A hybrid reverse osmosis/adsorption desalination plant for irrigation and drinking water

Assessing the potential of highly permeable reverse osmosis membranes for desalination: Specific energy and footprint analysis

Objectives : This article provides a comparative analysis of boron removal for brackish water reverse osmosis (BWRO), boron selective ion exchange (IX), or capacitive deionization (CDI) processes. Permeate of 1st-Pass RO process has to be post-treated for additional boron removal. Hence, we experimentally analyzed the performance of boron removal and specific energy consumption (SEC) of three aforementioned processes and investigated whether the processes are suitable for 2nd pass process of RO desalination.Methods : Raw feed water was prepared using NaCl and B(OH)3. Semi-pilot scale RO and IX systems (over 1 m3/hr capacity) and bench scale CDI system (over 2.5 L/min) were tested for performance comparison. Boron concentration was measured using Azomethine-H method for feed and product water. Energy consumption was monitored by using power quality analyzer.Results and Discussion : Each process has its own operating conditions. The RO process required high pH of feed water for high boron removal rate, the IX process was operated below breakthrough point considering adsorption capacity of boron selective resin, and the CDI process didn’t remove boron because chloride ion has higher ion selectivity for carbon electrode than boron. In terms of SEC, the pressure-driven RO process showed the highest SEC among three processes. The CDI process based on electrical adsorption of carbon electrode showed a considerable energy consumption as well. On the other hand, the IX process was operated at low energy consumption because its removal is just based on adsorption-desorption mechanism.Conclusions : The RO and CDI processes have received a lot of attention as leading and emerging technology while the IX process was regarded as a stubborn process because of regeneration of resin and its several segmentalized steps. However, we found that the IX process has a better performance for boron removal and energy consumption.

Optimizing energy efficiency in brackish water reverse osmosis (BWRO): A comprehensive study on prioritizing critical operating parameters for specific energy consumption minimization

This study investigated the hydrological cycle dynamics under water management measures in the Pengbo irrigation area of Tibet, analyzing and evaluating the water balance and water productivity at the irrigation area scale. The findings provide a theoretical foundation for enhancing water use efficiency and promoting high crop yields in the alpine irrigation regions of Tibet. Utilizing the water balance method and SWAT hydrological model simulations, the water cycle processes in the Pengbo Irrigation District were elucidated, and the irrigation water productivity along with crop water productivity for highland barley, winter wheat, and rapeseed were calculated and analyzed. The results indicate that:a) The SWAT model, calibrated and vali-dated using runoff data from 2022 to 2023, shows a strong agreement between measured and simulated values. The calibration and validation results meet the accuracy criteria with R²≥0.82 and NSE ≥ 0.70.b) The spatial distribution of deep seepage and irrigation water in the study area exhibits similar patterns; regions with higher irrigation water volumes are prone to increased deep seepage. The deep seepage in the study area ranges from 197.2 mm to 314.5 mm, constitut-ing 29.3–36.7% of the total rainfall plus irrigation. The evapotranspiration during the crop growth period varies from 465.1 mm to 616.8 mm, representing 60.1–74.2% of the total rain-fall plus irrigation. c ) The spatial distribution of crop irrigation water productivity inversely correlates with irrigation water volume; areas with higher irrigation volumes exhibit lower crop irrigation water productivity. The average irrigation water productivity for highland barley, winter wheat, and rapeseed was 1.97 kg·m⁻³, 2.38 kg·m⁻³, and 0.80 kg·m⁻³, respectively. The average crop water productivity was 1.16 kg·m⁻³, 1.41 kg·m⁻³, and 0.47 kg·m⁻³. Winter wheat demonstrates significantly higher irrigation and crop water productivity compared to highland barley and rapeseed.The SWAT model simulations effectively characterize the water balance features of the Pengbo Irrigation District in Tibet and are suitable for simulating water cycle processes in similar alpine regions. Future agricultural de-velopment should focus on improving water use efficiency by optimizing crop irrigation systems, transitioning from flood irrigation to border irrigation, sprinkler irrigation, and micro-sprinkler irrigation. Additionally, considering crop yield and water productivity, it is advisable to increase the cultivation of winter wheat and highland barley while reducing the area dedicated to rapeseed.

Domestic water use is one of India's primary water uses that also includes irrigation, industrial, and environmental water uses. However, there is a lack of reliable data that hinders the estimation of domestic water use in India. Previous large-scale assessments often estimated domestic water use using population alone as a predictor. Economic and technological development and the improvement in the country's living standards may increase per-capita domestic water use. The present study's objective was to develop a large-scale domestic water use model in India, which considered the temporal variation of per-capita domestic water use. The economic indicator per-capita Gross Domestic Product (GDP) was used to model the time-variant per-capita domestic water use. The model results showed acceptable performance (NSE>0.7) at both the national and state levels. Maharashtra exhibited the highest per-capita domestic water use in the country because of the rapid economic and technological development relative to other States.

Untangling the effects of shallow groundwater and deficit irrigation on irrigation water productivity in arid region: New conceptual model

Desalination of brackish groundwater (BW) is an effective approach to augment water supply, especially for inland regions that are far from seawater resources. Brackish water reverse osmosis (BWRO) desalination is still subject to intensive energy consumption compared to the theoretical minimum energy demand. Here, we review some of the BWRO plants with various system arrangements. We look at how to minimize energy demands, as these contribute considerably to the cost of desalinated water. Different configurations of BWRO system have been compared from the view point of normalized specific energy consumption (SEC). Analysis is made at theoretical limits. The SEC reduction of BWRO can be achieved by (i) increasing number of stages, (ii) using an energy recovery device (ERD), or (iii) operating the BWRO in batch mode or closed circuit mode. Application of more stages not only reduces SEC but also improves water recovery. However, this improvement is less pronounced when the number of stages exceeds four. Alternatively and more favourably, the BWRO system can be operated in Closed Circuit Desalination (CCD) mode and gives a comparative SEC to that of the 3-stage system with a recovery ratio of 80%. A further reduction of about 30% in SEC can be achieved through batch-RO operation. Moreover, the costly ERDs and booster pumps are avoided with both CCD and batch-RO, thus furthering the effectiveness of lowering the costs of these innovative approaches.

Determination of the spatial and temporal trends in domestic water use is vital for making adequate and sustainable water management strategies, especially in arid regions. In this study, domestic water-use models considering socio-economic factors were developed to analyse spatial and temporal trends in domestic water use at a resolution of 4 km × 4 km in the arid region of northwestern China in the period 1985–2009. The results indicate that total annual domestic water use increased from 305.34 × 106 m3/year in 1985 to 1188.53 × 106 m3/year in 2009. Per capita domestic water use increased rapidly, especially in urban areas. A spatial disparity in per capita domestic water use and total annual domestic water use was apparent. The pressure of high domestic water use on water resources was found in some river basins, particularly the Shiyang River basin. The presented models can be successfully applied for estimating domestic water use in this region. However, there are several uncertainties due to the lack of data. Despite these uncertainties, the modelling results can provide important information for managers and planners on sustainable water use in this region. Furthermore, these models have the potential to be applied for estimation of future domestic water use in other regions. Editor Z.W. Kundzewicz Citation Guo, B., Chen, Y.N., Shen, Y.J., Li, W.H., and Wu, C.B, 2013. Spatially explicit estimation of domestic water use in the arid region of northwestern China: 1985–2009. Hydrological Sciences Journal, 58 (1), 1–15.

Comprehensive analysis of water use and pollution management plays an important role in regional water security and sustainable socio-economic development. This study applies the environmental Kuznets curve (EKC), Gini index and elasticity coefficient methods to conduct an investigation of industrial and domestic water use and pollution management in Shandong. The results show that industrial water pollution generally displayed a coordinated relationship with socio-economic development, while an uncoordinated relationship occurred between domestic water pollution and socio-economic development. Meanwhile, the Gini index between domestic water use and population in 2017 (0.101) was superior to that of 2003 (0.165), and the Gini index of industrial water use and second industry output in 2017 (0.273) was better than that of 2003 (0.292), indicating that the allocation and equity of domestic and industrial water use in Shandong kept to a good development trend. Additionally, the industrial effect is better than the domestic effect in terms of the control of wastewater emissions and the governance of typical pollutants in wastewater. Accordingly, domestic water pollution has gradually become one of the major sources of water pollution, and the allocation of industrial and domestic water use has room to improve further in Shandong. Conjunctive use of the aforementioned three methods provides an approach to investigate the integrated management of water use and water pollution control from multiple angles.

Crop yield and water productivity under salty water irrigation: A global meta-analysis

Increasing farm labor scarcity and depletion of natural resources such as water are posing a major threat to the sustainability of traditional puddled transplanted rice (PTR) farming in Eastern India. Dry-seeded rice (DSR) or non-puddled transplanted rice (NPTR) could be used as an alternative to PTR. To understand the trade-off with different water management and rice genotypes under non-puddled conditions, a field experiment was conducted during 2014–2015 on a sandy clay loam soil of Bhubaneswar, Odisha. The treatments for water regimes were based on soil water tension (no stress, 10kPa, and 40kPa) at 15-cm soil depth and the cultivars used in the study were inbreds (Lalat and Sahbhagi Dhan) and hybrids (Arize® 6129, 6444, and US 323).In both years, rice yields were higher in the dry season than in the wet season. However, both establishment methods performed similarly in all the seasons. With an increase in water stress, there was a significant decline in yield and yield attributes in the dry season. Irrigation input in the dry season was roughly more than double that in the wet season. Irrigation input was relatively higher in DSR than in NPTR in all the seasons, which might be because of an extra irrigation required for DSR crop establishment than for transplanting in non-puddled conditions where watering is done only for ease of transplanting. There was irrigation saving of 25% and 58% in 10kPa and 40kPa, respectively, compared to no stress in the dry season. A consistent trend of an increase in irrigation water productivity (WPI) and input water productivity (WPI+R) was observed with an increase in stress. Arize® 6444 produced the highest grain yield, irrigation and input water productivity, and its performance was also better in terms of tiller density, LAI, and biomass. Our findings highlight the potential of hybrids compared with inbreds and their performance under DSR was found to be superior. Even though the yield in no stress was slightly higher than in 10andkPa, the irrigation water savings in 10kPa were distinctly significant.

Knowing how much water a plant has access to and how effectively it can use it is crucial for irrigation scheduling in order to prevent overwatering or under watering. To assess how onions responded to the irrigation schedule, a field experiment was carried out. (When and how much) and to identify water productivity under optimal irrigation regime. The recommended levels of soil moisture depletion for onions served as the basis for setting the treatments. Then, in order to assess the best irrigation timing, there are five degrees of available soil moisture depletion namely, 60% Available Soil Moisture Depletion Level, 80% Available Soil Moisture Depletion Level, 100% Available Soil Moisture Depletion Level, 120% Available Soil Moisture Depletion Level and 140% Available Soil Moisture Depletion Level of the FAO recommended value of onion were used. Three replications of the experiment were set up using a Randomized Complete Block Design. The highest total bulb yield obtained at 60% Available Soil Moisture Depletion Level that was 211.65 q/ha followed by 80%, 100% and 120% Available Soil Moisture Depletion Level with the values of 210.85q/ha, 191.89q/ha and 188.18q/ha respectively without any significant difference. The highest irrigation water productivity of onion to convert irrigation water to bulb yield were obtained under 60% Available Soil Moisture Depletion Level which had 3.87kg/m<sup>3</sup>/ha followed by 80%, 100% and 120% Available Soil Moisture Depletion Level with the values of 3.77, 3.63 and 3.37 kg/m<sup>3</sup>/ha respectively without any significant difference. Therefore, according to the current findings, the highest bulb production and irrigation water productivity are obtained when irrigation scheduling is applied for onions in the research and related agroclimatic areas and soil types at 60% Available Soil Moisture Depletion Level.

Production of irrigation water from bioremediation of acid mine drainage: comparing the performance of two representative systems

In areas with inadequate improved water supply, irrigation water serves as an alternative water source for domestic uses in addition to its prime purpose of agricultural production. This increased water availability for the household can generate positive hygiene and health impacts, but poor irrigation water quality can be a source of domestic water contamination and can be harmful to human health. Using primary household survey data from two rural districts of Ethiopia, this study seeks to disentangle these opposite effects: the results show that irrigation is associated with poor household water quality (adjusted odds ratio 1.68, 95%, CI 1.07–2.66) and a lower risk of diarrheal disease (adjusted odds ratio 2.07, 95%, CI 1.24–3.44). Domestic use of irrigation water, however, does not further degrade the microbial quality of household water. On the other hand, the domestic use of irrigation water reduces the burden of water collection (p < 0.01). Providing education and training programs to foster behavioral change towards sustainable improvements in water resource management, such as the safe use of irrigation water for domestic purposes through appropriate point-of-use water treatment, would be crucial to maximize the benefits of the domestic use of irrigation water and to minimize adverse environmental and health risks.

Assessing grain yield (GY), irrigation water productivity (IWP), and irrigation crop water use efficiency (ICWUE) provides valuable insights into optimizing irrigation water use while maintaining crop yield. For this purpose, irrigation is varied either in crop phenological stages or based on the maximum allowable depletion/deficit (MAD) or crop evapotranspiration (ETC) or ratio of irrigation water to cumulative pan evaporation. No study has been identified that analyzed and compared GY, IWP, and ICWUE for drip and flood irrigated treatments based on MAD, ETC, and conventional practices for wheat. This study analyzed and compared GY, IWP, and ICWUE among drip-irrigated (DI) and flood-irrigated (FI) treatments based on MAD, ETC, and conventional practices by conducting field experiments for the wheat crop during 2023-24. The treatments were 50% MAD (DI), 50% MAD (FI), 100% ETC (DI), 80% ETC (DI), 80% ETC (FI), 60% ETC (DI), 40% ETC (DI), and conventional practice replication (referred to as farmers’ field replication). Compared to farmers’ field replication, GY increased by 30.5%, 16.9%, 23.2%, 15.6%, 9.6%, and 0.4% in 50% MAD (DI), 50% MAD (FI), 100% ETC (DI), 80% ETC (DI), 80% ETC (FI), 60% ETC (DI) treatments, respectively. Furthermore, compared to the farmers’ field replication, the irrigation amount in 50% MAD (DI), 50% MAD (FI), 100% ETC (DI), 80% ETC (DI), 80% ETC (FI), 60% ETC (DI), and 40% ETC (DI) reduced by 16.4%, 7.9%, 18.3%, 36.8%, 33.9%, 52.4%, and 65.5%, respectively. IWP values in 50% MAD (DI), 50% MAD (FI), 100% ETC (DI), 80% ETC (DI), 80% ETC (FI), 60% ETC (DI), 40% ETC (DI), and farmers’ field replication were 29, 23.6, 28, 34, 39.2, 50.3, and 18.6 kg/ha-mm, respectively. For the same level of irrigation, IWP and ICWUE were higher in DI treatments compared to FI treatments. The values of IWP and ICWUE in 50% MAD (DI) increased by 23.1% and 41.5%, respectively compared to 50% MAD (FI). Similarly, IWP and ICWUE in 80% ETC (DI) increased by 20% compared to 80% ETC (FI). Among the treatments, the 50% MAD (DI) and 100% ETC (DI) produced significantly higher GY of 5336.2 kg/ha and 5036.3 kg/ha, respectively. Between these two treatments, GY was higher in 50% MAD (DI). This can be attributed to the MAD in the 100% ETC (DI) treatment reaching 67% during the high-water demand growth stage, which exceeded the MAD level in the 50% MAD (DI) treatment. This study suggested that with the priority to produce the higher grain yield and save irrigation water (16.4 to 18.3%) as compared to existing irrigation practices followed by the farmers in the study region, 50% MAD (DI) or 100% ETC (DI) treatment must be employed. With the priority of saving the highest irrigation amount (52.4 %) without compensating for the GY, 60% ETC (DI) can be utilized by the farmers in the local region.