Health benefits from point-of-use (POU) water treatment devices come only with consistent use. Embedded sensors can measure the consistency of POU-device use and can provide insights about improving it. We demonstrate both potentials with data from SmartSpouts: accelerometer-based sensors embedded in spigot handles that record the duration and timing of use. In the laboratory, most sensor readings correlated well (>0.98) with manually timed water withdrawals. In the field, SmartSpouts measured >60,000 water withdrawals across 232 households in Limpopo, South Africa. Sensors proved critical to understanding consistent use; surveys overestimated it by 53 percentage points. Sensor data showed when households use POU devices (evening peaks and delayed weekend routines) and user preferences (safe storage over filters). We demonstrate analytically and with data that (i) consistent use (e.g., 7 continuous days) is extremely sensitive to single-day use prevalence and (ii) use prevalence affects the performance of contact-time-based POU devices, exemplified with silver tablets. Deployed SmartSpouts had limitations, including memory overflows and confounding device relocation with water withdrawal. Nevertheless, SmartSpouts provided useful and objective data on the prevalence of single-day and consistent use. Considerably less expensive than alternatives, SmartSpouts enable an order of magnitude increase in how many POU-device sensors can be deployed.
Bibliographical noteFunding Information:
The authors acknowledge the RCT’s fieldworkers who administered surveys and collected SmartSpout data; Adam Terlson, Fei Liu, Francesco Zanini, and Marcus Österberg who supported SmartSpout app development; Jay Carlson and Charles Lee who supported firmware and circuit board development; Susan Murcott for suggesting sensing usage; and our anonymous reviewers for their constructive engagement. This work was supported by the National Science Foundation (CBET-1438619 to J.A.S.), the Thrasher Research Fund (13923 to E.T.R.M.), the U.S. National Academies of Sciences and USAID (AID-OAA-A-11-00012 to P.O.B.), the National Research Foundation of South Africa (114725 to P.O.B.), the National Institutes of Health, National Institute of Allergy and Infectious Diseases (K01AI130326 to E.T.R.M.), the UVA Center for Global Health and the UVA Environmental Resilience Institute (to K.M.), and MIT funds (to D.D.M. and N.C.W.) from MIT Ideas Global Challenge, Sandbox, and D-Lab. The opinions, findings, conclusions, and recommendations are those of the authors alone and do not necessarily reflect the views of any of the funders.
© 2021 American Chemical Society
- household water treatment and safe storage
- usage sensor
- water filter
- water sanitation and hygiene