A further study of the anaerobic biotreatment of malt whisky distillery pot ale using an UASB system

Pot ale from a pilot-scale malt whisky distillery was treated using a mesop hilic upflow anaerobic sludge blanket (UASB) digester. Stable operation was observed at organic loading rates (OLRs) of 5.46 kg COD/m(3) day or less w hen the pot ale was diluted with tap water. Digester failure occurred when undiluted pot ale was used, even though OLR was less than 5 kg COD/m(3) day . Overall performance was worse than that observed previously when UASB dig esters were used to treat pot ale from a different source supplemented with trace elements. A substantial proportion of effluent chemical oxygen deman d (COD) was present as volatile fatty acids (VFA), particularly during peri ods of reactor stress, indicating that overall performance was limited by t he rate of VFA conversion. Wastewater alkalinity rose during digestion. The sludge which developed in the reactor was flocculent but did not form comp act granules. (C) 2001 Elsevier Science Ltd. All rights reserved.