ABSTRACT
Industrialization and sustainable development are the essential needs of developing as well as developed countries. Molasses-based distilleries are one among the major industries that expel huge quantities of high-strength wastewater that has extreme potential toward causing tremendous water pollution. Spent wash is generally characterized by an unpleasant odor and highly recalcitrant dark brown color. Bioethanol distillation produces a highly concentrated effluent called vinasse or stillage in a ratio of 12:15 L of vinasse per liter of ethanol. To date, a significant number of physicochemical and biological distillery effluent treatment processes have been reported in the literature. Among the various treatment methods, anaerobic digestion is the most studied process for the treatment of spent wash/raw effluent due to its high content of biodegradable organic matter, which can be converted into biogas. This biogas could meet the energy demands of the treatment system or unit. Anaerobic treatment of industrial wastewater saves energy, generates energy in the form of methane, and produces only a small amount of excess sludge. The distillery industry generates a lot of wastewater from its processing and most distilleries end up disposing their untreated effluent into water bodies causing environmental threats to aquatic life due to high levels of biological contaminants. The objectives of this chapter are to discuss the role of different types of bioreactors such as anaerobic fluidized bed reactors, anaerobic fixed film reactors, expanded granular sludge bed (EGSB) reactors, upflow anaerobic sludge blanket (UASB) reactors, granular-bed anaerobic baffled reactor, high-rate anaerobic reactors in treatment of wastewater discharges from distilleries. This chapter also covers the basic configurations and working principles of the above-mentioned bioreactors along with their applications and limitations.
