Drivers of Microbial Risk for Direct Potable Reuse and de Facto Reuse Treatment Schemes: The Impacts of Source Water Quality and Blending

Abstract

Although reclaimed water for potable applications has many potential benefits, it poses concerns for chemical and microbial risks to consumers. We present a quantitative microbial risk assessment (QMRA) Monte Carlo framework to compare a de facto water reuse scenario (treated wastewater-impacted surface water) with four hypothetical Direct Potable Reuse (DPR) scenarios for Norovirus, Cryptosporidium, and Salmonella. Consumer microbial risks of surface source water quality (impacted by 0–100% treated wastewater effluent) were assessed. Additionally, we assessed risks for different blending ratios (0–100% surface water blended into advanced-treated DPR water) when source surface water consisted of 50% wastewater effluent. De facto reuse risks exceeded the yearly 10−4 infections risk benchmark while all modeled DPR risks were significantly lower. Contamination with 1% or more wastewater effluent in the source water, and blending 1% or more wastewater-impacted surface water into the advanced-treated DPR water drove the risk closer to the 10−4 benchmark. We demonstrate that de facto reuse by itself, or as an input into DPR, drives microbial risks more so than the advanced-treated DPR water. When applied using location-specific inputs, this framework can contribute to project design and public awareness campaigns to build legitimacy for DPR.

Quantitative Microbial Risk Assessment of Pediatric Infections Attributable to Ingestion of Fecally Contaminated Domestic Soils in Low-Income Urban Maputo, Mozambique

“… 60 Then, we simulated an intervention by reducing the ingested dose in increments of 1 log 10 to determine what reduction in dose, whether by contact or source control, would be necessary to achieve the EPA standard for drinking water (i.e., ≤1 in 10 000 annual infection risk). 61 …”

Evaluating the sustainability of indirect potable reuse and direct potable reuse: a southern Nevada case study

“…A more comprehensive triple bottom line analysis might even be warranted because of its ability to simultaneously consider the social, environmental, and economic implications of an engineering design (Haak, Sundaram, & Pagilla, ; Schimmoller, Kealy, & Foster, ; Schoen et al, ). With respect to social considerations, the recent literature demonstrates that, when designed and operated properly, potable reuse systems provide adequate protection of public health (Amoueyan, Ahmad, Eisenberg, & Gerrity, ; Amoueyan, Ahmad, Eisenberg, Pecson, & Gerrity, ; Chaudhry, Hamilton, Haas, & Nelson, ; Pecson et al, ; Pecson, Trussell, Pisarenko, & Trussell, ; Soller, Eftim, Warren, & Nappier, ). Particularly in California, potable reuse treatment trains often use both low‐pressure and high‐pressure (i.e., reverse osmosis [RO]) membranes, but when not mandated by local regulations or necessitated by salinity management, the use of membranes may lead to excessive costs or overall sustainability concerns (Bradshaw et al, ; Schimmoller et al, ).…”

Conceptual environmental impact assessment of a novel self-sustained sanitation system incorporating a quantitative microbial risk assessment approach

“…The probability of infection from ingesting a dose of each pathogen in a single event of exposure to one of the aforementioned routes has been modelled by functions well-established in QMRA analyses ( Chaudhry et al, 2017 ; Haas et al, 1999 ). For the Enterotoxigenic E. coli , Shigella spp .…”