Pre-Treatment To Enhance Biogas Yield from Pulp and Paper Mill Sludge
2014 (English)In: Journal of Chemistry and Chemical Engineering, ISSN 1934-7375, E-ISSN 1934-7383, no 8, 825-833 p.Article in journal (Refereed) Published
The purpose of this work was to study the potential to enhance biogas production from pulp and paper mill sludge by the use of thermal pre-treatment in combination with chemical pre-treatment. Biogas from waste is a renewable fuel with very low emissions during combustion. To further reduce the use of fossil fuels, more biogas substrates are necessary. Pulp and paper mill sludge is a large untapped reservoir of potential biogas. Pulp and paper mill sludge was collected from a mill that produces both pulp and paper and has a modified waste activated sludge system as part of its wastewater treatment. Pre-treatments were chosen heat (70 oC or 140 oC) combined with either acid (pH 2 or pH 4) or base (pH 9 or pH 11, obtained with Ca(OH)2 or NaOH). Biogas potential was tested by anaerobic digestion batch assays under mesophilic conditions. All pre-treatments were tested in six replicates. Biogas volume was measured with a gas-tight syringe and methane concentration was measured with a gas chromatograph. The methane yield from sludge subjected to thermal pre-treatment at 70 oC did not differ from the untreated sludge, but thermal pre-treatment at 140 oC had a positive effect. Within the 70 oC thermal pre-treatment group, the pH 2 acid was the most successful chemical pre-treatment, and Ca(OH)2 pH 9 had the least effect with no measurable improvement in methane yield. For the 140 oC thermal pre-treatment group, acid and NaOH impacted methane production negatively, while the Ca(OH)2-treated sludge did not differ from sludge with no chemical pre-treatment. In conclusion, thermal pre-treatment at 70 oC showed no effect, whereas, pre-treatment at 140 oC improved methane yield with 170%, and for this sludge additional, chemical pre-treatments are unnecessary.
Place, publisher, year, edition, pages
Libertyvill IL: David Publishing Company, 2014. no 8, 825-833 p.
Anaerobic, biogas, digestion, pre-treatment, sludge.
Engineering and Technology Water Treatment
Research subject Environmental and Energy Systems
IdentifiersURN: urn:nbn:se:kau:diva-34408DOI: 10.17265/1934-7375/2014.08.011OAI: oai:DiVA.org:kau-34408DiVA: diva2:755971