Acetate treatment in 70C upflow anaerobic sludge-blanket (UASB) reactors: start-up with thermophilic inocula and the kinetics of the UASB sludges

Two reactors were inoculated with a mixture of granulated sludges prior to feeding with sodium acetate solutions, one of which contained yeast extract, with controlled pH values. This experimental work was directed at developing and applying thermophilic anaerobic processes as an internal purification method for closed water circuits in pulp and paper production (where process temperatures of about 70C were used) and also for the treatment of the organic fraction of municipal solid waste. The maximal reductions in COD were 84 per cent for the feed that contained yeast and 71 per cent for the feed that contained no such supplement. Specific methane yield was maximized for UASB sludges formed at 70C with an acetate content of 4.6 mM. Overall, the treatment procedure was practical and reliable for UASB reactors operating at 70C. There are 32 references.