Onsite greywater reuse in a low-tech solar-driven pilot laundry facility : field insights on performance, self-sufficiency, and user acceptance

Abstract

This study evaluates the LaundReCycle system, a unique low-tech laundry facility designed for water and energy self-sufficiency through greywater treatment and reuse, rainwater harvesting, and solar power. Installed in Cape Town, South Africa, the system treats greywater using a settling tank, biofilter, sediment and activated carbon filters, and UV disinfection. Treated water is reused for washing, while rainwater replenishes losses and an off-grid solar setup supplies energy. The biofilter achieved 82% chemical oxygen demand (COD) and 95% turbidity removal after a 3-day retention time. This demonstrates effective treatment within a short timeframe. The results suggest potential suitability for low-grade laundry reuse. However, broader applicability may be limited by residual coloration and stable compounds. Water self-sufficiency improved during the study, reaching up to 93 %. Energy self-sufficiency reached 91.6 and 90.8 % in a scenario with increased energy efficiency and operational capacity, respectively. Complementary socioeconomic surveys in South Africa and Switzerland revealed cultural influences on attitudes toward greywater reuse. These findings support the scalability of decentralised non-potable reuse systems when adapted to local conditions