Engineering properties and mechanism of solidifying materials treated sludge

Abstract

The treatment of organic-rich sludge is significant in geotechnical engineering, which contributes to the resource utilization of sludge and environmental protection. In this paper, several solidifying materials, namely cement, quick lime, potassium ferrate, and super absorbent polymers are selected to treat sludge. Experimental results show that the unconfined compressive strength of treated soil samples is significantly enhanced, and the heavy metal ions concentration measured from the exudation fluid of soil samples is reduced by treatments. Furthermore, the treatment mechanism is investigated by using X-ray diffraction and Scanning Electron Microscopy at the micro scale. The mixing of solidifying materials into sludge leads to the formation of cementitious compounds and the flocculation of clay particles.