Abstract

ABSTRACT

Anaerobic Batch Treatment of Carbon Dioxide in Pulp and Paper Effluent
Xuejiao Jiang.
Concordia University, 2013

The increasing concentration of carbon dioxide (CO2), the most dominant component of greenhouse gases (GHG) in the atmosphere, has been of growing concern for many years. Since the beginning of the industrial revolution, atmospheric concentration of carbon dioxide has increased dramatically due to human activities. Many methods have been applied to reduce atmospheric CO2 concentrations, including capture, sequestration, and reduction of carbon dioxide emissions. However, these methods have proved to be not efficient or economical.

The pulp and paper industry is highly pollution and energy intensive. The pulp and paper manufacturing process contributes significant amounts of pollutants that are released to the environment. The Kraft wastewater from the pulp and paper industry has high COD levels, ranging from 1000 mg/L to 33600 mg/L, and feasible to be treated by anaerobic digestion.


Anaerobic digestion has been applied in this study. In this method, CO2 is converted to methane as a biogas during the biological treatment of industrial pulp and paper wastewater. The final step of anaerobic digestion is to use CO2 and hydrogen or acetic acid to produce methane. In order to know the feasibility of CO2 removal by this method, a series of batch tests on pulp and paper wastewater were performed. To determine the optimum conditions, the impact of different pH values (6.5, 7.0, 7.5) and temperatures (20, 30, 35ºC) on the efficiency of CO2 and COD removal and methane production was investigated. The efficiency of CO2 removal was found to be 66-90%, while the removal of COD ranged from 32% to 49%. The optimum conditions for the removal of both COD and CO2 were established at pH 6.5 and 35ºC. The methane generation rates ranged from 4 mL/d to 19 mL/d. The optimum conditions for the maximum generation of methane were found to be the temperature of 35ºC and pH 6.5 along with the injection of carbon dioxide. In conclusion, the applied method was shown to be applicable for CO2 removal, while producing biogas as a clean source of energy.