Despite the effective decolorization of the nZVI process, the TOC removal was not significant. Specifically, the TOC removal efficiency only increased from 0 to 16% as the nZVI concentration increased from 5 to 100 mg/L as shown in Fig. 1. As compared with decolorization, TOC removal was muchmore difficult with the nZVI process. Considering the low TOC removal efficiency of the nZVI process, further treatment processes or integrated processes are required to increase the TOC removal efficiency.