Organic matter and nitrogen removal from reclaimed wastewater used as landscape water was carried out by in situ bioremediation. A denitrifying bacterium Bacillus cereus DNF409 was introduced for this purpose, and the amount of B. cereus used was optimized. The total nitrogen (TN) content and chemical oxygen demand (COD) of the landscape water decreased from 9.86 to 3.1 mg/L (removal rate, 68.6%) and from 127 to 36 mg/L (removal rate, 71.7%). The transparency of water increased from 0.2 to 0.55 m.