Application Research Of Sediment Suspension Technique To Improve Slow Flow Water Quality

After the disturbance of sediment, the suspension has good adosorption and fixation effect of phosphorus in water, and also has certain adsorption effect of other pollutants such as nitrogen and organic matter. Nevertheless, migration and transformation of phosphorus in sediment and water is not only affected by the disturbances, but also influenced by water temperature, algal blooms and other factors. The studies about migtation and transformation of phosphorus were few under these three kinds of factors in the past. Therefore, with putting the actual water as the research object, analyzing the rules of the migration and transformation of phosphorus under the multiple influence of disturbance, water temperature, algae and other factors is important scientific significance, and combined with the application effect of the sediment suspension technology in water analyzes the application prospect of this technology. In this paper, in order to expand the application of space of the sediment suspension technology, Meiliang Bay for the study object, the variation of phosphorus forms in the overlying water and sediment in the conditions of the annual variation was analyzed, and the influence of technology on nitrogen and phosphorus and other nutrients was investigated.The study was doing monthly monitoring with all forms of phosphorus in the overlying water and sediment of the Taihu Meiliang Bay in2013. The results showed that TP, PP, DTP, DIP and BAP showed the trend of "high in summer and fall" and "low in winter and spring". And algal biomass also showed a similar rule. Under the multiple effect of wind disturbance, the growth of algae and water temperature and so on, there were the trend of the mutual conversion between DTP and BAPP. In the period of from June to October, the percentage of DTP to BAP (69.33%, average) was higher than the percentage of BAPP (30.67%, average), and was also higher than the annual average of the percentage of DTP (56.63%). The distribution of phosphorus forms in the sediment changed, and there was the obvious transformation from easy-releasing phosphorus to hard-releasing phosphorus from August.Putting the water and sediment in Meiliang Bay in winter as the study object, the impact of disturbance on the migtation and transformation of phosphorus was analyzed.The research showed that the decrease of TP, DTP, DIP and BAP in the overlying water in the repeated disturbance condition was more obvious than the controlled trial. And the distribution of different forms of phosphorus in sediments had significant changes, suggesting that repeated disturbance promote the transformation between different forms of phosphorus in sediments. With the disturbance going on, the percentage of NH4Cl-P and Fe/Al-P to Tot-P of the sediments were all decreasing, while Ca-P and Res-P were the opposite. Compared with the controlled trial, the trend was more obvious under the disturbed conditions, which showed that the disturbance would promote the transformation from easy-releasing phosphorus to hard-releasing phosphorus.Based on it, the sediment suspension technology was applicated in water, which promoted sediment suspension through aeration.The reaserch showed that under conditions of aerating to sediment, the changes of NH4+-N, TP, DTP, DIP and CODMn in the overlying water were obvious seasonal. And the removal effect of DTP, DIP and CODMn was better in the spring, summer. Aerating to sediment could remove NH4+-N and DIP, and it could maintain the effect in a period of time. With the extension of the aeration time, the removal effect of algae, NH4+-N, TP, DTP and DIP became better and better.