Combined zero valent iron and hydrogen peroxide conditioning significantly enhances the dewaterability of anaerobic digestate
Qilin Wang , Jing Sun , Kang Song , Xu Zhou , Wei Wei , Dongbo Wang , Guo-Jun Xie , Yanyan Gong , Beibei Zhou
DOI:10.1016/j.jes.2017.04.004
Received January 19, 2017,Revised April 06, 2017, Accepted April 06, 2017, Available online April 19, 2017
Volume 30,2018,Pages 378-386
The importance of enhancing sludge dewaterability is increasing due to the considerable impact of excess sludge volume on disposal costs and on overall sludge management. This study presents an innovative approach to enhance dewaterability of anaerobic digestate (AD) harvested from a wastewater treatment plant. The combination of zero valent iron (ZVI, 0–4.0 g/g total solids (TS)) and hydrogen peroxide (HP, 0–90 mg/g TS) under pH 3.0 significantly enhanced the AD dewaterability. The largest enhancement of AD dewaterability was achieved at 18 mg HP/g TS and 2.0 g ZVI/g TS, with the capillary suction time reduced by up to 90%. Economic analysis suggested that the proposed HP and ZVI treatment has more economic benefits in comparison with the classical Fenton reaction process. The destruction of extracellular polymeric substances and cells as well as the decrease of particle size were supposed to contribute to the enhanced AD dewaterability by HP + ZVI conditioning.
