A framework for wastewater sample collection from a sewage cleanout to inform building-scale wastewater-based epidemiology studies.

Wastewater-based epidemiology (WBE) is a public health tool utilized for drug surveillance, and more recently, infectious disease monitoring of SARS-CoV-2. Sample collection is historically performed at a wastewater treatment plant, however, at this spatial resolution, much information related to actionable and contextually relevant community health data may be lost. Sampling from within the sewer collection system is now being employed more widely, bringing unique challenges, including health and safety concerns related to sample collection. As proof of concept, we tested the efficacy of sampling at the building-level from a sewer cleanout at an undisclosed location in Greater Phoenix, AZ, USA, to (i) test the feasibility of wastewater sample collection from this alternative access point, (ii) assess the advantages and limitations experienced for both maintenance-hole and cleanout-level sampling, (iii) screen for chemical analytes to evaluate detectability, and (iv) create a sampling framework for future near-source WBE investigations. Results indicate that use of a sewer cleanout compared to a maintenance hole is cost-effective, practical, and safe, while still preserving the anonymity and privacy for the contributing population. Additionally, of the 37 biomarkers screened over two sampling events, 20 were detected that cover a wide range of human behavior, exposure, and activity, indicating use of a sewer cleanout to be entirely feasible for downstream analysis. This reported success of sewer cleanout sampling for WBE and corresponding framework may allow practitioners to isolate specific complexes or buildings of interest, while avoiding challenges that can arise from maintenance hole sampling, thus allowing for widescale implementation of WBE for public health purposes.