RESUMEN
Aims: Industrial wastewater can be processed by physical, chemical and biological treatment. Most biological treatment have no negative impact on environment and can minimize more cost. The aim of this study was to reduce ammonia in urea fertilizer industrial wastewater by Bacillus bacterial consortium. This strategy tried to develop biological processing of ammonia in wastewater with nitrification process. Methodology and results: Bacterial consortium consisted of three isolates: isolate W1.6 identified as Bacillus sp. A16ZZ, isolate W2.5 identified as Bacillus sp. BNPK-13, and isolate S2.6 identified as B. cereus strain CP1. Consortium culture was made based on shortest generation time on each isolate in order to be in exponential phase when it was used. Bacterial consortium was able to decrease ammonia concentration in wastewater seven days after incubation. Conclusion, significance and impact of study: Consortium of heterotrophic nitrification works optimally with concentration of 350 mg/L ammonia and decrease 96.28%. This consortium has potency to be developed as alternative biological agent in reducing ammonia compounds in high-concentrated urea fertilizer industrial wastewater.