Stillage as by-product of alcoholic fermentation

Abstract

Processes of bioethanol production from sugars, starch or cellulose produce enormous amounts of stillage (about 20 dm3 per dm3 ethanol), as a by-product. Chemically, stillage is an aqueous solution of different products obtained by alcoholic fermentation. Stillage has a high chemical oxygen demand (higher than 100 g/dm3) and is considered to be a potentially dangerous pollutant of the environment. For the processes of bioethanol production called "healthy energy", treatment and use of stillage is of great importance. This work reviews treatment processes by which stillage is converted into valuable products or feedstocks. The special attention is paid to the treatment processes which enable reuse of stillage. .

U postupku dobijanja bioetanola iz šećernih, skrobnih ili celuloznih sirovina nastaje, kao sporedni proizvod, velika količina džibre (oko 20 dm3 po dm3 etanola). Po sastavu, džibra je vodeni rastvor ostataka nakon destilacije fermentacione komine. Džibra ima veliku vrednost hemijske potrošnje kiseonika (veću od 100 g/dm3) i predstavlja potencijalno opasnog zagađivača životne sredine. Za proizvodnju etanola u procesima za dobijanje "zdrave energije" od značaja je tretman i upotreba džibre. U ovom radu je dat pregled postupaka obrade džibre u cilju njenog iskorišćenja i prevođenja u vredne proizvode ili kao sirovina za različite procese. Posebna pažnja je posvećena tehnološkim postupcima kojima se džibra vraća u proces. .