Distillery Industry Waste and Its Treatment

Distillery Industry Waste and Its Treatment

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  Distillery Industry Wasteand Its Treatment By- Lakhan Kumar Department of Biotechnology
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  Distillery Industries Wastes •The distilleries using molasses, a bye-product of sugar industry, for production of alcohol by fermentation and distillation process, generate highly organic and colored wastewater. • Considered as one of the most polluting industries. • Total waste volume is 6O to 100 litres per litre of alcohol produced. • The waste streams comprises spent wash, which is the main source of the waste water, spent lees and yeast sludge.
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  Continued…. • Spent leesis usually mixed with the spent wash. • In the production of alcohol from molasses, 3 to 10 kg of molasses are used for producing 1 litre of alcohol and for each litre of alcohol about 10 to 15 litres of spent wash is produced. • The distillery spent wash is hot, highly coloured and acidic, apart from containing high percentage of dissolved inorganic and organic matter, the latter being particularly responsible for high biochemical oxygen demand ( BOD ) and the polluting nature of the waste. • Spent wash, contains dissolved salts and has a persistent dark brown color.
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  Spent lees The sedimentof wine in barrels or the remnants of a liquid left in container, together with any sediment.
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  Yeast sludge • Yeastsludge containing about 30 percent solids settles down in the fermentation vats and constitutes a major source of waste. • The yeast sludge is disposed separately after drying. • In addition, waste water may be generating from Bottling, Fermentation tank cooling and washing and Utility section of the plant which is used as a diluent for the treated spent wash.
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  Sources of wastewater Ina distillery, sources of wastewater are • Stillage, • Fermenter and • Condenser • Cooling water and • Fermenter wastewater.
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  Treatment and managementof wastewater • The technology currently used by distilleries for treatment of waste water are biomethanation followed by two stage biological treatment and disposal in water courses or for utilization on land for irrigation, composting with or without biomethantion and concentration and incineration. • These technologies treat the waste water up to a certain level. • These are unable to remove total dissolved solids as well as colour to safe and acceptable limits for disposal into surface water or on land.
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  Characteristics of DistilleryWastewater Indian Standard guide for treatment of distillery effluents Management of distillery wastewater by CPCB.
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  Methods of treatment •Biological treatment: Distillery wastes are amenable to biological treatment, both anaerobic and aerobic. Since distillery wastes are of high biochemical oxygen demand, normally anaerobic treatment precedes any aerobic biological treatment. a) Anaerobic Processes - The anaerobic treatment of distillery wastes can be either anaerobic digestion or anaerobic lagooning. i. Anaerobic digestion: An excellent method of reducing about 90 percent of the biochemical oxygen demand of distillery waste, and a burnable gas containing high percentage of methane is also recovered as a by-product from this process. ii. Anaerobic lagooning - Anaerobic lagooning is cheap and effective method of treatment of distillery wastes. Subbarao reported 95 percent biochemical oxygen demand reduction in an anaerobic lagoon treating distillery wastes. (Subbarao ( B A ). Technical report on sugar distillery industry waste disposal. 1971. Walchand College of Engineering, Sangli.)
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  Biological treatment continued…. b)Aerobic Processes: The conventional aerobic biological processes, namely, trickling filters and activated sludge units have been adopted for treatment of distillery wastes. Extended aeration can also be adopted for treating these wastes. i. Trickling filters - Trickling filters, single-stage or two- stage, are adopted for treating either diluted distillery waste or pretreated distillery waste. Deep trickling filters made of plastics media are found to be useful in treating concentrated organic wastes including distillery wastes ii. Activated sludge process -The performance of activated sludge and extended aeration plants for treating diluted or pretreated distillery waste has been reported.
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  Disposal to Water Course •The spent wash may be treated by anaerobic process followed by one of the aerobic processes, such as extended aeration, activated sludge process, trickling filtration or aerated lagooning and diluted with condenser waters to keep the BOD of the final effluent below 100 mg/l before disposing of into a water course ( see Fig. ). • It may be necessary to dilute the influent to the aerobic processes. This can be done by using part of the condenser water. • If suspended solids in the spent wash are high then it is useful to separate them, dry and incinerate them or dispose of on land. The settled spent wash can then to be taken for biological treatment.
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  Land disposal The spentwash may be treated by an anaerobic process such as anaerobic digestion or anaerobic lagooning followed by an aerobic process such as activated sludge process, trickling filtration, or aerated lagooning and the treated effuent diluted to have a biochemical oxygen demand of less than 500 mg/l and used for irrigation or disposed of on land.
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  Other methods • Physicalmethods: includes Sedimentation, Screening, Aeration, Filtration (Membrane Technologies), and Flotation. • Chemical methods: includes Chlorination, Coagulation, Adsorption, and Ion Exchange.
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  Thank you….!