The environmental tariff of drinking water

The ecological footprint of country’s water supply system is nothing short of significant, TAU study finds.

49% OF ISRAEL’S drinking water comes from groundwater aquifers, 36% from desalinated water and 15% pumped from surface reservoirs like this one at Netufa. (photo credit: NATI SHOHAT/FLASH90)
49% OF ISRAEL’S drinking water comes from groundwater aquifers, 36% from desalinated water and 15% pumped from surface reservoirs like this one at Netufa.
(photo credit: NATI SHOHAT/FLASH90)
Domestic water infrastructure recently made headlines after water facilities in the Upper Galilee and Mateh Yehuda fell victim to cyberattacks. The attacks followed a more extensive cyberattack on the water supply system in April, which was attributed to Iran.
Even without attacks, water scarcity is among the hot topics in this country, and enormous efforts are being made to provide enough water to residents, despite the limited natural resources. 
However, the essential function of the Israeli water system has a price that the natural world has to pay. A study examined all the environmental damages caused by the various processes of the drinking water supply system in Israel and found that its ecological footprint is nothing short of significant.
Published in The International Journal of Life Cycle Assessment, the study was conducted in the laboratory of Vered Blass, a faculty member at the Porter School of the Environment and Earth Sciences at Tel Aviv University, as part of Noa Meron’s doctoral dissertation.
The researchers conducted a first-of-its-kind life-cycle analysis of the Israeli drinking water supply system – a complete assessment of the system’s environmental effects, which included the various sources of drinking water in the country. In 2015, for instance, 49% of the drinking water came from groundwater aquifers, 36% was desalinated water and 15% was pumped from surface reservoirs (such as the Sea of Galilee).
Every mechanism in the system was examined, from the pumping, the production and the transportation of the water, to the use of chemicals, as well as the effect of the materials that make up its infrastructure.
250 ml. of water = 270 gr. of waste
According to the findings, the volume of greenhouse gases released during the operation of the drinking water supply system in 2015 was 2.3 kg. per cubic meter of water (with greenhouse gases such as methane normalized as CO2 equivalence – equivalent to the effect of carbon dioxide as a greenhouse gas).
For comparison, this amount is similar to the amount of greenhouse gases released during a 9-km. car ride or in four 30° wash cycles. This figure is lower than the amount released in countries such as Italy (which stands at 3.4 kg. per cu.m. of water) and the US (2.5 kg.), but also higher than the values in many other places where seawater desalination is not used, such as Romania (1 kg.), Canada (0.2 kg.) or Switzerland (0.2 kg).
In addition, the researchers found that every glass of 250 ml. of water produces 270 gr. of waste throughout the system’s life cycle.
Price of desalination
The two processes that cause the greatest environmental damage in the drinking water supply system are the desalination of water and its distribution to the consumers.
According to the study, in 2015, desalination was responsible for 55% of the carbon footprint (i.e., greenhouse gas emissions that contribute to the exacerbation of the climate crisis) of the system. This is because, in reverse osmosis – the main stage in the desalination process – the water is forced through a membrane at a very high pressure (65-70 times the atmospheric pressure on Earth), which allows only the water to pass through, leaving the salts behind. The generation of this pressure requires enormous amounts of energy.
During the years examined in the study, there was a significant increase in the share of desalinated water out of all drinking water in Israel: 36% in 2015 from 22% in 2011. However, the volume of greenhouse gases emitted as a result of desalination has increased only slightly in those years, to 2.3 kg. of carbon dioxide per cu.m. of water from 2.2 kg.
The reason for that is a decrease in the use of highly polluting fuel oil and the increase of natural gas instead.
“Although we increased the percentage of desalination from 2012 to 2015, our energy has become cleaner, so the total greenhouse gas emissions per cu.m. of water have not changed substantially, and even decreased slightly,” Blass said.
The study said it will be possible to further reduce the environmental impacts of desalination if it starts relying more extensively on renewable energies (such as solar energy) instead of fossil fuels.
It also found that if renewable energies would fully power reverse osmosis desalination systems, the amount of greenhouse gas emissions would fall considerably – to 0.3 kg. of carbon dioxide per cu.m. of water to 2.3 kg.
Greenhouse gases in pipes
During the study, the scientists have established that the long-distance flow of water through large-diameter pipes and the help of large pumping stations is what causes 27% of the system’s carbon footprint. Short-term water flow through small-diameter pipes, which occurs within cities, is responsible for an additional 15%.
The volume of greenhouse gas emissions resulting from the various stages of water distribution in the years tested was 1-1.2 kg. of carbon dioxide per cu.m. of water.
Additionally, water distribution contributes to the ecological footprint of the system indirectly. The production of iron, for example, which some of the pipes are made of, also causes environmental damage. Another significant impact results from pipe leaks, which alone are responsible for 20%-25% of the carbon footprint of the drinking water supply system.
According to Blass, renewable energies could greatly reduce the environmental impact of the water transmission phase. “Large water pumping stations and local pumps use huge amounts of energy, and their environmental impact will depend very much on the type of energy with which they are generated.”
Water in big industry
“Research is a fundamental planning tool for the water sector, enabling us to find ways to streamline and reduce the various environmental impacts of the system and understand our situation compared to other countries,” said Blass.
According to her, the data can also be used by various commercial companies that use drinking water as part of their activities and products.
“Until now, when companies like Coca-Cola, for example, conducted analyses of the environmental impact of the production of their products, they may have used data from another country or some global data – and in many cases, this data is very different from our local data. Now, there is the possibility to use data that is adapted to the situation in Israel.”
Blass emphasized that the study illustrated the importance of cooperation between the various government ministries regarding the water economy, since many decisions on that subject pertain to different areas.
“This includes, for instance, any decision relating to desalination that affects the energy economy, the issue of water for agriculture or the issue of water for industry... One can see the connection between these different areas only when one adopts a life-cycle vision.
Blass said the study clarifies that the well-known water shortage in Israel is far from being the only environmental challenge of the local water economy.
“Even without regard to scarcity, the water economy has a significant environmental impact, and should be reduced in the most optimal way.”