Application of Engineered Cockle Shells and Zeolites for Phosphorus Removal in Controlling Algae Bloom in Eutrophic Water

摘要

Eutrophication is a significant environmental issue caused by excessive nutrients that lead to algae growth and fish kill. The objective of this project was to develop an in-situ deployable product to remove phosphorus (P) for algae bloom control in eutrophic water. This study showed that the naturally abundant cockle shells and zeolites as the raw materials yielded promising P removal efficiencies (30.4% for cockle shell; 99.5% for zeolites), and the effectiveness increased as the size of engineered cockle shells decreased. Fourier transform infrared-spectrum (FTIR) indicated cockle shells and zeolites have a characteristic CaCO3 peak (850 cm~(-1)) and silicate peak (1000 cm~(-1)), suggesting that precipitation and sorption are the respective mechanism. Adsorption to zeolite was found to fit Freundlich multi-layer adsorption isotherm. When applied to two local water bodies in Houston, engineering feasibility calculations on deployment dose, settling velocity using Stokes's law, and cost compared to the conventional dredging technique revealed that these novel materials are cost-effective, sustainable, and safe to use in controlling algae bloom in eutrophic water.