A new analysis led by Northwestern University found that the high-performance water filtration systems needed to alleviate water scarcity can also reduce costs and energy consumption.

In a new study, researchers performed a high-level analysis of membrane filtration systems to assess the costs, energy consumption and greenhouse gas emissions associated with desalination and wastewater treatment. Researchers specifically looked at antifouling membranes, high-performance filtration systems that resist the accumulation of contaminants.

Stain-resistant membranes can be expensive to buy, but they cost less over their lifetime than cheaper stain-resistant membranes that require frequent cleaning and replacement. In fact, the researchers found that municipal wastewater facilities could spend 43 percent more on antifouling membranes for wastewater treatment and up to three times as much on antifouling membranes for desalination.

With aging infrastructure and climate change stressing water supplies, many local governments and researchers are working to increase the availability of water from traditional water sources such as brackish water through desalination and wastewater treatment. I am looking for a process that can Investing in antifouling membranes up front can lower the cost of these typically expensive treatment systems.

Northwestern’s Jennifer Dunn, who led the effort, said: “But there is always a trade-off between engineering performance and cost. A filtration system may perform great, but if the cost is too high, people will not adopt the technology. We hope that modeling and analysis will guide research and development.”

The study was published in the journal August 15 ACS ES&T EngineeringIt is a global consortium of research institutes, water utilities, and private companies seeking new solutions to key challenges in the relationship between energy and water. CoWERC) is the first internationally co-authored paper. .

Dunn is Associate Professor of Chemical and Biotechnology and Director of the Center for Sustainability and Resilience in Engineering at the McCormick School of Engineering, Northwestern University. Members of Dunn’s lab, his Sabyasachi Das and Margaret O’Connell, are co-first authors of the paper.

In membrane filtration systems, the membrane acts as a physical barrier between drinking water and contaminants. A pump pushes water through a membrane filled with micro-, nano-, or even smaller-sized pores. The membrane traps particulates while allowing water to flow through the pores.

Fouling occurs when contaminants accumulate on the surface of the membrane and clog the pores. When fouling occurs on the membrane, high pressure is required to pump water through it. But eventually the fouling is so extensive that the membrane must be cleaned or completely replaced. The energy and costs associated with increased water pressure, cleaning and replacement can increase the operating costs of treatment facilities.

In contrast, antifouling membranes have specialized surface chemistries that prevent contaminant build-up. This reduces cleaning frequency and extends the overall lifetime of the membrane. In this study, researchers found that increasing membrane life was the most influential factor in reducing operating costs.

“The whole desalination process revolves around this membrane,” says Dunn. “Anything we can do to extend membrane life or reduce cleaning costs will help reduce the cost of clean water.”

Dunn said the study will help policy makers, decision makers, and water treatment plant operators understand that water treatment plants can afford the costs of using more expensive, high-performance membranes. I hope This is especially true for desalination plants, 65% of which already use membrane-based filtration systems.

“There are payoffs in terms of lower energy consumption and less frequent purchase of new membranes,” says Dunn. “If we want to build more desalination plants to solve the water shortage, we want to do it in a way that does not increase our energy consumption.

reference: Das S, O’Connell MG, Xu H, et al. Evaluate advances in antifouling membranes to improve process economics and water treatment sustainability. ACS EST Engineer2022. doi: 10.1021/acsestengg.2c00184

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