暂存库填埋调质污泥的压缩与固结特性

Compression and consolidation characteristics of chemical conditioned sludge stored in the temporary library

污泥暂存库区面临减量增容的严峻问题。由于暂存库中的污泥已经发生了较大程度的降解,其固结性质与新鲜污泥相比已发生了较大的变化,可直接影响到原位处理效果,故选用FeCl3和芬顿试剂对上海某污泥暂存库区的长期填埋污泥进行了调质改性,并对调质后污泥的固结压缩特性进行了研究。结果表明:经药剂调质后污泥的排水固结时间大大缩短,在初始低固结应力水平时压缩量较大,在后期高固结应力水平下沉降量较小;在初始低固结应力水平下,调质污泥的固结系数在10-3 cm2·s-1数量级范围内变化;添加FeCl3的实验组对应的Cv,max=2.91×103 cm2·s-1,芬顿调质实验组对应的Cv,max=9.88×10-3 cm2·s-1。渗透系数受固结应力影响较大,当FeCl3的掺量为40%时,初级固结应力下样品的渗透系数k=4.439×10-6 cm·s-1;在400 kPa固结应力作用下,渗透系数减小为3.796×10-8 cm·s-1;经芬顿试剂调质的污泥在初级固结应力下,渗透系数k=6.48×10-6 cm·s-1;在400 kPa下,渗透系数k=9.94×10-8 cm·s-1。以上结果对现场污泥真空固结法处理有一定的指导意义。

Owing to the high level degradation of stored sludge and great change in its consolidation characteristic compared with fresh sludge,the severe problems of volume reduction of stored sludge and capacity increase will be faced by the sludge temporary library,which can directly affect the in situ treatment effect of stored sludge.In this study,FeCl3 and Fenton reagent were used to condition the long-term landfill sludge in a sludge storage library in Shanghai,and the consolidation and compression characteristics of the conditioned sludge were studied.The results showed that the time for drainage and consolidation was significantly reduced for the conditioned sludge.The compression was large under the initial low load level,and the settlement was little under the latter high load level.Under the initial low load level,the consolidation coefficient of the conditioned sludge changed within the order of magnitude of 10-3 cm2·s-1.The Cv,max for the test group with FeCl3 addition was 2.91×10-3 cm2·s-1,and for the test group with Fenton conditioning was Cv,max=9.88×10-3 cm2·s-1.The permeability coefficient was greatly affected by the consolidation stress.When the FeCl3 dosage was 40%,the permeability coefficient k under the primary load was 4.439×10-6 cm·s-1.At the load of 400 kPa,the permeability coefficient decreased to 3.796×10-8 cm·s-1.For the sludge conditioned with Fenton reagent,its k value was 6.48×10-6 cm·s-1 under primary load,and was 9.94×10-8 cm·s-1 at the load of 400 kPa.The above results provide certain guidance significance for sludge field treatment by the vacuum consolidation method.