利用污水污泥制备有机物聚集介质的可行性探析

将城市污水中富含的有机物质或化学能回收利用,转化为有价值的产品或能源,是当前城市污水处理领域的研究热点。低浓度有机物的富集浓缩是实现城市污水有机物回收利用的首要前提。利用絮凝捕集方法将污水有机物转移聚集至污泥中,具有富集过程能耗低、碳转化损失少的优点。阐述分析了高分子有机絮凝剂的制备原理,尤其是天然高分子絮凝剂改性制备过程中各组分的作用、特性与效果,并将污泥水热处理液相产物中大分子有机物的组成和特性与之进行对比分析,介绍了接枝共聚、醚化、氧化等几种常见改性手法。结合相关实验研究,论证探析了以污水污泥为原料,通过水热处理和改性制备获取可用于城市污水有机物富集回收的絮凝聚集介质的可行性及意义,并提出了进一步深入研究需要解决的问题。

Experimental Study on Hydrothermal Drying for Sewage Sludge in Large-Scale Commercial Plant

The study was conducted to demonstrate the performance of the large-scale commercial plant of the hydrothermal drying of sewage sludge. Its performance was compared with that of the small-scale pilot facility to confirm the scaling effect of the facility. It has been shown that the optimum reaction temperature was 190℃ and reaction time was 30 minutes for both facilities. The dehydration performance of the products of the hydrothermal treatment and the natural drying performance of the dehydrated residue were almost the same for both facilities, which demonstrated that the small-scale pilot facility could simulate the commercial-scale plant well. With these optimum hydrothermal reaction conditions, the moisture content of the dehydrated product was less than 40% by the use of the frame filter, which had better dehydration performance than the centrifuge dehydrator. The moisture content of the dehydrated solid residue could be reduced less than 20% and 10% after 24 hours and 48 hours natural drying, respectively. The solubilization rate of sludge into the dehydrated liquid was 10% and 90% of the solid content in the raw sludge could be recovered as a dry solid fuel by this process with reduced energy requirement compared with conventional thermal drying processes. Too high reaction temperature or too long reaction time increased the content of solid material in the dehydrated liquid （solubilization rate of sludge） and reduced the yield of the dry solid fuel.

有机物捕集聚集介质制备条件的优化及效果评估

城市污水资源化受到了广泛关注,其中有机物回收是重要一步。为此,提出了将污水污泥水热处理,利用水热液中的大分子物质作为原料制备聚集介质,用于捕集回收污水中有机物。但前期制备方法复杂,阻碍了聚集介质的推广应用,因此通过减少精制步骤、改性单体使用种类、氮气通入时间对其制备工艺进行改良,并对制备条件(pH、温度、时间、改性单体用量比例)进行优化。结果表明,采用湿法制备,在接枝共聚反应前30 min内通入氮气、pH为5、反应时间为2.5 h、温度为70℃、液相大分子物质与甲基丙烯酰氧乙基三甲基氯化铵(DMC)投配比为1∶0.7时,得到的聚集介质具有较优的絮凝性能及经济性;在投加量为30 mg/L的条件下,该聚集介质能够捕获污水中54%的COD,捕获效率提升64%。