Using Two Ecological Engineering Technologies to Treat River Pollution in Changhua County, Taiwan

Abstract

AbstractPolluted rivers are a primary concern in Changhua County, Taiwan, due to the rapid development and expansion of agriculture and industry. A water purification system is tested on samples from the Yangzi‐Cuo River, Ci‐Tong Jiao, Changhua County. Two ecological engineering technologies (a gravel contact oxidation and a surface flow constructed wetland treatment) are investigated separately and in combination. The river pollution index (RPI) is measured before and after treatment and used to quantify the results. The inflow volume is 1534–2261 m3 day−1. Pollution elimination efficiencies are 62.83–95.83% for suspended soils, 55.02–86.02% for biochemical oxygen demand, 52.43–88.43% for total nitrogen, 11.95–82.43% for total phosphate, and 40.43–100.00% for ammoniacal nitrogen after using the combined methods. The inflow water is classified as highly polluted with an RPI > 6 mg L–1, whereas the post‐treatment outflow has medium or low pollution with RPIs of 3–6 or 2–3 mg L–1, respectively. The combination of both methods effectively purified Yangzi‐Cuo River water.