A local natural zeolite from Sarulla in North Sumatra has been isolated and activated with low thermal activation process to enhance its ammonia adsorption capacity. The Sarulla Natural Zeolite (SNZ) was prepared through crushing, shieving, washing, and thermal activation at 120oC for three hours. SNZ was further characterized and tested for ammonia removal using batch and fixed bed column adsorption processes. In the fixed bed column adsorption, the bed height and initial ammonia concentration were used to understand the adsorption process. The result demonstrates the low thermal activation process improves approximately 10% of adsorption capacity of SNZ. The kinetics study confirmed that the ammonia adsorption mechanism is chemisorption mechanism where the initial concentration plays the role to determine the mass transfer driving force. Furthermore, the rise on bed height do not provide more contact sites and extend the breakthrough time due to lack of flow blockage. The flow blockage limits the contact between zeolite and ammonia which further perform low adsorption capacity. 2 cm of bed height with 150 mg/L of initial concentration exhibit the highest adsorption capacity of 15.3551 mg/g. The result shows that the low thermal activation approach is an effective way to improve the SNZ adsorption capacity.