Tapping into untapped potential: Three approaches to develop new pathogen crediting frameworks

<jats:p>Key Takeaways: Potable reuse requires high levels of pathogen reduction, but many treatment processes do not have frameworks for claiming pathogen credits. There are three approaches that can be used to develop pathogen crediting frameworks: Modeling Approach: used for treatment processes whose mechanisms of pathogen reduction are well understood and whose performance can be accurately predicted using a model (e.g., an equation) with inputs that can be continuously measured. Surrogate Approach: relies on a parameter that: a) can be continuously monitored at the influent and effluent of the treatment process; and b) correlates well with the amount of pathogen reduction provided by the treatment. Operational Envelope Approach: establishes pathogen credits based on empirical studies conducted at one or multiple facilities. Credits are based on log reductions observed during the studies but requires the system to operate within the specific limits (i.e., the operational envelope) used during the study. The recently-developed frameworks for pathogen reduction crediting in membrane bioreactors provide an example of how new crediting frameworks can provide many benefits for the reuse industry.</jats:p>