By Karyn Simpson
Negev Desert, Israel – A country that is 70 percent desert faces a unique challenge in finding sustainable water sources, but by treating and reusing approximately 90 percent of its wastewater, Israel has done just that.
The small country is light years ahead of the rest of the globe – the next closest competitor is Spain, which reuses around 30 percent of wastewater, according to Dr. Jack Gilron, head of the department of desalination and water treatment at the Zuckerberg Institute for Water Research.
Yet Israel’s success in wastewater treatment and reuse likely won’t translate effectively to other countries.
“The problems are not just technical – they’re also social, and they’re also political,” Gilron said.
Sitting in Gilron’s office in the network of buildings, trees and concrete paths that make up Ben-Gurion University of the Negev, it was easy to forget that we were in the middle of the desert in a country with a vastly different political system than the United States when it comes to water. In Israel, almost all water belongs to the State of Israel. From the limited freshwater and groundwater to the more abundant sea water and even wastewater, every drop is a national resource to which the public is only granted temporary usage based on need and availability of sources. This allows Israel to control the water on a countrywide level and prioritize who gets it – and when.
“In the [United] States, you don’t have a national authority or the legal basis to treat water as a national resource,” Gilron said. “Water is a private property in the States, so as a result, if it’s on your property, you have water rights to use it. Whereas here, water is a national resource. Nobody can drill a well without first getting permission from Israel Water Authority.”
One of the benefits of this setup, Gilron said, is the ability to control how much groundwater and freshwater is pumped from different sources. This is increasingly important as Israel enters its sixth consecutive year of drought and groundwater and freshwater levels continue to drop, forcing the country to rely more on wastewater reuse and desalination to avoid causing irreparable damage to their aquifers and to the Sea of Galilee.
This also enables Israel to implement nationwide conservation initiatives. Israeli residents grow up with a conservation-first mindset, said Dr. Elie Rekhess, associate director for Israel Studies and visiting professor in the department of history at Northwestern University. Rekhess grew up in Israel during the infancy of Israel’s National Water Carrier system, and his wife and children still live in Tel Aviv.
“We grew up with the mentality that every drop counts,” Rekhess said. “You simply don’t leave the tap open, and you will be shouted at if you left a tap open… Water was definitely a commodity that one should economize on and be careful about.”
Most of Israel’s drinking water is supplied by five seawater desalination plants along the Mediterranean Sea. Treated wastewater is used primarily for agriculture, which receives 546 million cubic meters (about 144 billion gallons) of freshwater to supplement the 473 million cubic meters (about 125 billion gallons) of treated wastewater provided each year.
Israel is able to transport its treated wastewater to farms all across the country because the country is less than the size of the state of New Jersey.
“When you’re small enough, the distance between where you generate the water and where you need the water is small enough that the cost to transport the water is reasonable,” Gilron said.
In a country as large as the United States, or even in an expansive, drought-ridden state such as California, the transportation costs between large municipalities where the wastewater is treated and the agricultural areas where the water is needed might be too cost-prohibitive to allow water reuse for irrigation, Gilron said.
Gilron recommended that other countries think local if they want wastewater reuse to work effectively, but also advised that wastewater treatment can’t and won’t be the only solution to the global water crisis.
“You can’t work on the basis of large plants. You have to think more on the basis of distributive plants, which might be one of the things that become the next wave, or the next trend,” Gilron said. “But again, it won’t solve the problem if the problem is quantity. If the farmers are taking out more than the rain is providing, then the level will continue to drop.”
Officials at Shafdan Wastewater Treatment Plant, Israel’s main wastewater treatment facility, are constantly researching new ways to make their treatment process more efficient, but overall, the current processes do not vary significantly from those in other countries.
Israel’s wastewater, which is funneled primarily through Shafdan, is treated in a multi-step process that includes basic filtration and biological treatments and ends with a natural form of filtration called soil aquifer treatment (SAT). SAT allows the country’s abundant sand to filter remaining pollutants from the water – a six-month to one-year filtration process which deposits the water in an agriculture-specific aquifer beneath the filtration fields.
“[SAT] relatively consumes more land than other processes,” said Sivan Bleich, water treatment and supply department manager at WaTech – Mekorot, the group that oversees innovation at the Shafdan plant. “So here we are trying to simulate and test more intensive, more industrialized solutions for the last polishing step of treating the effluent to reach a very high water quality.”
Shafdan researchers have narrowed alternatives down to two approaches, Bleich said – more pretreatment before using SAT to allow for more expedited filtration, or focusing on new technologies that could achieve comparable water quality to using SAT.
“It could be a combination of many technologies – ultra-filtration, ozonation, absorbance, biological processes, membrane treatment,” Bleich said. “We are trying to optimize the right combination in terms of the water quality, and of course in terms of the costs.”
While reusing treated wastewater for agriculture has allowed Israel to become relatively water solvent, concerns remain about using treated wastewater to grow crops. For example, Israel’s current processes are effective at removing some organic compounds present in effluent, but research is not conclusive on any long-term danger from irrigating crops with water that may still contain endocrine-disrupting compounds (EDCs) found in birth control and hormones, which may not be removed by traditional treatment processes.
Gal Shoham, professional instructor in the operation and process department at Shafdan, said the levels of EDCs were too low to be of concern. But Bleich said, later, that removing EDCs was a target for “all the pilots,” meaning for all the test studies Shafdan researchers are currently performing.
In addition to reusing wastewater, Israel’s desalination plants and countrywide water conservation campaigns have given the country some distance from total water scarcity – quite an accomplishment for a country riddled with drought and with little available fresh water.
There is still room for innovation in wastewater treatment, Gilron said. While other countries may be circumstantially different from Israel, they can still move toward a more sustainable treatment and reuse model.
“It first requires becoming aware of the problem and being willing to look at the problem straight on and not sweep it under the rug,” Gilron said. “Technical is only part of it. The technical can provide the tools, some of the tools, but when it comes to decision making and allocation of resources, you need actually legal and social tools that allow you to effective deploy the technical tools.”