Design and implementation of water purification system based on deep ultraviolet light emitting diodes and a multi-pass geometry reactor

Abstract

A novel reactor was designed and implemented for water purification using deep ultraviolet light emitting diodes (LEDs). The focus was on minimizing the number of LEDs required for effective germicidal action. Simulation studies were carried out on the flow of water as well as the irradiance of UV. Variation was made in the beam divergence of the UV sources and reflectivity of optical coatings used for photon recycling. Based on optimized reactor designs, water purification was carried out both in the static and flow-through configuration. Water from various sources was spiked with a known bacterial strain, exposure studies were carried out and germicidal effect was determined. Our results indicate that under optimal design, a 3 mL volume of water shows a three order inactivation using a single UV-LED in a static reactor in 180 s. For a flow-through geometry, only three LEDs were used in the reactor implementation, and a multi-pass procedure was used to purify 150 mL of water from an Escherichia coli CFU count of 4.3 × 104/mL to 12/mL. While slow, this process requires less than 2 W, and can be powered from rechargeable sources. Faster processes can be implanted using multiple such reactor units in parallel, and can be optimized to the requirement and power levels.

Global Health Alert: Racing to Control Antimicrobial Resistant Candida auris and Waste Using UVC LED Technology

“…Due to the small size of UVC LED water reactors and affordable implementation, smaller villages in LMICs can also implement water disinfection infrastructure. There have been reportable success stories from across India and Thailand [224][225][226]. Sundar & Kanmani implemented a portable UVC water reactor at handpumps in a small village in South India, achieving a 2-log reduction of bacterial contaminants.…”

“…Sundar & Kanmani implemented a portable UVC water reactor at handpumps in a small village in South India, achieving a 2-log reduction of bacterial contaminants. Other portable UVC LED water reactors with multi-pass geometry were implemented throughout India with the effective elimination of testselected E. coli [225]. Both of these implementations were considered cost-effective and efficient due to the relatively affordable price, small size, low-to-zero energy requirements, and practical operation guides [225,226].…”

“…Other portable UVC LED water reactors with multi-pass geometry were implemented throughout India with the effective elimination of testselected E. coli [225]. Both of these implementations were considered cost-effective and efficient due to the relatively affordable price, small size, low-to-zero energy requirements, and practical operation guides [225,226]. In Thailand, the UVC LED wastewater reactor was implemented in conjunction with pre-treatment sand and settler filters.…”

UV-Based Technologies for SARS-CoV2 Inactivation: Status and Perspectives

“…In fact, as demonstrated [19,21,46] the range 240-280 nm is the best to induce modification of DNA and/or RNA in microorganisms, blocking their reproduction also with small optical power densities (> 10 mJ/cm 2 ). Other important applications in this wavelength range could be found in the wastewater and drinking treatments [47][48][49], that however require higher optical power densities; for this reason, nowadays for these processes are still used mercury UV lamps.…”