Potential of water hyacinth for phytoremediation in low temperature environment

Abstract

Water hyacinth, i.e., Eichhornia crassipes Solms can remove a large variety of different pollutants from water and are considered an excellent candidate for phytoremediation of contaminated waters. Nevertheless, exploitation of water hyacinth for phytoremediation has so far been limited to tropical or subtropical regions. In this study, the influence of temperature on the morphology, growth, and nutrient removal of water hyacinths was studied in a relatively low temperature range, 12–25°C, in the form of three night/day temperature cycles, i.e., 12/15°C, 15/20°C, and 15/25°C. It was shown that water hyacinth is very sensitive to temperature in the tested range and 15/25°C is the most favorable condition among the tested. A biomass productivity of 10.7 tons DW/ha/yr, total nitrogen removal rate of 400 kg N/ha/yr and total phosphorous removal rate of 65 kg P/ha/yr were estimated according to the experimental results on the basis of five operational months per year. No visible morphological changes were observed when the plants were cultivated at 15/20°C or 15/25°C but significant morphological changes were observed when the plants were transferred from a rooftop greenhouse to a growth chamber controlled at 12/15°C with plant size shrinking significantly. Nevertheless, substantial plant growth and nutrient removal were observed at 12/15°C, although with a prolonged adaptation phase of 2 weeks. Results of this research suggest good potential of water hyacinths for water phytoremediation in relatively cold regions such as Canada. © 2013 American Institute of Chemical Engineers Environ Prog, 32: 976–981, 2013