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World’s water-recycling leader has even higher aspirations

5th July 2013

By: Martin Zhuwakinyu

Creamer Media Senior Deputy Editor

  

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Water-constrained Israel hopes to recycle up to 90% of its municipal effluent for irrigation in the next decade – up from about 80% at present – as it continues to take measures to ensure adequate supply in the face of rising demand, resulting in part from an increasing population.

Recycling helps improve Israel’s water balance by allowing the replacement of freshwater with treated wastewater for the irrigation of crops, thereby saving limited freshwater resources for domestic use.

Effluent recycling – for which the country has earned international acclaim – is only one prong in Israel’s multifaceted water strategy, which also includes desalination of seawater and brackish underground water, as well as efficient use of available resources.

Attaining the 90% effluent recycling aspiration would further enhance Israel’s credentials in this arena, says Israeli Water Authority desalination and water technologies division head Abraham Tenne, who points out that Spain, the second-ranked country in terms of effluent reclamation, recycles only 17% of its wastewater. Other notable wastewater recycling nations are Australia, Italy and Greece, which recycle 9%, 8% and 5% respectively. The US and Central Europe recycle a paltry 1% each.

Much of the effluent recycling in Israel is undertaken by national water utility Mekorot, which generates 35% of all the retreated effluent and 60% of that used for agricultural purposes. The quality of the reclaimed effluent is among the highest in the world, according to Mekorot water quality engineer Dr Samir Hatukai.

The water utility operates six wastewater treat- ment plants with a daily flow of about 400 000 m3 and a yearly capacity of about 190-million cubic metres. The largest facility, the Shafdan, is located in the heavily populated Dan region, which includes the city of Tel Aviv. Serving about two-million people, it treats about 130-million cubic metres of effluent each year.

Secondary effluent from the plant is infiltrated into the fields in Rishon Lezion and Yavne, from where it is recharged into groundwater aquifers without being mixed with drinking water. The effluent undergoes natural physical, biological and chemical processes that improve its quality. “At the completion of this tertiary treatment, the result is very high quality effluent,” explains Hatukai.

The reclaimed effluent is transferred to the Negev desert, about 90 km away, where it is used for the irrigation of all types of crops, including citrus, carrots, potatoes, lettuce, wheat and flowers.

The independent recyclers of wastewater include not only big enterprises but also small entities like kibbutzim (agriculture-based collective communities), some of which opt to use the water they reclaim for their own purposes instead of selling it to Mekorot.

One such kibbutz, near Yad Mordechai, has seen its water cost drop from about 2 shekels per cubic metre to under 1 shekel per cubic metre since it decided to build its own wastewater retreatment facility about two years ago.

The plant uses proprietary technology devel- oped by Israeli company Aqwise. Known as the Attached Growth Airlift Reactor, or AGAR, the technology combines a fully open, fully protected biomass carrier with a highly efficient aeration and mixing design. This results in a superior effective surface area for biomass growth and enhanced-oxygen transfer efficiency.

Israel is also making a name for itself as a water desalination country, with the three fully operational seawater desalination plants on the Mediterranean coast supplying 300-million cubic metres a year – or about 20% of the country’s drinking-quality water. This number is set to increase to 450-million cubic metres as the Sorek plant, being built by Israel Desalination Enterprises Technologies (IDE), opens later this year. It is envisaged about 600-million cubic metres of desalinated water will be produced each year from 2014, when the Ashdod desalination plant starts operating.

IDE built Israel’s first desalination plant, at Ashkelon, between 2003 and 2005 and later built the Hadera plant. The country’s fourth plant, Palmachim, is run by the Via Maris consortium.

Mekorot is also involved in the desalination of both seawater and brackish water (its sudsidiary, Mekorot Development Enterprise, is building the Ashdod plant) and currently operates 32 plants that provide about 42-million cubic metres of potable water a year. Other players are also involved, ranging from small kibbutzim to bigger entities.

Mekorot is intent on remaining in the desalination arena for the long haul and will continue to invest in research and development of new technologies for maximum use of the country’s water resources, avers Hatukai.

However, desalination plants are intense users of energy – another resource Israel needs to conserve. According to Tenne, 3.5 kWh of electricity is required to produce a cubic metre of water. Against this background, the Israeli government is mulling the building of solar plants in the desert south to power the Mediterranean coast seawater desalination plants. Wind farms are also being considered.

Tenne remarks that Israel is leaving no stone unturned in ensuring an adequate water supply for its estimated eight-million people, noting that water – or the lack of it – is already threatening to be a source of conflict, an apparent reference to the war of words that has erupted between Ethiopia and Egypt over a massive dam the former plans to build on the Nile river.

Egypt contends that the proposed $4.7-billion Great Renaissance hydroelectric project would jeopardise a water supply vital for its 84-million people, who live mostly in the Nile valley and delta. Egyptian President Mohamed Morsi warned last month that while the Arab nation did not want war, it would keep “all options open”. Ethiopia is adamant that it will forge ahead with the project, come hell or high water.

It is perhaps with the possible dire consequences of an inadequate water supply that the Israeli authorities have worked diligently over the last few decades to ensure that the country has enough water for its own consumption as well as for export to neighbouring Jordan and Palestinian territory.

As part of its commitment to supplying high-quality water, Mekorot built the central filtration plant at the Eshkol site. “The plant, the largest of its kind in Israel and the fourth-largest in the world, places the State of Israel at the forefront of the Western world in the treatment of drinking water,” says Hatukai.

Besides effluent reclamation and desalination, an adequate water supply has been achieved through water saving education campaigns and the use of technologies such as drip irrigation, which, according to Tenne, has seen agricultural production double for every cubic metre of water used during the last 20 years.

One of the key players on the drip irrigation front – both in Israel and abroad – is Netafim, which, since its founding as a kibbutz-owned company more than 40 years ago, has expanded to include 16 factories in several countries, including South Africa, and is represented in 110 countries, according to chief sustainability officer Naty Barak.

He quips that drip irrigation entails “irrigating crops, rather than wetting the soil”, which results in substantial water savings. As 70% of the world’s freshwater is used by the farming sector, Barak calculates that a 15% saving in water used for agricultural purposes – through technologies like drip irrigation – would more than double the resources available for domestic use.

Barak says drip irrigation has turned wastelands such as Israel’s Arava desert, which receives a measly 20 mm of rainfall each year, into valuable farmland. The Arava currently accounts for 65% of Israel’s vegetable exports.

Edited by Martin Zhuwakinyu
Creamer Media Senior Deputy Editor

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