Bioremediation of bacterial algae is one of wastewater treatment by utilizing symbiosis of bacterial algae, which is relatively inexpensive and safe for the environment. The aims of this research were: (1) to investigate initial characteristic of boezem water of Kalidami Surabaya, (2) to investigate the effect of potassium (K) element and carbon source addition toward the reduction of NH3-N content and organic matter in KMnO4 of boezem water. The research conducted in a laboratory in batches without adding aeration. The initial stage of this research was conducting alga culture until it was obtained chlorophyll-a algae concentration of 3.5 ± 0.5 mg/L. The best result of range finding test was a comparison of boezem water volume with algal which were about 25%:75%. The research conducted in duplo over 18 d. The result of the research can be concluded that boezem water of Kalidami Surabaya for the parameter of pH, temperature, NH3-N, dissolved oxygen, chemical oxygen demand, biological oxygen demand, and number of KMnO4 show that it enables to do bioremediation of bacterial algae. Decrease efficiency occurred in a reactor with the addition of element K 3% and source C. NH3-N and KMnO4 final content 0.164 mg/L and 30 mg/L, respectively. Keywords: Algae, Bacteria, Bioremediation, Boezem water, KMnO4, NH3-N