Performance of a novel Circular-Flow Corridor wetland toward the treatment of simulated high-strength swine wastewater

An experimental continuous Circular-Flow Corridor (CFC) wetland was developed for the secondary treatment of high-strength swine wastewater. The removal performances of ammonium and phosphorus were investigated, and their mass balance was quantified. CFC wetland shows high efficiency toward the removal of COD, NH4-N and TP, with the average efficiency of which was all above 93.9%. CFC wetland exhibits promising efficiency even in winter, and as low as 5% decrease of the removal efficiency was observed in winter. In high temperature period (20-25 degrees C), nitrification and the adsorption of zeolite dominates in the removal of NH4-N with the average contribution of 45.1% and 31.3%, respectively. However, in low temperature period (3-7.5 degrees C), zeolite adsorption contributes to as high as 87.9% of the removal of NH4-N. The removal of phosphorus is achieved in the front of the wetland, mainly through the co-precipitation with Ca2+ and Mg2+ substituted from zeolite. The effect not only delays the clogging of porous media, but also increases the utility of released Ca2+ and Mg2+. Furthermore, to achieve the long-term treatment stability of the CFC wetland, only the regeneration of zeolite at intervals of 0.5 year is required. This CFC wetland is a reliable, cheap and effective treatment process for the treatment of high-strength swine wastewater. (C) 2012 Elsevier B.V. All rights reserved.