Abstract
This project focused on nitrogen contaminants and its removal process in wastewater treatment. Moreover, this project is to evaluate nutrients removal and oxygen consumption in the nitrification process. In this study, the experimental results reached high ammonia removal rate (>80%) under both continuous aeration and DO= 4 mg/L, medium ammonia removal (63%) for DO=2 mg/L, and poor ammonia removal (13.7%) for DO=0.5 mg/L. In addition, Ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) were detected in the systems. Presence of AOB and NOB under continuous aeration and DO=4 mg/L conditions confirmed the complete nitrification process. Future studies are encouraged to quantify the amount of AOB and NOB under different dissolved oxygen conditions by using quantitative PCR (qPCR). Then, the HRT should be extended to 48 hours under different dissolved oxygen. The results can be compared with results with HRT at 24 hours. It is assumed that HRT at 48 hours will result in higher ammonia removal rate than HRT at 24 hours due to a longer period for microbial growth or decay in the system.