Temporal And Spatial Evolution Of Dissolved Organic Matter In City River

The variation of dissolved organic matter along a river in a typical northern city in Hebei Province was studied in the project.The mainstream water was sampled form 11monitoring points along the river from September,2016 to April,2017.The organic organic matters of these water samples were determined and the composition of dissolved organic matter in the main recharge water source and its influence on the main stream were discussed by excitation-emission matrix(EEM),ultraviolet-visible spectroscopy(UV-vis)and fluorescence regional integration(FRI).The morphology and migration evolution of dissolved organic matters were analyzed as well.Through cluster analysis and the analysis of correlation(SPSS software),the correlation between the dissolved organic matter(DOM)and the conventional indexes of water quality was clarified.The results show:1.The DOM in the main stream is mainly humus and protein,and the DOM is present as humic acid in both the wet and the dry season.The content of DOM in the dry season is higher.Humus in the class of humic acid-based substances,the content of protein-like substances decreased with the increase in the downstream gradually increased.The changes of protein components in the watershed are more obvious and decrease gradually in the downstream.The humic degree of DOM in the main stream is deep,and the source of humus is mainly biogenic.2.In view of the water quality of the three sewage treatment plants,it is recommended that the sewage plant A strengthen the removal of the relatively difficult degradable humic acids in the water.The membrane treatment equipment can be used.The sewage plants B and C will increase the amount of Protein-like substance removal effect.Strengthen the removal of the DOM in the river water should pay attention to reducing the nitrogen and COD in the water.3.The main sewage of the river sewage treatment plant,One of the main sewage of the river,treatment plant A main components of humus and protein-like substances,humus in the secondary aerobic section stable at 4.123×10~7au-nm~2,which can not be completely removed in the process of water treatment;The total fluorescence proportion protein material decreased from 35.5%to 17%,which was removed in the hypoxia stage.The microbial community structure showed a significant trend with the change of water quality,which should pay attention to the removal of the class of humus.The degradation of refractory humic acids could be achieved through the interaction between the microbial,COD and phosphorus.4.The microbial diversity of the main stream is rich and the ecological function is stable.In the water body,Proteobacteria,Bacteroidete,Actinobacteria,Cyanobacteria,Firmicute and Planctomycetes were the dominant species,the total relative abundance ratio is more than 85%.