Oil Shale Ash As A Catalyst In Wastewater Treatment In The Pulp And Paper Industry
Price
Free (open access)
Transaction
Volume
140
Pages
12
Page Range
403 - 414
Published
2010
Size
669 kb
Paper DOI
10.2495/WM100361
Copyright
WIT Press
Author(s)
M. Kindsigo, R. Kuusik & J. Kallas
Abstract
The pulp and paper industry is one of the largest and most polluting industries in the world, mainly due to coloration and toxicity problems in wastewaters. Wood debarking, a primary wood treatment process, produces an aqueous effluent that is currently considered as one of the most toxic wastewaters in the papermaking industry. Due to the biological toxicity of the stream debarking wastewater, which contains hardly any biodegradable lignin, is the unsolved problem for wastewater biological treatment. Wet oxidation (WO), water treatment in elevated temperatures and pressures, is an effective process for lignin destruction in debarking water. The main problems in process realization are temperature that is too high (close to 200ÂșC), pressure that is too high and the long duration time of treatment (1.5-2 hours) for lignin degradation. The way to decrease the process temperature and pressure is to use catalytic wet oxidation (CWO). The catalytic effect of an Estonian oil shale alkaline ash (waste material of multicomponent composition forming in high quantities at heat and power production based on firing of local low-grade carbonaceous fossil fuel) in WO of lignin containing waters has been established. The composition of ash is presented. The results of CWO are compared with WO results without ash. Catalytic wet oxidation of lignin water using platinum (Pt) as the catalyst is also briefly presented. It is demonstrated that a certain amount of ash accelerates the oxidation process of organics in water; it degrades the lignins content more quickly, as well as the values of COD (Chemical Oxygen Demand) and TOC (Total Organic Carbon) in lower reaction temperatures and pressures, such as those in WO. Keywords: catalytic wet oxidation, lignin degradation, oil shale ash.
Keywords
catalytic wet oxidation, lignin degradation, oil shale ash