Reviewed by Mila PereraSep 13 2022
High-performing water filtration systems, which are essential for reducing water shortages, can also lower costs and energy usage, according to a recent study from Northwestern University.
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The cost, energy utilization, and greenhouse gas emissions related to desalination and wastewater treatment were assessed in the current study by a high-level evaluation of membrane filtration systems. In particular, the researchers studied antifouling membranes, a high-performance filtration system that prevents impurities from building up.
Although more expensive at the time of purchase, foul-resistant membranes are less costly over the course of their lives compared to cheaper, non-foul-resistant membranes, which need more regular cleaning and replacement.
The scientists determined that municipal wastewater facilities might spend up to three times as much on antifouling membranes for desalination and still keep their base operating expenses the same by spending 43% more on wastewater treatment antifouling membranes.
Many towns and scientists are investigating procedures, such as desalination and wastewater treatment, that can boost water availability from less traditional water resources, such as brackish water, as aging infrastructure and climate change place stress on water supplies.
Antifouling membrane purchases made up front might assist in reducing the price of these frequently pricey treatment systems.
With increasing water scarcity, technologies like desalination are becoming more important than ever. However, there are always tradeoffs between engineering performance and cost. A filtration system might have amazing performance, but if the cost is too high, then people will not adopt the technology. We’re hoping that our modeling and analysis can help guide research and development.
Jennifer Dunn, Study Lead Author, Northwestern University
On August 15th, 2022, the study was published in the ACS ES&T Engineering journal. The U.S.-Israel Collaborative Water-Energy Research Center (CoWERC), a global alliance of academic institutions, water companies, and private businesses that investigates creative solutions to crucial problems at the energy-water nexus, has released its first paper with international co-authors.
Dunn is the director of the Center for Engineering Sustainability and Resilience and an associate professor of chemical and biological engineering at Northwestern’s McCormick School of Engineering. The paper’s co-first authors are Sabyasachi Das and Margaret O’Connell, who both worked in Dunn's lab.
A membrane serves as a physical barrier between contaminated water and drinkable water in membrane filtration systems. Water is forced through a membrane that has pores that are micron, nano, or even smaller by pumps. While enabling water to pass through the pores, the membrane captures tiny particles.
Fouling occurs when impurities build up on the membrane’s surface and clog the pores. Higher pressures are required to push the water through a fouling-prone membrane.
However, eventually, fouling accumulates to the point where the membrane needs to be cleaned, if not completely replaced. The energy and money required for increased water pressure, cleaning, and replacement can raise the running expenses of a treatment facility.
Antifouling membranes, in contrast, contain unique surface chemistries that stop pollutants from collecting. As a result, washing is required less frequently, and the membrane lasts longer. In their investigation, the researchers discovered that prolonging the membrane’s lifetime had the greatest impact on lowering operational costs.
The entire process of desalination revolves around this membrane. Anything we can do to improve the membrane’s lifetime or reduce cleaning costs will help reduce the cost of clean water.
Jennifer Dunn, Study Lead Author, Northwestern University
Dunn believes that this research will make legislators, decision-makers, and managers of water treatment plants aware of the fact that they can afford to use more costly higher-performing membranes. This is especially true for desalination facilities, where 65% already employ membrane-based filtration techniques.
“There is a payback in terms of reduced energy consumption and reduced frequency of buying new membranes. If we want to build more desalination plants to reduce water scarcity, we want to do it in a way that does not increase energy consumption. It’s all interconnected,” Dunn said.
Journal Reference:
Das, S., et al. (2022) Assessing Advances in Anti-fouling Membranes to Improve Process Economics and Sustainability of Water Treatment. ACS ES&T Engineering. doi.org/10.1021/acsestengg.2c00184.