Start-up performance of a novel constructed riparian wetland for removing phosphorus from agricultural runoff

Abstract

The overloading agricultural phosphorus inputs play significant roles in accelerating eutrophication of receiving waters. For the propose of phosphorus removal from agricultural runoff, a field-scale free surface flow constructed riparian wetland system, with cost-effective and easily maintainable design, was constructed for receiving runoff from a small agricultural watershed on the northeastern lakeside rural areas of Liangzi Lake, China. During the start-up period, the system potentially provided a buffering capacity in irrigative and rainy periods. Wetland vegetations grew relatively well during the observed period (1 August–30 October 2012). Furthermore, the growth of vegetations has assisted in transforming the constructed riparian wetland structure to fit well with the surrounding landscape. The reductions in average concentrations of PO4-P and total phosphorus (TP) during the start-up period were approximately 75.6% and 46.5%, respectively. Moreover, the influences of environmental conditions on PO4-P and TP removal and retention in the constructed riparian wetland system were also analyzed. The results indicated that water temperature, conductivity, dissolved oxygen, and pH were important factors controlling phosphorus redistribution in the studied system. Generally, the constructed riparian wetland system preformed satisfactory during the start-up period, and it might be a suitable wastewater treatment tool for farms in poor rural areas.