High-performance water filtration systems – needed to reduce water scarcity – can also reduce costs and energy consumption, according to a new analysis led by Northwestern University.
In the new study, the researchers performed a high-level analysis of membrane filtration systems to assess the cost, energy consumption, and greenhouse gas emissions associated with desalination and wastewater treatment. The researchers specifically looked at antifouling membranes, a high-performance filtration system that resists the buildup of contaminants.
Although smudge-resistant membranes may cost more upfront, they cost less over their lifetime than less smudge-resistant membranes, which require frequent cleaning and need to be replaced more often. In fact, researchers found that municipal wastewater treatment facilities could spend 43% more on antifouling membranes for wastewater treatment and up to three times more on antifouling membranes for desalination, while maintaining their costs. basic operating.
43%
Wastewater Treatment Facilities Could Spend 43% More on Antifouling Membranes While Maintaining Baseline Operating Costs
As aging infrastructure and changing climates strain water supplies, many municipalities and researchers are exploring processes, including desalination and wastewater treatment, that can increase water availability from less conventional water resources, such as brackish water. Investing in antifouling membranes upfront could help reduce the costs of these typically expensive treatment systems.
“With increasing water scarcity, technologies such as desalination are becoming more important than ever,” said Jennifer Dunn of Northwestern, who led the work. “But there are always tradeoffs between engineering performance and cost. A filtration system can have amazing performance, but if the cost is too high, people won’t adopt the technology. We hope that our modeling and analysis can help guide research and development. »
The study was published Aug. 15 in the journal ACS ES&T Engineering. This is the first study published and co-authored internationally by the United States-Israel Water and Energy Collaborative Research Center (CoWERC), a global consortium of research institutions , water utilities and private companies that explores new solutions to critical challenges in the energy-water nexus. .
Dunn is an associate professor of chemical and biological engineering at Northwestern’s McCormick School of Engineering and director of the Center for Engineering Sustainability and Resilience. Sabyasachi Das and Margaret O’Connell, both members of Dunn’s lab, are co-first authors of the paper.
In membrane filtration systems, a membrane acts as a physical barrier between drinking water and contaminants. The pumps push water through the membrane, which is filled with micro, nano or even smaller sized pores. The membrane traps fine particles while allowing water to flow through the pores.
Fouling occurs when contaminants accumulate on the surface of the membrane, clogging the pores. When a membrane becomes fouled, higher pressures are required to pump water through. Eventually, however, the fouling becomes so severe that the membrane must be cleaned or even completely replaced. The energy and costs associated with increasing water pressure, cleaning and replacement can increase the operating costs of a treatment facility.
“With increasing water scarcity, technologies such as desalination are becoming more important than ever.” — Jennifer Dunn, Chemical Engineer
In contrast, antifouling membranes have specialized surface chemistries that prevent contaminants from building up. This leads to a decrease in cleaning frequency and an extended overall membrane life. In the study, researchers found that increasing membrane life was the most influential factor in reducing operating expenses.
“The whole desalination process revolves around this membrane,” Dunn said. “Anything we can do to improve membrane life or reduce cleaning costs will help reduce the cost of clean water.”
Dunn hopes this study will help policy makers, decision makers and water treatment plant operators realize that water treatment facilities can tolerate the cost of using more expensive and better performing membranes. . This is particularly true for desalination plants, 65% of which already use membrane filtration systems.
“There is a return on investment in terms of reduced energy consumption and reduced frequency of purchasing new membranes,” Dunn said. “If we want to build more desalination plants to reduce water scarcity, we want to do it in a way that doesn’t increase energy consumption. Everything is interconnected.
The study, “Assessing Advances in Antifouling Membranes to Improve Process Economics and Sustainability of Water Treatment,” was supported by the binational Israel-American Foundation for Industrial Research and Development (BIRD) ( grant number EC-2019-09-15).
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