UN study highlights new chemical-laden brine disaster
Factories that turn salty sea water into drinkable fresh water discharge enough chemical-laden leftover brine in one year to cover Florida under a foot of brine!
This is one of the surprising facts highlighted by a new United Nations-backed study of the scramble in the Middle East, North Africa and other places, including the US, to use the earth’s vast oceans to quench the world’s thirst for fresh water.
A newly-updated dataset – the most complete ever compiled –on desalination plants has been analyzed by experts at the UN University’s Canadian-based Institute for Water, Environment and Health, Holland’s Wageningen University, and South Korea’s Gwangju Institute of Science and Technology.
Starting with just a few desalination plants in the Middle East’s desert kingdoms, the number has grown to 15,906 plants in 177 countries. Their freshwater output capacity is 95 million cubic meters per day – comparable to 40% of the high season flow over Niagara Falls.
For every liter of freshwater output, desalination plants produce on average 1.5 liters of brine, although this value varies depending on the feedwater salinity, the desalination technology used and local conditions.
“Globally, plants now discharge 142 million cubic meters of hypersaline brine every day — a 50% increase on previous assessments,” the study said.
Brine causes serious problems for human health wherever it is produced, whether near a coastline or far from it. Very few economically viable and environmentally sound brine management options exist, and impacts on human health and the natural environment can be very destructive.
Brine disposal methods usually include direct discharge into oceans, surface water or sewers, deep well injection and brine evaporation ponds. Almost 80% of untreated waste brine is produced within 10km of a coastline and is most often discharged directly back into the marine environment.
Two-thirds of desalination plants are in high-income countries and 55% of global brine is produced in just four countries — Saudi Arabia (22%), United Arab Emirates (20.2%), Kuwait (6.6%) and Qatar (5.8%).
They largely operate plants using seawater and thermal desalination technologies, which typically produce four times as much brine per cubic meter of clean water as plants where river water membrane processes dominate, such as in the US.
The coastline countries dump their chemical-laded brine waste in the ocean, which can be devastating because the waste depletes dissolved oxygen in the receiving waters upsetting marine ecosystems, plant life, fish and other creatures.
That greatly increases the salinity of the receiving seawater and pollutes oceans with toxic chemicals used in the desalination process, including copper and chlorine which are major concerns. The ecological effects are observable throughout the food chain.
Brine produced inland at a distance greater than 50km from the nearest coastline poses increasing problems for human health and the environment in 64 countries located in all world regions.
East Asia and Pacific and North America produce 18.4% and 11.9% of the global desalinated water, primarily due to large capacities in China (7.5%) and the USA (11.2%) respectively. The widespread use of desalination in Spain (5.7%) accounts for over half of the total desalination in Western Europe (9.2%).
Yet, brine is not all bad. It can create economic opportunities in aquaculture, electricity generation and other uses, if the salt and metals are recovered, including magnesium, gypsum, sodium chloride, calcium, potassium, chlorine, bromine, lithium, boron, strontium, rubidium and uranium.
Desalination is a necessity in many countries because of increasing fresh water shortages. About 2 billion people live in countries with insufficient fresh water, so improving the safety of desalination technologies and reducing their costs can be very helpful.
For instance, eight countries – the Maldives, Singapore, Qatar, Malta, Antigua and Barbuda, Kuwait, The Bahamas and Bahrain –meet all of their water needs through desalination. Six others meet over 50% of their water needs through desalination: Equatorial Guinea, UAE, Seychelles, Cape Verde, Oman and Barbados.