These compounds are not soluble in acidic water so they remain with the pulp during washing. These organic substances do dissolve in water. In fact, most of the color and organic waste in mill effluent comes from this first extraction stage. There is much less organic waste in the second extraction phase, if one is used, because very little lignin is removed in the later stages of the bleaching process. Cl 2 Elemental chlorine and chlorine dioxide react differently with lignin.
Elemental chlorine breaks up the lignin molecule by adding chlorine to the lignin.
Chlorine dioxide transfers an oxygen to the lignin to break up the rings. Hypochlorous acid is also formed. It can react directly with the aromatic rings on the lignin or be converted to elemental chlorine. Thus, the only way to be sure that chlorinated organic compounds including dioxins are not formed in the bleaching process is to eliminate all chlorine-based bleaching chemicals. The organic waste in the effluent must be discharged to the effluent treatment system and ultimately rivers and lakes.