As the UAE grows, its people need ever more water. We cannot keep taking ever more from the Arabian Gulf – so instead we are increasingly turning to wastewater as a source of fresh water.
But that takes effort. Wastewater from our homes, offices and factories contains many different kinds of pollutants. To reuse it, we need to remove the various chemicals, microbes, sediments and other contaminants that it contains.
There are already many ways of doing this but they take time and money – and come with their own environmental impacts. We have to make wastewater treatment more effective, efficient and affordable.
It is for that reason that our research team at Masdar Institute’s recent development of a novel membrane for membrane bioreactors (MBRs) is particularly exciting.
MBRs offer a compact way to produce high-quality water that can even be coupled with biogas recovery, resulting in two useful products – water and biogas. But this technology still faces challenges.
The membranes at the heart of the technology easily become clogged with microorganisms and algae that grow on them – a process known as biofouling. Nothing can get through the membrane's pores, making it no use as a filter for wastewater – so treatment has to stop for the membrane to be either cleaned or replaced.
The loss of productivity, along with the cost of the treatment chemicals or new membranes, reduces the cost effectiveness of the MBR.
A membrane that prevented biofouling could make MBRs a far more attractive option for water treatment. That is where our novel membrane comes in.
Building on European research, we have created a membrane that is highly resistant to biofouling and also improves the through-flow of water. This was achieved by improving the membrane structure, porosity and surface chemistry.
In particular, our membrane has a pattern of valleys and hills on its outer surface that promotes turbulence in the water, which enhances movement of the wastewater through the filter.
The 3D pattern also increases the effective filtration area of the membrane, giving it twice the filter surface area – and therefore twice the productivity. Lastly and most importantly, the improved flow hydrodynamic makes it harder for unwanted organisms to stick to the membrane.
To test our product, we placed our membranes in actual municipal wastewater gathered from Masdar City.
Standard membrane bioreactor membranes need to be cleaned or replaced daily. After a month, our membranes were still fairly clear of biofouling and functioning as they should.
These are very promising results that we expect to be of interest to the wastewater treatment technology market, which is expected to grow further in the coming years as natural freshwater sources are stretched to meet needs of growing populations.
We hope this research can be utilised by industry and academia to make wastewater treatment and reuse through membrane bioreactors more widely adopted not only here in the UAE, but around the world.
Dr Hassan Arafat is an associate professor of chemical and environmental engineering at the Masdar Institute of Science and Technology. Dr Muhammad Ro’il Bilad is a post-doctoral associate and Jehad Kharraz is a master’s student in the same department
