Expanding the ability to anaerobically digest pulp and paper mill waste

Funding Details
Natural Sciences and Engineering Research Council of Canada
  • Grant type: Strategic Projects - Group
  • Years: 2012/13 to 2014/15
  • Total Funding: $489,400
Principle Investigator(s)

Project Summary

In order for the Canadian pulp and paper industry to stay globally competitive and leave a smaller environmental footprint, its extensive water usage requires optimization. Anaerobic digestion is a cost-effective wastewater treatment option, decreasing the amount of residual sludge while recovering energy in form of utilizable methane. The difficulty to digest waste streams that are specific to pulp and paper mill operations is the most significant obstacle to more widespread use of anaerobic treatment. Pulp and paper wastewater and biosludge generated during wastewater treatment contain high concentrations of substances that are inhibitory or toxic to anaerobic microorganisms. To date only a few Canadian mills operate anaerobic digesters. One of them, the Tembec pulp mill in Temiscaming, recovers ~20,000 m3 biogas, largely consisting of methane, per day from anaerobic digestion of selected in-mill streams. Although toxic substances in such streams occasionally cause operational disturbances, the digesters provide a substantial cost saving to Tembec's mill. We propose to develop strategies to extend the range of in-mill wastewater streams that can be fed to anaerobic digesters. Further, we want to investigate the potential of anaerobic treatment of solubilized biosludge generated in pulp and paper mills. If a wider range of organic wastes could be anaerobically digested, the incentive for mills to install anaerobic reactors would significantly rise. To address these issues we propose to investigate various methods of pretreatment to enhance the anaerobic digestibility of recalcitrant wastewaterand sludge. We will investigate enzymatic, hydrothermal, and hydrodynamic pretreatment in terms of digestibility, removal rate of organic matter, as well as biogas production. Furthermore, we will study and optimize the anaerobic process in pulp and paper mill digesters by means of laboratory studies using lab-scale reactors, a monitoring study involving the digesters from our industrial collaborators, as well as various cutting-edge research analysis tools. The results of this project will allow Canadian pulp to notably save waste treatment costs and at the same time contribute to a greener, more sustainable future of this industry.