Integration And Demonstration Of Enhanced-Purification And Ecological Rehabilitation Technology For Polluted Rivers In Cities

An array of combined ecological floating beds（CEFBs）were constructed to study their performances for the remediation of polluted river water,including removal efficiencies of typical pollutants and their removal kinetics.Taguchi method was used to optimize the CEFBs conformation associated with plants,biofilm carries and aeration duration.The purification efficacy under the Taguchi optimized conditions was also predicted theoretically.The results obtained are summarized as follows:（1）A pilot-scale study with 49 days treatment duration on three different CEFBs,noted as A-CEFB（Planted with Hydrocotyle vulgaris and using volcanic rock as biofilm carries）,B-CEFB（Planted with Myriophyllum verticillatum L and using sponge as biofilm carries）,and C-CEFB（Planted with Jussiaea stipulacea Ohwi and using combined packing as biofilm carries）,was conducted to look at their pollutants removal performances.It was found that,the average mass removal rate for the CEFBs can achieve 6.51-6.80 mg.d^-1.m^-22 for NH₃-N,27.30-28.52 mg.d^-1.m^-22 for TP and 414.34-443.32 mg.d^-1.m^-2for COD.（2）The kinetics study on the A-CEFB,B-CEFB and C-CEFB show that,the first order kinetic model is efficient for predicting removal performance for NH₃-N,TP and COD.The first order kinetic constants for the A-CEFB were found to be 0.0236d^-1 for TP,0.0264 d^-1for NH₃-N and 0.0146 d^-11 for COD.The kinetic constants for the B-CEFB were found to be 0.0264 d^-1 for TP,0.0291 d^-11 for NH₃-N and 0.0147d^-11 for COD.The kinetic constants for the C-CEFB were found to be 0.0249 d^-1 for TP,0.02591 d^-1for NH₃-N and 0.0161 d^-11 for COD.（3）The Taguchi-based analysis produced an optimum combination of purification conditions for TP,NH₃-N and COD,respectively.Impressively,it was found that aeration duration had considerable effect on NH₃-N and COD removal efficacy,but no significant effect on TP removal efficacy.The type of the biofilm carries was found to have significant effect on NH₃-N removal efficacy,but showing insignificant effect for COD and TP removal.The type of the plants was found to have insignificant effect on the performance for TP NH₃-N and COD removal.