Recovering by-products in a brewery.
Measures that can be taken to recover by-products and treat effluent are illustrated by reference to a brewery producing 2200 brews (O.G. 14 degree P) of 600 hl annually. The annual savings made at each stage during brewing and packing are given (in US dollars) together with the capital investment costs involved in setting up recovery procedures. Savings are produced by removal of dust (2% to 7% of malt) from malt during transport to storage, transfer to milling and the milling process (53,846), processing of spent grains (671,794), last runnings and whirlpool trub (68,000), waste in pumping wort during cooling (33,974), fermentation and maturation yeast (94,230), beer rests from fermentation and maturation (192,307), transferring of beer to storage and bottling (89,102), diatomaceous earth from beer filtration (23,076), bottling (22,435), recovery of caustic soda and label pulp (58,333) and recovery of glass (12,179). These recoveries have produced in addition, a substantial reduction in the COD level of effluent with an associated saving in the cost of effluent treatment. Capital investment would be required for the recovery procedures, last runnings and whirlpool trub (90,153), diatomaceous earth from beer filtration (32,051) and bottling (16,025). Further savings could be made by setting up an aerobic treatment plant to handle the residue from pressing husk, the wastage from extracting alcohol, cellar waste and soap resulting from conveyor lubrication. The plant needed and the capital costs and savings involved have been estimated.
Keywords : air anaerobic brewery by-products costs economisation effluent pollution recovery treatment