Antimicrobial resistance in advanced water treatment systems and supply networks

Antimicrobial resistance has been identified by the water industry as a growing concern in the delivery of wastewater treatment and water recycling schemes. Research has shown that antimicrobial resistance genes are consistently being measured in treated wastewater, however, limited scientific knowledge exists to explain this phenomenon. The implications of the presence of antimicrobial resistance in water supplies is part of a ‘one-health’ public health burden with broad regulatory relevance. The Australian Drinking Water Guidelines (ADWG) do not include a guideline relevant to antimicrobial resistance as the understanding of the water industry’s role in the ‘one-health’ burden has not yet established.

This project characterised the occurrence and fate of antimicrobial-resistant organisms and genes across an advanced water treatment plant and supply system. The supply network investigated was comprised of secondary treated wastewater feeding into an advanced water treatment plant (which included microfiltration, reverse osmosis, ultraviolet advanced oxidation, and chlorine disinfection steps), released to a pipe network, and ultimately discharged into a natural water storage.

The project drew on both grey and published literature, expert opinion, and monitoring data to explore factors that influenced the presence and persistence of antimicrobial resistance genes and the effectiveness of treatment technologies designed as critical control points for pathogen removal. The knowledge gained through these avenues formed the basis of a Bayesian Belief Network model. This model was designed as a decision support tool for stakeholders to help understand and manage antimicrobial resistance in an advanced water treatment plant and supply network. The ability to incorporate uncertainty and complement data with expert knowledge made Bayesian Network modelling a valuable tool to support environmental health risk assessment, decision-making, and strategy evaluation.

This project provided greater insight into the implications of the presence of antimicrobial resistance genes in water supplies, contributing to the understanding of the ‘one-health’ public health burden and addressing the globally significant challenge of antimicrobial resistance.