Abstract
Hydroponic biofilter method which is a kind of technique for constructed wetlands was applied to purification of hyper-eutrophic Lake Kasumigaura water during July to September in 1994. Several kind of plants, such as Chinese Puk-Bung, Water Cress, Water Funnel and Spearmint, were cultured using artificial channels, and removal rates of particulate and dissolved nutrients from lake water were surveyed.
Average removal rates (g·m-2·d-1) of organic carbon, total nitrogen and total phosphorus during the summer period were as following; Chinese Puk Bung, 13.1, 3.05 and 0.095 ; Water Cress, 12.7, 1.80 and 0.029 ; Water Funnel, 8.4, 0.66 and -0.013 ; Spearmint, 14.7, 1.75, and 0.045 ; Control (filamentous green algae), 10.3, 1.65 and 0.021, respectively. Chinese Puk Bung showed high removal rates.
