ZO/BPL/Distillery/ / Date: April 19, 2011

Transcription

1 ZO/BPL/Distillery/ / Date: April 19, 2011 To The Member Secretary Central Pollution Control Board Parivesh Bhawan East Arjun Nagar Delhi Sub: Report on Assessment of grain based fermentation technology, waste treatment options, disposal of treated effluents Sir, As per the Annual Action Plan , a detailed study of Assessment of grain based fermentation technology, waste treatment options, disposal of treated effluents has been completed by this office. The report is enclosed for your kind perusal. Yours faithfully (S. Suresh) Zonal Officer Encl: As above. Page 1 of 37

2 A Report On Assessment of grain based fermentation technology, waste treatment options, disposal of treated effluents Central Pollution Control Board Central Zonal Office Bhopal Page 2 of 37

3 Report On Assessment of grain based fermentation technology, waste treatment options, disposal of treated effluents Principal Coordinator : Sh. S. Suresh, Zonal Officer Coordinator : Sh. P. Jagan, Scientist C Sh. Sunil Kr Meena, Scientist B Monitoring Team : Sh. Sunil Kr Meena, Scientist B Dr Anoop Chaturvedi, JSA Report Compilation : Sh. Sunil Kr Meena, Scientist B Ms. Anamika Singh, SSA Type Set By : Sh. Sunil Kr Meena, Scientist B Page 3 of 37

4 Contents S. No Details Page no. 1 Map Showing the Locations of Distilleries in Central Zone (State-wise) Abstract Introduction Process details Grain based distillery units Effluent treatment technologies Conclusions Annexures I Process flow diagram for Grain based alcohol plant II Effluent treatment Schematic diagram for Grain based alcohol plant Case Studies 01: M/s United Spirits Limited, Udaipur (Rajasthan) Case Studies 02:M/s Bhatia Wine Merchant s Pvt Ltd, Bilaspur,(Chattisgarh) Case Studies 03: M/s Gwalior Distillers Ltd., Rairu, Gwalior (Madhya Pradesh) Page 4 of 37

5 Map Showing the Locations of Distilleries in Rajasthan Page 5 of 37

6 Map Showing the Locations of Distilleries in Madhya Pradesh Page 6 of 37

7 Map Showing the Locations of Distilleries in Chattisgarh Page 7 of 37

8 Central Pollution Control Board Zonal Office Bhopal Assessment of grain based fermentation technology, waste treatment options, disposal of treated effluents Abstract Management of industrial waste is one of the most critical environmental problems faced by the world. It s become costly as well as difficult to treat the variety of wastewater pollutants generated through various industrial processes. Wastewater characteristics and levels of pollutants vary significantly from industry to industry. Now-a-days emphasis is laid on waste minimization and revenue generation through byproduct recovery. Pollution prevention focuses on preventing the generation of wastes, while waste minimization refers to reducing the volume or toxicity of hazardous wastes by water recycling and reuse, and process modifications and the byproduct recovery as a fall out of manufacturing process creates ample scope for revenue generation thereby offsetting the costs substantially. Critical environmental problems raised because of Red Category Molassas based distilleries due to its very high Biological Oxygen Demand (BOD 40,000-65,000mg/l), Chemical Oxygen Demand (COD 80,000-1,40,000 mg/l), inorganic impurities & dark brown color presence in spent wash. Lots of conventional effluent treatment technologies recommended Page 8 of 37

9 e.g. Anaerobic treatment of spent wash to generate biogas, aerobic surface composting to manufacture bio-compost and reverse osmosis or multiple effect evaporation systems for concentration of spent wash but the performance of treatment is very poor. It s become very tough to achieve the Environment (P) Act, 1986 prescribed standards & to follow the Corporate Responsibility for Environmental Pollution (CREP). Many molassas based distillery units are switching to grain based distillery process because of low COD 40,000-50,000mg/l load of Raw Spent Wash. Guidelines of effluent discharge & CREP for grain based distillery units is yet to come. CPCB Zonal Office Bhopal has taken up the performance study of grain based distillery units of Central Zone to assess the current pollution status. It is suggested to have the new grain based guidelines as notification to have the proper check on distilleries. Page 9 of 37

10 Introduction Alcohol has assumed very important place in the Country s economy. It is a vital raw material for a number of chemicals and become the source of large amount of revenue for government as Excise Duty. In India about 350 distillery units of 4.0 billion litres & 100 distillery units of 1.8 billion litres are molasses & grain based respectively. Typical Indian C heavy massecuites byproduct of Sugar industries is being used as raw material in molasses based distilleries. Potatoes, Rice, Maize, Malt, Wheat, Barley, Sugarcane & Sugarbeet are various raw materials used in grain based distilleries. Molasses based distilleries in India are classified as Red Category because of the large volume of high strength waste water (spent wash) generation (12-15 litres per litre of alcohol). Spent wash has very high Biological Oxygen Demand (BOD 40,000-65,000mg/l), Chemical Oxygen Demand (COD 80,000-1,40,000 mg/l) and high BOD/COD ratio. The high amount of inorganic impurities as Chlorides, Sulphates, Phosphates, Potassium and Calcium arise critical environmental pollution. Its recalcitrant nature is due the presence of melanoidins, ceramal, polyphenols and variety of sugar decomposition products such as anthocyanin, tannins and different xenobiotic compounds. The unpleasant odour of the effluent is due to the presence of skatole, indole and other sulphur compounds, which are not effectively decomposed during fermentation and distillation. Melanoidins are formed by Millard amino carbonyl reaction and have antioxidant properties, which make them toxic to many microorganisms. The high COD, total nitrogen and phosphate content of spent wash can result in eutrophication of natural water bodies. The highly colored compounds of the spent wash reduce sunlight penetration in water bodies, which in turn decrease both photosynthesis activity and dissolved oxygen concentration affecting aquatic life. Application of spent wash is also hazardous to the vegetation; reduce soil alkalinity and manganese availability result in seed germination inhibition. Use of biomethanated spent wash for irrigation without proper monitoring can affect groundwater quality by altering its physiochemical properties such as colour, ph, electrical conductivity etc. due to leaching down of organic and inorganic ions. Page 10 of 37

11 To treat the generated effluent effectively many technologies has already been approved by CPCB. Anaerobic treatment of spent wash to generate biogas, aerobic surface composting to manufacture bio-compost and reverse osmosis or multiple effect evaporation systems for concentration of spent wash. The existing treatment technologies and their short-falls are as below: 1. Anaerobic Digester followed by controlled land application. 2. Anaerobic Digester followed by anaerobic filter, two stage aerobic treatment and dilution with fresh water and applied on land as ferti-irrigation. Controlled land application appears to be one of the viable alternatives if it is practiced scientifically. The protocol developed by CPCB is based on the practices followed in other parts of the world with a great success and also studies carried out by Agricultural Universities in India. However, the Regulating Agencies feel that Controlled Land Application is not practicable as monitoring and controls are very difficult, even though the task was entrusted to Agricultural Universities Anaerobic Digestion followed by controlled land application/ferti-irrigation is not encouraged by the CPCB/SPCB as these technologies are found to pollute land and ground water sources also adoption of ferti-irrigation may not be a feasible alternative as the secondary treatment is not able to yield the desired results. The dilution water requirements are huge to meet irrigation standards. 3. Concentration and Incineration in Boiler o The condensates from evaporators have high COD and require treatment before discharged into environment or recycled as process water. o Sludge from spent wash is to be removed before it is sent to evaporators for concentration. o The sludge requires treatment such as "composting" which is not permitted as per the present protocol. o The operation and maintenance problems of Boilers, especially the clogging of Boiler tubes appear to be very frequent. Page 11 of 37

12 o Some suppliers recommend stand- by Boilers which makes the project very expensive. o Complaints regarding techno-economic viability of these plants are not properly assessed. o The Industry and also the suppliers of these plants are not willing to share the success of the process. o The sustainability of this technology needs to be established 4. Anaerobic Digestion followed by evaporation & composting o The filler material press mud is not available in required quantity o The ratio of press mud to spent wash of 1:2.5 appears to be impracticable. o Needs revision depending on the moisture content of press mud. o The disposal of compost as manure also appears to be difficult in some parts of the Country. o The land requirement is around 0.25 hectares per KL of spirit production which is huge area. o Due to the large requirement of press mud, the technology may not be suitable for large capacity Distilleries. o "Composting" process is not permitted for stand-alone Distilleries as per the present guidelines. o Technology is not allowed for raw spent wash due to the fear that leachate concentrations may be high when raw spent wash is used. o Whenever "composting" process is adopted, the Distillery should not operate during rainy season. o Thus 270 days of operation in a year is only permitted. 5. Recently, the CPCB initiated a project "Co-Incineration" wherein concentrated spent wash is burnt as fuel in Cement/Steel industries along with other fuels/raw materials. Even though, the initial trails appear to be encouraging, the effect of inorganic constituents in spent wash on the finished product is to be assessed. The applicability of the technology for Distilleries which are located far away is to be assessed in terms of cost effectiveness. Page 12 of 37

13 The huge quantities of high toxic spent wash and high COD load makes conventional technologies insufficient to achieve the prescribed standards of inland discharge of treated effluent. In most of the cases, the treated effluent also yields very high BOD, COD, TSS, and TDS level with black colored and odor effluent to rivers & natural water streams. Compared to molasses-based spirit, grain-based spirit is costlier. But, with the rise in price of molasses over the past few years, the cost of production from grain is almost at par with that from molasses. Consequently almost all distilleries who were having only molasses based fermentation have also installed grain based units so as to have continuous operation of the plant. Although the grain based process may escalate the cost of production of alcohol the waste water quality and quantity is reduced. In the financial year an exercise was made to assess the grain based fermentation technology, waste treatment options, disposal of treated effluents from distilleries operating in central zone. In central zone (Madhya Pradesh, Chattisgarh and Rajasthan), there are about 20 distilleries situated. Most of them have switched over to grains from molasses for distillation. Out of them 03 purely grain based distilleries (M/s Gwalior Distilleries Ltd, Gwalior (M.P.), M/s Bhatia Wines Merchant Pvt. Ltd, Bilaspur (C.G.) & M/s Udaipur distillery Co, Udaipur (Raj.)) were inspected to assess their adopted fermentation technology and to study the performance of effluent treatment plants. This study will further guide in conducting studies in remaining distilleries. Page 13 of 37

14 Process details Grain based distillery units Raw material Mostly Broken Rice, Kinki, Millet and Sorghum or mixed grains are being used as raw material in these distillery units. Under table is about the starch percentage & alcohol yield from various grains. Raw material Fermentable Carbohydrate (Starch %) Alcohol yield (Lit. of alcohol/mt) Rice Sorghum Wheat Potato Malt Maize Composition of various grains: Grain Starch Gluten & other substances Dextrin, glucose, etc. Fatty matter Cellulose Inorganic salts (Silica, Phosphates, etc.) Wheat ,50 2,69 Rye Barley Oats Corn Rice Details given in tables state that potato as raw material gives very poor alcohol yield because of the low starch contents. Rice, Sorghum, Wheat & Maize as raw material gives alcohol yield of 30-40% and found very much suitable for fermentation process. Page 14 of 37

15 Process (Raw material milling to distillation of alcohol) Annexure-I Before the milling quality of the grain is being checked. After the quality check grain is cleaned for removal of dust, lumps, sand, stone, iron etc. and finally store in Silo s. Milling: The cleaned grain is sent to milling machines for grinding grain flour (size µ) is conveyed to pre-masher for slurry preparation. In pre-masher, flour & required water of ratio 1:2 are mixed by agitator. Uniform grain slurry is made and transferred to another low shear tank (slurry tank) for proper mixing. In slurry tank required ph of is maintained by using lime if required and temperature as 55 0 C to 60 0 C. An enzyme called α-amylase is added here in small (20-25%) dose before the cooking process starts. Cooking: The grain slurry is pumped to Jet Cooker (Hydro Heater) through open impeller centrifugal pump. In jet cooker steam is applied at 8 to 10 kg/cm 2 pressure to cook the starch slurry to break down the chemical structure of starch in presence of enzymes. The temperature of grain slurry at outlet of jet cooker is maintained between 115 to C. After cooking the grain slurry is passed through the holding coil, which has several U bends in series and sufficient capacity to provide desired retention time at a given flow rate to convert starch into dextrin. In this step slurry pressure & viscosity reduces. The slurry which is hot is transferred into the flash tank to reduce the temperature of the slurry to C before sending to saccharification tank. Flash tank is attached to flash condensers where vapours are condensed and condensate is sent to slurry tank. Liquefaction: Grain slurry is transferred to liquefaction tank from flash tank where remaining 75 to 80% of enzymes of α-amylase is added which convert starch to dextrin and 1-4 α-glycosidase linkages are hydrolyzed into amylose and amylo pectin. Enzymatic activity rapidly breakdown the starch to soluble dextrins and oligosaccharides. To have good conversion of starch to dextrin retention time should be about 2 hrs. Page 15 of 37

16 Saccharification and Fermentation: Many distilleries have Partial Pre- Saccharification tanks for saccharification process. Whereas conducting saccharification and fermentation together is another process adopted. The liquefied slurry pumped through Plate Heat Exchanger (PHE) to the fermenters. The outlet temperature of grain slurry from PHE is 32 to 35 0 C. In fermenters saccharification & fermentation takes place simultaneously by adding glycol-amylase enzyme and yeast culture. Fermentation of starch from grain is somewhat more complex than fermentation of molasses sugars because starch must first be converted to sugar and then to ethanol. Starch is converted enzymatically to glucose either by diastase presents in sprouting grain or by fungal amylase. The resulting dextrose is fermented to ethanol with the aid of yeast producing CO 2 as co-product. A second co-product of unfermented starch, fiber, protein and ash known as distillers grain (a high protein cattle feed) is also produced. Glucoamylase hydrolise dextrin into maltose. In this complete conversion of dextrin takes place and to reduce the viscosity further spent wash after decanter is mixed to save water. Maltose further breaks into glucose & fructose. Yeast i.e. Saccharomyces cerevisiae which produce invertase and zymase enzyme convert glucose & fructose into alcohol. Above both processes takes place in a fermenter. Glucose is converted into ethyl alcohol and carbon dioxide evolved is let out. The total duration required is 60 to 65 hours. The entire material is sent for distillation and yeast sludge in continuous process is settled at bottom is mixed with water and used for fresh batch whereas in Batch process the entire yeast sludge was let out. Due to more fermentation time side byproducts i.e. acids & higher alcohols are high as compared to molasses which affects proper alcoholic fermentation. The pre fermenters are filled with mash and loaded with contents of the yeast vessel. The purpose of the aerated pre-fermentation is to allow time for the yeast cells to multiply (01 gram of dry yeast for 01 litre of Rectified Spirit) and reduce the chances of contamination. When the pre-fermentor contents are transferred to the main fermenters, the concentration of yeast cells is high enough Page 16 of 37

17 to substantially reduce the leg time associated with yeast growth in fermentation process. The overall transformation takes place into three steps: Amylase / Gluco-amylase n(c 6 H 10 O 5 ) + n(h 2 O) n(c 6 H 12 O 6 ) n(162) n(18) n(180) Invertase C 12 H 22 O 11 + H 2 O C 6 H 12 O 6 + C 6 H 12 O Saccharomyces cerevisiae C 6 H 12 O 6 2C 2 H 5 OH + 2CO The speed of this transformation process can be influenced by two elements i.e. temperature and available quantity & quality of water Distillation It s a physical process various compounds of a mixture get separated by virtue of their differences in boiling points. Two types of distillation system are employed in distilleries. I. Atmospheric distillation system: To separate & concentrate the fermented wash to 95% alcohol concentration (rectified spirit), separation of components is carried out at close to atmospheric pressure. There are five columns in this atmospheric distillation system: 1. Degassifying column: The distillation column consist number of bubble cap plates where wash is boiled and alcoholic vapours are separated and concentrated on each plate stage by stage. The fermented wash first enters the beer heater, which is a condenser for condensing alcoholic vapours by using wash as cooling medium. The objective of the beer heater is to recover the heat from the hot vapours of alcohol. Fermented wash from the beer heater goes to degassifying column and degasifying column bottom goes to the top plate of the next column. Page 17 of 37

18 2. Wash/Analyzer column: This column consists 18 plates. The steam is admitted through the steam sparger situated at the bottom of the column. As the steam rises up, the wash descending from the top to the bottom of the column gets heated and by the time it reaches to bottom plate, it consist practically no alcohol. The wash going out is called spent wash, which is discharged to the drainpipe. The vapours coming from the wash column now consists approximately 50% alcohol and 50% water with impurities such as higher alcohols, aldehydes, acids, sulfur containing compounds etc. 3. Aldehyde or Heads concentration column: Part of wash column vapours led to heads concentration column where low boiling impurities are separated from spirit which is produced at the rate of 10% of total production depending on the extent of purity required & stored separately. 4. Rectification column & Exhaust column: Other portion of wash column vapours, which is major quantity, is led to rectifying column, consists 44 plates, which helps the removal of bad smelling fusel oil, which is a mixture of higher alcohol. As the vapours coming from wash column rise to the top of rectifying column, the concentration of alcohol goes on increasing & finally it reaches to the concentration of 95.5% alcohol. The alcoholic vapours from rectifying column are condensed in the beer heater against the wash and then in principle condensers and finally in vent condenser using water as coolant. The condensates of all three condensers go back to the top of the rectifying column & uncondensed gasses are let out from the top & cooled in alcohol cooler & taken out as a product. The fusel oil which is a mixture of higher alcohol is drawn from the 6 th to 10 th plate from bottom of rectifying column as a stream of vapours; it is condensed, cooled & led into a decanter where it is mixed with water. Fused oil being immiscible with water collects at the top and is decanted through a funnel and sent to storage. The lower portion contains water and Page 18 of 37

19 alcohol and is sent back to wash column for recovery of alcohol. Fusel oil is recovered at the rate of 0.2% of alcohol produced. II Multiple-pressure vacuum distillation system: Vacuum distillation is defined as that in which the operating pressure in the system is either less than atmospheric pressure or more than atmospheric pressure. Vacuum is nothing but sub-atmospheric pressure (negative gauge pressure). Fermented wash to rectified spirit: Multi-pressure vacuum distillation system for production of Rectified Spirit consists of distillation columns namely- 1. Degasifying cum analyzer column- Operation under vaccum 2. Pre-rectification column- Operation under vaccum 3. Rectification cum exhaust column- Operated under pressure 4. Fusel oil concentration column- Operated under atmospheric Fermented wash is preheated in pre-heater and fed at the top of the Analyzer column, which is fitted with thermo-syphon reboiler. Top vapours of analyzer column are spent to pre-rectifier column. Rest of the fermented wash flows down and is taken out as spent wash from analyzer column bottom. Prerectifier/stripper bottom liquid is preheated with thermo-syphon reboiler and fed to rectifier cum exhaust column. Low boiling impurities are concentrated in the pre-rectifier column. A top reflux draw of condenser is taken out as impure alcohol from the top of the pre-rectifier column. Rectifier exhaust is operated under pressure and bottom liquid is preheated with thermo-syphon reboiler. Alcohol is enriched towards the top and is drawn out as Rectified spirit. Fusel oil build up is avoided in the Rectified column by withdrawing side streams of fusel oil is sent to decanter for further separation. The fused oil wash water is recycled back to the column. A top draw is taken out as impure alcohol from the top of fused oil column. Page 19 of 37

20 Fermented wash to extra neutral alcohol (ENA): Multi-pressure vaccum distillation system for production of Extra Neutral Alcohol consists of distillation columns namely- 1. Degasifying-cum-analyzer column- Operation under vaccum 2. Pre-rectification-cum-Exhaust column- Operation under vaccum. 3. Extractive Distillation Column- Operation under pressure 4. Rectifier-cum- Exhaust column- Operated under pressure 5. Recovery/Fused Oil Column- Operated under pressure 6. Simmering Column- Operated under atmospheric or Vaccum Pre-heated fermented wash is fed at the top of the Degassifier column. Analyzer Column is provided with reboiler. Top vapours of analyzer column containing all the alcohol in the wash are sent to Pre-rectifier column and are taken out as spent wash from Analyzer column bottom. Low Boiling impurities are concentrated in the Pre-rectifier column. A draw of impure alcohol is taken out from the top of the Pre-rectifier column. RS draw is taken from the top of Pre-rectifier column, which further is sent to Extractive Distillation (Purifier) column. Dilution water in the ratio of 1:8 to 1:9 is fed to this column. The Extractive Column operates on the principle of inversion of relative volatility. Low boiling impurities are separated in the purifier column & bottom is sent to Rectifier-cum-Exhaust column. The Rectifier/Exhaust Column concentrates the alcohol to 96% v/v. The high- grade spirit is drawn from upper trays of the rectification column. Fusel oil build up is avoided in the Rectifier-cumexhaust column by withdrawing side streams (Fusel oils). Purifier condensates, Degasifier condensates & fusel oil draw from Rectifier/Exhaust column are sent to Recovery column where these fusel oils are concentrated and then sent to decanter where these streams are diluted with Page 20 of 37

21 water and fusel oil rich layer is separated. Washings are sent back to the column to recover alcohol. The high spirit draw from the Rectifier column is sent to the Simmering column where methanol is separated in the form of a cut from the top and ENA is taken out from the bottom. ENA draw from the simmering column is taken to the receiver after cooling in ENA cooler. The steam consumption of this set up would be of about 6.5% of total spirit production. Benefits of pressure vaccum distillation: Following are the advantages of pressure vaccum distillation 1. Since the analyzer column operates under vaccum, the formation of by-products such as acetal may minimize there by improvement in quality of alcohol. 2. Pre-rectification column ensure removal of sulfur compounds/mercaptans and also reduces load of lower boiling volatile compounds passing on to Rectifier-cum-exhaust column. 3. The chances of scaling due to invert solubility of certain precipitating inorganic salts are minimized in vaccum distillation. 4. Vaccum distillation requires low steam consumption with reboiler i.e. 2.2 Kg/lit. of Rectified spirit and 3.2 Kg/lit. of Extra Neutral Alcohol. Distillation System with reboilers: Some of the old atmospheric distillation based as well as all new multi-pressure distillation based distilleries have installed reboilers along with distillation column to concentrate spent wash & reduce effluent generation. Use of reboilers results in indirect heating of distillation columns and restricts the mixing of steam condensate with spent wash. Steam condensate can be recycled as boiler feed water or can be used as process water. Distillation with integrated evaporation system: Integrated evaporation or standalone evaporation systems are now getting installed in few distilleries with an Page 21 of 37

22 intension to concentrate the spent wash as per their requirement. It helps to reduce the final quantity of spent wash generation. Integrated evaporation system uses alcohol vapours as heating media for heating the spent wash. Thus, good amount of steam saving can also be achieved in integrated evaporation systems. Integrated evaporation is expected to concentrate the spent wash to about 22-30% solids concentration depending on the type of fermentation system used and final alcohol concentration in wash. Page 22 of 37

23 Effluent treatment technologies Annexure II The effluent aqueous stream with some dissolved solids and some suspended solids (including fibre) called as raw stillage, is fed to a decanter for separation of suspended solids from clear solution (called thin stillage). The thin stillage is to be further processed to reduce it to soilds. Part of it practicing to be recycled to fermentation to reduce water consumptions in fermentation process. Balance thin stillage is being fed directly to multi effect evaporator (MEE) to reduce the volume of the stream or being fed in Up-flow Anaerobic Sludge Blanket (UASB) for bio-methanation. Bio-methanation is being followed by extended aeration, clarifier effluent treatment technologies and finally stored in lagoons used for ferti-irrigation as par the CREP. In MEE the evaporated water is recycled back to fermentation process and concentrate is mixed with the suspended solids separated in decanter. This mixer is rich in nutrients solids and can be used as animal feed. It is called as distiller s wet grain stillage (DWGS). It has high moisture content and putrefied very easily. It increases the shelf life it is being dried by stream. It is called DDGS (Distillers dried grain stillage). Distillery can achieve the Zero Discharge Limit through adopting MEE. Reverse osmosis (RO), a membrane based separation technique that permits the separation of certain species in a fluid by a combination of sieving & sorption mechanisms. An RO is a high-pressure membrane process (15 kg/cm 2 to 60 kg/cm 2 ) for separating low molecular weight species from a feed stream. The pore size 5-20 Å, typically will reject 99% of most ions & most organics over 150 molecular weight cut off. Incineration of concentrated spent wash: Concentrated spent wash at 55 to 60% solids or spent wash powder can be used to run a specially designed boiler with or without subsidiary fuel. Steam generated can be used to run a steam turbine to generate electricity and exhaust steam can be used for distillery and evaporation plant operation. The overall system becomes self-sustaining after initial stabilization period. This is a zero pollution system with generation of ash from Page 23 of 37

24 spent wash. It has been found that the concentration and incineration system of spent wash disposal is not economical for distilleries below 60 KLPD capacity. The co-processing of spent wash concentrate in cement kiln has been investigated by CPCB and draft guidelines for the same has been prepared. Co-processing of spent wash concentrate in cement kiln has following benefits: (a) (b) (c) (d) Wastes are destroyed at a higher temperature of around C and longer residence time, Inorganic content gets fixed with the clinker apart from using the energy content of the wastes leaving no residue behind The acidic gases, if any generated during co-processing gets neutralized, since the raw material in cement kiln is alkaline in nature, and Such phenomenon also reduces resource requirement. While in case of incineration, residuals require to be disposed suitably. Page 24 of 37

25 Conclusions The outcome of the limited studies conducted by this office could be used at national level to prepare desired action plan in the studies proposed by M/s Vasantdada Sugar Institute, Pune. However, there is a strong need to look into following issues: i. The existing system of treating the effluents till secondary clarifier is not able to meet the standards. ii. The dilution water is not adequate enough to dilute the treated effluent generating from ETP for further usage like ferti-irrigation. iii. The MEE technology adopted seems to be giving good results. However this may be cross checked with cost effectiveness. iv. The monitoring results at M/s United Spirits Ltd., Udaipur indicates that the presence of the algal growth is helping to reduce the COD load. This may further investigated. v. The further augmentation of the treatment system with tertiary treatment could further help in reduction of overall load. vi. The mal-functioning of decantering system is adding to the total load on the treatment system. Hence, there is a need to maintain the decanting system in scientific manner to achieve the better results. vii. viii. The presence of thermophilic micro-organisms consortia in the bio-digester is playing a vital role in the reduction of COD load. The in-depth study of microbial consortia can throw more light on the issue. The possibility of studying micro-algal growth in effective COD reduction requires to be investigated. Page 25 of 37

26 ix. A detailed study of ground water quality assessment on use of treated effluent for ferti-irrigation requires to be conducted. x. The possibility of adding CO 2 to grow algae in lagoons (used for storage of treated effluent) in reduction of pollution load may also be explored. Page 26 of 37

27 Annexure-I Process flow diagram for Grain based alcohol plant Grain handling & storage Grain Cleaning Grain Milling Flour Pre-mashing & Slurry Preparation Flour Slurry Recycle Steam Initial Liquefaction Pre-liquefied Slurry Cooking Cooked Slurry Final Liquefaction Low Pressure Steam CO 2 High Pressure Steam Distillation Simultaneous Saccharification & Fermentation Saccharified Slurry Partial Saccharification Page 27 of 37

28 Annexure-II Effluent treatment Schematic diagram for Grain based alcohol plant Steam Whole Process Stillage Thin Slop Condensate Distillation Decantation Evaporation Dehydration ENA/Potable alcohol Wet Cake Distillers Wet Grains Stillage (DWGS) Syrup (30% Solid, 70% moisture) ENA as Product Stream Dryer Vapours Water Ethanol Storage (Denaturing) Ethanol as Product Distillers dried grain DDGS Co-product stillage (DDGS) Page 28 of 37

29 Case Study 01: M/s United Spirits Limited, Udaisagar Road, Udaipur (Rajasthan) inspected & monitored on 11 th March, 2011 to access the performance of treatment plant. Date of Commissioning Grain based plant started in 2006 Capacity 15 KLD Water consumption (Source: Purchase water) Purpose Process Steam generation 9.0 Consumption in KLD Washing Nil Cooling 54.5 Domestic 20.0 Waste water generation Type of waste water Quantity in KLD Spent wash Spent Leese 18.5 Fermenter washing -- Floor washing -- Bottle washing -- Condensate -- Cooling 1.6 Other 2.4 Total KLD Effluent treatment technologies adopted Mode of disposal of treated effluent Decanter UASB digester First stage clarifier-cum-aeration Second stage clarifier-cum-aeration Tertiary clarifier-cum-aeration Used for plantation & horticulture in factory premises area Page 29 of 37

30 Observations 01. The industry is using Rice as a raw material, procured from Gujarat. 02. The industry has 7.77 Acre land which includes plant and green belt area. The treated effluent is being used in industrial premises for plantation (HRTS) and horticulture. 03. High Speed Diesel (HSD) is being used as fuel in boiler; Coal is not used as a fuel. 04. Decanter was not working properly, only working at 15-20% of its total solid removal capacity. 05. UASB of 1526 m 3 volume, 150KLD hydraulic, 4.5 Kg COD/m3/d organic load is being used to treat the effluent. Lime is being used for neutralizing the Raw Spent Wash because the digestor volume is very less & retention time is more e.g. 6-7 days. 1000m 3 is the biogas generation out of which 11.36% biogas is being used in boiler as fuel. 06. After the UASB digester, three stage clarifier-cumaeration treatment technology is being used. Red algal and green algal growth was observed in second stage & third stage clarifier-cum-aeration respectively due to sufficient amount of oxygen availability. 07. To access the performance of treatment technologies adopted by distillery waste water samples were collected and analyzed at Zonal office, Bhopal laboratory. Analysis report of samples collected on 11 th March, 2011 Location ph TS TSS COD BOD UASB I/L UASB O/L First (clarifier-cum-aeration) O/L Second (clarifier-cum-aeration) O/L Final outlet Permitted under EP Act Note: All units are mg/l accept ph. Page 30 of 37

31 08. The analysis report of samples collected to study the performance of treatment facility suggest that at inlet of UASB, COD load is 61,200mg/l and after the digestion it decreases to 10,520mg/l, 82.81% of COD removal is taking place only at biomethanation level. The COD load after UASB O/L is being treated at three stage Clarifier-cum-aeration, where in presence of red & green algal growth the % removal of COD is 73.93%, 66.88% & 87.88% respectively. The overall % removal of COD is 99.82%. Suggest that treatment technologies are working effectively. 09. The TSS before decanter was 18,450 mg/l & after decanter was 15,100 mg/l. It suggests that decanter s suspended particles (Solid s) removal is only 18.15% that is very poor. 10. Overall the decanter followed by UASB digester & three stage Clarifier-cumaeration treatment technology can allow distillery to achieve the prescribed effluent discharge limit as per E(P)Act,1986. Decanter s efficiency should to be improved through timely maintenance to get good amount of wet cattle feed as by-product. Page 31 of 37

32 Case Study 02: M/s Bhatia Wine Merchant s Pvt Ltd, Bilaspur (Chattisgarh), inspected & monitored on 24 th February, 2011 to access the performance of treatment plant. Date of Commissioning In the year Capacity Plant -1 Molasses & Grain (30KLD) Plant-2 Grain based 30KLD Water consumption Purpose Consumption in KLD (Source: Borewell) Process Plant 1- Molasses based -300 Grain based- 150 Plant 2 Grain Based Steam generation 296 Washing 40 Cooling 392 Domestic 204 Waste water generation Type of Quantity in KLD Treatment/mode waste water of disposal Spent wash Plant 1- Molasses based -360 Grain based- 150 Plant 1- Primary ETP, double stage Secondary ETP & Plant 2 Grain Ferti-irrigation Based Plant 2- MEE Spent Leese 96 Recycle for spirit dilution Fermenter 10 Goes to ETP washing Floor 5 washing Bottle washing 25 Lagoon no. 03 (for dilution storage) Condensate 144 Boiler feed tank Cooling 10 Lagoon no. 03 (for dilution storage) Other 204 Lagoon no. 03 (for dilution storage) Effluent treatment technologies adopted Complete mixed reactor UASB digester Activated Sludge process Page 32 of 37

33 Observations 01. The industry is having two plants; one is running on molasses as well as grain (Rice) and another is purely on grain (Rice) as a raw material. 02. The industry has 25 Acre land which includes plant and green belt area.the treated effluent is being used in ferti-irrigation through proper networking. 03. The effluent generated in plant 01 from molassas as well as grain is being first sent to equilization tank (complete mixed tank) of 50m 3.Equilization tank is followed by UASB(supplied by M/s Praj Industries Ltd, Pune) of 3626 m 3 volume, 240KLD hydraulic, 18 Kg COD/m3/d organic load is being used to treat the effluent m 3 /hr is the biogas generation out of which 60% biogas (methane) is being used in boiler as fuel that gives saving of 20-25% rice husk. After the UASB digester, the effluent is being treated in extended (Two-stage) aeration treatment technology. Primary aeration followed by primary clarifier. Secondary aeration is followed by secondary clarifier. Finally the treated effluent is stored in lagoons to use the effluent in ferti-irrigation. 04. The effluent of plant 02 (grain based) is being decanted and then send to Multi effect evaporator to concentrate the effluent. The decanted solid is being used as cattle feed along with the MEE concentrate. This MEE technology can achieve zero discharge of effluent through concentrating the spent wash. Generation of biogas is not possible in MEE technology as we concentrate the wash through steam. Also MEE technology is not suitable for molasses based distillery due to sticky nature of molasses. 05. To access the performance of treatment technologies adopted by distillery waste water samples were collected and analyzed at Zonal office, Bhopal laboratory. Page 33 of 37

34 Analysis report of samples collected on 24th February, 2011 Location ph TS TSS COD BOD UASB I/L ,764 13,700 55,255 22,600 UASB O/L ,772 3,880 9,095 3,150 Primary aeration tank O/L ,436 2,880 8,820 2,800 Clarifier - A O/L ,770 2,480 5,027 1,792 Extended (Secondary) Aeration O/L ,016 1,520 1, Treated effluent used for ferti-irrigation , MEE concentrate Permitted under EP Act Note: All units are mg/l accept ph. 06. The analysis report of samples collected to study the performance of treatment facility suggest that at inlet of UASB, COD load is 55,255mg/l and after the digestion it decreases to 9,095mg/l, 83.53% of COD removal is taking place only at bio-methanation level. The COD load after UASB O/L is being treated at two stage extended aeration, where % removal of COD is 3.02%, 43.00% & 72.36% respectively. The overall % removal of COD is 98.29%. Suggest that treatment technologies are working effectively but the treatment efficiency of clarifier and aeration system is very poor because improper sludge removal practices. Primary clarifier was not working at the time of inspection. 07. The outlet of MEE concentrate of plant 02 is 240mg/l COD & 88mg/l BOD suggest that this concentration technology can achieve the prescribed limits of effluent discharge. But the loss of biogas generation & used only for grain based raw material make this not economical and profitable technology for distillers. 08. Overall the MEE outlet can allow distillery to achieve the prescribed effluent discharge limit as per E(P)Act,1986 at the cost of no biogas generation. If the sludge removal practice followed seriously and regularly then grain based distillery can achieve all effluent discharge limits. Page 34 of 37

35 Case Study 03: M/s Gwalior Distillers Ltd., Rairu, Gwalior (Madhya Pradesh), inspected & monitored on 27 th January, 2011 to access the performance of treatment plant. Date of Commissioning 1986 Capacity Grain based 180 KLD, On the day of inspection production was 100KLD. Earlier was running on molasses. Water consumption Purpose Consumption in KLD (Source: Borewell & R.O.) Process 486 Steam generation 480 Washing 10 Cooling 32 Domestic 14 Waste water generation Type of Quantity in Treatment/mode of waste water KLD disposal Spent wash 632 Biomethanation followed by secondary treatment Spent Leese 276 Recycle for spirit dilution Fermenter washing 30 Floor washing 5 Bottle washing 10 To ETP Condensate 4.8 Cooling 12 Other 9.3 Effluent treatment technologies adopted Decanter UASB digester Extended aeration system Page 35 of 37

36 Observations 01. The industry is using Bajra (Millate), Jawar & Rice as a raw material. 02. The industry has 185 Acre land which includes factory premise and green belt area. The treated effluent is being used in plantation (HRTS) & ferti-irrigation through proper networking. 03. In plant there are two type of digester system; Bulk Volume Fermentor (BVF-Mesophilic digestor) & UASB (Thermophilic digestor). The effluent generated is being first sent to decanter unit to separate out the solids as cattle feed. Decanter is followed by BVF(supplied by UEM,Delhi) of 1000m 3 volume & UASB (supplied by M/s Aqua Technos Asia Co. Ltd, Thailand) of 1500m 3 volume, 2500KLD hydraulic, 135 Kg COD/m 3 /d organic load is being used to treat the effluent. 15,000m 3 /day is the biogas generation that is being used as fuel in boiler. After the UASB digester, the effluent is being treated in extended (Three-stage) aeration treatment technology. Primary aeration followed by primary clarifier & primary clarifier is followed by Secondary clarifier-cum-aeration system. Finally the treated effluent is stored in lagoons to use the effluent in ferti-irrigation. Earlier Turbo Mist Evaporator technology was used to concentrate the treated effluent, but as the technology is not CPCB approved. Use of said technology has been stopped. 04. To access the performance of treatment technologies adopted by distillery waste water samples were collected and analyzed at Zonal office, Bhopal laboratory. Page 36 of 37

37 Analysis report of samples collected on 27 th January, 2011 Location ph TS TSS COD BOD UASB I/L or decanter O/L ,080 9,350 46,291 14,625 UASB O/L ,876 4,130 11,404 3,166 Primary aeration tank O/L ,360 2,040 8,525 2,088 Primary Clarifier O/L ,184 2,850 6,358 1,276 Secondary Clarifier-cum- Aeration O/L , , Treated effluent used for ferti-irrigation , Permitted under EP Act Note: All units are mg/l accept ph. 05. The analysis report of samples collected to study the performance of treatment facility suggest that at inlet of UASB, TSS load is 9,350 mg/l e.g. is very less, it suggest that decanter is working with good efficiency, COD load is 46,291mg/l and after the digestion it decreases to 11,404mg/l, 75.36% of COD removal is taking place only at bio-methanation level. The COD load after UASB O/L is being treated at three stage extended aeration, where % removal of COD is 25.04%, 25.41% & 76.07% respectively. The overall % removal of COD is 96.71%. Suggest that treatment technologies are working effectively but the treatment efficiency of clarifier and aeration system is very poor because improper sludge removal practices. 06. Overall the distillery is not meeting the prescribed limits of ferti-irrigation because of poor sludge removal practice that was observed during visit. If the sludge removal practice followed seriously and regularly then grain based distillery can achieve all effluent discharge limit as per E(P)Act,1986. Page 37 of 37