High-intensity pulses of light found to eliminate water contaminants

This photodegradation process was already known to be feasible, its use was limited by the long treatment times it required.

But researchers at KAUST in Saudi Arabia have now demonstrated that it can be dramatically sped up by using high-intensity light pulses generated from a xenon flash lamp.

“An interesting aspect of this work is that we combined the expertise and technologies of two different fields,” said researcher Luca Fortunato.

The team used a pulsed light system that was previously used to process semiconductor materials for transistors and solar cells.

Organic micropollutants (OMPs), which are known as emerging contaminants, include a long list of pharmaceuticals, hormones, compounds in personal care products and industrial chemical additives.

They are an increasing problem in waterways as they are released from many locations and are highly persistent in water, with potential toxic effects on human health even at very low concentrations. As little as a few nanograms per litre can be harmful in some cases.

“They are being continually released into waterways by wastewater treatment plants, with conventional treatment methods proving to have only limited effects in removing these contaminants,” says Fortunato.

The researchers found that the effectiveness of high-intensity pulsed light (HIPL) varied significantly depending on parameters including the number of pulses and the total energy dose delivered by the light.

This allowed them to identify the most effective conditions for treating a test solution containing 11 significant OMPs, including drugs, hormones and industrial chemical contaminants.

They found that the HIPL treatment triggers decomposition of the OMPs with extraordinary degradation rates.

“Our innovative approach allows for efficient removal of OMPs from water within milliseconds, making it ideal for high-throughput water treatment applications,” said researcher Thomas Anthopoulos.

The team believes the treatment method has the potential to become a straightforward and scalable solution to an increasing environmental problem.

They are currently working to improve the system’s efficiency increase its throughput. Their next step is to scale up the treatment set-up.

“We hope to soon build a pilot-scale reactor to more realistically assess the efficiency of the treatment on wastewater effluent,” Fortunato added.

Last year, the Environment Agency’s annual water report for England showed that water firms are consistently failing to meet their expectations on environmental performance, with too many pollution-related incidents.

In July, researchers at Cardiff University developed a water disinfectant using hydrogen and air that is purported to be millions of times more effective at killing viruses and bacteria than traditional commercial methods.