Constructed wetlands were used to remove nitrogen from lightly polluted wastewater. Adding aeration devices at the bottom increased the removal of ammonia nitrogen but did not improve total nitrogen removal significantly. Optimal conditions for high removal rates were identified for different types of constructed wetlands. Ammonia nitrogen removal was best with 7-17 hours of aeration and hydraulic loadings of 0.05-0.20 m3/(m2•d) in zeolite wetlands, and with more than 11 hours of aeration and hydraulic loadings of 0.10-0.45 m3/(m2•d) in limestone wetlands. Total nitrogen removal was highest with less than 5 hours of aeration and hydraulic loadings less than 0.11 m3/(m2•d) in zeolite wetlands, and less than 8.5 hours of aeration and hydraulic loadings less than 0.13 m3/(m2•d) in limestone wetlands. Ammonia nitrogen removal increased significantly, while total nitrogen removal decreased after adding bottom aeration devices.