Effects Of Nutrients On The Substrate Biofilms In The Integrated Vertical-flow Constructed Wetland

摘要

A L9 orthogonal array design involving 3 factors (C_6H_(12)O_6, KNO_3 and NaH_2PO_4) and 3 levels for each (C_6H_(12)O_6: 0.2, 0.4 or 0.8 g/L; KNO_3: 0.4, 0.8 or 1.6 g/L, NaH_2PO_4: 0.05, 0.1 or 0.2 g/L), was used to study the effects of nutrients on dehydrogenase activity and polysac-charide content of substrate biofilms in the integrated vertical-flow constructed wetland (IVCW). Results showed that C_6H_(12)O_6 and KNO_3 were the main factors for dehydrogenase activity and polysaccharide content of biofilms, respectively. The combinations of three nutrients at different concentrations had different effects on dehydrogenase activity and polysaccharide content of biofilms. The optimal combination for dehydrogenase activity was obtained by locating the concentrations of C_6H_(12)O_6, KNO_3 and NaH_2PO_4 at 0.2, 0.8 and 0.05 g/L, and the optimal combination for polysaccharide content was obtained by locating the concentrations of C_6H_(12)O_6, KNO3 and NaH_2PO_4 at 0.2, 0.4 and 0.2 g/L, respectively. The corresponding maximum activity and polysaccharide content were 5.40 μg TF/g substrate/ 12 h and 3454.6 μg/g substrate, respectively. These results would provide the laboratory foundation for optimizing the purification function of the wetland systems.