Increasing desalination can improve water quality and save the economy some NIS 500 million a year, according to a new survey commissioned by the Israel Water Authority. Experts from the Environmental Protection Ministry, however, believe desalination plants' costs outweigh their benefits.
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Desalination systems account for a fifth of the freshwater used in Israel and, according to existing plans, by the end of the decade that amount will be doubled. Recently the Water Authority commissioned an economical value survey through Adan Technical & Economic Services.
The study focused on the benefit of decreasing the amount of salt and scale in desalinated water, since until recently the amount of scale in groundwater supplied to customers was high. The study inspected the quality of water supplied to Tel Aviv and Jerusalem, who have recently received desalinated water distilled with other sources.
According to the study, the amount of salt and scale in the water decreased by 25 percent in the past five years, and a further 30-40 percent decrease is expected within three years, when the desalination plant being built south of Rishon Letzion will become operative.
The main benefit to households is the energy saved as a result of less scale in the pipes, and expenses saved for energy that otherwise would have been spent on reducing scale. As for agricultural use, lower salt levels would increase the crop.
All in all, the study estimates that the total economical benefit would be NIS 0.45 per metric cube. Today the cost of a metric cube of desalinated water is NIS 2-3, and the total yearly benefit would be NIS 185 million, eventually reaching an annual sum of NIS 500 million.
Adan's study did not take into account further possible benefits, such as the lack of dangerous cancerous chemicals in the water, or pollution by residues of medicines and hormones. Another benefit would be the longevity of household electric appliances following the decrease in scale.
On the downside, desalinated water does not include magnesium, which has many health benefits and exists in water from other sources. The government recently decided not to add magnesium to the water system due to prohibitive costs.
The results of the study are expected to strengthen the existing trend in the Water Authority, which tends to support further desalination. However, a steering committee dealing with climate change in the Environmental Protection Ministry recently presented a different and critical view.
The ministry has, so far, refused to publish the complete report by the committee, which consisted of water and environmental experts, but several of its conclusions were presented last month in a University of Haifa convention dealing with climate change.
Prof. Nurit Kliot, one of the members of the ministry's climate change steering committee, said that the committee did not specify desalination systems as a preferred policy move. "These systems produce large amounts of water, but their benefits do not justify their high costs - including the environmental costs, which nowadays aren't taken into consideration," Kliot said.
While she failed to specify the costs, it is assumed that Kliot was referring to the fact the systems occupy much coastal space, use a lot of energy and emit to the sea huge concentrates of salt and chemicals used during the desalination process.
Kliot recommended that the amounts produced by desalination should be determined every so often according to the varying conditions and needs. The committee is set to recommend steps encouraging water preservation, prevention of leaks, purification of polluted wells and use of gray water (which is already done in some 30 countries ).
Kliot also mentioned purification of sewage and planning of building sites in a way that would allow rainwater to seep in. The committee estimates that these steps could save some 100 million cubic meters a year, and probably even more.