- P-ISSN 1225-0163
- E-ISSN 2288-8985
The decolorization of wastewater and the collecting conditions of final sludge from hanji production were investigated. Black wastewater (50 mL) from the process cooking with NaOH could be effectively decolorized by 2.0 g of <TEX>$Ca(OCl)_2$</TEX> So, if excess bleach <TEX>$Ca(OCl)_2$</TEX> used in bleaching process were recycled, the decolorization of wastewater by adding less <TEX>$Ca(OCl)_2$</TEX> would be successfully realized. However, the decolorization by electrolyzed oxidation was ineffective. The final sludge could be effectively collected by polymer coagulator, but the addition of <TEX>$Al_2(SO_4)_3$</TEX> was required, and the pure fibrous sludge could not be collected. Therefore, surfactants such as triethanolamine and Triton X-100 were used instead of polymer coagulator. The collecting yield was obtained about 85% as good as those by polymer coagulator. When mixed surfactants were used in collecting the final sludge, <TEX>$Al_2(SO_4)_3$</TEX> was not required. In addition, as the pure fibrous sludge could be collected, the effective recycling of sludges would be done.