Abstract: High concentration of NH3-N on surface water could cause problems in drinking water treatment. The raw water in this condition usually polluted by NH3-N and organic matter. In order to remove those pollutant a pre-treatment process is needed. This treatment generally uses chemical and physical processes such as chlorination and activated carbon that produce harmful byproducts. Moving Bed Biofilm Reactor (MBBR) is one of the solutions developed to reduce the nutrient and organic levels in raw water. The research was conducted using a bench-scale reactor with 6 L capacity operated with Kaldness K1 as the medium and oxygen supply of 7 L/min. Reactor performance is assessed based on parameter removal efficiency with variations of Hydraulic Loading Rate (HRT) which were 1, 1.5 and 2 h. After operated for 48 days, the result showed that the optimum residence time is 1.5 h with the ability to remove Chemical Oxygen Demand (COD) and NH3-N 51.8%±0.2 and 54.3%±0.28, respectively. Batch experiment were performed to study nitrification kinetics. It showed that the kinetics of the ammonia removal rate in MBBR takes place at zero order with a rate constant removal of 0.0056 g/m2day. The results showed that by providing contaminants with high concentrations, the reactor could achieve higher removal efficiency.