Research On The Design, Application And Microbial Mechanism Of A New Kind Of Ecological Floating Island

Nansi Lake is one of the main pollution control units in China. Because of lacking moderate recovery and ecosystem management, the ecosystem structure, stability and of water self -purification capability in Nansi Lake were poor. There are 53 rivers, whose water quality conditions were the key factor for improving the water quality in Nansi Lake basin. Xiaosha River was the typical area in Nansi Lake basin, which had a short length and holded most of the wastewater from domestic sewage and sewage treatment plant. During the flood season, the flow rate of water can reach the maximam of 61000 m3/d. The paper studied a new type of ecological technology for water remediation.First of all, we studied the wastewater purifying efficiency of ecological floating island by static experiment. The result showed that the decontamination effect of ecological floating island was better than that of common island and biological island. After 10 days, removal efficiency of COD, NH3-N, TN and TP was 24.87%～28.34%, 35.94%～64.84%%,71.47%～82.74% and 26.7%～33.18%, respectively.And then, we compared the improving efficiency of water purification in ecological floating island with common floating from May to Dec. The results showed that the average COD, TN and TP removal efficiencies of IEFI were much higher than those of conventional floating island (CFI) (p<0.05). The highest removal efficiency was present in September, May and November, respectively.Thirdly, we carried on the experiment of carrying capacity for the new ecological floating island. The results showed that the new ecological floating island had a well polluntion removal effect, especially for the wastewater containing medium and low concentration pollutants. The degradation of pollutants accorded wih the first-order rate equation with high correlation coefficients and the degradation fit curves were preferable.At last, this study assessed the role of microbe on biofilm carrier.The results, which played an important role in improving water quality and were different with microbial group on other biofilms, indicated that clones affiliated Proteobacteria dominated more than 67% of the total clones, following by Bacteroidetes. Within the Proteobacteria, Betaproteobacteria group was the most abundant, following by Alphaproteobacteria and Deltaproteobacteria groups. For Alphaproteobacteria, more than 60% of the phylum was related to Rhodobacter. The Betaproteobacteria clones were mostly related to Burkholderiale. Flavobacteria dominated 75% of Bacteroidetes group. Functions of Acidobacteria, Deltaproteobacteria, and Actinobacteria are still unknown and need to be further studied. In addition, Bacillariophyta group were also detected in biofilm carriers.