Effect of Graphene Oxide on the Ammonia Removal and Bacterial Community in a Simulated Wastewater Treatment Process

Abstract

Potential environmental risks posed by graphene oxide (GO) should be evaluated. Wastewater treatment plants will be one of the last barriers for GO wastes. Hence, this study investigated the effects of GO on ammonia removal and bacterial community in a simulated wastewater treatment process. Reactors were fed with influents containing 0, 5, and 25 mg/L of GO (12 h cycles) for 11 days. Results showed that the ammonia removal efficiency increased as the GO dose varied within 5–25 mg/L in reactors after 7 days. The abundance of Firmicutes, Sphingobium, and Leuconostoc in reactors fed with GO at concentration of 25 mg/L were significantly higher than that in control reactors, and the abundance of Sphingobium increased with the increasing concentration of GO in reactors; however, the abundance of Klebsiella decreased with the increasing concentration of GO in reactors. The results indicated that a reasonable microbial community restructured by GO might play a crucial role in promoting ammonia removal. The findings in this work help to promote the understanding of biological characteristics of GO.