The Use of Earthworms in Lab-scale Constructed Wetlands to Treat Swine Wastewater

Abstract

This study investigated the effect of adding local earthworms (Pheretima peguana) into several configurations of the lab-scale constructed wetlands reactors receiving swine wastewater in terms of their treatment performances, namely a decrease in organic matter, TKN, and solids. The results indicated that the performance of the lab-scale units with earthworms was better in the presence of earthworms. In terms of optimal configuration, the vertical subsurface-flow constructed wetlands with earthworms, sequentially followed by horizontal subsurface-flow constructed wetlands had generally the best treatment performance. This configuration decreased BOD, COD, TVSS, and SS by more than 90%, as well as TKN and TS by more than 85%. Based upon these results, it is recommended that future pilot-scale studies should be configured and operated by using vertical-flow constructed wetlands with earthworms followed by horizontal-flow constructed wetlands.