OPERATIONAL PARAMETERS FOR HIGH-LOADING OXIDATION DITCH PROCESS WITH CONTINUOUS AERATION FOR NITROGEN REMOVAL FROM DOMESTIC SEWAGE

Abstract

At an extremely small-sized oxidation ditch (OD), intermittent aeration has been required for the nitrogen removal from domestic sewage. This paper examined the effect of high-loading operation on nitrogen removal in the OD process with continuous aeration. High-loading operation made it possible to obtain more than 80% nitrogen removal even under the conditions of the recirculation time less than 10min.. DO recirculation rate (R_DO) was demonstrated theoretically as one of the important operational parameters in the process. The experimental results also showed that the increase of R_DO led to the deterioration of the nitrogen removal. Nitrogen removal in the process was also affected by net C/N ratio for denitrification (η value) which was defined after consideration of DO inflow into the anoxic zone.