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Since 2005, wastewater reclamation and seawater desalination have become key in assuring an adequate supply — 2.1 billion cubic meters annually — to Israeli households, industry and agriculture.
Some 31 percent of irrigation water originates from wastewater treated at more than 150 plants. Treated brackish water (not as salty as seawater) is supplied from 45 plants for both agricultural and non-agricultural needs.
Sixty to 80% of Israel’s municipal water, adjusted according to season and real-time demand, flows from large coastal desal plants in Sorek, Ashkelon, Ashdod, Palmachim and Hadera.
“In 2014, we thought we had enough [desalinated water] capacity, 600 million cubic meters...” says Yaacoby. “That was a mistake. We are lacking 100 million to 200 million cubic meters of water per year in Israel these days.”
Two more desalination plants are to be completed in the next few years. “Altogether, in 2025 we will be getting 1.1 billion cubic meters of desalinated water,” Yaacoby says…
From Sorek, it costs about 55 cents per cubic meter; somewhat more from the other four plants.
By comparison, it costs 10 cents to get a cubic meter of freshwater from Israel’s natural sources – whose supply is fast declining. In some other countries, desalinated water costs as much as $3 per cubic meter.
IDE developed proprietary technologies to minimize costs and environmental impact, says Boris Liberman, CTO and VP of Membrane Technology.
Desalination normally uses chemicals, which present an environmental problem when the brine is discharged back to the sea. IDE uses chemical-free biological and physical processes customized for each installation.
“We use biological filters to remove bacteria, silt, algae and other suspended solids. We don’t kill anything, even bacteria,” says Liberman.
To avoid harming the little fish and fish eggs that pass through the screens on the intake pipes bringing in 40,000 cubic meters of seawater per hour, IDE is developing “nursery” tanks where the creatures are harbored until they choose to swim back to their habitat via rotating doors.
As for the plant’s effect on the Mediterranean, “What we pump back into the sea is twice as saline and one degree warmer than seawater,” says Liberman. “We use diffusers to spread it widely. We don’t believe it negatively affects marine life.”
Desalinating about 500 liters requires 1.5 kilowatts of electricity, similar to the power consumption of a refrigerator, Liberman says. Sorek therefore produces most of its water at night to avoid straining the national grid. Each plant has a different energy source; some have their own power stations...
Covering 250 acres, Shafdan is the biggest wastewater treatment plant in a country that recycles more water (85-90%) than anywhere else. The reclaimed water, which Yaacoby says is close to drinking quality, is pumped to Negev farms for irrigation.
“Shafdan uses biological and mechanical means to treat all sewage effluent from the Dan (Greater Tel Aviv) region, home to approximately 250,000 to 300,000 people,” Yaacoby explains during a tour of the plant, one of the most advanced of its kind in the world.
Shafdan, established in 1955, receives 470,000 cubic meters of raw sewage daily. Reclaiming the water from this sewage supplies 140 million cubic meters to Israeli farms annually just from this one facility.
Like desalination, wastewater reclamation is energy-intensive. (Mekorot is the biggest client of the Israel Electric Company, racking up a $200 million bill annually, says Yaacoby.)
However, over the past two years at Shafdan, enough biogas has been generated onsite from the anaerobically treated sludge to provide 90% of the facility’s energy needs.
“We don’t even call sludge ‘waste’ anymore because it is a resource from which to make energy, bioplastics and fertilizer,” Yaacoby says.
