Research On In-situ Control Technology Of Nitrogen And Phosphorus Release From Sediments And Its Mechanisms

The development of in-situ control technology of nitrogen and phosphorus release from sediments of surface water has made a good progress in the past years. However, more studies need to be conducted about the systematic investigation of the technology and related mechanisms for its widely practical application. As one part of "The State Key Project of Environment Protection for Small Town Development from Ministry of Science and Technology of China" , the purpose of this paper focuses mainly on the efficient control of nitrogen and phosphorus release from the sediments of surface water. By appllying three ways of technology including aeration, capping on sediments and in-situ reagent treatment, our research has investigated the effect of aeration, zeolite capping, calcite capping, calcium nitrate in-situ treatment, capping of nitrate loaded surfactant modified zeolite(SMZ) and compound capping with zeolite and calcite under various conditions, and proposed two efficient combined methods for the controlling of nitrogen and phosphorus release from the sediments of surface water. The related possible control mechanisms of the nitrogen and phosphorus release from sediments have been discussed. The results presented in this paper will be a good help for the development of pollution control of surface water both in practice and theory.The detailed results of this study include the following aspects:(1) Dissolved oxygen was the main parameter for controlling the release of nitrogen and phosphorus from sediments, and anaerobic conditions can stimulate nitrogen and phosphorus release from sediments. The release of nitrogen and phosphorus from sediments in eutrophic waterbody was inhibited by aeration under normal conditions. Under high pH value and aerobic conditions, a great deal of phosphorus released from sediments. The amount of sediment phosphorus released under the stirring condition was more than that under still condition. When TP concentration in overlying water was high, phosphorus in water will be absorbed by sediments under aerobic conditions. The release of ammonia and total nitrogen from sediments was greatly influenced by temperature. The amount of ammonia and total nitrogen released from sediments under the stirring condition was more than that...