Battling superbugs with ozone

21-11-2013 | Foresight | Marc-Olivier Buffle

Drug resistant bacteria call for enhanced water treatment technologies

The occurrence of chemical and micro-pollutants in streams and lakes is already well known and has been widely reported. Pesticides, hormones, x-ray contrast media find their way into waterways and are increasingly gaining the attention of regulators. However, such contaminants are typically found at extremely low concentrations and in an infinite number of combinations, so that their impact on health is difficult to measure: though long term effects are possible, they are largely unknown. For this reason, most efforts to reduce their concentrations in our waterways are mostly introduced as a precautionary principle rather than based on quantified evidence.

Source: Dodd, Buffle & von Gunten, Environ. Sci & Tech., 2006

Another class of pollutants that does have an acute, albeit indirect impact on human health, however, is antibiotics found in wastewater. Hospital sewage, for example, typically contains relatively high concentrations of pathogenic bacteria and residual antibiotics not metabolized by the patients. If the concentration of such antibiotics is large enough to inhibit the growth of pathogens present in the waste water, bacteria containing an antibiotic-resistant gene survive and develop. This natural selection process automatically leads to an increasingly drug resistant pathogen population. Such organisms can then find their way into ecosystems and spread their resistant genes. The emergence of these superbugs is widespread, making some illnesses and bacterial infections increasingly difficult to treat. In 2012, the WHO reported that 25,000 people die annually in Europe due to resistant pathogens.

One solution that could help slow this trend is the application of ozone technology to wastewater. Ozone gas, once dissolved in water, has the ability to oxidize and break down antibiotic molecules. Moreover, it can kill bacteria and damage their drug resistant genes, thereby preventing the reabsorption of these genes by other microorganisms, a process which can occur even after the death of the parent cell.

Although this area of wastewater treatment still requires additional research, current results are promising. Companies offering ozone technology solutions such as Wedeco (Xylem), Ebara Jitsugyo, and Ozonia (Suez-Environnement) are likely to benefit from the growing need for this specific type of water purification technology.

“The growing concentrations of antibiotics and pathogens in hospital wastewater create a ripe breeding ground for resistant strains of bacteria. The use of ozone technology to treat wastewater can help limit the spread of these superbugs.”

marc-olivier-buffleMarc-Olivier Buffle, PhD
Co-Head of Sustainability Investing Research

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