Effect of Flow Intermittency on Lipid Degradation Behavior during In-sewer Purification by the Intermittent Contact Oxidation Process

Abstract

Lipid degradation behavior was examined during the Intermittent Contact Oxidation Process (ICOP) for application in in-sewer purification. Lipids are known to accumulate in the sewer environment making the study of its degradation behavior relevant for in-sewer purification. Changes in the lipid substrate during various flow conditions and the subsequent effect of these transformation on the performance of a channel incorporating ICOP were focused on. Biomass was first developed for 84 days in three types of sponges. Oxygen consumption rates, indicative of aerobic lipid degradation, were then observed during three flow conditions which were: extended no flow condition, frequent flow condition, and a combination of extended no flow and frequent flow condition. Oxygen consumption rates decreased over time during extended no flow condition while they were generally similar during frequent flow condition for all sponge types. Lipid samples analyzed after treatment revealed that intermittent flow affected the composition of residual free fatty acid species. Overall, the study provides insights on the effect of flow intermittency on lipid degradation behavior during the application of the ICOP for in-sewer purification.