New eyes on old GAC: toward optimization and automated control of carbon filters in drinking water treatment

Organic micropollutants (OMPs) in water resources, including pharmaceuticals, represent a health risk that must be minimised during water treatment.

In treatment plants, filters containing granular activated carbon (GAC) particles often present the last line of defence against OMP pollution. OMPs attach to porous surfaces and are efficiently removed by fresh GAC media.

But GAC ages rapidly; within months, surfaces become occupied and OMPs start to leak through, potentially impacting human health and the environment.

Observing the transformation from new to old GAC, and predicting breakthrough, is hampered today due to a lack of sensitive, low-cost technologies capable of detecting changes in reactivity and quantifying reductions in GAC’s effectiveness at adsorbing OMPs.This project will develop and demonstrate a novel system for optimising GAC operations based on a new type of optical sensor.

The sensor, which will use our patent-pending algorithms, has been designed to detect tiny differences in reactivity and predict how well OMPs will adsorb on to GAC.

Additionally, the sensor will detect how water’s composition is changed due to exposing it to GAC, revealing when new GAC has become old and needs to be replaced.

This is a first necessary step toward implementing sustainable control systems for GAC filters in water treatment plants, necessary to maximise the benefits of water treatment while minimizing the environmental, social, and economic costs.