中文摘要：

研究了溶解和胶体物质在整个混合办公废纸回用过程中的变化情况。碎浆段的DCS浓度最高，经过浮选以后DCS各参数变化不大，洗涤后各参数值大幅下降，总糖基、RFA的浓度分别约为碎浆段的10％和56％。经过过氧化氢漂白后，总糖基、RFA的浓度分别约为碎浆段的50％、26％。在宏观上表现为，碎浆段DCS的CODcr值、TOC值和浊度值明显高于洗涤段和漂白段，而与浮选段没有明显的差别。

英文摘要：

The changes of DCS composition and concentration on different recycling stages of mixed office waste paper were studied. The results show that the concentration of DCS reached its highest on the repulping stage, and there was little parametric variation after floatation whereas the parameter values saw a great decline after washing with the concentrations of total carbohydrates and total RFA decreased to 10% and 36% of those on repulping stage. After hydrogen peroxide bleaching, the concentrations of total carbohydrates and total RFA decreased to 50% and 26% of those on the repulping stage respectively. On the whole, the CODcr, TOC and turbidity values of DCS during the repulping stage were apparently higher than those during the washing stage and bleaching stage and had no dramatic differences from those during the floatation stage.