Novel insights into enhanced dewaterability and consolidation characteristics of landfill sludge and fresh sludge conditioned by Fe~(2+) activated sodium persulfate

摘要

Considering the reduction and resource utilization of landfill sludge (LS) and fresh sludge (FS), Fe~(2+) activated Na_2S_2O_8 is proposed. The effects of the molar ratio of Fe~(2+)/S_2O_8~(2-) and the addition of Na_2S_2O_8 on the dewatering performance of sludge were studied by vacuum filtration experiments. Consolidation tests were conducted on the sludge with different Na_2S_2O_8 dosage, and the compression, consolidation, and permeability characteristics of the sludge were researched. Besides, via particle size distribution (PSD) and scanning electron microscope (SEM) test, the variation of particle size of sludge was studied from the microscopic perspective. The results are as follows: the specific resistance of filtration (SRF) of LS and FS decreases by 99.3%, 95.2% at an optimal dosage (the molar ratio of (Fe~(2+)/S_2O_8~(2-)) = 1, 30% Na_2S_2O_8); the particle size of LS and FS is significantly smaller; the consolidation and permeability coefficients are increased by 1-2 orders of magnitude compared with non-conditioned sludge; the water content of LS and FS drops from 86.5% to 58.4%, 82.4%-59.7%. The research results have certain guiding significance for the in-situ treatment of sludge deep dewatering.