Department of Environmental Science, Shaanxi Normal University, Xi’an Shaanxi 710062, P. R. China
Approach of organic material anaerobic biodegradation and species of organic matter in sediment are discussed, and then a classifying method of the species is proposed on a new viewpoint. The pore water sediment oxygen demand (SOD) numerical model in bottom sediment system is proposed originally, which differs from other advection-dispersion-sorption (ADS) model in adding a SOD-creating term. The model was preliminarily validated via pilot experiment. Finally, this model was used to simulate SOD concentration of pore water in bottom sediment, and the sensitivity of parameters in the model was analyzed. The results indicate that SOD-creating factor at beginning stage and pore water SOD-attenuating factor in bottom sediment are the most important coefficients in the new model and should be estimated accurately. Because of the assumption of equilibrium of sorption/desorption, the new model appears to be valid only with less than 5 m/ d vertical velocity of pore water.