Extraction of zinc from airport stormwater runoff using oyster shells

Abstract

Zinc (Zn) in stormwater runoff have been found to be highly toxic to aquatic ecosystems. A pilot program was evaluated for the removal of Zn levels from stormwater runoff at a west coast airport facility showing high levels of Zn runoff in the stormwater drainage. The objective of this research was to evaluate the effectiveness of the pilot program by reviewing three aspects of the stormwater runoff: 1) water sampling from influent and effluent roof runoff; 2) whether Zn particles were absorbed into the oyster shell fragments; and 3) whether Zn particles were attached to fragmented oyster shells and/or compost materials. The use of fragmented oyster shells mixed into compost and sand served as a medium for the remediation of Zn from stormwater runoff from unpainted galvanized hangar roofing. Influent and effluent water samples determined the effectiveness of an oyster medium in the removal of Zn levels. Data obtained from the influent water samples showed excessive amounts of Zn particles in stormwater, whereas the effluent levels showed a capture rate of > 99% of Zn from the stormwater system. No signs of Zn particles were found inside the fragmented oyster shells, nor were there an abundant amount of Zn particles found in the other medium.