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Title: Effect of Ash in Paper Sludge on Enzymatic Hydrolysis

Journal Article · · Biomass and Bioenergy

The valorization of paper sludge is a high-potential process to develop renewable fuels and chemicals, which can be integrated with pulp and paper mills. Calcium carbonate is the main ash component in sludge, which plays a role in buffering pH and potentially lowering the conversion during enzymatic hydrolysis. Therefore, it is important to investigate the effect of ash on sugar yields and examine pH change to introduce efficient and economical enzymatic hydrolysis of sludge. Carbohydrate conversion was enhanced when the ash was removed by fractionation. On the other hand, the highest sugar recovery was obtained when the sludge contained 20% ash content. The pH change during enzymatic hydrolysis was influenced by ash and explained why sludge-derived hydrolysate showed lower carbohydrate conversion. Therefore, a high shear process with the increased acid amount is suggested to prohibit the negative effect of ash and enhance the accessibility of cellulase to fibers. This study highlights the feasibility of using wet waste streams generated by the paper industry.

Research Organization:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Sustainable Transportation Office. Bioenergy Technologies Office
DOE Contract Number:
Report Number(s):
NREL/JA-2800-84061; MainId:84834; UUID:eac1b7fd-ed98-4e86-8d0d-440441f4b527; MainAdminID:67532
Journal Information:
Biomass and Bioenergy, Vol. 165
Country of Publication:
United States

References (13)

A review of secondary sludge reduction technologies for the pulp and paper industry journal June 2006
Production of lactic acid from paper sludge using acid-tolerant, thermophilic Bacillus coagulan strains journal December 2009
Effects of Washing, Autoclaving, and Surfactants on the Enzymatic Hydrolysis of Negatively Valued Paper Mill Sludge for Sugar Production journal January 2019
Conversion of Industrial Paper Sludge to Ethanol: Fractionation of Sludge and Its Impact journal August 2014
Bioconversion of Kraft Paper Mill Sludges to Ethanol by SSF and SSCF journal January 2010
Valorization of Residual Streams from Pulp and Paper Mills: Pretreatment and Bioconversion of Primary Sludge to Bioethanol
  • Mendes, Cátia V. T.; Rocha, Jorge M. S.; Carvalho, M. Graça V. S.
  • Industrial & Engineering Chemistry Research, Vol. 53, Issue 50
journal December 2014
Bioconversion of paper mill sludge to bioethanol in the presence of accelerants or hydrogen peroxide pretreatment journal September 2015
Enzymatic treatment of deinking sludge – effect on fibre and drainage properties journal August 2017
Compositional Analysis of Lignocellulosic Feedstocks. 1. Review and Description of Methods
  • Sluiter, Justin B.; Ruiz, Raymond O.; Scarlata, Christopher J.
  • Journal of Agricultural and Food Chemistry, Vol. 58, Issue 16, p. 9043-9053
journal August 2010
Measurement of cellulase activities journal January 1987
Controlling microbial contamination during hydrolysis of AFEX-pretreated corn stover and switchgrass: effects on hydrolysate composition, microbial response and fermentation journal November 2015
Contaminant occurrence, identification and control in a pilot-scale corn fiber to ethanol conversion process journal November 2007
Conversion of recycled paper sludge to ethanol by SHF and SSF using Pichia stipitis journal May 2008