Sand capping for controlling phosphorus release from lake sediments

Abstract

In this research, the use of the sand capping technique for controlling phosphorus release from lake sediment was evaluated experimentally. Multiple acrylic columns were prepared to measure the dissolved oxygen, oxidation reduction potential, total phosphorus, and phosphate concentrations of the overlying water on the capping layer with thicknesses of 0, 40, and 80 mm. Sand capping effectively slowed down the reactions that depleted the dissolved oxygen, which as a result, controlled the total phosphorus release from the sediment. Oxidation reduction potential of overlying water was estimated by measuring dissolved oxygen in situ or vice versa by an empirical model proposed in this research. Sediment disturbance should be considered during field construction of the cap system. The experimental results showed that phosphorus existed in a more stable form with capping than without capping.