NOVELTY - Producing (M1) fermentable sugars and acetic acid from a biomass-derived extract involves: clarifying a liquid extract produced during steam or hot-water cooking of biomass, where the liquid extract comprises hemicelluloses, acetic acid, dissolved lignin, and suspended solids by sedimentation/centrifugation; introducing clarified extract to ultrafiltration unit; introducing ultrafiltration permeate to nanofiltration unit; introducing nanofiltration permeate to reverse-osmosis membrane and introducing nanofiltration concentrate to a hydrolysis reactor.    USE - For producing fermentable sugars and acetic acid from a biomass-derived extract for producing alcohol (selected from ethanol or butanol) and acetic acid from a biomass-derived extract; and for producing acetic acid from a biomass-derived extract (all claimed); for post treatment of effluent from forest product or food or beverage plant.    ADVANTAGE - The method is integrated with the host plant process to minimize the effect of loss of heat value from the extracted hemicelluloses and eliminate the need for the waste water treatment plant.    DETAILED DESCRIPTION - Producing (M1) fermentable sugars and acetic acid from a biomass-derived extract involves: a) providing a liquid extract produced during steam or hot-water cooking of biomass, where the liquid extract comprises hemicelluloses, acetic acid, dissolved lignin, and suspended solids; b) clarifying the liquid extract by sedimentation or centrifugation for removing the suspended solids, to produce a clarified extract comprising the hemicelluloses and the acetic acid; c) introducing the clarified extract to an ultrafiltration unit for removing the dissolved lignin with a molecular-weight cutoff range of 3000-10000 g/mol, to produce an ultrafiltration concentrate comprising the dissolved lignin and ultrafiltration permeate comprising the hemicelluloses and the acetic acid; d) introducing the ultrafiltration permeate to a nanofiltration unit for removing the hemicelluloses, to produce a nanofiltration concentrate comprising the hemicelluloses and nanofiltration permeate comprising the acetic acid; e) introducing the nanofiltration permeate to a reverse-osmosis membrane, to produce a reverse-osmosis permeate comprising water and reverse-osmosis concentrate comprising the acetic acid; and f) introducing the nanofiltration concentrate to a hydrolysis reactor, to produce a hydrolyzate comprising fermentable sugars. INDEPENDENT CLAIMS are included for the following:    (1) producing (M2) an alcohol and acetic acid from a biomass-derived extract involving: the steps a)-f) and g) fermenting the fermentable sugars to an alcohol; and    (2) producing (M3) acetic acid from a biomass-derived extract involving: the steps a)-e) and recovering the acetic acid.