Feasibility Study of Oyster Shell Filtration Media for Stormwater Pollutants Removal

The depletion of resources has raised interest in reusing or incorporating by-products into alternative materials. In the effort for net zero emissions, waste reduction, and a circular economy, it is crucial to reinvent the alternative utilization strategy for by-products as construction materials sustainably. This research examines the alternative utilization strategy for oyster shell by-products in regular stormwater pollutant removal best management practices (BMPs). Numerous research has examined the utilization of oyster shell waste as a construction material in Asia and Europe, specifically focusing on the physical properties of crushed oyster shells as alternatives for aggregates. No studies have been identified in the Americas. This study seeks to pioneer research globally on the performance of waste oyster shells as a filtration medium for capturing significant pollutants in stormwater runoff and to take initiative in the United States through studying on oyster shells as a construction material. It will assess the capacity of waste oyster shells to capture key pollutants in stormwater runoff, including Total Suspended Solids (TSS), Total Dissolved Nitrogen, and Total Dissolved Phosphorus. The study investigated the pollutant removal efficacy of waste oyster shells in different size distributions and in both calcined and uncalcined forms. This study determined that waste oyster shells are significantly more effective at capturing nearly 100% of Total Suspended Solids (TSS), with the median Total Dissolved Nitrogen (TDN) removal rate for four variations of waste oyster shell filtration media ranging from 50% to 62%, and with the average TDP removal rate across all oyster shell variants ranging from 36.39% to 42.7%. This outcome indicates that waste oyster shells serve as a suitable material to be used in the filtration medium, regardless of whether they are calcined or non-calcined, and crushed or non-crushed. This study highlights innovative approaches that redefine oyster shells from an environmental and economic burden into a resource that mitigates these issues by replacing conventional materials that are costly to both the environment and economy.