『Abstract
　The influences of suspended particles (SPs) on NH4⁺ adsorption and nitritation occurring in the water system of the Three Gorges Reservoir (TGR) were evaluated in this study. The results indicated that the adsorption of NH4⁺ was significantly affected by the SPs concentration under the conditions typically present in the TGR. The amount of ammonia adsorbed per unit weight of suspended particles was inverse proportional to the concentrated of suspended particles. However, the influences of the particle size and the organic matter concentration existing in SPs were insignificant under the experimental conditions. The effects of suspended particles on nitritation were determined by the use of ammonia-oxidizing bacteria (AOB) strain SW16, identified as Nitrosomonas nitrosa, which was isolated from sediment samples of the TGR. Suspended particle concentration in water-sediment solution played an important role in the nitritation process. The rate of nitritation enhanced with the increase of the suspended particle concentration. It was found that the critical factor controlling ammonia oxidizing rate was the AOB biomass resulting from the AOB growth rate. Moreover, results demonstrated that both particle size and organic matter content showed little effect on the nitritation process under the experimental conditions.

Keywords: Ammonia adsorption; Ammonia-oxidizing bacteria; Nitritation; Nitrosomonas nitrosa; Suspended particles; Three Gorges Reservoir』

Introduction
Materials and methods
　AOB strain and preparation of inocula
　Sample preparation
　Analysis and enumeration
　Experimental approach
Results and discussion
　Ammonia adsorption in sediments
　　Influence of suspended particle concentration on ammonia adsorption
　　Ammonia adsorption with different particle sizes and organic matter contents in the SPs
　Ammonia nitritation
　　Influence of suspended particle concentration on nitritation
　　Influence of particle size and organic matter content on ammonia oxidation
Conclusion
Acknowledgments
References