Water Scarcity Issues Research Articles

Consumer preference, growth and profitability of African catfish (Clarias gariepinus) grown in treated and aerated wastewater fed ponds in Kumasi, Ghana

Recycling of wastewater provides a substantial solution to the global issue of water scarcity and high water use in aquaculture. However, this sustainable way of wastewater use has not been given much attention and exploration. This study focused on the consumer preference for fish grown in treated wastewater as well as the effect of aeration on the growth performance and economic benefit of African catfish (Clarias gariepinus) grown in treated wastewater. Two hundred (200) respondents from two communities (Chirapatre and Gyinyase) near the wastewater treatment plant in Kumasi were interviewed to determine their willingness to accept and pay for African catfish grown in treated wastewater. For the growth trial, a total of 600 fish (of average initial weight 39.12g) were stocked in two maturation ponds with 4 h (3:00am–7:00am) of aeration daily. The trial lasted for 12 weeks and variables monitored included the survival, growth performance (weight gain, specific growth rate, and yield) and water quality. Fish cultured in non-aerated wastewater ponds (NWFPs) under similar conditions as in aerated wastewater-fed ponds (AWFPs) served as control. The results indicated most important considerations for consumers in their choice of fish to consume were in order of importance; food safety, freshness of fish, taste and packaging. The proximity of consumers to the treatment plant, the price of fish, religion, and age and whether or not they were fish consumers affected their willingness to pay for African catfish grown in the treated wastewater significantly. For the growth trial, dissolved oxygen concentrations in the aerated ponds were significantly higher than in the NWFPs and this led to more than a doubling of the growth rates in the African catfish grown in the AWFPs (189.10g ± 11.32) as compared to the NWFPs (90.70g ± 11.59). The pond aeration improved fish growth significantly (p < 0.0098). On economic benefit, the aerated system yielded profits of 618.83 (€103.13) as compared to a loss of 104.99 (€17.50), which was incurred in the non-aerated ponds. Education of the consumers on the process of wastewater treatment and establishment of food safety guidelines will therefore be recommended to increase consumer interest in consuming fish from the treated wastewater.

Devising technology for utilizing water treatment waste to produce ceramic building materials

Based on the modern ideas about environmental protection, this paper reports a study into the utilization of water-treated waste from heavy metals (using copper(II) compounds as an example) for the manufacture of ceramic building materials. The examined clay minerals from local deposits and the optimal conditions for their heat treatment (at 1,100 °C) have been proposed for the sorption removal of pollutants of inorganic origin from wastewater. The use of wastewater after its treatment makes it possible to address several tasks at the same time: to protect the environment from pollution by technological wastewater, as well as to reuse wastewater in order to resolve the issue of water scarcity. Ceramic building materials were manufactured based on water purification waste (in the amount of 5 %) and clay raw materials. Their structural-mechanical and physicochemical characteristics have been comprehensively studied. Sintering processes begin at lower temperatures, which is why, with an increase in the annealing temperature to 1,000 °C and higher, their strength rapidly decreases. In the temperature range of 600‒1,100 °C, there are possibilities to apply ceramic technology to immobilize heavy metals in ceramic matrices. The prospect of utilizing water purification waste in the technological process of manufacturing inorganic ceramic materials has been shown. The safety of the building materials, manufactured by leaching pollutants from the ceramic samples using various aggressive environments (leaching to 6.4 %, 0.083 mg·cm2/day) has been investigated. The high strength and degree of the copper ion fixation in the structure of polymineral clay have been confirmed while secondary environmental pollution is almost absent

A Critical Review of Water Resources and Their Management in Bhutan

Bhutan is a small yet water-abundant country. The country suffers from frequent flooding and is lately experiencing a growing risk of localized droughts due to inappropriate water resource management and climate change. Such a situation calls for much more efficient use and management of water in Bhutan. This paper undertakes an extensive analysis of the country’s water resources for better planning and management of the available water resources. Bhutan can be divided into three zones, the Southern Foothills, the Central Inner Himalayas, and the Higher Himalayas. The top four leading industries of Bhutan are related to water, either directly or indirectly. The country at present is at a very early stage of development. The government has prioritized water resources management over recent years. Water for hydropower in Bhutan has been in focus as compared to that allocated for irrigation, industries, and environmental demand. The demand for water in Bhutan has also increased in the last decade due to population increase, changes in lifestyle, and economic advancements through tourism and hydropower projects. Climate variation, deteriorating water quality, frequent floods, and increasing urbanization threaten the sustainability of water resources. Water accessibility issues for settlements due to the country’s harsh geographical landscape is leading towards localized water scarcity. Serious attention to rainwater harvesting and groundwater recharge is required to address localized water scarcity issues.

The feasibility survey of an autonomous renewable seawater reverse osmosis system with underwater compressed air energy storage

Water scarcity issue is increasingly obvious due to rapid population growth and flourished industrialization. As an energy intensive technology, the desalination has been gained more attention nowadays, which is transformed to renewable sources driven for a sustainable future. In this paper, an autonomous renewable seawater reverse osmosis system with the support of underwater compressed air energy storage is proposed. As the primary power source, the wind turbine and solar photovoltaic are applied to generate electricity. Meanwhile, the underwater compressed air energy storage system acts as an energy buffer to manage the stochastic power generation and consumption. The simulation results show that the loss of power supply probability and the loss of water supply probability in 1% maximum loss of power supply probability threshold condition are 0.9993% and 1.3667%, respectively. Meanwhile, the energy demand can be matched well by renewable supply, despite some deficient exists. In addition, the power source configuration, the volume and pressure of flexible energy bag, the reverse osmosis membrane area and the wind turbine hub height have effect on system performance. This work can provide some useful information about the potential of compressed air energy storage in seawater reverse osmosis plant for future development.

Water resources of Balochistan, Pakistan—a review

Water is extremely important for human survival and economic development globally. The largest province of Pakistan, Balochistan, is facing drought conditions, water scarcity and quality issues, which has badly affected community livelihood and health. The agriculture sector contributes over 26% gross domestic product (GDP) of the country and engages 44% of the total labour force. Due to the steep slope, the limited surface is ephemeral. So, groundwater is the only option for various activities in 90% area of the province while 10% area has waterlogging and extremely bad-quality groundwater issues. Major reasons for limited research work on water issues across the province were because of security, political and socio-economic issues. Previous studies depict that groundwater quality in the entire province contains a high concentration of various contaminants and pathogens. Pakistan Economic Survey revealed in a study that over 50 million people across the country do not have access to safe water, and over 0.25 million children died due to polluted water. More than 72% of the rural population in Balochistan depends on dug wells and streams for drinking water. This review paper covers various anthropogenic factors that contaminate groundwater and surface water, uses and available overall water resources in the province. Previous studies indicate the public in Balochistan is facing health issues from contaminants such as arsenic, fluoride, pathogenic, etc. in drinking water. In this article, spatial maps show the spatial variation of pollutants, water table and geological formations. Balochistan can be divided into two regions, south and north, containing different climate and water availability conditions. Basin wise water monitoring system could be the best option to sustain water resources, and low delta crops reduce stress on groundwater. The stakeholders and active community participation and serious effects could help to overcome water issues.

Water conservation in hotel industry: A case study of Rajasthan

Water is major requirement for any business, be it agricultural, food processing industries, construction, textile, or others. Hotel industry is also one of them that required huge amount of water every day to provide different services to their guests. The industry only provides luxuries and exotic services to their guests it does not produce any product. Thus, the responsibility towards the environment is forefront for the hospitality industry. Water is the most prominent source of nature that is the most burning issue all over the world now days. Hotel industry need to focus on their water uses and must limit it with applying various measures by reusing, recycling and conserving. Water scarcity issues are not hidden to anyone nowadays, from domestic to industrial level many technologies and measures are employed by users, providers and promoted by government to save and conserve water. The present study focuses on the water saving systems of hotels of Rajasthan. Rajasthan is a hot region and it has water shortage since years thus the responsibility of the hoteliers towards to save water by implementation of different useful techniques is expected high for water conservation. The study also provides an overview on water scarcity in the region and significance to preserve water resources. The study result shows that most of the five stars and four-star hotels are implementing water saving measures in their properties while majority of three-star hotels have no such policy.

Sanitation By-Products Used for Lettuce (&amp;lt;i&amp;gt;Lactuca sativa&amp;lt;/i&amp;gt; L.) Production: Quantitative Microbial Risk Assessment

Sanitation by-products (i.e. greywater, human urine and toilet compost) reuse for agriculture presents an opportunity to enhance food security while overcoming water scarcity and fertilizers issues in developing countries. However, the risks to health from farmers and consumers’ exposure to pathogenic micro-organisms persistent in sanitation by-products has hindered their popularity in these regions. This study was conducted to apply a quantitative microbial risk assessment to estimate the annual risk probability of Salmonella infection associated with these sanitation by-products reuse for lettuce production and explore options for health risk reduction. Risk was performed a Monte Carlo simulation for farmers and consumers. The exposure routes were contaminated soil ingestion, urine/greywater/compost ingestion and lettuce consumption without washing. Results showed that the annual infection risks of Salmonella through ingestion contaminated soil associated with urine and compost were typical scenario: 9.04 × per-person-per-year (pppy) and 2.97 × pppy, respectively, are higher than the WHO benchmark (≤1.0 × pppy). Conversely, those contaminated from greywater were 6.83 × pppy are meet the WHO benchmark. On the other hand, annual risks through lettuce consumption fertilized with urine (1.20 × pppy) were less than the risks from compost (6.20 × pppy) and greywater (7.76 × pppy). Moreover, the annual risks of infection from greywater ingestion (1.77 × pppy) exhibits a much higher risk than that urine ingestion (6.20 × pppy) approximately two orders of magnitude, and which are higher than the WHO tolerable limit of risk. The risk assessment outcomes of using sanitation by-products to lettuce production should be promoted with proper awareness of the risk by farmers and consumers.

Investigation on a desiccant based solar water recuperator for generating water from atmospheric air

Drinking water scarcity becomes the alarming issue in recent days. On the other way, the atmospheric air carries a huge amount of water content in the form of water vapour. The suitable harvesting method can appositely address the water scarcity issue to a certain extent. This paper investigates a method of recovering potable water from the atmospheric air with the help of a desiccant based solar recuperation system. The orange silica gel was used as the desiccant by which the water molecules from the atmospheric air were adsorbed during the night time. The water from the laden silica gel was recuperated using a solar recuperation system during the day time. The experiments were conducted for three similar solar days during the month of April 2020 in Coimbatore, India, and the average results are presented. It was observed that the system produced 0.98 L of potable water per day, economically.

Water Scarcity in Aligambai Village, Alayadivembu Divisional Secretariat, Sri Lanka

The scarcity of drinking water creates major impacts on the rural community, in particular. The people living in Aligambai have been facing numerous problems in getting a safe drinking water supply, even for their daily drinking purpose. This paper sets out to identify the contributing factors toward water scarcity and how to cope with it by increasing water productivity as an integrated approach in the study area. This study is a combination of research methods; quantitative and qualitative data collection techniques. It is built on the premise of the cultural theory, which can be used to study water scarcity issues in rural water points. Mainly, it tries to understand the gap between the performance of the rural water supply sector and the SDG Goal 6: ‘water &amp; sanitation for all’ through networking with pluralist institutions and mechanisms. Research methods, such as interviews with key informants, direct observations, and Focus Group discussions, have been employed for the study. The secondary data were collected from the Aligambai Resource Profile, records from the GND/DS office, and the statistical records from the National Water Supply &amp; Drainage Board. This study found that water scarcity has affected the community in terms of life and livelihood activities in Aligambai. Therefore, it tries to bring out potential solutions to coping with water scarcity by suggesting measures for water productivity at all levels through an integrated approach in the study area.

Optimizing future electric power sector considering water-carbon policies in the water-scarce North China Grid

The North China Grid has the highest proportion of fossil fuel-based electricity generation in China and also suffers from severe water scarcity issues. This study uses a multi-objective optimization model to explore future configurations of generating and cooling technologies of the electric power sector in the North China Grid subject to constraints imposed by existing policies on water conservation and carbon reduction in 2030. Our findings highlight that the current carbon reduction commitments of China do not have significant impacts on the North China Grid's electric power sector development while policies in the water sector generate much larger impacts. Imposing water constraint according to the ‘Three Red Line’ Policy requires increasing utilization of wind power and air cooling systems, which simultaneously increases economic cost and carbon emissions compared to the business as usual scenario. Imposing enhanced carbon emission and water consumption constraints reap the co-benefits of carbon reduction and water conservation by increasing the proportion of solar PV generation to 8.21%, which increases the unit electricity cost from RMB 0.82 per kWh to RMB 1.37 per kWh. In 2030, electricity generation in the North China Grid generates 1599.88 to 1690.89 million tons (Mt) of carbon emissions under different scenarios whereas imposing water constraint reduces water consumption from 3.34 billion m3 to 1.94 billion m3.

Water Scarcity and Sustainability in an Emerging Economy: A Management Perspective for Future

Water scarcity is rising as a global issue, because the planet earth is facing a global water crisis, which is considered something that can destroy environmental sustainability of our planet. The fact is that humanity’s demand is depleting natural resources faster than nature can replenish itself; if human habits and unsustainable use of water resources do not change, water scarcity will inevitably intensify and become a major cause of conflict among different nations of the world. The water scarcity issue is a crucial issue but unfortunately it has not received due attention in past. Pakistan, which once was a water abundant country, now facing a situation of water scarcity. Pakistan has a poor irrigation system which results 60% loss of its water; Pakistan uses more water for crop production than other countries. Likewise, the country harvests water from rainfall, rivers, snow, and glaciers. The country is facing a serious water crisis that is caused by different factors, such as changing climatic conditions, rising population, poor irrigation system, poor political will, and rapid urbanization. The water crisis of Pakistan is expected to worsen in coming years. This is a drastic situation which calls for emergency measures. With this background, the present study provides a detailed view of the water situation in the country with challenges to water management. The study also suggests some recommendations for policymakers to improve the water crisis situation in the future.

Impacts of rainfall change on stormwater control and water saving performance of rainwater harvesting systems

Rainwater harvesting is widely implemented to deal with urban water scarcity and stormwater control issues. In the context of climate change, however, the impacts of rainfall change on rainwater harvesting systems (RHS) are still unknown in many regions. In this study, effects of rainfall change on both water saving and stormwater control performance of RHS across six cities in different climatic zones of Pakistan were investigated and location-specific and adaptive measures to mitigate the negative impacts of rainfall change on RHS were proposed. The commonly defined “dry gets drier, wet gets wetter” rainfall change pattern is not retained in the cities. Water saving performance of RHS is positively affected by increasing trend of rainfall at Khanpur and Peshawar, whereas negatively affected by rainfall decreases at Zhob and Murree. Conversely, increasing trend of rainfall is non-beneficial for stormwater control at Khanpur and Peshawar but rainfall decreases are beneficial at Zhob and Murree. Islamabad and Lahore do not have notable changes in performance of RHS due to the non-significant changing trends in rainfall. The impacts of rainfall change on performance of RHS are dependent on not only the trends and extents of local rainfall change, but also tank sizes and water demands. At Khanpur and Murree, the negative impacts of rainfall change on performance of RHS can be resolved by enlarging tank sizes. At Zhob and Peshawar, however, adjusting contributing areas or water demands should also be considered. Therefore, location-specific and adaptive measures should be adopted for RHS to accommodate rainfall change.

Application of algae to free surface wetlands for effluent reuse

AbstractThe main goal of this study is to assess the role of Algae in the treatment of wastewater and its capability to improve the performance of the free surface wetland as a green solution. It offers a non‐conventional water resource that participate in solving the water scarcity issue in Egypt. This study was carried out in Lake Manzala Water Research Station which is located at the tail end of Bahr El Baqar Drain in Northern Delta in ‏Egypt. A pilot scale wetland consisting of four parallel basins under natural climatic conditions were used for the experiment. The first cell was cultivated with Reeds (traditional plant used in wetlands), while the algae were cultivated in the three other basins. Three different microalgae and algae species (Chlorella, Spirulina and Azolla) were experimented and compared to assess for the finest removal efficiency for different contaminants as BOD, COD, TN, TP, TC, FC and heavy metals. A tailor‐made module was developed with Excel Visual Basic Application programming language to compare the efficiencies of the different treatment systems. Results showed that BOD and COD best removal results were reached by Chlorella with 88% and 84% removal efficiencies respectively. Results also showed that Azolla is the most efficient treatment media for drainage water containing high concentrations of TN while Spirulina was found to be the most efficient in extracting the heavy metals such as Aluminum (Al), Iron (Fe) and Manganese (Mn).

Transboundary cooperation a potential route to sustainable development in the Indus basin

With a rapidly growing population of 250 million, the Indus river basin in South Asia is one of the most intensively cultivated regions on Earth, highly water stressed and lacking energy security. Yet, most studies advising sustainable development policy have lacked multi-sectoral and cross-country perspectives. Here we show how the countries in the Indus basin could lower costs for development and reduce soil pollution and water stress by cooperating on water resources and electricity and food production. According to this analysis, Indus basin countries need to increase investments to US$10 billion per yr to mitigate water scarcity issues and ensure improved access to resources by 2050. These costs could shrink to US$2 billion per yr, with economic gains for all, if countries pursued more collaborative policies. Downstream regions would benefit most, with reduced food and energy costs and improved water access, while upstream regions would benefit from new energy investments. Using integrated water–energy–land analysis, this study quantifies the potential benefits of novel avenues to sustainable development arising from greater international cooperation. The Indus river basin in South Asia is water stressed, energy insecure and intensively farmed, and research on this region often lacks a systemic approach to the issues. This study shows how the path to development in the region could be made less costly and more environmentally friendly by fostering transboundary cooperation.

Rapid Urbanization and Agricultural Intensification Increase Regional Evaporative Water Consumption of the Loess Plateau

AbstractChanging evapotranspiration (ET) will impact freshwater availability, knowledge of which is a critical prerequisite for policy development related to water resources management in an evolving climate, especially for water‐limited regions. However, the socio‐economic effects are not considered due to the lack of detailed information about this. Here we used a well‐validated remote sensing model and multiple socio‐economic factors to investigate the driving factors of ET changes over the Loess Plateau during 1982–2012. Results showed that the modeled annual ET significantly increased by ~2 mm yr−2 during this period (p &lt; 0.001), caused by increased transpiration (2.16 mm yr−2) and interception (0.27 mm yr−2), which was partly offset by decreased soil evaporation (−0.47 mm yr−2). Meanwhile, although the average ET of the forest was larger (480.4 ± 14.8 mm yr−1), it was found that the change in total ET of the region was dominated by that in grassland and cropland (1.1 km3 yr−2, 90% altogether). Factorial simulations indicated that the intensifying ET over 79.4% and 9.1% of the study area can be explained by vegetation greening and climate change, respectively. Further analysis suggested that the vegetation greening and the increased ET were primarily associated with the rapid urbanization and agricultural intensification. Our findings highlight the potential unfavorable effects of socio‐economic activities on water resources management on this coupled natural‐human system that is already facing water scarcity issues.

Performance Analysis of Thermal Storage Assisted Cooling Tower with Night Cooling

As global warming and water scarcity issues continue to grow, it is essential to increase resources efficiency for air conditioners and power plants. In order to increase the efficiency, the systems need to be modified to take the advantages of the low night temperature and thermal storage tanks. In this study, the low night temperature and thermal storage tanks effects on the cooling tower is studied using TRNSYS. Using a chiller operating from 8:00 to 16:00 as a case study, hot water from the condenser is partially stored on daytime and cooled slowly during the night. The storage tank volume is optimized by considering two big tanks and five small tanks. The results show that night cooling reduces cooling water temperature by 5.8 °C or 21.8% while the cooling efficiency is increased by 36%. The thermal storage tanks enable to have the low continuous flow rate and help to reduce the fan power by 67.1%. On the storage side, compared to two tanks system, the tanks volume is reduced by 16.5% when 5 tanks are used. In theory this reduction can go up to 50% by increasing the number of tanks and reducing their individual size.

Wetting-resistant photothermal nanocomposite membranes for direct solar membrane distillation

Efficient use of solar energy for desalination is one strategy to solve the world's water scarcity issues. In this work, a dual functional, omniphobic−photothermal nanocomposite membrane was developed to achieve wetting resistance and low energy consumption in desalination by direct solar membrane distillation (DSMD). The membrane was prepared by forming a hierarchical structure of 1H,1H,2H,2H-perfluorodecyltriethoxysilane (FAS17) modified carbon black (CB) nanoparticles (NPs) on a polyvinylidene fluoride (PVDF) membrane surface. The fluorinated CB NPs absorbed sun light to provide localized heating for DSMD, which increased membrane flux by 25% upon simulated solar irradiation at one sun unit. The utilization efficiency of solar energy in the DSMD process, 75.4%, is more than one order of magnitude higher than the energy efficiency of the conventional direct contact membrane distillation process. Furthermore, the re-entrant structure formed by the CB NPs together with the hydrophobic FAS17 coating led to low surface energy and hence omniphobicity, increasing the contact angle of the 80 vol% ethanol-in-water from 0 to 94.2°. As a result, the dual functional membrane exhibited much higher resistance to wetting by surfactants. Whereas the pristine PVDF membrane was wetted by 0.2 mM SDS, SDS had no effect on the dual function membrane over the whole SDS concentration range tested (0.1–0.4 mM). The photothermal activity, improved thermal efficiency, and strong wetting resistance make the dual functional omniphobic−photothermal membrane an excellent membrane material for the DSMD process.

A Review on Oleaginous Microorganisms for Biological Wastewater Treatment: Current and Future Prospect

The water scarcity issue is becoming a critical issue to the climate change, industrialization and urbanization. Prompt to the advances in biotechnology, Oleaginous microorganisms have been discovered and successfully applied in biological wastewater treatments, which are highly effective for wastewater clean-up and energy efficient lipid conversion to value-added products. This paper aims to review the recent advances of the application of different types of Oleaginous microorganisms (e.g. yeasts, microalgae, and fungi) as well as the advantages, limitations and application fields (food industry, municipal waste and chemical plant). The future prospect and challenges of Oleaginous microorganism that warrant in environmental settings or engineered systems are also highlighted in the review. In order to improve the Technology Readiness Level (TRL), the future research direction should be more focussed on the economic and environmental studies.

Self-Suspended Photothermal Microreactor for Water Desalination and Integrated Volatile Organic Compound Removal.

Steam generation and photocatalytic degradation of organic pollutants based on solar light are regarded as two important strategies for addressing the water scarcity issues. The water evaporation efficiency was greatly inhibited by the high cost, low stability, and low efficiencies of solar light absorption and photothermal conversion of photothermal materials. Moreover, volatile organic compounds (VOCs) are easily volatilized and enriched in as-distilled water during the photothermal process. Inspired by the structure of biomass materials in nature, a bifunctional solar light-driven steam generation and VOC removal microreactor was explored by coating commercial TiO2 (P25) powders on a carbonized biomass waste Flammulina. With the 3D aligned porous carbon architectures, this microreactor exhibited both a high water evaporation rate (37.0 kg m-2 h-1) and a high energy conversion efficiency (91.2%) under simulated sunlight irradiation (light intensity = 25.5 kW m-2). A high VOC removal rate (80.9% in 40 min) was also achieved during the steam generation process via choosing phenol as the probe pollutant molecules. The nature-inspired designing concept and bifunctional microreactor in this study may open up a new strategy for producing clean distilled water from seawater with an efficient removal of VOCs.

Sustainable membrane technology for resource recovery from wastewater: Forward osmosis and pressure retarded osmosis

There has been increasing attention in osmotically driven membrane processes (ODMPs), which include forward osmosis (FO) and pressure retarded osmosis (PRO). They provide a sustainable solution against water and energy scarcity issues by utilizing the osmotic pressure difference between two water bodies, feed (low salinity) and draw solution (high salinity), across a semipermeable membrane. Indeed, their main applications, water treatment (e.g., desalination and wastewater treatment) and power generation, facilitate resource recovery from wastewaters. This review updates the recent development of FO and PRO by providing a comprehensive review on their fundamentals, membrane properties, potential applications as well as advanced techniques. In addition, economic analysis and environmental impacts are critically reviewed to highlight their feasibility and sustainability. Resource recovery from wastewaters (e.g., water, nutrient and energy) using FO and PRO is also discussed followed by their commercialization and future trends in order to push forward laboratory research to full-scale commercialization.