Dewaterability and energy consumption model construction by comparison of electro-dewatering for industry sludges and river sediments

Abstract

Electro-dewatering (EDW) is an emerging technology for improved sludge/sediment dewatering enabling subsequent cost effective treatment for toxicity and pathogenic reduction if required and/or disposal, but the effects of sediment/sludge properties on the efficacy of EDW remain unclear. Here we investigate EDW in the absence of chemical conditioning which can result in secondary pollution. The influence of sediment/sludge volatile solids content (VS), electrical conductivity (EC), pH and zeta potential (ζ), on mechanical and electrical behaviors determining dewaterability and energy consumption (PE) was investigated. Optimization of EDW parameters increased the final solids content (DSf) from 40 wt% to more than 55 wt% for river sediment, while the solids content in municipal sludge was only increased from 10 wt% to 15–20 wt%. Multiple linear regression and statistical analysis showed that electro-dewatering performance is primarily affected by VS and PE is mainly affected by EC. A theoretical basis for engineering design and selection of operational parameters for sludge/sediment electro-dewatering is provided by this study.