Surfactanct Degradation Using Hydroponic Wheat Rhizosphere.

Hygiene water can be recycled using hydroponic systems as plant roots by provide a substrate and root exudates for bacterial growth. However, reduced plant growth can occur during batch mode additions of high concentrations of surfactant due to poor aeration. An analog hygiene water stream containing surfactants (Steol CS330 and Mirataine CB) was added to a hydroponically-grown wheat plant root zone. The hydroponic system was inoculated with biofilm from a bioreactor and rates of surfactant degradation were measured daily based on reduction in chemical oxygen demand (COD). The COD decreased from 400 to 100 mg/L after 2 days following batch addition of the analog hygiene water to the hydroponic system. Measurements of dissolved oxygen concentration and solution temperature suggest that the root zone was adequately aerated to meet both oxygen demands from plant and microbial respiration during the degradation of the surfactant. Results from this study show that hydroponic systems can be used to enhance rates of hygiene water processing for use in future, sustainable life support systems.