Ammoniacal nitrogen (AN) is a hazardous component and a pollutant in rivers that is challenging to be treated using conventional chemical treatment. The purpose of the project was to remove the AN in synthetic wastewater using a seaweed-based ionic liquid and Bacillus spp. Bacterium, which is required to achieve the Department of Environment (DOE) environmental quality (industrial effluent) requirement 2009. It is set at 20 ppm AN for Standard B area. The Standard B is a water quality indexed set by the DOE to ensure the effluent discharge from industry. A denitrification and ion exchange process occurs in the bioreactor that remove the ammonia ions. The process variables used to evaluate the removal efficiency are pH and temperature while taking into account the COD, BOD and sludge of the effluent. The pH used was between 6 to 8 and a temperature that varies between 30oC to 40oC. Furthermore, to evaluate the effect of pH and temperature during the biological treatment process of ammonia removal. The optimum pH and temperature values set as design parameters are 7 and 37oC, respectively. The result was then used as a constant to study the optimum condition for the bacteria either in aerobic and anaerobic condition. It was found that the aerobic condition was the best condition. The ammonia removal rate was 94% with a final concentration of ammonia at 5.8 ppm treated using 12.0 g of bacteria for 24 hour in a bioreactor.