Solar wastewater treatment could bring clean water to remote places – Advanced Science News

This cost-effective solar evaporation device could supplant lengthy and costly filtration systems normally used in wastewater treatment.

Wastewater and seawater purification can be an energy-intensive process. According to some estimates, wastewater treatment plants account for between 1% and 3% of total global energy output. And as climate scientists predict longer, more intense periods of drought through the end of the century and beyond, it’s clear that the world needs more efficient ways of delivering clean, drinkable water to the communities that need it the most.

Addressing a Global Need

In their paper published in Advanced Materials, researchers at the National Engineering Research Center for Marine Aquaculture, Marine Science and Technology College at Zhejiang Ocean University in Zhoushan, China present a solar-powered device called CCMs-x that can turn wastewater into clean water. Unlike previous studies that focused on desalination, this research aims to remove organic pollutants from industrial and domestic wastewater.

The CCMs-x device utilizes solar vaporization technology to purify and desalinate water at a reduced cost and with greater efficiency compared to conventional water purification systems. The researchers believe that a device capable of both desalination and pollutant removal would have practical applications for inland and remote areas, as well as coastal regions.

Yingtang Zhou, one of the researchers involved in the project, stated that the technology was developed to address the need for an inexpensive wastewater purification system that could be used in economically disadvantaged communities.

With approximately two billion people lacking reliable access to clean water worldwide and nearly half of the global population experiencing water scarcity at some point each year, vulnerable communities face risks of water-borne diseases, thirst, and crop failure. However, bringing clean drinking water to these communities is often challenging, especially in remote areas where large-scale desalination plants are costly to maintain. Basic techniques like sunlight exposure or ceramic and biosand filtering are sometimes used to treat contaminated water, but they do not always remove all contaminants.

Better Results at a Reduced Cost

The CCMs-x device, as described in the researchers’ paper, can remove over 95% of pollutants in less than one hour. It is not only more efficient than conventional devices but also safer and easier to use. The device incorporates organic-inorganic hybrid nanocomposites, containing both organic molecules and inorganic materials. Photothermal materials, which absorb light energy and convert it into heat, are placed near the evaporation surface to enhance steam production and separate water from impurities.

Zhou explained that the CCMs-x device features a specialized sponge with numerous channels for efficient water flow, along with advanced materials like silicon dioxide and cobalt oxide to maintain a slippery surface and break down pollutants. Compared to conventional systems, the CCMs-x device is less expensive to install and operate. It can be scaled up for areas with higher demand and is easily transportable due to its bendable and foldable materials. The device is also durable, salt-resistant, and resistant to bacterial contamination.

Although further research and development are needed before the CCMs-x device can be practically implemented, its potential is evident. Zhou emphasized that cost-effective solar evaporation devices have the potential to replace lengthy and expensive filtration systems used in wastewater treatment, providing substantial economic benefits and addressing freshwater scarcity in remote areas.

Reference: Y. Zhou, et al., Customized Microenvironments Spontaneously Facilitate Coupled Engineering of Real-Life Large-Scale Clean Water Capture and Pollution Remediation, Advanced Materials (2023). DOI: 10.1002/adma.202306103

Feature image credit: Cia Gould on Unsplash