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Portable Solar Desal for Remote Communities

Researchers working at a remote indigenous community in Western Australia have demonstrated that portable, solar-powered desalination can provide water security for a small community.

A team from UTS, Murdoch University and the WA Department of Housing aimed to develop an energy-efficient and chemical-free pre-treatment process that would sustainably deliver water to the drought-prone community of Tjuntjuntjara, 800 km north-east of Kalgoorlie.

Tjuntjuntjara obtains its water supply from an area of internal drainage, known as a donga groundwater catchment, roughly 4 km from the town. Stormwater flows into the donga and percolates down through the strata, forming a thin blackish lens of drinkable water floating atop hypersaline water.

“Their existing water source has a very, very high content of salt – roughly twice the levels of saline as seawater. We also found it to be contaminated with iron and nitrate, exceeding the recommended level for infants and pregnant women,” said Gayathri Naidu, a UTS PhD student working on the project.

“The safe yield of the donga is thought to be about 23 kL/day, but the lens shrinks during periods of drought,” Naidu said. “Who knows what the community would do then? Trucking in water is too difficult because Tjuntjuntjara is too remote. It would take at least 3 days to get there.”

The prototype system tapped the hypersaline water and treated it by membrane distillation. Modifying an existing MemSYS desalination system, the team was able to treat water with thermal energy sourced from solar panels. A simple filter was used to remove the iron.

“The memSYS membrane desalination technology proved to be a promising alternative technology for small-scale drinking water production. It is compact, produces less wastewater and is easy to clean,” said Prof Saravanamuth Vigneswaran of UTS. “We were able to optimise the conditions by identifying the best temperature for the system, how to wash it, what processes we needed to remove the iron, etc. We also didn’t want to use anything that required chemicals because of the remoteness of the plant.

“In the end, we’ve got a desalination system that is technically robust, low-maintenance, economically competitive and eco-friendly for small-scale application.”