Response of graywater recycling systems

This study investigates the impact of three classes of surfactants—anionic, amphoteric, and nonionic—on the performance of hydroponic systems utilizing graywater recycling. The primary objective was to assess the degradation of surfactants and their effect on the growth of dwarf wheat (Triticum aestivum cv. USU Apogee) over a series of 21-day trials. The methodology involved adding surfactants in two different modes: a temporally dynamic mode and a continuous mode, followed by monitoring surfactant levels and vegetative growth. Results indicated that sodium laureth sulfate (SLES) degraded rapidly without detrimental effects on plant growth, while cocamidopropyl betaine (CAPB) and alcohol polyethoxylate (AE) showed significant degradation delay and reduced biomass by 20–25%. The microbial communities associated with the plants effectively degraded CAPB and AE, and subsequent acclimation of these communities enhanced degradation rates and reduced phytotoxicity. Overall, the findings reveal that small hydroponic systems can efficiently handle typical surfactant production per person with minimal adverse effects on crop growth.