Abstrait

Expanded Shale Flue Dust as an Additive for the Coagulation-Flocculation of Wastewater

Alan Hodges*, Issa Hamud, Ronald Sims, Charles Miller

Municipal and industrial wastewater production in North America is estimated at 85 cubic kilometers per year, and a significant proportion of this wastewater is treated using coagulation-flocculation systems. Therefore, there is an interest to develop new effective, low cost coagulants to be utilized in these systems. This study demonstrates the feasibility of a novel, low cost coagulant blend of expanded shale, a ceramic derived from the concrete industry, and an industry standard coagulant, ferric sulfate. Triplicate jar tests were operated using synthetic wastewater flocculated with varying concentrations of either ferric sulfate, expanded shale, or a combination of both components. The wastewater was subsequently analyzed for turbidity removal. The optimum concentration for turbidity removal, 0.1 g/L expanded shale and 0.01 g/L ferric sulfate, removed 84.7% and 91% of turbidity and suspended solids, respectively. This blend outperformed the ferric sulfate only treatment, demonstrating expanded shale as an effective additive to traditional coagulation-flocculation systems. Additionally, zeta potential was used to determine the mechanism of flocculation for this novel treatment blend.