Demand For Potable Water Research Articles

The Use of Permeable Interlocking Concrete Pavement to Filter Stormwater for Non-Potable Uses in Buildings

A reduction in potable water demand in buildings could be made by using non-potable water for certain uses, such as flushing toilets. This represents a sustainable strategy that results in potable water savings while also using an underutilised resource. This work assesses the use of permeable interlocking concrete pavement to filter stormwater that could be used for non-potable purposes in buildings. Two pavement model systems were tested. One of the model systems presents a filter course layer with coarse sand and the other model system has no filter course layer. In order to evaluate the filtering capacity, the model systems were exposed to rain events. The amount of water infiltrated through the layers was measured to represent the potential quantity available for use. Stormwater runoff samples were collected from a parking lot paved with impermeable interlocked blocks and then, these were tested in both model systems. Water samples were subjected to quality tests according to the parameters recommended by the Brazilian National Water Agency. The model system with no filter course showed filtering capacity higher (88.1%) than the one with a filter course layer (78.8%). The model system with a filter course layer was able to reduce fecal coliforms (54.7%), total suspended solids (62.5%), biochemical oxygen demand (78.8%), and total phosphorus concentrations (55.6%). Biochemical oxygen demand (42.4%) and total phosphorus concentrations (44.4%) increased in the model system with no filter course layer. In conclusion, one can state that the filter course layer used in permeable interlocking concrete pavement can contribute to decreasing pollutants and can improve stormwater quality. The use of permeable interlocking concrete pavement showed to be a potential alternative for filtering stormwater prior to subsequent treatment for non-potable uses in buildings.

Trend of Mortality by Water Related Intestinal infectious Diseases: A Study of National Capital Territory of Delhi, (2001 to 2011)

National Capital Territory (NCT) of Delhi is experiencing rapid urbanization for the last few decades. The area is lagging behind in water and waste management infrastructure. This is due to the fact that Delhi is recording high growth rate of population mostly through in-migration over the year which is taxing much upon the existing water resources and the provisions made for water supply. Consequently demand is higher than supply of the safe drinking water. The consumption of unsafe drinking water is therefore increasing and is causing serious health problems among the fellow residents of NCT of Delhi. These health problems are basically related to the digestive as well as excretory systems of the human body. These disorders are promoting mortality particularly among those segments of population which do not have access to potable drinking water. This paper is therefore a modest attempt towards examining the population growth rate and the scenarios of demand and supply for potable water as well as the overall water related intestinal infections and related mortality at present and their future occurrence. This requires synergy between the different sectors of the state to overcome the problem. of intestinal infection diseases in the region.

Technical feasibility analysis of rainwater harvesting system implementation for domestic use

Iran is facing the problem of the water crisis; however, rainwater harvesting can be a solution to manage sustainable water resources in this country. This study aims to investigate the technical feasibility of rainwater harvesting system (RWHS) implementation in 7 cities located in the north of Iran. The analysis conducted on a particular scenario of rainwater demand based on water balance concept and analysis of the rainwater tank capacity compatibility. Results indicate that RWHS implementation is technically feasible in the majority of houses of the residential sector of all the seven cities, while a few numbers of apartments can implement the system for the scenario. Therefore, the influence of the roof area variation on the potential for potable water savings in the apartment sector was evaluated to find a more efficient design of RWHS for future construction. The main conclusion drawn from the research is that the potential for potable water savings in order to investigate the technical feasibility for implementing RWHS, be evaluated for each location, as it depends extremely on potable water demand. An inconsistent result with Ghisi et al. (2007) was found by this research that shows cities with higher potable water demand require larger tank capacity.

Simulation and Evaluation of a Hybrid Renewable Energy System for Supplying a Desalination Unit on the Island of Lipsi, Greece

Water scarcity is a serious problem for the Aegean Islands in Greece. Due to the fact that tourist development grows in a continuous way, the situation has deteriorated over the last years. Current water resources management practices involving the exploitation of the groundwater reservoirs have provoked the salty water intrusion into the aquifers and in many arid islands water is transported by sea, at a considerably high cost (reaches about 12 €/m³ in some cases). Desalination is foreseen as a solution to this problem and it has already been adopted in many islands, as it is a process that can provide fresh and potable water in the required quantities, at a much lower cost. The coupling of desalination with renewable energy sources (RES) constitutes an appealing and promising option. This paper presents an integrated case study regarding the design and operation of a water-energy system for meeting irrigation and potable water demand in Lipsi Island (Dodecanese complex, Greece). As the desalination unit operation depends on the wind power, a detailed description regarding the generation of synthetic time series of wind speed data is also presented. Finally, a Cost-Benefit Analysis is carried out to discuss each scenario we examine from a financial perspective.

Analysis of the Performance of Bank Filtration for Water Supply in Arid Climates: Case Study in Egypt

Bank filtration (BF) is acknowledged as a sustainable and effective technique to provide drinking water of adequate quality; it has been known for a long time in Europe. However, this technique is site-specific and therefore its application in developing countries with different hydrologic and environment conditions remains limited. In this research, a 3-discipline study was performed to evaluate the feasibility of the application of this technique in Aswan City (Egypt). Firstly, a hydrological model was developed to identify key environmental factors that influence the effectiveness of BF, and to formulate plans for the design and management of the BF system. Secondly, water samples were collected for one year (January 2017 to December 2017) from the water sources and monitoring wells to characterize the bank-filtrate quality. Lastly, an economic study was conducted to compare the capital and operating costs of BF and the existing treatment techniques. The results demonstrated that there is high potential for application of BF under such hydrological and environmental conditions. However, there are some aspects that could restrict the BF efficacy and must therefore be considered during the design process. These include the following: (i) Over-pumping practices can reduce travel time, and thus decrease the efficiency of treatment; (ii) Locating the wells near the surface water systems (<50 m) decreases the travel time to the limit (<10 days), and thus could restrict the treatment capacity. In such case, a low pumping rate must be applied; (iii) the consequences of lowering the surface water level can be regulated through the continuous operation of the wells. Furthermore, laboratory analysis indicated that BF is capable of producing high quality drinking water. However, an increase in organic matter (i.e., humics) concentration was observed in the pumped water, which increases the risk of trihalomethanes being produced if post-chlorination is implemented. The economic study ultimately demonstrated that BF is an economic and sustainable technique for implementation in Aswan City to address the demand for potable water.

Capillary-driven solar-thermal water desalination using a porous selective absorber

The desalination of seawater has the potential to address the increasing demand for potable water. Specifically, solar-thermal water desalination can generate clean water without relying significantly on fossil energy. However, the inefficient use of solar energy often limits the overall performance, which affects the rate, efficiency, and feasibility of large-scale implementation. This study shows the use of a spectrally-selective nanomaterial as an absorber to improve the performance of solar-thermal desalination. This material is designed to maximize the absorption of sunlight and minimize the loss of energy by thermal emission, which allows higher throughput and efficiencies compared to broadband absorbers. In this study, we show a 10% enhancement in the evaporation rate of water by using a selective absorber compared to a graphite absorber. We demonstrate a scalable approach involving the use of wicking materials interfaced with the spectrally-selective absorber for the desalination of saline water to get 73% of overall efficiency using a solar flux of one sun. This demonstration of an inexpensive strategy for producing clean water can potentially transform the field of solar-thermal desalination to address the rising demand for water.

Vulnerability of Water Resources to Climate Change: Adaptation and Resilience Strategies for Sustainable Development in Nigeria

Nigeria faces inexorable climate change in recent times. This phenomenon will have a profound effect on the long-term sustainable socio-economic development and is also likely to jeopardize achievement of economic development of the country. All economic and social sectors will be adversely affected. The water resources sector is one that will be strongly impacted by climate change. Against a background of increasing demand for potable water, sea-level rise may lead to flooding of lowlands and seawater intrusion into coastal aquifers, while variability in climate may see more intense rainstorms resulting both in increased run-off leading to increased flooding and reduced recharge leading to aquifer depletion. Such impacts are already having negative ripple effects on other vital aspects of the economy such as the tourism, recreational, agricultural and industrial sectors. Unfortunately, adequate management of water resources in Nigeria is sorely lacking. Extensive studies to quantify the likely impacts of future climate change and climate variability on water resources in Nigeria are not available. In many cases, baseline data which may be used to track changes are sparse or non-existent. The impacts of climate change and economic value of water resources will form the basis for the development of adaptation strategies with regards to the sustainable management of regional and national water resources. This paper therefore explores the probable effect climate change will have on water resources in Nigeria, the fall-out from these effects and strategies for mitigating potential negative impacts for sustainable development.

From yards to cities: a simple and generalizable probabilistic framework for upscaling outdoor water conservation behavior

Outdoor watering of lawns accounts for about half of single-family residential potable water demand in the arid southwest United States. Consequently, many water utilities in the region offer customers cash rebates to replace lawns with drought tolerant landscaping. Here we present a parcel-scale analysis of water savings achieved by a ‘cash-for-grass’ program offered to 60 000 homes in Southern California. The probability a resident will participate in the program, and the lawn area they replace with drought tolerant landscaping, both increase with a home’s outdoor area. The participation probability is also higher if a home is occupied by its owner. From these results we derive and test a simple and generalizable probabilistic framework for upscaling water conservation behavior at the parcel-scale to overall water savings at the city- or water provider-scale, accounting for the probability distribution of parcel outdoor areas across a utility’s service area, climate, cultural drivers of landscape choices, conservation behavior, equity concerns, and financial incentives.

Parameter analysis and energy optimization of a four-bed, two-evaporator adsorption system

A four-bed two-evaporator adsorption chiller is a promising and environment-friendly technology that utilizes waste thermal/renewable energy to produce chilled water and high-grade potable water simultaneously. Unlike existing works that focus solely on improving chillers’ cooling performance under constant ambient conditions, this work develops optimal cycle time correlations, factoring varying external conditions, to maximize specific daily water production of a multi-bed adsorption chiller prototype. A poor selection of its operational parameters can negatively impact the chiller’s performance, particularly when the cooling and potable water demands vary. Accordingly, a dynamic-based model has been judiciously developed to study the operating characteristics of the chiller. Further, Monte Carlo simulations are employed to assess and rank the influencing strength of key operating parameters on the chiller’s performance. The parameter sensitivity on the chiller’s performance in terms of improving its cooling capacity, coefficient of performance, and specific daily water production are statistically analysed. Experiments have also been performed to validate the dynamic model. Comparisons showed good agreement between simulated specific daily water production results and experimental data with a maximum discrepancy of 4.1%. The developed correlation is able to estimate the chiller’s optimal cycle time with an R-square of 0.96. Key results revealed that the respective hot and cooling water mass flow rates entering the chiller are the most influencing parameters that quantify the chiller’s coefficient of performance. And chilled water mass flow rate and cycle time are critical parameters that impact the chiller’s cooling capacity, while the operational cycle time dictates its specific daily water production.

Synthesis of a moringa based coagulant functionalized by iron oxide nanoparticles

Currently, Zimbabwe as a whole has been facing economic challenges in various ways, and this has greatly affected the functionality of quite a number of industries. Taking into consideration of the water treatment industries, mainly all city councils have been facing difficulties in meeting the potable water demand due to lack of funds to purchase the highly expensive chemicals required for raw water treatment. This research serves to provide an alternative to the coagulant used in most water treatment facilities in Zimbabwe, with reference to the City of Gweru. A moringa based coagulant functionalized by iron oxide nanoparticles was synthesized consisting of a ratio of moringa seed extract and iron oxide nanoparticles in a ratio of 3:1. In addition to the economic benefits of the moringa based coagulant, it is also environmentally friendly. The amount of non-biodegradable sludge resulting from the use of aluminium sulphate can be reduced. The synthesized coagulant is partly organic due to the presence of the moringa seed extract, making it biodegradable. It also has magnetic properties due to the presence of the iron oxide nanoparticles. These can be separated easily from the organic part of the sludge through application of a magnetic field and reused again in the synthesis of the coagulant or for other purposes. Jar test experiments were carried out to determine the optimum dosage of the moringa based coagulant and also to compare properties of water treated with the magnetic coagulant to water treated with aluminium sulphate and moringa seed extract separately. The magnetic coagulant gave the best results with a minimum dosage of 45 mg/L. A turbidity removal of 91.5% and a pH of 7.04 was observed.

Effect of Desalination Discharge on the Abundance and Diversity of Reef Fishes.

Global growth in desalination industries has increased the need for an evidence-based understanding of associated environmental impacts. We completed a seven-year assessment of the responses of fish assemblages to hypersaline discharge from the large Sydney Desalination Plant. At 12 times before, eight times during, and four times following the cessation of discharging hypersaline brine, we sampled reef fishes at two outlet sites and two close reference sites, as well as four reference sites that were located from 2-8 km from the outlet. At each site and each time of sampling, five 50 m video transects were used to sample reef fish assemblages. Following the commencement of discharging, there was a 279% increase in the abundance of fish around the outlet, which included substantially greater abundances of pelagic and demersal fish, as well as fishes targeted by recreational and commercial fishers. Following the cessation of discharge, abundances of fishes mostly returned to levels such that there was no longer a significant effect compared to the period prior to the commencement of the desalination plant's operations. Overall, our results demonstrate that well-designed marine infrastructure and processes used to support the growing demand for potable water can also enhance local fish abundances and species richness.

Techno-economic feasibility study of a solar-powered distributed cogeneration system producing power and distillate water: Sensitivity and exergy analysis

To satisfy the increasing demand for energy and potable water, large-scale cogeneration is widely integrated. However, in remote locations, the lack of power system infrastructure limits the integration of large-scale systems. Consequently, a large portion of inhabitants has no access to electricity and the pressure on groundwater resources increases drastically. To address this power and water scarcity, a distributed cogeneration system consisting of a solar-powered micro Gas Turbine and desalination system is considered. Since the integration of solar energy in distributed cogeneration systems is uncertain, we performed a feasibility study. This paper covers the modelling, sensitivity and exergy analysis and 3 desalination systems designs, each making a trade-off between smaller plant size and higher performance. Introducing solar energy in the micro gas turbine results in an increase in electrical efficiency by 3.2% absolute. The proposed designs achieve a levelized cost of water between 1.78$/(m3/d) and 1.92$/(m3/d), which is comparable with conventional solar-powered desalina-tion plants. Therefore, these designs demonstrate the feasibility of integrating solar energy in distributed cogeneration systems and provide a promising solution towards cost-efficient, renewable-based power and water cogeneration in remote locations. The future work will enhance the economic analysis by including an intermittent solar energy supply.

Forest-water interactions in the changing environment of south-western Australia

In a major Australian city, water supply has been decoupled from forests as a result of management and climate change. Water yield and quality are closely related to forest cover and have been manipulated through broad-scale intervention. The forests remain important for biodiversity protection and considering water as a forest product will fund interventions that maintain the forest’s environmental values. Perth, an Australian city of 2 million people and a potable water demand of 300 GL/year, occurs in a region that has experienced a decline in rainfall and a major reduction in surface runoff to water supply reservoirs over the last 40 years. This has led to a major impact on water policies, with the collapse of surface water supply from forested watersheds resulting in the almost complete substitution of Perth’s water supply with groundwater and desalinated water. Thus, water supply has been decoupled from forests and forest management processes. In this paper, we review the interactions between forest cover and water supply in the drying environment of south-western Australia, exploring studies on the hydrological effects of extensive deforestation for agricultural development, widespread reforestation, forest management, and reduced annual rainfall. We draw conclusions applicable to other regions that are experiencing the combined impacts of climate change and pressures from land-use intensification. We find that streamflow and water quality are clearly linked to forest cover and this is affected by both climate and forest management. Streamflow increases with a reduction of forest cover (through deforestation or thinning) and decreases with reforestation and reduced rainfall. Stream salinity increases with deforestation and decreases with reforestation. Hydrological responses occur where forest cover treatments have been applied and maintained at watershed-scales. Surprisingly, where water yield or quality has been improved, this has not been rewarded financially and there is a need to develop methods of financing treatments to maintain streamflow. Whereas forests were initially maintained for water and timber supply, with biodiversity protection as a co-benefit without a defined value, the decoupling of forests from water supply has substantially reduced the financial resources for any form of direct forest management. As the forests remain important for biodiversity protection, a key recommendation is to consider water as a forest product and thus provide funds for watershed-scale treatments, such as forest thinning, that maintain the forest’s environmental values in a drying climate.

SAFE REUSE OF TREATED WASTEWATER AND SLUDGE IN DECENTRALIZED SYSTEM

The unsafe water and solid reuse from decentralized wastewater treatment plant still occur due to the lack of improved and effective water management. This paper has aims to provide research findings of main management aspect of decentralized wastewater treatment plant with water reuse orientation. The scope of analysis includes wastewater treatment process performance evaluation, health risk, water reuse constraints and community motivation. The decentralized wastewater system had been designed as green technology in some settlements areas, which have low maintenance, low sludge production, and have high potential of water reuse for non potable water demand. According to the treatment schemes for water reuse system, the management is affected by treatment performance, proper maintenance, environmental condition and community motivation. The treated water quality according to water reuse standard of USEPA can be a source for agriculture or non-potable water demand and reduce contamination of water sources. Achievement of the effective wastewater management system could provide non-potable water source to fulfill 50-65% of clean water demand according water reuse standards. There are some constraints of wastewater reuse that were minimized through some steps to enhance wastewater system towards safe water and solid reuse.

Investing in Water Purification Infrastructure in an Emerging Market: Some Considerations for Impact Investors in South Africa

This study investigated the role that impact investors could play in the water purification infrastructure sector. Impact investors are individuals and institutions that invest in companies, organisations and funds with the aim of generating social and environmental impact alongside financial return. These investors are increasingly interested in emerging markets such as South Africa. As scholars have raised concerns about investors and companies profiting from the provision of a basic human right, the views of 20 experts were also gauged on this topic. Semi-structured personal interviews were conducted with key role players in the South African impact investment value chain (mostly investors) and the water provision system. Interviewees saw an important role for private sector investment in water purification infrastructure given government’s inability to meet the growing demand for potable water. Participants were, however, wary of private-public-partnerships and felt that investors and companies will only face a moral dilemma if they overcharge consumers for purified water. Impact investors should give careful consideration to domestic water users’ ability to pay as well as their needs and expectations. The development of a blended financing model is proposed. Keywords: Impact investing; emerging market; water purification infrastructure; South Africa; basic human rights; ethical concerns

Experimental Study on Productivity of Different Designs of Solar Stills in Hot Climatic Conditions

Because of the large increase in energy and water demand for agriculture, industry and human needs, and the increase in water pollution problems due to urbanization, industry and human activities, the demand for potable water has increased. Solar desalination is an alternative approach to save energy and converting saltwater into high-quality drinking water using solar energy. This work aims to design, manufacture, and test two types of solar still images (i.e. single slope and transparent tent) in order to improve their heat absorption and thereby improve efficiency under the prevailing hot climatic conditions of Al-Medina Al-Monawra. Accordingly, solar energy has been used for distillation purposes for saltwater purification to be used for drinking and irrigation in arid areas. Although solar devices are still simple in design, their values and advantages are very high. It also relies solely on renewable energy sources that are clean, free and unpolluted. In addition, economic analysis and comparisons of water productivity between the single slope solar still and the transparent tent have been presented. The results have indicated that the productivity of water per square meters per day for the transparent tent solar still is higher than the one of the single-slope solar still by about 6%. From economic analysis, the recovery period for both systems has been found to be about 3.5 years.

Identifying and overcoming barriers to onsite non-potable water reuse in California from local stakeholder perspectives

Abstract Onsite (a.k.a. decentralized) water reuse can reduce overall potable water demand and aid in meeting water reduction goals. In spite of clear benefits, onsite non-potable water systems (ONWS), specifically non-blackwater commercial systems, face many challenges that are preventing growth and expansion in California. This study utilized a technical advisory committee and a survey to identify the most significant challenges facing onsite water reuse systems, how these challenges affect ONWS stakeholders, and potential solutions at the state level. The given methods found that the most prevalent challenges hindering the growth of ONWS appeared to be the absence of a local regulatory program, system cost, poor access to training for regulators, and limited public education about alternate water sources. Survey results revealed several possible drivers for the existence of these challenges including that informational and training resources are not adequately disseminated to target groups. The study concluded that the creation of trainings for regulators, the development of an organization dedicated to onsite systems, expanded technology certifications, policy changes, and highlighting existing systems might help overcome the challenges hindering growth and allow for greater expansion of onsite non-potable water systems throughout California.

An Analysis of Eco-Technology Allowing Water and Energy Saving in an Environmentally Friendly House—A Case Study from Poland

The Life Cycle Cost (LCC) analysis on selected alternative systems was carried out to reduce the demand for potable water and energy in a detached house designed in accordance with the concept of environmentally friendly house. The tests included a rainwater harvesting system, graywater recycling system, solar panels, photovoltaic panels, air heat pumps, ground heat pumps, wind turbines, drain water heat recovery units, and biomass boilers. The analysis was made for many investment variants where different combinations of the mentioned solutions were applied. In addition to the LCC analysis, some tests were also carried out to determine an impact of the investment options on the environment. This was done by calculating CO2, SO2, NOx, CO and dust emissions. The research was carried out for a different number of occupants and variable levels of water consumption, which allowed determining the impact of these parameters on the results obtained. They showed that for any of the computational cases the traditional option of the installation was not the most advantageous solution in financial and environmental terms, and the systems in question could be an alternative to this option. Thanks to their implementation, the consumption of fossil energy resources and natural water resources will be reduced, and the emission of pollutants will be limited, which will contribute to an improvement of the natural environment.

Trend of Mortality by Water Related Intestinal infectious Diseases: A Study of National Capital Territory of Delhi, (2001 to 2011)

National Capital Territory (NCT) of Delhi has been experiencing rapid urbanization for last few decades. The area is lagging behind in water and waste management infrastructure. This is due to the fact that Delhi is recording high growth rate of population mostly through in-migration over the years which is taxing much upon the existing water resources and the provisions made for water supply. Consequently demand is higher than supply of the safe drinking water. The consumption of unsafe drinking water is therefore increasing and is causing serious health problems among the fellow residents of NCT of Delhi. These health problems are basically related to digestive as well as excretory systems of the human body. These disorders are promoting mortality particularly among those segments of population which do not have access to potable drinking water. This paper is therefore a modest attempt towards examining the population growth rate and the scenarios of demand and supply for potable water as well as the overall water related intestinal infections and related mortality at present and their future occurrence. This requires synergy between the different sectors of the state to overcome the problem of intestinal infection diseases in the region.

Experimental parametric study of membrane distillation unit using solar energy

Solar distillation is a promising method for the supply of freshwater to rural communities because water is a vital factor for the survival of humans. Therefore potable water demand is increasing continuously because of the industrial, population and, fast agricultural applications. Nowadays, different techniques for water purification have been created to provide freshwater from salty and polluted water such as solar distillation method to distill brackish/saline water. This work presents an experimental study of the solar membrane distillation unit which is coupled with direct contact membrane (DCMD) which located at Kairouan University. The system is installed as part of a cooperation project research and development between Tunisian Electromechanical Systems Laboratory and German Institute for Solar Energy Systems entitled: Solar driven membrane distillation for resource efficient desalination in remote areas. For the heating of the hot feed water stream, a heat exchanger is included which can be operated with any external heat supply between 60 and 80 °C. For the cooling of the cold feed water stream, no heat exchanger is included. The cooling can be provided over the intake of cold feed water. The effect of solar irradiation and all temperature on the journal productivity of the unit has been presented.