Water Supply Options Research Articles

Water supply problems of the small settlements

The study of the problems of providing drinking water to the population in small settlements allowed us to identify the most important ones in the extraction of water, its preparation and transportation. The conclusions are based on statistical data on water supply problems. The causes of problems are identified and the directions of development of water supply systems are determined. The dynamics of aging of water supply systems in small settlements is analyzed. Various water supply options were investigated. Various water supply systems were simulated and a set of calculations was performed. Options for combining existing systems and reconstructing them are modeled. Water supply systems with a water tower are investigated. Variants of the water supply system’s exit from the crisis situation have been developed.

Water reuse versus water conveyance for supply augmentation: Cost and carbon footprint

AbstractWater‐stressed communities are beginning to consider alternative sources of water supply augmentation. We provide a comparison of water conveyance and potable water reuse over a range of water demands. On a unit basis (US$/1,000 gal) and under current practice, water reuse is generally less costly at low flow rates (<10 mgd) as compared with water conveyances of 20 miles or more. This is true especially for advanced water treatment schemes that are based on biologically activated carbon (BAC). At greater distances (>100 miles), treatment schemes that are based on reverse osmosis (RO) also become cost competitive. Similarly, both BAC‐based and RO‐based reuse schemes have a lower or comparable carbon footprint on a unit basis (g CO2‐equiv/1,000 gal) for a flow rate of 20 mgd. In spite of public reluctance, managers would do well to consider reuse in their portfolio of water supply options.

Reverse Osmosis Options for Water Supply to a Thermal Power Station

Water in industry is used for operations such as production processing, washing, dissolving, cooling, transportation. Industries often require large amount of water with vary quality. Water quality depends on the purpose of water use. The steam electric power generation industry is defined as those establishments primarily engaged in the steam generation of electrical energy for distribution and sale. Those establishments produce electricity primary from a process utilizing fossil type fuel (coal, oil, or gas) or nuclear fuel in connection with a thermal cycle employing the steam –water system as the thermos-dynamic medium [9]. Water with in boiler drum and steam generation tubes and headers must be soft and clean. Reverse Osmosis is an effective and proven technology to produce water that is suitable for many industrial applications that require demineralized or deionized water with neutral pH and without turbidity and aggressive.

Reverse Osmosis Options for Water Supply to a Thermal Power Station

Water in industry is used for operations such as production processing, washing, dissolving, cooling, transportation. Industries often require large amount of water with vary quality. Water quality depends on the purpose of water use. The steam electric power generation industry is defined as those establishments primarily engaged in the steam generation of electrical energy for distribution and sale. Those establishments produce electricity primary from a process utilizing fossil type fuel (coal, oil, or gas) or nuclear fuel in connection with a thermal cycle employing the steam –water system as the thermos-dynamic medium [9]. Water with in boiler drum and steam generation tubes and headers must be soft and clean. Reverse Osmosis is an effective and proven technology to produce water that is suitable for many industrial applications that require demineralized or deionized water with neutral pH and without turbidity and aggressive.

A Rainwater Harvesting Accounting Tool for Water Supply Availability in Colorado

Rainwater harvesting (RWH) is a renewable water supply option for nonpotable use, most commonly used for landscaping irrigation. Water rights in Colorado prohibit all RWH except residential rain barrels and a pilot project program that allows centralized rainwater harvesting for new development. Development of a natural catchment creates impervious surfaces, thereby increasing runoff, with a subsequent decrease in infiltration and losses to evapotranspiration; pilot projects are allowed to harvest a volume equal to the predevelopment runoff losses that would have occurred on new impervious areas at the site. To support this administrative policy, a tool was developed for the efficient calculation of daily allowable harvest at nearly any project site in Colorado. A reliable and useful policy tool requires the incorporation of hydrologic science with widely applicable, user-friendly design, a challenging balance of rigor and accessibility that is welcomed by engineers and policymakers alike. The daily allowable harvest is determined for each soil group as a percentage of infiltrated rainfall less the groundwater return. Horton’s infiltration method is used to model rainfall‒runoff for a range of soil parameters (NRCS hydrologic soil groups) and precipitation events (0.25- to 25-year return periods and 15-min to 24-h durations). For most events, the percent infiltration is 90% of the precipitation depth; this ratio decreases when precipitation exceeds the infiltration rate. Results are simplified in a spreadsheet tool for policy application, with allowable harvest rules binned by event duration and frequency. Simulations using the tool for a 2010‒2017 precipitation record from Colorado’s Front Range showed that RWH can supply up to 50% of the annual demand for traditional landscaping and over 100% of the water-smart landscaping demand.

Natural volcanic tuff as a soil mulching: effect on plant growth and soil chemistry under water stress

Efficient water management in agricultural sector necessitates the manipulation of all possible options for water supply and demand management methods. The purpose of this study was to determine the usefulness of using natural volcanic tuff as a soil mulching on plant and soil properties under different water levels. The experiments were performed using 1-year-old olive transplants planted in barrels filled with silty clay soil. Half of the barrels were covered with a coarse volcanic tuff, while the other samples were remained without covering and considered as control. The two sets of barrels were irrigated with four levels of water which correspond to 75%, 65%, 55%, and 45% of the field capacity. The treatments were arranged in a randomized complete block design with three replications. Results revealed that plant height, number of branches, trunk diameter, shoots length, shoot diameter, number of leaves, and plant weight for soil covered with volcanic tuff were significantly greater than control plants after the fifth growing season. The leaf water potential and relative water content of plants grown in mulched soil were significantly greater than those of control. An increase in nutrient contents of soil and plant tissues was found as a result of soil amendment with volcanic tuff. In summary, a positive influence of volcanic tuff additions on olive growth, leaves water status, and soil nutrient levels was determined.

A flexible framework for assessing the sustainability of alternative water supply options

Increased water scarcity is driving water utilities to consider alternative water supply options (WSOs). Identifying the most sustainable WSOs that meet environmental, economic, and social objectives is challenging due to the overwhelming number of both assessment criteria and treatment configurations, including a growing number of potable reuse options. Conventional approaches using process-based life cycle assessments are data-intensive and site-specific, and therefore not suitable for the early stages of assessing WSOs. To address this gap, we have combined hybrid multi-regional input-output-based life cycle assessment (MRIO-LCA), social impact analysis, and multi-criteria decision analysis (MCDA) to develop a novel, flexible framework with unit process level resolution for the comprehensive evaluation of WSOs. Here we describe the formulation of the framework along with an application to two US utilities considering alternative WSOs. In both cases, given sufficient levels of community acceptance and optimum system design, the results favoured potable reuse WSOs due to their climatic resilience, cost effectiveness and lower environmental impacts (compared to other non-conventional options such as desalination). The generalised and globally applicable framework developed for this study can be used to assess sustainability trade-offs between diverse WSO configurations, providing valuable insights for decision-making processes at the early planning stage, as a complement to existing urban water supply scenario and optimisation models.

Valuing the water supply: ecosystem-based potable water supply management for the Legedadie-Dire catchments, Central Ethiopia

BackgroundThere is a substantial interest in the values that consumers place on drinking water quality and supply. Financial resources are crucial to improving the urban potable water supply in developing countries that are characterized by low-cost recovery rates and a high and rapidly growing demand for more reliable services. This study examined households’ willingness to pay (WTP) for the improvement of water services by identifying their water choice decisions and the mode of water supply that they prefer the water supply authority to use among several alternative water supply options. Stated-preference data were collected from 322 randomly selected households in Addis Ababa, who were presented with three sets of choices (three alternative bundle choices, including the reference scenario). The data were analyzed using the mixed logit WTP space model. Three approaches to modeling the distribution of WTP (fixed, uncorrelated, and correlated) using mixed logit WTP space models were compared.ResultsThree-quarters of the households agreed to contribute money toward ecosystem-based water supply management (EBWSM) intervention programs on a monthly basis. The average contribution that the respondents were willing to pay was 150.5 Ethiopian Birr (ETB) as a one-off lump sum to kick off the EBWSM activities. Most of the respondents chose a bundle of water supply options that provides risk-free and high-quality water with no months of shortages than moderate water quality that is safe to drink and palatable with 1 month shortages annually. This implies that households would need to be supplied with risk-free, high-quality water without interruption at an appropriate flow pressure. The model with correlations fitted the data well with the highest simulated log-likelihoods at convergence and gave the best estimate of the households’ WTP for water improvement. Nearly 46% of the sampled households were willing to pay more than 33 ETB per month, and 49% of the households were willing to pay between 21 ETB and 33 ETB per month for the monthly water bill. Overall, approximately 95% of the sampled households were willing to pay more than 21 ETB.ConclusionCustomers are willing to pay to avoid most types of water supply restrictions. Moreover, WTP is sensitive to the scope of service improvement, income, affixed price, and elicitation method. In summary, mixed logit WTP-space models can help accurately predict household-level WTP, which can be used to select improvements in drinking water access and services in the Legedadie-Dire catchments.

Risk management and environmental benefits of a prospective system for indirect potable reuse of municipal wastewater in France

Abstract This paper presents the assessment of a planned scheme of indirect potable reuse (IPR) in the Vendée region of France in its potential risks for human health and ecosystems, and also in its overall environmental impacts. Methods of risk assessment (quantitative microbial and chemical risk assessment) and life cycle assessment (LCA) are used to characterize the risk associated with the use of reclaimed water for IPR, but also the environmental benefits compared with other options for additional drinking water supply. The LCA results show that IPR is competitive with other options of water supply in its energy demand and greenhouse gas emissions. Pathogens as the main health hazard are controlled effectively by existing and planned preventive measures. For chemicals the number of potentially relevant substances could be reduced substantially by the assessment. A demonstrator phase should now be implemented to validate the outcomes of this prospective assessment by improving data quality of the initial state and by monitoring effective impacts in an operating mode.

Hydrological Restoration and Water Resource Management of Siberian Crane (Grus leucogeranus) Stopover Wetlands

Habitat loss is a key factor affecting Siberian crane stopovers. The accurate calculation of water supply and effective water resource management schemes plays an important role in stopover habitat restoration for the Siberian crane. In this paper, the ecological water demand was calculated and corrected by developing a three-dimensional model. The results indicated that the calculated minimum and optimum ecological water demand values for the Siberian crane were 2.47 × 108 m3~3.66 × 108 m3 and 4.96 × 108 m3~10.36 × 108 m3, respectively, in the study area. After correction with the three-dimensional model, the minimum and optimum ecological water demand values were 3.75 × 108 m3 and 5.21 × 108 m3, respectively. A water resource management scheme was established to restore Siberian crane habitat. Continuous, area-specific and simulated flood water supply options based on water diversions were used to supply water. The autumn is the best season for area-specific and simulating flood water supply. These results can serve as a reference for protecting other waterbirds and restoring wetlands in semi-arid areas.

A multi-objective optimization approach for sustainable water management for places with over-exploited water resources

Rainwater harvesting (RWH) is analyzed in this work as an option for water supply for places with over-exploited water resources. The model is formulated under a multi-period, multi-objective optimization model. The objective is two fold, first to assess the potential of RWH as an alternative water source, and second to design an optimal water distribution network in which both natural and alternative sources work as an integrated system. The problem is formulated to account for three different objectives, namely maximum profit, minimum groundwater usage and minimum investment cost. A case study for the city of Queretaro in Mexico was considered to show the applicability of the proposed approach. The results show that as much as 27% of the domestic demand in Queretaro City could be supplied by RWH, which would lead to a significant recovery of deep wells currently under depletion.

Performance investigation and economic benefits of new control strategies for heat pump-gas fired water heater hybrid system

More recently, the hybrid system equipped with the combination of heat pump and gas fired water heater in one device is increasingly attracting people’s attention from both the industry and academia. In this study, the hybrid system with two control strategies is presented as the alternative option for domestic hot water supply and space heating with the aim of revealing its economic benefits. For the control strategy I, the two heating sources, i.e. heat pump and gas heater, can be switched and there are only two modes: heat pump mode, and gas heater mode. While for the control strategy II, the two heating sources could be handled with the proper arrangement for the loading share. There are 3 modes under this control strategy: heat pump mode, hybrid mode, and gas heater mode. The auxiliary resistance heater is used for heat pump mode if necessary, not for the hybrid mode. Various climate conditions, water initial temperature and final temperature are investigated for the hybrid system, and different heating supply forms are compared. Regarding the domestic hot water demand of 70 L per apartment per day, the gas heater can lead to a ∼38% operation energy cost saving from electric heater, and both of the two control strategies with hybrid system can result in a ∼20% to ∼65% more operation energy cost reduction than gas heater under climate condition of −5 °C to 20 °C, with a more pronounced reduction towards hot climates. Control strategy II, as the most cost-efficient option, can achieve a ∼10% to ∼23% more energy cost saving than strategy I, especially under climate condition of 0 °C to −12 °C. In the hybrid mode with strategy II, a decrease of the final temperature, results in a better economic merit. Regarding the hourly under-flooring heating case, the control strategy II, as the best option, can lead to a ∼6% to ∼70% more hourly process energy cost saving compared with the gas heater from −15 °C to 20 °C ambient conditions. During the typical heating season with ambient (−15 °C to 7 °C), the lowest process energy cost can be achieved by control strategy II. In the same external conditions, the under-flooring heating application has a lower system operation energy process cost than the indoor radiator heating case.

Productivity implications of the water-energy-emissions nexus: An empirical analysis of the drinking water and wastewater sector

Abstract Water, energy and greenhouse emissions issues are intertwined and are difficult to resolve in isolation. One of the challenges in addressing the water-energy-emissions nexus is the lack of studies that integrate both the environmental and economic aspects. The provision of drinking water and wastewater services is a complex operation that involves a significant energy input resulting greenhouse emissions. Using an environmentally sensitive productivity growth index, this paper analyses the productivity growth trends in the Australian drinking water sector from 2005 to 06 to 2014–15. Specifically, the paper estimates the global Malmquist-Luenberger productivity index and its drivers for the sector whilst incorporating an undesirable output – greenhouse emissions. Findings suggest that the overall environmentally sensitive productivity growth remained stagnant up until 2012–13 and experienced a decline of 7.2% and 4.6% during 2013–14 and 2014–15, respectively. In cumulative terms, the productivity growth of the sector has declined by about 28% from the 2005-06 level when accounted for greenhouse emissions. The productivity growth decline can be mainly attributed to the efficiency change rather than technical change over the study period. The findings call for a greater understanding of energy and emission intensity of various water supply options and wastewater operations.

Management preferences and attitudes regarding environmental impacts from seawater desalination: Insights from a small coastal community

The use of seawater desalination as a water supply option is increasing worldwide. Compared to other marine sectors, studies on marine users' perceptions and attitudes towards this new sector and its impacts on marine ecosystems are very limited. This study assessed differences in coastal stakeholder groups' preferences for managing marine impacts of a seawater desalination plant in a small coastal community. The majority of respondents placed high importance on the marine ecosystem, including ecosystem features that are less visible and charismatic, and were highly concerned about potential impacts on marine ecosystems and marine activities from the new desalination facility. Coastal residents further rated multiple management measures to reduce and off-set marine impacts as highly important, but indicated a lack of trust in institutions involved in regulating and managing environmental impacts. Logistic regression revealed that lack of institutional trust and concerns about marine impacts were significant predictors of opposition to the desalination facility and appeared to play a critical role in shaping local attitudes towards desalination. Findings further revealed that local opinions were primarily shaped by how respondents used the nearby marine system, and by gender. Age, education, and race did not seem to shape local opinions. At the same time, there were differences between consumptive and non-consumptive marine user groups' opinions indicating the potential for conflict regarding the most important management strategies.

Integrated Evaluation of Hybrid Water Supply Systems Using a PROMETHEE–GAIA Approach

There are pressures on existing centralized water infrastructures in urban centers which justify the search for alternatives. An increasingly important alternative is to shift from centralized to hybrid systems, often in response to climate variability and demographic changes. In a hybrid system, water is supplied and discharged through a mix of centralized and decentralized systems. There is usually no single objective that justifies the choice of hybrid water systems, but they typically are justified based on the consideration of a number of different criteria in order to evaluate the overall quality of service provision. The most important criteria include meeting water demand, as well as reducing demand for fresh water and instead using local alternative water supplies. Integration of multiple objectives to evaluate the hybrid water supply systems can be accomplished by multi-criteria decision aid techniques. This paper evaluates a number of hybrid water supply scenarios using a case study based on the Northern Growth Area of Melbourne, Australia. It uses the Preference Ranking Organization METHod for Enrichment Evaluations (PROMETHEE) and Geometrical Analysis for Interactive Decision Aid (GAIA), one of the multi-criteria decision-making methods through D-Sight software, to rank the hybrid water supply scenarios, and this ranking is validated by means of sensitivity analysis. The centralized system combined with stormwater harvesting and the centralized system combined with treated wastewater and rainwater tanks yielded the first and second most preferred scenarios, while the centralized water supply system combined with treated wastewater yielded the worst hybrid water supply option.

Modelling the water energy nexus: should variability in water supply impact on decision making for future energy supply options?

Abstract. Many countries, like South Africa, Australia, India, China and the United States, are highly dependent on coal fired power stations for energy generation. These power stations require significant amounts of water, particularly when fitted with technology to reduce pollution and climate change impacts. As water resources come under stress it is important that spatial variability in water availability is taken into consideration for future energy planning particularly with regards to motivating for a switch from coal fired power stations to renewable technologies. This is particularly true in developing countries where there is a need for increased power production and associated increasing water demands for energy. Typically future energy supply options are modelled using a least cost optimization model such as TIMES that considers water supply as an input cost, but is generally constant for all technologies. Different energy technologies are located in different regions of the country with different levels of water availability and associated infrastructure development and supply costs. In this study we develop marginal cost curves for future water supply options in different regions of a country where different energy technologies are planned for development. These water supply cost curves are then used in an expanded version of the South Africa TIMES model called SATIM-W that explicitly models the water-energy nexus by taking into account the regional nature of water supply availability associated with different energy supply technologies. The results show a significant difference in the optimal future energy mix and in particular an increase in renewables and a demand for dry-cooling technologies that would not have been the case if the regional variability of water availability had not been taken into account. Choices in energy policy, such as the introduction of a carbon tax, will also significantly impact on future water resources, placing additional water demands in some regions and making water available for other users in other regions with a declining future energy demand. This study presents a methodology for modelling the water-energy nexus that could be used to inform the sustainable development planning process in the water and energy sectors for both developed and developing countries.

Understanding the impact of hybrid water supply systems on wastewater and stormwater flows

This paper analyses the impacts of various hybrid water supply systems, conceptualised as the combination of centralized and decentralized water supply systems, on wastewater and stormwater flows and contaminants. The analysis comprises of seven alternative scenarios: i) centralized only, ii) centralized along with recycled water, iii) centralized along with treated greywater, iv) centralized along with rainwater harvesting, v) centralized along with stormwater harvesting, vi) centralized along with greywater tanks and stormwater harvesting and vii) centralized along with rainwater harvesting and recycled water. The water, wastewater and stormwater flows and associated wastewater and stormwater quality parameters (TSS-Total Suspended Solids, TN-Total Nitrogen, TP-Total Phosphorous, BOD-Biochemical Oxygen Demand, COD-Chemical Oxygen Demand,) are modelled under various scenarios. The results are utilized to comparatively evaluate the impacts of different hybrid water supply options on stormwater and wastewater flows as well as contaminant loads. The study provides insights by quantifying the relative benefits and challenges of a series of strategies before implementation. Further, the quantification of flow and contaminants provided by this paper could help operationalize the better integration of hybrid systems by identifying risks associated with contaminant loads, and thus could inform improved sewerage and drainage design, operation and maintenance planning.

Energy-efficient resin wafer electrodeionization for impaired water reclamation

A robust ion-exchange resin wafer electrodeionization technology was used to demonstrate the energy efficiency of impaired water desalination. The loose ion exchange resin beads used in conventional electrodeionization were immobilized and molded to form a porous resin wafer material. In this study, the energy efficiency of brackish water desalination using resin wafer electrodeionization was evaluated along with salt removal ratio, current efficiency and productivity. Several key operating factors, including treatment time, applied electrical energy and feed flow rate were selected through experimental design. In addition, the removal rate constant in resin wafer electrodeionization was determined via a pseudo first-order kinetic model, and then correlated with operation parameters. Furthermore, the prediction models of the productivity and energy consumption were established using response surface methodology. Results suggest that resin wafer electrodeionization can improve energy efficiency to greater than 35% in comparison to reverse osmosis (normally ∼12%) for impaired water desalination. The energy consumption of resin wafer electrodeionization was found to be 0.35–0.66 kWh/m3 with productivity of 20.1–44.7 L/hr/m2 (i.e., 5.3–11.8 gal/hr/m2) for brackish water desalination. Furthermore, a preliminary economic evaluation on impaired water desalination using resin wafer electrodeionization comparable to commercial reverse osmosis process was provided. It suggests that resin wafer electrodeionization offers the potential for an abundant source of fresh water from impaired water desalination at a cost-effective manner, which should be viewed as a crucial component in the portfolio of water supply options.

The handpump choice is yours: a pilot study in Rumphi District, Malawi

In sub-Saharan Africa, moving towards the Sustainable Development Goals will require an approach to water and sanitation service delivery for many rural communities where handpumps still dominate infrastructure. This paper reviews a case study of allowing users (local government and communities) in Rumphi District, Malawi, to choose a handpump model based on information about the life-cycle costs. The results indicate that there is some awareness within communities and within the local government of several handpump options for the rural water supply in the study area. Given a choice of different handpump models in the treatment communities, each community chose the rope pump. Allowing communities to choose the type of handpump model, with input from both local government and donors on low cost borehole drilling, should be considered as an innovative approach to rural water service delivery.

Energetic aspects and opportunities for reusing water on offshore platforms in Campos Basin, Brazil

In the drilling and production of oil at sea, a large quantity of potable water used is most commonly transported to oil platforms using offshore supply vessels (OSVs). Sea water desalination is used as well, but only in a few oil platforms. To minimize energy consumption, water supply options were studied. The desalination of seawater and the reusing of streams of grey water and black water were evaluated and compared with the characteristics of the current supply via OSVs. In both desalination and OSV water supply options an electrolytic wastewater treatment plant is used. The objective of this study was to analyze the current situation regarding water supply on offshore platforms located in the Campos Basin, Rio de Janeiro, Brazil, and to propose measures to take advantage of opportunities to reuse water and reduce energy expenditure. Two alternative scenarios were developed that involved the reuse of water that comes from the effluent of a biological wastewater treatment plant (WWTP). Information on the logistics of supplying water to platforms was obtained through direct consultation with companies and sources in the literature. The results show that annual energy consumption (uptake, treatment, transportation, use and waste water treatment) of water on offshore platforms is currently 1.89 GWh, and that a reduction of 1.8 GWh of the energy consumed can be achieved using advanced reuse treatments. Energy consumption in the water reuse treatment is more competitive than those of transport by OSVs or seawater desalination.