Sensor Electronic Technology Inc (SETI) Columbia, SC, USA has been awarded a $475,000 Small Business Innovation Research (SBIR) Phase II award from the US National Science Foundation (NSF) to develop point-of-use (POU) drinking water disinfection systems based on deep ultraviolet LEDs (DUV LEDs).

Deep UV LEDs and lamps are currently commercially available from SETI at wavelengths of 240–400nm for applications including air and surface disinfection, UV curing, scientific instrumentation medical diagnosis and therapy. In particular, SETI claims to be the only commercial supplier of DUV LEDs operating in the germicidal wavelength range, and has standard UVCLEAN lamps available with optical output power of up to 50mW at 275nm.

SETI also, just last week, entered a joint development agreement with Kyma Technologies Inc of Raleigh, NC, USA, which provides crystalline III-nitride semiconductor materials including gallium nitride (GaN) and aluminum nitride (AlN), to develop low-defect aluminium gallium nitride (AlGaN) substrates and high-performance optoelectronic and electronic devices based on the substrates, targeting higher-efficiency DUV LEDs for applications such as water disinfection.

During the new Phase II of the SBIR project, SETI will design, develop, fabricate and demonstrate all-LED water treatment units with reduced power consumption and extended reliability. The main effort will focus on increasing the germicidal efficacy and reducing the cost of LED disinfection units through advances in LED packaging and disinfection chamber design.

Through Phase I of the NSF SBIR program, SETI recently demonstrated 99.99% disinfection of E-coli in a POU drinking water system with water flowing at 1 liter per minute using its 275nm UVCLEAN LED lamps emitting about 30mW of optical power. SETI has since begun to ship bespoke proof-of-concept units to companies for evaluation in consumer products.

The firm says that further development of UV disinfection technology using semiconductor UV lamps will use unique device characteristics, such as controlled UV spectral power distribution, fast switching time, lower power consumption, high reliability, small size and ruggedness. SETI believes that these advantages will enable new opportunities to incorporate UV disinfection into consumer water purification systems.