Effect of Different Inoculum/Substrate Ratios on Anaerobic Digestion of Pulp and Paper Mill Sludge

Pulp and paper industry is considered as one of the most polluted industry in the world and also energy and water intensive. Paper industry produce huge amount of wastewater, hence sludge production is a major issue. Conventional sludge management methods such as landfilling produce leachate and incineration emits greenhouse gases, therefore public opposition and strict regulatory pressure have been perceived in many countries. Anaerobic digestion a versatile technology for alternative disposal options. The aim of this study was to evaluate the effect of different inoculum/substrate (I/S) ratio on the anaerobic digestion of pulp and paper mill sludge (PPMS). A laboratory scale reactor was used to analyses the four different I/S ratio varies from 1.0 to 2.5 plus control on VS basis were used for this study. The different parameter i.e. pH, volatile solid, volatile fatty acid and cumulative methane production from different I/S mixture was measured and it was observed that the maximum methane production of 3329 mL was achieved in I/S ratio 2.0. Hence the study concluded that I/S ratio of 2.0 was good for better methane production.