Assessing Thermal Based and Reverse Osmosis Desalination
There are currently two types of seawater desalination technologies used the Middle East market; namely Thermal based and Reverse Osmosis (RO) based desalination with the former providing about 70% of usable water in the region. Both types of desalination technologies are very energy–intensive with the Thermal process requiring energy in the form of steam & electricity while RO uses only electrical energy.
Historically, the thermal process has dominated the seawater desalination market in the Middle East as energy prices were much lower, and there was less of a concern on the environmental impact of such processes. However, in the last couple of decades, the market share of RO has increased, owing to the development of better techniques, more awareness of the impact of high energy consumption, and lower capital cost.
Although the use of desalinated water is unavoidable in the Middle East, there is an increasing awareness that it is an environmental nightmare.
Dealing with the Environmental Impacts of Desalination
The desalination process itself uses fossil fuels to evaporate and condense the water and has a substantial amount of greenhouse gas emissions. Additionally, about half of the water pumped from the sea is pumped back in after the process. The water returned to the sea has a higher concentration of salt and impurities, usually referred to as brine, which harms natural marine ecosystems in our oceans. This is especially true in the Persian Gulf where a considerable amount of desalination occurs on the shores of a small, relatively shallow and enclosed sea. Several potential solutions to this problem are currently being explored, ranging from the low–cost option of salt harvesting to the high–cost option of operating the units under a “Zero Liquid Discharge- ZLD” scheme with a multitude of options in between.
The Need for Evolution in Desalination
Either way, desalination needs to become evolved to deal with our water crisis. With over 46% of the worlds water desalination happening the Middle East and North Africa, we need to think of alternative ways to fulfill our requirements, and with temperatures only set to raise, we will become increasingly reliant on our seawater. As a society, we don’t have the option to continue desalinating our water in the way we currently do; we must utilise and develop environmentally friendly solutions.
Thankfully organisations involved in desalination are taking steps to protect our environment.
Recently, the Dubai Electricity and Water Authority announced a Seawater Reverse Osmosis project (the greener of the two processes) to commence production in 2023, using better technologies and less energy. There has also been an increasing number of desalination plant specifications calling for the use of renewable energy such as solar and wind.
Overall the region is beginning to pave the way for sustainable water desalination, and it should be celebrated.
What does the future look like?
As the region moves away from its dependence on oil and focuses on new energy, we can expect to see some exciting innovation and risk–taking – who knows; maybe we could anticipate brine itself creating the energy to power desalination plants, or maybe the use of desalination plants becoming obsolete altogether? Perhaps a simple treated cloth on the end of a pump will be enough?
Not only do we need clean water for our physical health, we need it for our overall well-being; if we want to keep public parks and green spaces, peaceful natural waterfalls or simply our pet goldfish, we need to embrace innovation within desalination today – giving ourselves, and our communities the best chance at thriving in the future.