Response of graywater recycling systems based on hydroponic plant growth to three classes of surfactants

摘要: Anionic (sodium laureth sulfate, SLES), amphoteric (cocamidopropyl betaine, CAPB) and nonionic (alcohol polyethoxylate, AE) surfactants were added to separate nutrient film technique (NFT) hydroponic systems containing dwarf wheat (Triticum aestivum cv. USU Apogee) in a series of 21 day trials. Surfactant was either (1). temporally dynamic mode (1-3 g surfactant m(-2) growing area d(-1)) as effected by automatic addition 300 ppm solution meet plant water demand, or (2). continuous (2 slow (10 mLh(-1)) 2000 beginning at 4d after planting. SLES showed rapid primary degradation both experiments, with no accumulation 24 h initial addition. CAPB AE degraded less rapidly, 30-50% remaining addition, but levels below detection limit for the remainder study. No reductions vegetative growth observed response SLES, biomass reduced 20-25% AE. Microbial communities associated roots wetted hardware surfaces actively surfactants, determined monitoring following pulse additions 20 (with plants) (after removal). In order test whether biofilm could ameliorate phytotoxicity providing microbial community acclimated decay, exposure planted seeds crop removal 21. Acclimation resulted faster (>90% within 24h) phytotoxicity. Overall, studies indicate that relatively small areas (3-5m(2)) can process per capita production mixed (5-10 x person(-1)d(-1)) minimal effects on growth.