废纸造纸循环水中DCS的好氧和厌氧生物可降解性比较

Comparison of Aerobic and Anaerobic Biodegradability of Dissolved and Colloidal Substance in Recycled Water from Regenerated Paper Making

溶解及胶体物质(DCS)随着造纸用水循环系统的日益封闭而不断积累,给生产和成纸质量带来严重影响,急需有效的方法加以去除.通过实验室模拟,进行了DCS的好氧和厌氧生物可降解性的比较研究.结果表明:营养物的加入对好氧生物降解DCS具有积极作用,使CODCr的去除率提高了15.3%,DCS中木素及其衍生物的好氧生物降解需要必要的共代谢基质,在工程应用上应配以添加合理的营养底物;厌氧生物降解的第1天,DCS,CODCr和UV280的去除率分别超过了40.5%,55%和68%,明显优于好氧生物降解;DCS中难以被生物降解的长链脂肪酸和木素聚合物属互养型底物,其降解过程会因乙酸和氢气的积累而受到抑制,在工程应用上,应考虑调节厌氧微生物的适应性或增加水力停留时间,以强化污染物的持续有效分解.

Dissolved and colloidal substance （DCS） accumulates gradually with the reduction of freshwater consumption in the pulp and paper industry. Too much DCS, which needs effective measures to deal with, harms the stability of paper machine operation and the quality of products. The aerobic and anaerobic biodegradability of water samples accumulated with DCS was comparatively researched through laboratory simulation. The results show that the aerobic disposal ratio of chemical oxygen demand （ CODCr ） from DCS can be increased 15.3% by adding nutrient substances. Aerobic biodegradation of lignin and its derivatives in DCS need co- metabolism substances. Therefore, engineering projects should add moderate nutrient substances to improve lignin＇s degradation. However, DCS was removed obviously by anaerobic microbes. The results of the experiment indicate that the removal percentage of DCS, CODCr and UV280 are more than 40.5% , 55% and 68% respectively after one day, after which the degradation of DCS will be at a standstill, because the fatty acids with long chains and lignin polymers are syntrophism substrates, and their anaerobic biodegradation might be inhibited by the accumulation of acetic acid and hydrogen. Therefore, we should domesticate the anaerobic microbes and enhance the hydraulic retention time to increase their sustainable decomposition ability.