A small wetland was built at Buji Sewage Plant in Shenzhen to clean up the water in Buji River. The wetland did a good job at improving the water quality by removing pollutants like COD, NH+4-N, TN, and TP from the sewage plant's wastewater. The wetland worked better in the summer than in the autumn and winter, with TN being affected the most by seasonal changes.