A Pilot Household Greywater Treatment and Reuse System Produces High-Quality Water under Simulated Household Illness Test Conditions

As water scarcity and plumbing challenges continue to affect small and rural communities, direct potable reuse has the potential to improve household access to clean, potable water. A pilot household greywater reuse system was built and operated daily for nine months to determine whether high-quality water that was safe for human contact could be produced consistently on site. Sixty gallons of water were produced per day under normal and stress conditions, including a simulated whole household illness when viruses were spiked into the system to attempt to overwhelm the effectiveness of the treatment. The system produced high-quality potable water for more than 2 weeks, requiring the addition and removal of only 30 gal of outside water weekly for the household to have 420 gal of treated water available each week and meeting recommended virus reduction standards for small and household-level direct potable reuse systems. Wash water had a low level of total organic carbon, low turbidity, and low conductivity, normal pH, and high ultraviolet transmittance. The treatment process train provided >18 log₁₀ reduction of viruses and >8 log₁₀ reduction of bacteria. While the system produced sufficient wash water to protect health, the concentrated wastes produced could pose a threat to the household if proper waste disposal methods are not facilitated.