Nutrient Accumulation in Typha latifolia L. and Sediment of a Representative Integrated Constructed Wetland

This paper investigates the role of plants and sediment in removing nutrients from wastewater being treated in a representative integrated constructed wetland (ICW). It discusses the role of plants and sediment in removing nutrients from an ICW treating agricultural wastewater for more than 7 years. More nitrogen and phosphorus were stored in wetland soils and sediments than in plants. The first cell had the highest depth of sediment accumulation (45 cm). Over the 7-year operation period, the accretion rate was approximately 6.4 cm/year. With respect to maintenance, desludging of the first wetland cell of the ICW system appears to be necessary in 2011. An average of 10,000 m(3) per year of wastewater entered the ICW. Approximately 74% (780 kg) of the phosphorus and 52% (5,175 kg) of the nitrogen that entered the wetland system was stored in the wetland soils and sediments. Plants stored a small fraction of nutrients compared to soils (< 1% for both nitrogen and phosphorus). This study demonstrates that soils within a mature wetland system are an important and sustainable nutrient storage component.