The flux and impact of wastewater infrastructure microorganisms on human and ecosystem health.

Wastewater infrastructure is designed, in part, to remove microorganisms. However, many microorganisms are able to colonize infrastructure and resist treatment, resulting in an enormous flux of microorganisms to urban adjacent waters. These urban-associated microorganisms are discharged through three primary routes 1) failing infrastructure, 2) stormwater, and 3) treated wastewater effluent. Bacterial load estimates indicate failing infrastructure should be considered an equivalent source of microbial pollution as the other routes, but overall discharges are not well parameterized. More sophisticated methods, such as machine learning algorithms and microbiome characterization, are now used to track urban-derived microorganisms, including targets beyond fecal indicators, but development of methods to quantify the impact of these microbes/genes on human and ecosystem health is needed.