Ultraviolet (UV) light is highly effective against pathogens that cause enteric and diarrheal disease. Existing UV light emitting diode (LED) technology can already provide sufficient UV dose to disinfect such pathogens, including Salmonella, Shigella, and Vibrio cholerae. However, UV disinfection is limited by the need for a reliable power supply.
Figure 1. Proof of concept for hydropowered UV LED reactor.
To address this limitation, we combined two technologies: UV LEDs and microhydropower water turbines to disinfect flowing water with UV light without an external power supply (Figure 1). This is an off-grid, chemical-free UV water disinfection technology that will be applied at or near the point-of-use in developing communities to help reduce disease burden from waterborne pathogens.We prototyped a hydropower UV LED reactor and characterized the flow rate dependent voltage generation of the turbine as well as disinfection kinetics (Figure 2).
Figure 2. Hydropower UV LED prototype running while attached to sink.
We tested the flow through disinfection performance of the hydropower UV LED reactor across various flow rates using a single water turbine to power the UV LED (Figure 3). The flow rates were varied using a flow control valve and the flow rates were measured in between samples using a graduated cylinder. The microorganism stock solution was pumped through the reactor continuously and flow rates were incrementally increased from around 0.5 to 7 liters per minute for each experiment.
Figure 3. Flow through testing set up.
MS2 was enumerated before and after passing through the UV LED reactor to determine the log inactivation. Enumeration was by single-layer agar spot plating using E. coli Famp as host organism.
This work was presented at the 2021 OAWWA Fresh Ideas Poster Competition at One Water Technical Conference.