Performance evaluation of up-flow anaerobic sludge blanket (UASB) reactor for treatment of paper mill wastewater

The present study deals with the performance evaluation of the UASB reactor under varied organic loading rate (OLR) for the treatment of paper mill wastewater. The sludge granulation process started after 120 days from the start-up period. Sludge granules size was found to be 0.8 mm at OLR of 1.72 kgCOD/(m3 x d), which reached maximum size of about 1.0 to 1.2 mm at OLR of 2.1 kgCOD/(m3 x d). At the end of initial OLR of 1.0 kgCOD/(m3 x d) the VSS concentration was 12.86 gVSS/L, which got increased to 38.05 gVSS/L at the end of an OLR 2.1 kgCOD/( m3 x d). Most of the times VFA recorded were well within the limit of VFA reported in anaerobic fermentation process. Many times the pH observed was between 6.5 and 7.8, which is more favorable for any anaerobic process. It is also found that pH within the reactor increases along with the height of reactor. The total maximum biogas production was found to be 0.40 L/gCOD removals at OLR of 2.1 kgCOD/(m3 x d) and the maximum BOD removal at this stage was observed to be 90%.