[Combined Remediation of Eutrophic Water by Phoslock and Aerobic Denitrifying Bacteria].

Nitrogen and phosphorus are the leading causes of water eutrophication, and it is challenging to remove nitrogen and phosphorus effectively through a single water remediation method. In this study, an aerobic denitrifying bacterium (AD-19) isolated from eutrophic water was used to construct an immobilized biofilm and combined with Phoslock to remove nitrogen and phosphorus from the water. The phosphorus control efficiency of Phoslock, nitrogen removal performance of the denitrifying bacteria, and combined remediation performance for the eutrophic water were studied. The results demonstrated that the removal rate of PO-P in the simulated eutrophic water reached 95% with a dosing ratio of 80 (mass ratio of Phoslock to PO-P), and phosphorus release from sediment was effectively inhibited at the same time. Strain AD-19, which was identified as sp. Using the 16S rDNA method, had a good heterotrophic nitrification and aerobic denitrification ability, and more than 97% of the nitrogen was removed when NH-N or NO-N was used as the nitrogen source. The feasibility of the combined remediation of the eutrophic water was demonstrated using a lake simulation device. Furthermore, this technique was used to restore a eutrophic pond in a park in Wuhan city. After 16 days of treatment, the water quality indices for nitrogen and phosphorus were improved from worse than Grade Ⅴ to Grade Ⅲ (GB 3838-2002, Ministry of Environmental Protection of China, 2002) and remained stable for more than 270 days, indicating that Phoslock combined with the immobilized biofilm could quickly and effectively restore eutrophic water as well as maintain the water quality for long periods.