Phosphorus storage dynamics and adsorption characteristics for sediment from a drinking water source reservoir and its relation with sediment compositions

Water and sediment samples were collected from a representative drinking water source reservoir to investigate the nutrient spatial distributions, phosphorus storage, adsorption features and its relation with sediment compositions. Monitored water TN, TP concentrations, sediment pH values exhibited a gradual decrease trend from the upstream to the downstream. Sediment A1T content (total aluminum oxides) was 2-4 times higher than FeT (total iron oxides) which mainly comprised with Fed (free iron oxides) and Feox (amorphous iron oxides). Phosphorus fractional analysis found that Ca-P was the major phosphorus component while Ex-P +Al-P + Fe-P contents accounted for no more than 20% to sediment TP. Phosphorus adsorption process followed the pseudo-second-order kinetic model and Langmuir isotherm equations better than other kinetic and isotherm models. Film-diffusion was the rate-limiting step and physic processes dominated phosphorus adsorption. Maximal phosphorus adsorption capacities could be significantly well simulated with sediment Feox, FeT and TP concentrations (r(2) =0.96). (C) 2014 Elsevier B.V. All rights reserved.