Applicability of Oxidation Reduction Potential Response on a Full-Scale Intermittently Aerated Suspended Culture System

Abstract

On-line monitoring of oxidation reduction potential (ORP) was conducted at the full-scale aeration basin operated with intermittent aeration schedules and fed with the wastewater generated from fruit fly rearing facility owned by the California Department of Food and Agriculture, Waimanalo, Hawaii. The characteristics of the wastewater were fluctuated, severely. The 90 percentile level of total chemical oxygen demand, total Kjeldahl nitrogen, and total suspended solids for the wastewater are 5,200, 142, and 3,350 mg/L, respectively. Two aeration schedules of 4 h aeration/2 h nonaeration and 3 h aeration/3 h nonaeration were investigated in this study. Typical ORP curve with bending points of β (beginning of denitrification), χ (disappearance of nitrate), and plateau