Preliminary Evaluation of a Sediment Resuspension Technique for Reduction of Phosphorus in Lake Water

Lake Caron is a shallow and hypereutrophic lake situated 75km from Montreal, Quebec, Canada. This study is aimed to evaluate the resuspension of sediments in Lake Caron, followed by filtration of the resuspended particles. The intention is to improve water quality by removing excessive phosphorus. The effectiveness of the resuspension technique could be directly evaluated by measuring phosphorus content in water before and after the resuspension. It was shown that resuspension successfully improved the water quality by reducing phosphorus content in water by 96.7 % compared to the initial concentration. To understand the retention of phosphorus in the surface sediments, selective sequential extraction was also performed. Core sediment samples were also collected along with the surface sediment. The phosphorus content in surface sediments was 131 mg/g, whereas the sediment from the bottommost layer resulted in 28.7 mg/g phosphorus content, a 64.5 % difference. The phosphorus distribution was also calculated on the basis of different particle sizes. Particles which were smaller than 45 mu m showed 37 % higher phosphorus content on average than the particles larger than 75 mu m. Therefore, these results are a preliminary indication of the potential for resuspension as a method for managing the phosphorus content in sediments.