Advances in water harvesting methods could offer hope of tackling a looming global crisis, according to a review of collection technology carried out at Duke Kunshan University.
Water harvesting from fog, dew, rain and even the atmosphere could fill freshwater shortages as they become increasingly severe, if the technology is made more efficient, robust and sustainable, the review paper said.
“Despite the tremendous amount of water on Earth, only 2.5 percent is fresh water, mainly stored in glaciers and ice caps. Within this only 1.2 percent of fresh water is stored on the Earth’s surface,” said Weiwei Shi, assistant professor of material science at DKU.
“Limited freshwater resources and their uneven distribution have led to water crises in many regions, and this is becoming more emergent with the increasing demand of water for industrial, agricultural and domestic consumption,” she added.
Shi, the corresponding author, worked with DKU undergraduate student researchers Kuanfu Chen, first author, and Yujie Tao, second author, to conduct the review, which was published in the environmental journal Sustainability. They found a rapidly developing technology though still mainly in the laboratory stages, apart from desalination which is already used commercially on a large scale.
Technology that is efficient in small laboratory prototypes needs to be tested further in realistic conditions in order to provide data that would encourage mass production, the review said. That would show the real costs of running and maintaining the technology, its robustness in potentially harsh outdoor environments and its suitability for different local conditions. Fog harvesting could be a suitable harvesting technology for coastal desert areas, for example, while rain harvesting would not be, where there is plenty of coastal fog but rare rainfall, said Dr. Shi.
Water quality from harvesting methods requires greater investigation, the review said, and water treatment potentially integrated into the technology to provide directly available drinking water without the need for transportation or further treatment elsewhere.
Of the technologies currently being developed, collection from the atmosphere would be the most useful as it is unrestricted by local conditions, said Dr. Shi, but at present it remains prohibitively expensive to develop on a large scale.
Greater investment from governments and business could be key to speeding up the development of all water harvesting technologies, bringing down costs, and taking them from the laboratory to commercial use, she added.
Despite the difficulties that still need to be overcome, water harvesting technologies being developed today offer a “bright future” in terms of alleviating freshwater shortages, said Chen. However, they will take time and resources to scale up for commercial use, added Tao.
Author: John Butcher
