Design and actual performance of constructed wetlands for river renovation in Taiwan
Journal
Desalination and Water Treatment
Journal Volume
131
Pages
114-122
Date Issued
2018
Author(s)
Abstract
This study evaluated the treatment efficiencies of constructed wetlands having design flow rates greater than 3,000 m3/d by using Wetland Contribution Index (WCI) and Wetland Grant Index (WGI). The process of river renovation of Tamsui River Water shed in Taiwan is also studied. The results showed WCIDesign values ranged between 1 and 74.9 kg/103 m3 with an average of 16.6 kg/103 m3. WCIActual values ranged between –2.48 and 40.8 kg/103 m3 with an average of 14 kg/103 m3. WGIDesign values ranged between 2.59 and 2350 kg/103 m3-million USD with an average of 265 kg/103 m3-million USD. WGIActual values ranged between –17 and 1650 kg/103 m3-million USD with an average of 221 kg/103 m3-million USD. Larger WCI values imply that wetlands have higher pollutant removals; larger WGI values have higher benefit-construction cost ratios for pollutants. In renovation of Tamsui River, water quality has been improving by the in-situ wastewater treatment facilities. Non (slightly)-polluted length increased from 168.3 km in 2006 to 242.2 km in 2016, while severely-polluted length decreased from 27.8 km in 2006 to 9.3 km in 2016. Heavy rainfalls usually led to lower River Pollution Index (RPI) values.
Type
journal article