A Model for Integrated Water Resources Management in Water-Scarce Regions: Minimization of the Impacts of Groundwater Exploitation on Society and the Environment

We have developed a model for planning water supply from diverse sources, including groundwater, the National Water Carrier, wastewater and seawater. The model integrates hydrological, technological and economic considerations, and estimates the economic and environmental impacts of alternative water management policies; it was implemented in a case study of the Emek Heffer and northern Sharon regions in Israel. A unique hydrological database was constructed and a hydrological model was developed for planning water resources use and forecasting the chloride concentration in the aquifer. The costs of desalination processes and of the water supply to the region under various scenarios were estimated. The results include recommendations for the water treatment level and for desalination of different water sources, and forecasts of the implementation costs. We conclude that the economic cost of improving the quality of the supplied water and of the aquifer water should be considered in decision making.

Rising agricultural water scarcity in China is driven by expansion of irrigated cropland in water scarce regions

Hybrid systems in seawater desalination-practical design aspects, status and development perspectives

Both brackish water desalination and seawater desalination processes are well established and in common use around the globe to create new water supply sources. The farther the location of the source water from the ocean or seashore, the lower the salinity (TDS) of the water and the lower the osmotic pressure that needs to be overcome when desalinated water is produced. This is one of the major reasons that brackish desalination is often considered less costly than seawater desalination. A number of project considerations, however, indicate that seawater desalination can be beneficial and more cost-effective than brackish water desalination. To make a fair comparison, we need to properly compare all major aspects of both types of projects to define the best and most appropriate desalination technology. While brackish water has less feed water TDS, it is more challenging to dispose of the produced concentrate. Also, although brackish water desalination needs less energy to overcome osmotic pressure, it usually requires more energy to draw the water from the well than it takes to pump seawater from the open ocean intake. Another factor is that the temperature of the brackish well water may be lower than the temperature of ocean water, giving seawater desalination an advantage in energy demand. In comparing brackish to seawater desalination, these major aspects should be evaluated: (1) Locations of seawater and brackish water plants, relative to the major consumers of the desalinated water, (2) Transportation (pumping and disposal) costs of the feed water and produced water, (3) Potential colocation of a seawater plant with a large industrial user (e.g., power plant) of the seawater for cooling or other purposes, (4) Produced quality of brackish water and seawater desalination in terms of major minerals and emerging contaminants, (5) Sustainability of the water source: capacity and depth of the brackish water wells, as well as the type of soil. (6) Technical and economic aspects of produced concentrate disposal, (7) Permitting process costs for brackish and seawater desalination, and (8) The economics of both brackish and seawater desalination treatment processes: capital costs, operational and maintenance (O&M) costs, lifetime water cost, and total water cost (TWC). This paper discusses the major evaluation criteria and considerations involved in properly comparing the economic and technical aspects of brackish and seawater desalination to determine the more favorable desalination technology for a given desalination project.

Designing production processes with reduced environmental impacts is becoming more important. In many industries, including but not limited to agricultural production, water use and wastewater generation have a major share in the total environmental impact of the production processes. Integrating water and wastewater processes into industrial processes requires a multidimensional analysis that takes into account the various potential water sources, as well as the different options of wastewater treatment available. We developed a model for planning water supply from diverse sources, including groundwater, the water from national supply sources, wastewater reuse and seawater desalination. The model integrates hydrological, technological and economic considerations, and estimates the economic and environmental impacts of alternative water management policies. The model was implemented on the case study of agricultural production processes, based on the unique geographical characteristics of Emek Heffer and northern Sharon regions in Israel. The hydrological model was developed on the basis of the specific hydrological database for these regions, and enabled to plan the local water resources use and forecast the chlorides concentration in the aquifer. Based on the results of the model and economic data, the costs of desalination processes and of the water supply to the region under various scenarios were estimated. The results include recommendations for the water treatment level and for desalination of different water sources, and forecasts of the implementation costs. We conclude that the economic cost of improving the quality of the supplied water and of the aquifer water should be considered in the planning of agricultural production to reduce its environmental impacts at minimal economic cost.

An increase in groundwater storage in aquifers in arid areas improves water security. Most desalination water production around the globe involves the private sector in the form of “build, operate, and transfer” or “build, operate, and own” agreements. Take-or-pay contracts are the most dominant contracts in the desalination industry. The water utility buys a fixed volume of water from the desalination company over a fixed period of 20 to 25 years. The contract between the two parties is established prior to building the plant to help ensure a profitable investment for all stakeholders. This regularly implies a surplus supply of desalinated water during low water demand periods. Given the absolute water scarcity in arid regions, maximizing the banking of surplus water in an aquifer is considered in this paper. For this purpose, a numerical groundwater flow simulation model, called MODFLOW, and a heuristic multiobjective optimizer, namely, NSGA-II, are coupled to optimize the injection and recovery of seasonal excess desalinated seawater in an alluvium coastal aquifer in Oman. Dual wells are considered for injection and abstraction of the water. The optimal daily abstraction and injection rates are determined by defining a multiobjective optimization framework. The four objective functions considered in this study are maximizing the total volume of desalinated water recharged into the aquifer; minimizing the groundwater losses to the sea; minimizing seawater intrusion by minimizing the maximum seasonal mean drawdown; and maximizing the total benefit from the recharge and recovery of the desalinated water. Analysis of the results revealed that we would be able to use 84% of the excess produced desalinated water (i.e., 8.4 of the 10 Mm3/year) that is currently returned to the sea. The net benefit from storage and recovery ranged between $14.77 million/year and $17.80 million/year. The increasing number of desalination plants at the global level calls for an integrated approach to bank the excess desalinated water and to improve the water security of coastal cities in arid and semiarid regions.

Non-conventional water resources and opportunities for water augmentation to achieve food security in water scarce countries

Hybrid systems in seawater desalination—practical design aspects, present status and development perspectives

The desalination process is used to reduce the salinity of water to meet the water demand in water-scarce regions. There are several methods available for water desalination, each with merits and demerits in terms of raw water treatment, process operations, and water quality management. In the present analysis, a systematic review of various desalination processes is presented based on technical, economic, and environmental analyses. Thermal and Reverse Osmosis (RO) processes are widely studied in the literature and used for Sea Water (SW) desalination on a larger scale to produce drinking water. The technical and economic criteria are used to show that Seawater Reverse Osmosis (SWRO) technology is better when compared to other desalination technologies.

Hybrid membrane system for desalination and wastewater treatment : Integrating forward osmosis and low pressure reverse osmosis

An integral and multidimensional review on multi-layer perceptron as an emerging tool in the field of water treatment and desalination processes

Seawater desalination for agriculture by integrated forward and reverse osmosis: Improved product water quality for potentially less energy

This article deals with the desalination of seawater and brackish water, which can deal with the problem of water scarcity that threatens certain countries in the world; it is now possible to meet the demand for drinking water. Currently, among the various desalination processes, the reverse osmosis technique is the most used. Electrical energy consumption is the most attractive factor in the cost of operating seawater by reverse osmosis in desalination plants. Desalination of water by solar energy can be considered as a very important drinking water alternative. For determining the electrical energy consumption of a single reverse osmosis module, we used the System Advisor Model (SAM) to determine the technical characteristics and costs of a parabolic cylindrical installation and Reverse Osmosis System Analysis (ROSA) to obtain the electrical power of a single reverse osmosis module. The electrical power of a single module is 4101 KW; this is consistent with the manufacturer's data that this power must be between 3900 kW and 4300 KW. Thus, the energy consumption of the system is 4.92 KWh/m3.Thermal power produced by the solar cylindro-parabolic field during the month of May has the maximum that is 208MWth, and the minimum value during the month of April, which equals 6 MWth. Electrical power produced by the plant varied between 47MWe, and 23.8MWe. The maximum energy was generated during the month of July (1900 MWh) with the maximum energy stored (118 MWh).

Live seawater experience in Japan with hollow fiber permeators

Chapter 6 ended with the somewhat wintry observation that regional circumstances in Himalayan Asia, including asymmetrical power configurations, persistent animosities and distrust, competing national security agendas, and unsettled international political conditions, while not precluding efforts aimed at cooperative regional management of water resources would certainly act to impose severe handicaps upon them. Fortunately, none of these circumstances rules out the possibility that there exists an alternative and potentially smoother path to water security, namely that of innovative water technologies. Such technologies are nowadays both diverse in kind and abundant in number. Naturally, each has its variously motivated protagonists; and each, of course, has its vocal critics. We undertake our assessment of them blinded neither by excessive skepticism nor by unbridled enthusiasm. On the contrary, we understand our task to be the objective and informed assessment of the practical suitability and likelihood of successful adoption in the countries of Himalayan Asia of an array of technological fixes. We begin the discussion with an examination of what many must imagine to be the simplest and most obvious of all the fixes — desalination of sea water.