NITROGEN REMOVAL FROM SEWAGE IN A SERIE OF AEROBIC-ANOXIC SUBMERGED BIOFILTERS

Resumen

This paper presents the results of an alternative technology with combination of aerated and anoxic biofilters, filled with corrugated cut conduit, low cost and simple operation. These filters receiving domestic sewage previously treated in anaerobic reactors. The study was divided in three phases: during the first phase the air flow to the aerated filter was 0.10 m3/minute, and in phases 2 and 3 air flow increased to 0.15 m3/minute. In the last phase 1 m3/day of the anaerobic effluent was used as a supplemental source of carbon to the anoxic filter. The filters were capable of reducing the ammonia concentration to below 10 mg/L. In addition, the system was able to produce the final effluent concentrations of TSS and COD of 5.3 mg/L and 25 mg/L, respectively, without sludge removal, or any other step for phase separation.

Keywords: sewage, denitrification, nitrification, nitrogen removal, submerged biofilter, sludge retention.