Positive feedback on dewaterability of waste-activated sludge by the conditioning process of Fe(II) catalyzing urea hydrogen peroxide.

The treatment and disposal of sludge is a complex environmental problem because of the high moisture content. Herein, We reported the process of Fe(II) activating Urea hydrogen peroxide (UHP) to improve waste activated sludge (WAS) dewaterability for the first time. Fe(II)/UHP was proven to significantly improve WAS dewaterability.

Enhancing the dewaterability of waste activated sludge by the combined ascorbic acid and zero-valent iron/persulfate system.

In this work, a reducing/chelating agent, ascorbic acid (HA) was introduced to the traditional zero-valent iron (Fe)/persulfate (PS) process for waste activated sludge dewatering. The experimental data indicated that HA-Fe/PS process significantly enhanced the dewatering performance of sludge and enhanced the oxidation efficiency of Fe-PS treatment. Under optimal conditions, the capillary suction time ratio before and after treatment (CST/CST) of HA-Fe/PS treated sludge increased by 118% and 31.

In-depth research on percarbonate expediting zero-valent iron corrosion for conditioning anaerobically digested sludge.

Anaerobically digested sludge (ADS) is commonly hard to dewater for the presence of extracellular polymeric substances (EPS) and the liberation of glutinous soluble microbic products during anaerobic digestion. Sodium percarbonate (SPC) expediting zero-valent iron (ZVI) corrosion (SPC/ZVI) process firstly conditioned ADS to amend its dewaterability. Results showed that SPC/ZVI conditioning decreased moisture content of dewatered cake from 90.