Photocatalysts could help to reduce groundwater pollution

Engineers in the US are hoping to improve the use of light to reduce groundwater pollution from disease-causing nitrates.

Researchers at Arizona State University have received more than $295,000 (£187,000) from the National Science Foundation (NSF) to advance the use of photocatalysts — chemicals that break down nitrates using light — in water-supply systems.

An additional $500,000 grant from the Environmental Protection Agency (EPA) will support another project to improve the effectiveness of water monitoring and treatment systems in small communities.

The team of engineers will experiment with different types of photocatalysts to produce reactions at the nanometre scale that will convert nitrates, which can also lead to the excessive growth of algae or plankton, into a non-threatening form.

‘This will bring some of the most recent and significant advances in light-based technology and materials nanotechnology into engineering better water-treatment systems,’ said research leader Prof Paul Westerhoff from the university’s School of Sustainable Engineering and the Built Environment.

The researchers also plan to develop an open-access website to provide information on nitrate occurrence, health risks and proven strategies for water treatment.

The EPA project will focus on ways to improve water systems in communities with populations of roughly 50 to 500 residents, focusing on developing chemicals that can remove multiple contaminants and automatic sensor networks.

In a statement, Westerhoff said that such communities rarely have the resources to maintain timely, effective and thorough methods of ensuring their water meets basic safety standards. He added that it wasn’t enough to scale down larger systems designed for urban areas because rural and remote towns had different environmental and contaminant issues.

Water systems in small communities must typically deal with multiple pollutants in ground water, making treatment and compliance with health regulations complicated, said Westerhoff.

The team plans to develop types of hybrid sorbents (materials designed to absorb liquids and gases) capable of simultaneously removing multiple contaminants.

The researchers will also develop monitoring and sensing networks to enable simplified automated operation and the testing of water systems designed to optimise the groundwater sorbent treatment systems.