De-coloring of dark-brown waste water from Korean-paper manufacturing process was investigated by using UV irradiation over TiO₂ photocatalyst and Fe/MgO catalyst. Decomposition of dark-brown color by UV irradiation on TiO₂ photocatalyst was significantly improved up to 70% of de-coloring efficiency by adding the hydrogen peroxide. Most efficient system for de-coloring (more than 80%) of dark-brown color of wast water was an UV irradiation over the mixture of TiO₂ and Fe/MgO catalyst. Optimum condition of sludge as an worm feed was pH=5-8. It was appeared that worm ingested about 8.1% of total dried amount of sludge, indicating that sludge could be recycled as a feed of worm.