The last POU technology in this study is UV with LEDs as the source of disinfection. These lights generally are considered more environmentally sustainable as they do not contain mercury like the lamps for traditional UV systems. This unit also allows the UV dose to be adjusted and offers design flexibility as the UV LEDs can be arranged in different formats to optimize disinfection. The design capital materials included quartz, stainless steel, aluminum, and 30 UV LEDs. The unit was designed in a flow-through system so the water is surrounded by arrays of UV LEDs separated from by a quartz material that allows adequate transmittance of UV lights for disinfection. As shown in Figure , the plan view UV LEDs are set up with 15 LEDs on each side of the unit. The system is set up such that an array of UV LEDs require 23 W of electricity. UV LEDs used in this study are estimated to have a life span of approximately 10,000 hours. Other study and manufacturers have reported higher lifetime of up to 100,000 hours, although many of these are still in a developing stage. The unit is designed to incorporate the influence of water quality similar to the unit for UV with mercury lamp. Turbidity of > 10 NTU was assigned a double retention time factor, which was used for the accounting of electricity demand and the lifetime of the lamps.