Treatment of high-strength ammonia nitrogen wastewater using sequencing batch reactor

Abstract

Recent studies on biological nitrogen removal processes such as anaerobic ammonium oxidation (ANAMMOX) and SHARON focused on the reduction of organic carbon for denitrification. The mechanism, however, has not been completely understood and we have difficulty maintaining these systems in field operation. In order to overcome these problems, the simple, economical nitrogen removal process for landfill leachate, tannery wastewater, and piggery wastewater was suggested using a sequencing batch reactor (SBR) with zeolite addition. In order to evaluate the efficacy of the sequencing batch reactor on treating ABS (acrilonitrile butadiene styrene) resin wastewater with high levels of ammonium nitrogen and industrial toxicants, three types of operation modes, conventional pre-denitrification, influent distribution, and carbon addition were tested. The decanting was 33% of the working volume in one cycle, whose period was 12 h in total, and whose HRT was 1.5 days. The COD removal efficiencies in all operation methods were over 90%, but T-N removal efficiencies were quite different. In the conventional operation mode, the T-N removal efficiency was about 67% due to denitrification and nitrification. When the feed was added to supply organic carbon for denitrification in the pre-and post-anoxic periods, T-N removal efficiency increased to 83%. Meanwhile, when the acetate was added in the post-anoxic phase with acetate/$NO_3$-N ratio of higher than 4.0, T-N removal efficiency increased to 95%. With the acetate addition mode, it was necessary to add a proper amount of phosphorus for complete denitrification. Although the acetate addition in the post-anoxic period had an advantage of enhancing nitrogen removal, excess sludge production and the high operating cost had to be considered. In the extended continuous operation, SRTs longer than 30 days provided stable organic and nitrogen removal compared to that of 10 and 20 days SRTs. From this experiment, it was found that the ...