Adnan Abbas Al-Samawi - Professor Emeritus of Environmental Engineering, University of Technology, Iraq
Mohammed Siwan Shamkhi - Assistant Professor of Water Resources Engineering, Wasit University, Iraq

This study includes two parts; in the first part, enrichment of high active ammonium oxidizing organisms (AOO) in sequencing batch reactor (SBR) in moderate weather and without temperature control , while in the second part; consideration of the influence of major operational parameters including; temperature,pH, dissolved oxygen concentration (DO) , and free ammonia (FA) and free nitrous acid (FNA) formation to evaluate the process performance in moderate weather without temperature control are investigated. Results revealed that the maximum removal efficiencies of ammonium from synthetic reject water in the SBR inoculated with mixed liquor activated reactor was within 71.09%. The NAR had with a maximum value of 95.74% which refers to strengthen of growth of AOO. The specific ammonium oxidation rate was with 0.085 mg NH4 +-N/mgVSS.h which refer to high active enriched AOO and feasibility of enrichment of high activity nitrifiers in moderate weather

nitrifier, enrichment, SBR, moderate, weather