Mekorot aims for 90% wastewater reuse

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Joining up Israel’s network of wastewater projects could further improve the country’s record on wastewater reuse. Sustainable water pricing is the backbone of the scheme.

State-owned Israeli water company Mekorot says it can raise the country’s wastewater reuse levels to 90% by joining up a series of sewage transmission and treatment projects to form a national treated wastewater distribution grid.

Mekorot, which supplies 70% of all the water in Israel and 80% of the household water supply, as well as operating wastewater reuse facilities in the country, said linking up the projects would allow treated wastewater to be moved to areas where it is in demand – either for commercial reuse, or to replenish groundwater sources through the Shafdan aquifer injection project.

Israel already has an enviable record on wastewater reuse, with about 80% of domestic and industrial effluent reclaimed for use in agriculture and irrigation at peak times. While a small amount of sewage is not treated – particularly in rural areas – there is still some 65 million m3/yr (178,000m3/d) of treated wastewater which is not beneficially reused.

Of the 550 million m3/yr (1.5 million m3/d) of domestic and industrial effluent produced, 435 million m3/yr (1.2 milllion m3/d) are currently reused after being treated to a secondary or tertiary level. Reuse is incentivised by the low cost of treated wastewater.

Consumers are charged a flat rate of $0.23-0.26/m3 for treated wastewater, depending on the level and quality of the treated water. This compares to an initial rate of $0.55/m3 for fresh water, with the price escalating for customers using larger volumes.

Mekorot is waiting for approval from Israel’s Water Authority to construct the pipelines and pumping stations that would allow it to transfer treated wastewater between the regions covered by its nine STPs (see table), and estimates that construction could start within 1-2 years if the project is given the go-ahead.

Avi Aharoni, the head of wastewater treatment and reuse at Mekorot, told GWI that the benefits of improving reuse levels would be both environmental – in terms of reducing agricultural demand on fresh water supplies – and economic, in terms of creating an improved revenue stream for the company.

“Within ten years we can increase the reuse level to around 90%,” he predicts. “There are strong benefits in reusing wastewater – we are in a semi-desert country, and if we were not reusing wastewater we would have to desalinate more water.”

Mekorot operates nine wastewater reuse projects in Israel, supplying a total of 240 million m3/yr (657,500m3/d) of treated wastewater to customers. Its latest wastewater project, the $90 million Yarqon River Rehabilitation scheme, is currently under construction.