Removal of food soil by ozone-based oxidation processes: Cleaning and wastewater degradation in a single step

Abstract

The cleaning of heat-treated cornstarch adhered to stainless steel is analyzed in a simulated Cleaning-In-Place system. The effects of temperature (20–60 °C), cleaning time (30–120 min), and ozone (0.00–42.30 g/Nm³) on both detergency and chemical oxygen demand (COD) are analyzed. Two mathematical models are proposed to evaluate the detergency and COD fitting satisfactorily the experimental results. The highest detergency is obtained at 60 °C and 120min, reaching 68 and 88% when the ozone concentration is 0.00 and 42.30 g/Nm3, respectively. Ozone diminishes the COD in the wastewater. Higher ozone concentration, cleaning time and temperature produces the greater reduction of COD/Detergency ratio. So, ozone promotes starch degradation, reducing the contamination charge of the wastewater during the cleaning process providing new possibilities for the optimization of cleaning processes in starch end-user industries by combining cleaning and depuration processes in a single step.