Whey arising from cheese and casein manufacture has a BOD of 35-45 kg
m-3 and must be treated prior to disposal. Bioconversion of lactose in
whey to ethanol, yeast biomass or methane has been used to produce sa
leable products whilst reducing the organic load by greater than 75%.
Higher BOD reductions can be achieved by combined processes, such as m
ethane production from whey distillery effluents, but in most cases so
me aerobic treatment prior to final disposal is also required. The eco
nomics of such bioconversions can be favourable but market opportuniti
es for other products and the demands of whey processing have limited
the adoption of these technologies by the dairy industry.