Connected for COP26: How Water Treatment Scientists Can Help Achieve A Carbon Zero Economy
By Rami Elias Kremesti M.Sc., CSci, CEnv, CWEM
This year, the UK will host the 26th UN Climate Change Conference of the Parties in Glasgow on 31 October – 12 November 2021.
The COP26 summit will bring parties together to accelerate action towards the goals of the Paris Agreement and the UN Framework Convention on Climate Change. The UK is committed to working with all countries and joining forces with civil society, companies and people on the frontline of climate change to inspire climate action ahead of COP26.
As part of the efforts to achieve a Carbon Zero economy, the UK government recently launched its plan for the Hydrogen economy.
The UK government analysis suggests that 20-35% of the UK’s energy consumption by 2050 could be hydrogen-based. This means demand for water demineralization technology is going to grow too.
There is a connection between water treatment and achieving net zero, specifically the connection between the emerging hydrogen economy and demineralized or “Demin” water treatment technology.
What is demineralised water?
Demin water is water that is free from minerals that are dissolved salts. To produce demineralized water, three kinds of technology can be used: ion exchange, reverse osmosis and thermal distillation.
My name is Rami Elias Kremesti I am Chartered with CIWEM, the Science Council and the Society for Environment. I studied chemistry in the USA and I have a master’s degree in the subject. I used to work in power stations for over 10 years, and I know how “Demin” water is produced for boilers using all three technologies. High pressure boilers and turbines in power stations need ultra-pure water with no salts in it so they can function efficiently otherwise they suffer from severe corrosion and scale problems.
I am spearheading an effort at CIWEM to establish a centre of excellence and training in reverse osmosis (RO) to support the UK’s vision for a carbon-free economy. There are a lot of RO, ion exchange and desal technology providers in the UK, however it is rare to find a provider that combines mechanical knowledge of these systems with chemical and micro-biological knowledge of water which is required. Pre-treatment design of the feed systems for demin water production is needed to avoid problems of scaling, fouling or biofouling. Unfortunately, these issues evade a lot of mechanical designs.
How do you produce demineralised water?
To produce ultra pure water, first you need to start with a water that is of potable water quality. That means there should be no colloids in it or bacteria or organics. If you start with a surface water, then you need to go through stages of removal of suspended and colloidal solids, as well as removal of bacteria.
Once potable water quality is achieved, we are faced with the task of removing the minerals or salts from the water. For this, desalination or demineralization technology is needed. Desalination occurs in nature when sea water evaporates then it comes down as rain. Sea water evaporates when warmed, leaving behind the salts, and the rising water vapor condenses and falls down as rain which is desalinated water.
This is the principle of thermal distillation technology. It used to be the BAT (Best Available Technology) for sea water desalination, but it requires a lot of energy because water by its very nature has strong hydrogen bonds at the molecular level and it takes a lot of energy to convert it from the liquid state to the vapor state.
Sea water Reverse Osmosis (SWRO) is much more efficient at desalinating sea water because it does not require the water to be evaporated. RO works by pushing mineralized water through a semi-permeable membrane which leaves the salts behind. Ion exchange works for desalinating only potable water, it does not work for sea water because of the very high salinity.
How water scientists will help achieve net zero
Through my experience, RO membranes are the most efficient way to desalinate water than contains dissolved minerals. However, it requires specialist knowledge for a good design of a pre-treatment system and requires high levels of O&M personnel knowledge.
For example, RO membranes can scale and biofoul, and a Clean In Place (CIP) procedure using specialist chemicals is required to clean the membranes every once in a while otherwise you get what is called irreversible fouling and the expensive membranes have to be replaced.
This is where water treatment scientists will play a vital role in training the next generation of O&M personnel that will run the demin systems. The demin systems will be needed for the production of the demineralised water that will be electrolyzed in the future to produce the hydrogen, powering the Net-Zero economy.
For more specialized training in RO technology, please contact CIWEM where we will be launching an RO training program very soon.