A new clean technology was applied in the ethanol
production industry to eli&ate the end of pipe technology
currently being used for the treatment of distillery
waste (stillage). By introducing a membrane separation
process, the distillery waste could be recycled to
the fermentation step and a zero-discharge system as
far as stillage is concerned could be established. This
new process gave a little longer fermentation time, but
the average ethanol production yield (8.8%) was similar
to that in the conventional process (9.0%). This process