低温热处理对剩余污泥有机物溶出及脱水性能改变的影响

Effect of Low Temperature Thermal Treatment on Organic Matter Solubilization and Dewaterability Change of Waste Activated Sludge

为了提高剩余污泥厌氧消化过程中的水解速率,采用批次试验对处理实际生活污水的剩余污泥进行低温热处理,研究了在处理时间为10~80 min,处理温度50~90℃条件下,低温热处理对有机物溶出、溶解性碳水化合物(SC)和溶解性蛋白质(SP)相对分子质量变化及脱水性能改变的影响.结果表明:随着热处理时间的延长,溶解性化学需氧量(SCOD)、SC和SP分别在90℃、80 min,90℃、70 min和70℃、40 min条件下达到最高值,较原污泥中各项指标分别增长了15.5、19.2和5.2倍.升高温度可以促进大分子物质向小分子物质的转化,在50~90℃,SC最小相对分子质量从163 u降低到2.5 u,SP从1.41 u降低到0.26 u.通过污泥毛细吸水时间(CST)来表征污泥的脱水性能,CST在80℃后增长速率加快,70℃、80 min条件下较原污泥增长了108.8 s,而在90℃、80 min条件下增长了375.7 s.根据以上研究结果得出结论,最合适的热水解条件为70℃、30 min.

In order to improve the hydrolysis step in the process of excess sludge anaerobic digestion,static batch test was conducted to investigate the effect of low temperature treatment on the actual domestic sludge generated.The research was to investigate the effect of low temperature on organic matter solubilization,soluble carbohydrates and soluble protein molecular weight changes and the changes of dewaterability on the condition that the treated time between 10 and 80 min and the treated temperature between 50 and 90 ℃.The results show that the concentration of soluble chemical oxygen demand,the soluble carbohydrates and the soluble protein get the highest concentration on 80 min and 90 ℃,70 min and 90 ℃,40 min and 70 ℃,increase 15.5 times,19.2 times and 5.2 times to the raw sludge respectively.In the range of 50-90 ℃,through gel permeation chromatography method for analyzing molecular weight of the SC and SP,the results show that minimum molecular weight of the SC changed from 163 u to 2.5 u,and SP changed from 1.41 u to 0.26 u with the rise of temperature and time.Capillary suction time(CST) was investigated to evaluate the sludge dewaterability,and the value of CST have significant rise after 80 ℃,increase to 108.8 s on 80 min,70 ℃ and increase to 375.7 s on 80 min and 90 ℃.According to the above research,there comes a conclusion that,the optimum condition is 70℃ and 30 minutes.