Effect of black liquor on the activated sludge process: An experimental investigation of the effect of black liquor on the activated sludge treatment of bleached kraft mill effluents.

摘要

The Activated Sludge Process is the most widely used wastewater treatment process in the pulp and paper industry. Black liquor from the Kraft Pulping Process is characterized by high inorganic and organic load; it also contains toxic compounds. Upsets in the plant operation lead to disturbances in the activated sludge process and the process fails to produce effluents that meet regulatory standards. In this project, the effect of black liquor on the activated sludge was studied.;Experiments were carried out in batch reactors and growth kinetics for the activated sludge were studied for each condition. In addition, the removal of chemical oxygen demand (COD), total organic carbon (TOC) and soluble lignin was studied with respect to time. Results from initial rate were compared. Characterization of activated sludge was done using the 'Biolog' technique. An attempt was made to correlate the results of the kinetic study and the activated sludge population.;Results from the specific rates indicate that for 0% black liquor, initial specific rates of COD (or TOC) removal (or the activity of microorganisms) were different for different initial biomass concentration. This trend however was not clear for the black liquor concentrations. For all conditions of biomass concentration, the specific rate was nearly the same. Due to the toxicity of black liquor, microorganisms that can survive the toxicity shock or those that can adapt to black liquor, may lead to a similar population in the system resulting in the same specific rate or the activity of the microorganisms. This was confirmed by the sludge characterization technique.