A study of the effects of methanol in start-up of Uasb reactors

Upflow anaerobic sludge blanket reactors were started up, using a stepped loading regime, on a dairy waste prepared from raw ice-cream production waste from an ice-cream manufacturing plant. One UA SB was supplemented with methanol. Granules were detected in the methanol-fed UA SB at 3 weeks after start-up. The maximum load of 6.7 kgCO D m - 3 day- 1 with an HR T of 0.75 days could not be sustained during the 73 days of operation. Complete granulation had, however, occurred by the 4th week. Methanol addition at start-up aided rapid biomass granulation, and enhanced the settling velocity and specific activity of the sludge. However, wash-out was severe and residual biomass was sensitive to methanol withdrawal and produced no net growth