Plants can play an important role in wastewater treatment and water reuse in terrestrial and space systems. Chive growth in biologically treated graywater, simulating the anticipated early planetary base graywater, was evaluated in this study for NASA. Phytotoxicity due to physiochemical parameters such as ammonium-nitrogen (NH4 +-N), nitrite-nitrogen (NO2 --N), pH, and sodium (Na+) was assessed using a series of hydroponic experiments in an environmentally controlled growth chamber. Nitrification in wastewater was observed in all graywater treatments, which converted NO2 --N (a toxic form of nitrogen) and NH4 +-N (toxic at high concentrations) to nitrate-nitrogen (NO3 --N) (preferred N form for plant uptake). Irrespective of the increase in the NO3 --N concentration due to nitrification, chives in the wastewater treatments typically had poor or no growth. The high levels of Na+ present in the graywater treatments affected potassium uptake and may have affected other nutrient uptake. The impact of nitrification on wastewater pH and NO2 --N toxicity is believed to be the critical factor affecting chive growth and may hinder the use high nitrogen waste streams for plant growth unless NO 2 --N concentrations are controlled during biological treatment of graywater.
- Advanced life support
- Sodium toxicity