Start-Up Performance of Hybrid Up-Flow Anaerobic Sludge Blanket Reactor Treating Pulp and Paper Mill Effluent

A study was performed on hybrid up-flow anaerobic sludge blanket reactor to identify the start-up time and optimum HRT required for treatment of pulp and paper mill wastewater. Initially, the reactor was loaded at an OLR of 0.117 kg COD/m³.hr and HRT of 24h. Loading rates were increased by reducing HRT 24, 20, 16, 14, 12, 10, 8, 6h, which corresponds to the OLR of 0.117, 0.141, 0.175, 0.201, 0.233, 0.294, 0.348, 0.458 kg COD/m³.h. An optimum HRT of 8 h, HUASB reactor shows COD and TSS removal efficiency of 80% and 85% respectively. When HRT was reduced beyond 8h, lower COD removal efficiency of 71% and TSS removal efficiency of 70% were observed. Finally, the reactor took 120 days for complete start-up. The granule formation was observed inside the reactor by drawing the sample along the port, which shows sizes of 1-2 mm.