ANAEROBIC TREATMENT OF BREWERY WASTE-WATER USING UASB REACTORS SEEDEDWITH ACTIVATED-SLUDGE

In this study, two upflow anaerobic sludge blanket (UASB) reactors see ded with aerobic activated sludge were used to treat brewery wastewate r. The reactors were identical in design and were continuously operate d at 19-24 degrees C. Reactor A war seeded with 1.98 g volatile suspen ded solids (VSS) per liter of acclimatized activated sludge, while Rea ctor B was seeded with 1.98 g VSS l(-1) of acclimatized sludge and 3.9 5 g VSS l(-1) of unacclimatized sludge (a total of 5.93 g VSS l(-1)). The study examined reactor performance in terms of treatment efficienc y and methane production under different hydraulic retention times (HR T) and organic loading rates, and evaluated the effect of amount of se ed sludge on reactor start-up and performance. The results indicate th at as the chemical oxygen demand (COD) loading rate increases with tim e, the influence of the amount of seed sludge becomes more pronounced. Reactor B consistently out-performed Reactor A under shorter HRTs of 1.5 days to 12 h with maximum COD and VSS removal rates of 91% and 81% , respectively at a sludge lending rare of 0.25 g COD g(-1) VSS day(-1 ) anti an HRT of 18 h. The results also confirm that an acclimation pe riod of at least 2 weeks is necessary to prevent delays in the start-u p process when using activated sludge as seed. Using 5.93 g VSS l(-1) of activated sludge as seed enabled Reactor B to achieve satisfactory, performance. (C) 1998 Published by Elsevier Science Ltd. All rights r eserved.