Anaerobic digestion of pulp and paper mill solid wastes: Evaluation of operational parameters and microbial diversity.

摘要

Large portions of pulp and paper mill solid wastes are currently land filled or incinerated. These methods are not viable in the long term. Anaerobic digestion has been proven effective in the treatment of municipal solid wastes and sewage sludge, with minimal environmental impact, and with the added benefit of production of a fuel (natural gas). Laboratory scale tests were performed to determine the anaerobic capacity of pulp and paper mill solid wastes, and to determine the feasibility of operating the process on an industrial scale. A simple mesophilic batch reactor was designed for the study. Optimal operational parameters were determined. An inoculum was developed using a simple enrichment protocol. Under optimal conditions, the mesophilic batch reactors were able to convert up to 80% of the organic matter content into methane and carbon dioxide. The remaining material can be used as a soil amendment after a short aerobic incubation period. Knowledge of the microbial population in the digester is necessary to control the performance of the reactor, and to optimize its capability. The microbial groups present in the pulp and paper mill solid waste digesters were determined over the life of the digestion process. The populations were found to be very similar to the populations in a fluidized bed reactor treating wine waste, but very different from a UASB (Upward flow Anaerobic Sludge Blanket) reactor fed artificial wastewater.