Local researchers have teamed up with a private electroplating firm in Shenzhen to test out a filtering technology - said to be the first of its kind - in an effort to purify the neighbouring city's groundwater.
The University of Science and Technology team hopes the trial will prompt adoption of the system on the mainland, which is battling pollution after decades of rapid industrialisation.
Team leader Irene Lo Man-chi said the system worked by injecting reusable magnetic particles of a material known as zero-valent iron to remove metals that can cause disease.
"After wastewater treatment, if the water meets a discharged standard, it can be sent to the river," said Lo, a professor of civil and environmental engineering.
She said prototypes showed a removal efficiency rate of about 97 per cent and that the system was faster and more sustainable than conventional methods.
A year from now, the researchers and the electroplating firm will examine the groundwater's contamination level for heavy metals like chromium.
The system currently costs an average of HK$10 per cubic metre but would cost less if it is expanded across the mainland.
The researchers have been developing the system for more than 20 years, but Lo stressed that clean-up strategies were redundant without government intervention. "Policy is needed to stop the pollution discharge."
The team also developed a treatment system that tackled the sulphate odour problem in Sha Tin's Shing Mun River in the mid-1990s.