WASTE-WATER TREATMENT WITH UPFLOW ANAEROB IC SLUDGE BLANKET REACTORS IN THE SUGAR-INDUSTRY

Waste water treatment in the sugar industry has so far found little us e for the upflow anaerobic sludge blanket (UASB) reactor because of th e added lime in the flume and wash water circuit. This paper shows tha t lime precipitations can be controlled provided that the Ca2+ ion con centration in the reactor feed is held to no more than 2000 mg/l and c ertain process steps are observed. Thanks to the development of granul ated mud pellets with higher biomass density and activity, greater mec hanical stability and better settling eficiency, compared with mud flo ccules, and the three-phase separator incorporated in the reactor, the effluence of anaerobic mud particles is largely avoided. This makes p ossible volume loads of 15 kg COD/(m3 . d) with digestion rates of up to 95% and stable operation of the reactor.