Distillieries - Environmental Clearance

Distilleries11 Phosphorous 200 – 300 300 – 500 1600 – 2000 mg/L12 Sodium 400 – 600 1400 – 1500 1200 – 1500 mg/L13 Calcium 2000 – 3500 4500 – 6000 5000 – 6500 mg/LSource: Draft report prepared on “Development of Methodology for Environmental Auditing” byDr. B. Subba Rao of EPRF, Sangli, for CPCB.The spent lees obtained from the bottom of the rectification column after separation ofalcohol is about 2% of the spent wash, the characteristics of spent lees is given in thefollowing Table 3-9.Table 3-9: Characteristics of Spent LeesS.No Parameter Range1 pH 3.6 – 4.52 COD 5000 - 6000 mg/L3 BOD 200 – 300 mg/L4 Total SolidsDissolved SolidsSuspended Solids5000 – 6000 mg/L500 – 1000 mg/L5 Chlorides 50 – 100 mg/LSource: Draft report prepared on “Development of Methodology for Environmental Auditing” byDr. B. Subba Rao of EPRF, Sangli, for CPCB3.4.2 Rectified spiritMolasses-based distilleries are more common in India. The main process steps in thisoperation are graphically shown in Figure 3-3 and listed below. However, the detaileddescription of the manufacturing process for rectified spirit is given in Annexure I.Dilution - Preparation of molasses for fermentationFermentation - Production of alcohol from fermentable sugars in molasses solutionDistillation - Product recoveryDilutionMolasses available from Indian sugar mills has a solid content varying between 76 and90% while the total sugar content varies between 45 and 55%.The main dilution operation occurs in a diluter where the solid concentration is broughtdown to 20-25° Brix. The bulk of this diluted molasses is fed to the fermentation tankwhile a small quantity is further diluted to 10-15° Brix and used for preparation of thefinal yeast inoculum. Propagation of yeast for the final inoculation is done in successivestages in volumes of 10, 100, 1000 and 10,000 litres where, in each stage, 10 parts ofdiluted molasses is inoculated with 1 part of yeast culture.FermentationFermentation in the fermentation tank continues for about 30 to 45 hours after the finalinoculum is added to it. The basic reaction in the fermentation process is exothermic.TGM for Distillery Industry 3-14 August 2010