Sustainable removal of formaldehyde using controllable water hyacinth

This paper verified the feasibility of water hyacinth for the treatment of formaldehyde in wastewater. In laboratory study, water hyacinth exhibited high removal efficiency for input 100–300 ppm formaldehyde. Formaldehyde consumed by water hyacinth root was lifted from the root to stem and then to leaf, and finally it was converted into some acidoid. Particularly, the removal activity was strengthened with enhanced root activity and chlorophyll in water hyacinth in the presence of 0.5 ppm Eupatorium odoratum L. extract. Meanwhile, the growth of water hyacinth was effectively controlled, exhibiting suppressed emergence of sprouts and low growth rate (≤0.032 g.day−1). In pilot study, water hyacinth also exhibited excellent removal ability to formaldehyde during the four recycle experiments and the growth rate was maintained to a low value about 0.023 g.day−1. In conclusion, water hyacinth managed with Eupatorium odoratum L. extract was proposed as a sustainable biotechnical treatment for formaldehyde.