for environmentally friendly and cost-effective desalination of blackish water, integrating moisture-induced electrical power generators (MIEPGs). By coating a layer of carbon black on the surface of cellulose acetate fiber columns, which are readily available as cigarette filters, compact MIEPGs can be conveniently fabricated. These MIEPGs can generate electricity from trace amounts of moisture by leveraging the streaming potential induced along nanoscale channels between the carbon black particles. A notable voltage output (13.5–22 V) is achieved from the series connection of 90 cells using a customized module frame. The substantial power output derived from the stacked MIEPGs enables the successful desalination of modeled brackish water with a salt removal ratio of 92%.

Application Of Remote Sensing Technologies On Industrial Outfalls

Industrial effluents are a byproduct of various industries. They may contain harmful and toxic substances of organic or inorganic origin, such as pesticides, pharmaceuticals, hydrocarbons, detergents, and oils. In addition, industrial effluent can also come from thermal power plants in the coastal area, which use seawater for cooling, which they return to the environment after the process. Hence, the zone near the outlet has increased temperature, affecting the mortality and reduction of certain types of fish and algae, variations in the number of phytoplankton, and other ecological problems (Zhao et al., 2015). Nowadays, an increasing amount of industrial wastewater from desalination processes is brine, which is considered a minor risk to public health but has a more significant impact on the environment (Lattemann and Amy, 2013). Due to the increase in population, the demand for drinking water has increased, especially on the islands and coastal areas. With the desalination process, drinking water is produced from sea or brackish water by removing suspended matter and dissolved minerals, mainly salt, and the effluent, i.e., brine, is discharged back into the coastal area. An increased amount of salt can potentially negatively affect the marine ecosystem, leading to the dehydration of cells and possible death of organisms (Missimer and Maliva, 2018). In addition, the brine may have a higher temperature than the environment and contain heavy metals and residues of hazardous chemicals applied in the process, such as anti-scale agents, flocculation agents, and coagulants (Panagopoulos and Haralambous, 2020.). The increasing hydrogen generation from renewable sources requires more freshwater. Consequently, a significant increase in this type of effluent is expected in the future. Therefore, analysis and monitoring of the operation of industrial outfalls is essential to preserve the marine environment and public health. Previous research (Law and Tang 2016) proposes long-term monitoring after the outfall has been commissioned to study environmental effects. Historically, monitoring of wastewater outfalls was mainly obtained by in situ sampling methods to ensure water quality in coastal areas (Gierach et al., 2017). Such practices have temporal and spatial limitations with high costs; hence, they are impractical for analyzing a larger coastal area. Therefore, in this research, we propose using remote sensing technologies for monitoring industrial outfalls.

Clustering evaluation of water quality for various classes of in-flow rivers in connected brackish lakes.

Brackish waters and estuaries at the lower reaches of rivers accumulate organic matter and nutrients from various sources in the watershed. Sufficient light and shallow water depth stimulate phytoplankton growth, resulting in a more diversified ecosystem with higher trophic levels. For effective watershed management, it is crucial to characterize the water quality of all rivers, including small and medium-sized ones. Our field survey assessed water quality parameters in 26 inflow rivers surrounding Lakes Shinji and Nakaumi, two consolidated brackish lakes in Japan. The parameters included water temperature, salinity, chlorophyll-a, and nutrients. The study used hierarchical clustering. The Silhouette Index was used to assess clustering outcomes and identify any difficulties in dispersion across clusters. The 26 rivers surrounding Lakes Shinji and Nakaumi were classified into six groups based on their water quality characteristics. This classification distinguishes itself from earlier subjective methods that relied on geographical factors. The new approach identifies a need for improved management of river water quality. The results of the cluster analysis provide valuable insights for future management initiatives. It is important to consider these findings alongside established watershed criteria.

Not that many leech species after all: Myzobdella lugubris and Myzobdella patzcuarensis (Annelida: Hirudinida) are the same species

The genus Myzobdella groups five species of leeches parasites of fishes mainly of freshwater but with tolerance to brackish waters. Native distribution of these species includes the New World from North to South America. Myzobdella lugubris Leidy, 1851, the type species of the genus, was briefly described based on specimens from the USA, but subsequently their morphology, known distribution and host range were expanded; however, less is known about the other four species of the genus. As part of a survey focusing on characterizing the diversity of leeches from Mexico, specimens of Myzobdella patzcuarensis (Caballero, 1940), from the type locality of the species were included for the first time in a phylogenetic study. In addition, specimens assigned to Myzobdella from the southeast of Mexico as well as from Nicaragua, were also included. In the resulting phylogenetic tree, our newly generated sequences were found nested in the same clade that M. lugubris; with unresolved relationships and relatively low genetic divergence, suggesting conspecificity. In addition, the internal morphology of the specimens of Myzobdella from Mexico is consistent with the description of M. lugubris. Our morphological examination reveals high degrees of variability in the external pigmentation of the specimens. Based on our results we formally synonymize M. patzcuarensis under M. lugubris.

Halophiles and their adaptations: A comprehensive review on recent progress and prospects in biodesalination applications

AbstractWorldwide climate change, rising population, and industrialization have raised the global demand for freshwater. Desalinating brackish water has become a sustainable technology for drinking and agriculture to overcome global water scarcity. Thriving biodesalination technology has become more attractive and eco‐friendly than the present physicochemical desalination methods, which are expensive and energy‐intensive. Researchers are exploring the bioutilization of nature's potential for desalination using halophiles like haloarchaea, halobacteria, halophytic algae, and plants. Biomimetic desalination membranes have been developed, inspired by the desalination mechanism in animals. This comprehensive review explores recent advancements and potential applications of halophiles in biodesalination to exploit them effectively. It provides an overview of the opportunities and challenges associated with harnessing halophiles for the removal of salts from brackish and seawater sources. This review also focuses on insights into biomolecules produced by the halophilic microorganisms and halophytes in the desalination process. Understanding the mechanism of action of these biomolecules will edify the effective unexplored research areas in biomimicry and bioutilization to overcome the existing limitations in water treatment.

Continuous year-round isolation of giant viruses from brackish shoreline soils.

Giant viruses, categorized under Nucleocytoviricota, are believed to exist ubiquitously in natural environments. However, comprehensive reports on isolated giant viruses remain scarce, with limited information available on unrecoverable strains, viral proliferation sites, and natural hosts. Previously, the author highlighted Pandoravirus hades, Pandoravirus persephone, and Mimivirus sp. styx, isolated from brackish water soil, as potential hotspots for giant virus multiplication. This study presents findings from nearly a year of monthly sampling within the same brackish water region after isolating the three aforementioned strains. This report details the recurrent isolation of a wide range of giant viruses. Each month, four soil samples were randomly collected from an approximately 5 × 10 m plot, comprising three soil samples and one water sample containing sediment from the riverbed. Acanthamoeba castellanii was used as a host for virus isolation. These efforts consistently yielded at least one viral species per month, culminating in a total of 55 giant virus isolates. The most frequently isolated species was Mimiviridae (24 isolates), followed by Marseilleviridae (23 isolates), Pandoravirus (6 isolates), and singular isolates of Pithovirus and Cedratvirus. Notably, viruses were not consistently isolated from any of the four samples every month, with certain sites yielding no viruses. Cluster analysis based on isolate numbers revealed that soil samples from May and water and sediment samples from January produced the highest number of viral strains. These findings underscore brackish coastal soil as a significant site for isolating numerous giant viruses, highlighting the non-uniform distribution along coastlines.

A Study on Potential Feed Sources to Boost Guppy Fish, Poecilia reticulata Productivity

Aquaculture may simply be referred as “Underwater Agriculture.”India is a major maritime state and an important aquaculture- based country in the worldhaving major aquaculture activitiesin the production of Carp from Freshwater,Shrimp from Brackish water, etc. Feed requirements of fish vary in quantity and quality according to the feeding habits, physiological stages of the species and environmental variations viz., temperature; amount and type of natural food availability in the culture system.A nutritious and cheap feed is a pre requested for profitable aquaculture. Though, use of commercially available feed is in practice in many countries. The feed cost consumes more Than half of running expenditure. Therefore, the search of nutritionally well-balanced feed Prepared from very cheap locally available ingredients in progress in all the aqua farming countries. In the present study, an attempt has been made to well-balanced nutritious feed Particularly from the locally available cheaper ingredients. The objectives of the present study are: to assess the effect of feed on the growth of finfish and shellfish in the laboratory, to prepare the conventional feed with traditional ingredients and to check the effect of feed on the growth performance of ornamental fish - Guppy, Poecilia reticulata.

Brackish and seawater pretreatment processes: A systematic literature review

The water cycle is greatly affected by climate change, leading to prolonged droughts that have a significant impact on communities' economic and social aspects. To mitigate these effects, desalination of sea and brackish water is a promising solution. However, the success of this approach depends on the efficiency of pre-treatment processes to ensure optimal water quality. This study aims to identify best practices for pretreatment processes of marine and brackish waters. This will contribute to make an inventory of a wide range of pretreatment categories, their associated techniques and the expected performances according to the literature, creating a reference for designing pretreatment processes. In order to achieve the objectives of this study, the steps for the elaboration of a Systematic Literature Review (SLR) were followed.A list of 526 scientific articles collected on this topic was used as input to the review process. The obtained results led to an examination of the different techniques used for the pretreatment and their performances, which allowed us to have a clear idea on the techniques to be integrated and area for further research that we would choose depending on their performances and the characteristics of the water to be pretreated.

Direct experimental comparison of batch reverse osmosis (RO) technologies

Batch RO technologies can help fulfil the growing need for high-recovery desalination. Several experimental studies have given results for batch and semi-batch RO processes individually, but under differing conditions. There is a lack of side-by-side comparisons. Here we report, for the first time, experiments with a high-pressure RO system that can be operated in batch, semi-batch, or hybrid semi-batch/batch mode. Using the same membrane and supply pump at pressures up to 110 bar, we compare performance against semi-batch mode as the baseline throughout. With seawater feed, batch RO reduces electrical SEC by 10 % at recovery of 0.655. With brackish water feed, we use hybrid mode to avoid an excessively large work exchanger volume. Working at recovery of 0.94, a work exchanger volume of 20 L reduced SEC by 23 %. A work exchanger volume of 40 L reduced SEC further, resulting in SEC of 1.81, 1.89 and 2.02 kWh/m3 at recoveries of 0.9, 0.92 and 0.94 respectively, thus representing a 22–32 % reduction against the semi-batch baseline. The results also showed permeate conductivity reduced by up to 50 %. The study confirms the advantages of batch and hybrid RO over semi-batch RO, especially for brackish water desalination at high recovery.

Multi-dimensional parametric study for enhancing Brackish Water Reverse Osmosis membrane performance suited for desalination of low salinity feeds.

Reverse osmosis (RO) effectively provides clean drinking water. Different RO membrane types are tailored to treat saline water feeds with varying characteristics. In the context of low brackish water feeds, the objective is to remove only a minimal excess of salinity through the membrane. Our study introduces a method of membrane post-treatments capable of achieving controlled salt rejection while concurrently enhancing permeate flux, which is vital for achieving effective and energy-efficient desalination of low brackish water. The post-treatments were conducted on our in-house-developed membranes using aqueous solutions of N,N-Dimethylformamide and glycerol for different drying times at the coupon level. The process was scaled up at the module level, allowing us to assess its potential for commercial application. At the coupon level, the permeate flux increased significantly from 3.7 ± 0.9 to 10.6 ± 0.2L/m2·h·bar, while the salt rejection decreased from 95.6 ± 1% to 70.5 ± 1% when measured with a feed of 2,000 ppm NaCl concentration. At the module level, we observed a higher flux of 12.8L/m2·h·bar, alongside a salt rejection of 55.5% with a similar feed. Varying post-treatment parameters at the coupon level allowed us to attain the desired salt rejection and permeate flux values. Physical changes in both pristine and post-treated membranes, including polymer swelling, were observed without chemical alterations, enhancing our understanding of the post-treatment effect and its potential for broader commercial use. PRACTITIONER POINTS: Post-treatment of RO membranes enhances flux. Physical structuring through polymer swelling was observed with the chemical structure unaltered. Post-treatment of RO opens doors for broader energy-efficient desalination application.