Anaerobic treatment of brewery wastewater using a UASB reactor seeded with activated sludge

The start-up of two upflow anareobic sludge blanket (UASB) reactors seeded with aerobic activated sludge and treating brewery wastewater is presented in this thesis. Both reactors were identical in design and were continuously operated at 19 - 23 ° C. Reactor A was seeded with 1.98 g VSS/1 of reactor, while Reactor B was seeded with 5.93 g VSS/1 of reactor. The reactors were first operated at a hydraulic retention time of 5 days. The hydraulic retention time was then reduced in a step-wise fashion to 3 days, 1.5 days, 18 hours then 12 hours in order to increase the organic loading rate. This method of increasing the organic loading rate by decreasing the hydraulic retention time allows for higher liquid upflow velocities which act as a selection pressure to retain better settling sludge in the reactor while washing out the poorer quality sludge. The waste strength varied from 600 to 5600 mg/1, and the average organic loading rate ranged from 0.39 g COD/l/d to 3.62 g COD/l/d. The average sludge loading rate was different for both reactors since each was seeded with a different amount of sludge. The sludge loading rate ranged from 0.20 to 3.67 g COD/g VSS/d for Reactor A and from 0.07 to 0.58 g COD/g VSS/d for Reactor B. The maximum methane production rate achieved was 0.98 1 CH4 /l/d for Reactor A and 1.33 1 Cltyl/d for Reactor B, with COD removal rates of 69% and 89%, respectively, at the maximum organic loading rate of 4.27 g COD/l/d and hydraulic retention time of 12 hours.Applied Science, Faculty ofChemical and Biological Engineering, Department ofGraduat