Dewatering Strategies and End Use Examination of Paper Mill Residuals

Abstract

Industrial productivity is often judged solely by the primary product’s marketability, while opportunities for secondary products derived from process waste are often overlooked. Port Hawkesbury Paper LP (PHP), located in Port Hawkesbury, Nova Scotia, produces over 7 wet tonnes per hour of waste sludge with a seasonally dependent dryness ranging from 25-38%. To enhance potential end uses and value of the sludge, it was further dewatered through a comparative in situ study contrasting ferric sulfate and sulfuric acid; both treatments yield a ~4% increase in dryness, with commensurate potential for numerous economic and environmental benefits; the process has since been implemented permanently. Comparatively, sonication, the use of ultrasonic waves to cause molecular disruption, has been investigated with the potential to act as a supplemental practice regarding dewatering or as a replacement for acidification hence decreasing safety concerns by removing hazardous acid injection.