Abstract: A bio-remediation experiment zone, using a stereo bio-system consisting of submerged, floating-leaf and emergent aquatic plants to purify water was set up at the Xiaomiao Bay in the east of the Gehu Lake. Monitoring of physico-chemical indices of the waterbodies in the open waters (CK) and the zone was performed from December 2009 to November 2010. Results show that the bio-remediation was quite effective in removing suspended solids with an average annual removal rate of 24.85%. Iit also significantly improved transparency of the waterbody or by 11.24% as compared with that in CK. The remediation reduced TP and Chl-a contents by 21.9% and 22.83%, respectively. Moreover, its effects on removal of TN and NH₃-N and COD_Mn were not so significant. It reduced COD_Mn by 9.49% and NH₃-N by 3.52%, only, and however, even increased TN by 6.69%. Its water purification effect varied with the seasons and affected by growth of the aquatic plants.

Key words: Gehu Lake, aquatic plants, water purification, ecological remediation