This chapter focuses on a study to determine the contribution of the Nakivubo swamp sediments in the removal of phosphorus (P) from the wastewater. The sediment P retention function depends on the redox potential, solubility equilibria and the pH of the overlying water. P fixation onto sediments within a water body by adsorption and/or the formation of insoluble compounds is the only significant sink in aquatic systems for the conservative P. Sediment dynamics were studied for the lower Nakivubo swamp. The sediment load generated by the continuous decay of the floating mat, overlying vegetation and the transported material was measured using sediment traps. Sediments were obtained using an Eijkelkamp multisampler which could extract up to 1 m depth of sediment and overlying water. An estimate of the sediment accretion and decomposition/erosion rates in the swamp was made by considering that the measured mean material deposition rates gave the gross flux. Nutrient and metal ratios are important in P sorption.