| Organic pollution in water environment is important domain to research about environment protection over the world. Especially, in China, the status is more severe, and since 90s, it has threatened the healthy of people and the ecological balance. Bottom sediment, as a key medium, acts on transport, chemical and biological reaction of organic contaminants in water system. Based on the batch experiments and theoretical analysis, the issues concerning transport and transform of organic contaminants in water system sediment are addressed in this paper. The results obtained will be take as follow.First of all, the experiment on bottom sediment pore water was carried out for studying the specification of COD contaminant in bottom sediment and its influence factors. The result showed that the COD contaminant, dissolving in pore water and adsorbing on surface of sediment particle through adsorption/desorption balance, is most part of the contaminant in bottom sediment. At same time, effects of temperature on organic contaminant creating in pore water and the equilibrium concentration were also significant, and at low temperature, the equilibrium concentration is low.The layering properties of bottom sediment were studied. The layering bottom sediment experiment shown that bottom sediment of water system and organic contaminant in bottom sediment had different layering properties. At the top layer, organic contaminant transporting to the upper water body, its concentration in pore water is lower a little than that in middle layer, but under 1cm, the concentration is uniform. Additionally, following the increment of depth, the density of bottom sediment increases, and the pore water content falls.The effects of heavy metal and organic matter from different origins on the properties of bottom sediment pore water were studied. Because of the complex condition of bottom sediment system, the bio-chemical reaction in the system is influenced by many factors, in which the existence of heavy metal and the origin of organic matter are the most important. By a 90d experiment, it showed that the action of added copper is significant to influence the properties of pore water, which enhanced the pH value of pore water, increased the concentrations of silicon and Potassium, and decreased that of iron. The contrastive experiment of two kind organic materials showed that in the anaerobic condition of bottom sediment, the organic matter which decomposes quickly and has low molecular weight, can reduce Eh and height pH of pore water. Additionally, the action of the easily decomposing material depressed at the end of experiment but that of difficultly decomposing material enhanced.The development of jet flow was researched. Having the potential core, the velocity profile in initial region of jet is different from that of fully developed region. And in former researches, the two regions were studied separately. Furthermore, the velocity profile in fully developed region is a gaussian distribution. When jet initial region is short comparatively, the disposal can be valid, but when the effect of initial region is very significant, especially to jet with large-scale exit, such as the ship propeller jet, the disposal can be invalid. Based on theoretical analysis, a new velocity profile formula of jet was proposed to unit the initial, transitional, fully developed regions. Then, the definite radius of jet with a large exit and velocity profiles based on the definite radius were deduced. And the factors influencing the development of environment jet such as outlet velocity, ambient fluid velocity, size of exit, were analyzed.Based on the gained jet formula, the distribution of water velocity on the bottom of river,under the action of ship propeller, was researched, and the main factors influencing the velocity distribution were analyzed. Then the areas of the bottom sediment initiation and the influence factors were studied, and we found that jet velocity at exit, water depth, ambient fluid velocity and its direction all are...
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