Induced air flotation for fat, oil, and grease recovery in urban wastewater: A proposed methodology for system optimization and case study

Abstract

Induced air flotation (IAF) is a well-known technology that is widely applied in urban wastewater treatment plants (WWTP) for fat, oil, and grease (FOG) removal. However, most IAF systems are not optimized and typically operate with fixed parameters, regardless of inflow variations. Furthermore, the optimization of IAF systems is limited by the lack of equipment in WWTP laboratories to determine FOG concentrations in wastewater. In this study, an adapted sulfo-phospho-vanillin method for FOG quantification in wastewater is proposed for optimization and automation of the IAF system. The proposed methodology requires simple equipment that is widely available in WWTP laboratories, paving the way for in situ FOG determination. The method was successfully employed to determine the optimal operating conditions of the IAF system in terms of hydraulic retention time and organic loading rate. Furthermore, a full-scale IAF system was optimized using this methodology and its energy demand was reduced by 40 %.