Wastewater characteristics from Greek wineries and distilleries

Transcription

1 Wastewater characteristics from Greek wineries and distilleries A.G. Vlyssides 1, E.M. Barampouti 2 and S. Mai 3 Chemical Engineering Department, National Technical University of Athens, 9 Heroon Polytechniou Str., Zografou Campus, Zographou , Athens, Greece ( 1 avlys@tee.gr; 2 belli@central.ntua.gr; 3 mai@central.ntua.gr) Abstract The present paper deals with the characterization of wastewater generated from Greek wineries and wine distilleries. The quantity and the quality of the wastewater of a distillery depends on the type of wine (white or red), on the processes followed for the of wine as well as on the volume of the tanks that are used. The total of wastewater from a winery is about 1.2 times greater than the of wine with BOD mg/l and 1970 mg/l for white and red wine respectively, while the corresponding prices for COD are 3112 mg/l and 3997 mg/l and for the total phenolic compounds 280 and 1440 mg/l respectively. From these results, it is expected that the biological treatment of wastewater from white wines will be more efficient than that from red wines. The characteristics from the waste (vinasses) from the distillation of wines and wine lees are also presented. Keywords Alcohol manufacturing; vinasse; wastewater; wine lees; wine ; wineries Introduction Winemaking is one of the most traditional agricultural industries in Greece. The total annual of grapes in Greece is about 1.6 million tonnes while the total area of vineyards is 171 thousand hectares covering 4.9% of the total cultivated area. The wine is about 5 million hectolitres, 40% red and 60% white wine. This amount represents 1.8% of worldwide and the 3.35% of European. The 65% of the wine is produced by organized wineries and is available in the market while the producers themselves for self-consumption prepare the remaining 35%. The organized wineries are about 320, from which 250 are private and the rest are associations, with about 680,000 m 3 total capacity in tanks. Of the annually produced wine 5.4% is taken to distilleries for the of ethyl alcohol. In Greece, ethyl alcohol is exclusively produced by fermentation. The distillation industries utilize as raw materials several agricultural or agro-industrial products and byproducts. The primary raw materials for this process in Greece are molasses, mainly from beets (around 64%) but also from cane (around 9%), from raisins (around 14%), from figs (around 4%), from wines (4%) and from wine lees (5%) (Danilatos, 1986). In Table 1 the main raw materials used for ethanol are presented. The eight Greek distilleries have a total of ethanol of about r10 5 anhydrous hectolitres, although it is variable from year to year. On the basis of this, it can be calculated with good approximation that r10 6 m 3 of effluents, commonly named vinasses, are produced annually and 3.2r10 6 m 3 of cooling water is necessary. In this paper, results of research carried out on wastewater from winemaking as well as on two kinds of Greek vinasses from wine and wine lees distillation are reported. 53 Water Science and Technology Vol 51 No 1 pp ª IWA Publishing 2005

2 Table 1 Annual consumption of wine and wine lees, and alcohol and waste from Greek distilleries No. Raw material Consumption Alcohol Vinasse A.G. Vlyssides et al Wine (10 3 tonnes) Wine lees (10 3 tonnes) Total (10 3 tonnes) Production process and sources of wastes Winemaking The main stages of the process of a winery are as follow. 1. Grape reception: It takes place for almost 15 working days from the end of August to the beginning of October. The produced wastewater from this stage comes from the washing of the mechanical machinery and that of the floors. 2. Must : The grapes come through a pneumatic press and produce the must and the solid residues. The produced amount of must is about 80l/100 kg of grapes. The produced wastewater from this stage comes from the washing of the machinery (pneumatic press and solid residues removal screw), the washing of the room, the loss of must due to its transfer to the fermentation vessels as well as the pre-washing of the fermentation vessels. The amount of water that is used for the cleaning of the fermentation vessels and the wine storage tanks depends on the size of the tanks. 3. Fermentation: This takes place in the fermentation vessels and lasts about 15 days for each tank from the day they are filled with 80% must. From this stage, no wastewater is produced. 4. Decanting: This takes place after the fermentation and lasts about 2 days at the beginning of September for red grapes and about 5 days at the beginning of October for white grapes. During the decanting, the supernatant wine is separated from the produced wine lees and is fed by pumps to empty tanks that are filled 100% for further stabilization. The wine lees are 5% v/v, and are led to alcohol. The produced wastewater from this stage comes from the washing of the tanks, from the pre-washing of the stabilization tanks, from the cleaning of the decanting pump, from the washing of the room as well as from losses during wine decanting. 5. Maturation stabilization: It takes place in the tanks and lasts about 15 days for each tank from the day it is filled 100% with decanted wine. From this stage, there is no wastewater produced. 6. Filtration: The produced wine is filtered in order to improve its quality and takes place through a diatomaceous earth filter and is decanted into empty tanks. This stage takes place for a ten-day period at the beginning of December. The produced wastewater of this stage comes from the washing of the tanks, from the pre-washing of the storage tanks, from the cleaning of filters, from the transportation pump, from the washing of the room as well as the possible wine losses during its transfer. The diatomaceous earth, after the end of the filtration, is collected and is usually co-composted with the solid residues and is sold as fertilizer. 7. Transportation disposal: The produced wine is sold either in bulk or as bottled which is charged from tanks to transportation trucks or in the packaging unit. This stage lasts approximately a semester, from the end of January up to the end of July and the produced wastewater comes from the washing of tanks, the washing of the transportation pump and the washing of packaging room.

3 A.G. Vlyssides et al. Figure 1 Winemaking procedure The stages of process as well as the produced by-products and wastewater are presented in the following diagram (Figure 1). Ethyl alcohol Ethyl alcohol is the final product of a multistage distillation process. Figure 2 is a simplified flow sheet illustrating the steps of the of alcohol in Greece from wines and wine lees. Table 1 gives the total annual amounts of waste from each raw material. Methods Many wastewater samples from each winemaking stage of ten Greek wineries as well as from all Greek wine distilleries and for long time (five years) were carefully collected and analyzed for various parameters. Total Solids, Total Volatile Solids, Suspended Volatile Solids, BOD 5, COD, Ammonium Nitrogen, Organic Nitrogen, Total Phosphorus, Sulfates and Chlorides were determined according to the standard methods (Standard Methods for the Examination of Water and Wastewater, 1989). Metals were determined using Atomic Adsorption Spectrophotometer (Perkin Elmer Model 103). The analysis for Total Carbon and Total Nitrogen was performed using a Carlo Erba Analyser (Model CNSH-O EA1108). Total lipids as well as the dissolved sugars and lignin were determined according to the Official Methods of Analysis, AOAC (1975). Total proteins and total carbohydrates were determined using the colorimetric method as proposed by Gaudy (1962). Figure 2 Schematic alcohol using wine and wine lees as raw material 55

4 30 A.G. Vlyssides et al. wastewater, % Aug Sept Oct Nov Dec Jan Feb Mar Apr Mai Jun Jul Figure 3 The distribution of wastewater of wineries throughout a year Table 2 Characteristics of final wastewater produced from all stages of wine Parameter White wines Red wines 1. ph Total solids (mg/l) Total volatile solids (TVS) (mg/l) Suspended solids (mg/l) Suspended volatile solids (mg/l) BOD 5 at 20 C (mg/l) COD (mg/l) Total Kjeldahl nitrogen (mg/l) Total phosphorous (mg/l) Fats and oils (mg/l) Total phenolic compounds (mg/l) Results and discussion Due to the long period of our research the distribution of the wastewater of wineries during a whole year could be determined (Figure 3). In September and December when machinery washing is necessary, the greatest percentages of wastewater are observed. The characteristics of the final wastewater produced from a winery are illustrated in Table 2. Specifically, the specific volume as well as the BOD 5 and COD concentrations for each stage of wine are presented in Table 3. The data of Table 3 can prove to be a useful tool for the prediction of the amount of the produced wastewater as well as their BOD 5 and COD content. The specific volume was found to be strongly dependent on the size of the tanks for the stages that include tanks such as the following: 2.1 (Fermentation vessels pre-washing), 4.1 (fermentation vessels post-washing), 4.2. (storage tanks pre-washing), 6.1. ( post-washing of maturation tanks), 6.2. (pre-washing of storage tanks) and 7.1. ( postwashing of storage tanks). This is illustrated in Figure 4. A mathematical regression of the results of Figure 4 gives the following equation: specific volume = V x where V is the tank volume in m 3. The results of Table 2 resulted from wineries with 30 m 3 tanks. After processing the data of Table 3, the following figures were constructed. In Figure 5 the specific volume of each stage of winemaking is illustrated, while in Figures 6 and 7 the corresponding BOD 5 and COD concentrations are presented.

5 Table 3 Wastewater and pollutants from wineries in relation to particulate wine stages Specific BOD 5 Specific COD White wines** Red wines** White wines** Red wines** Specific volume* From grapes to wine processes 1. Reception of grapes 1.1. Machinery washing 76.75t t t t t Floor washing 56.67t t t t t Must process 2.1. Fermentation vessels pre-washing 23.85t t t t t Machinery washing t t t t t Floor washing 56.67t t t t t Must losses 8.33 t t t t t Fermentation process 4. Decanting into maturation tanks 4.1. Fermentation vessels post-washing 23.85t t t t t Storage tanks pre-washing 23.85t t t t t Washing of transportation pumps 76.75t t t t t Floor washing 56.67t t t t t Fermenting must loses 8.33t t t t t Maturation and stabilization process 6. Filtration process and decanting into storage tanks 6.1. Post-washing of maturation tanks 23.85t t t t t Pre-washing of storage tanks 23.85t t t t t Machinery washing t t t t t Floor washing 56.67t t t t t Wine losses 8.33t t t t t Disposal from storage tanks into the vessels of transportation trucks 7.1. Post-washing of storage tanks 23.85t t t t t Machinery washing 76.75t t t t t Floor washing 56.67t t t t t Wine losses 8.33t t t t t1.53 * litres of wastewater per hectoliter of alcohol content in the final product (wine); ** kg per m 3 of wastewater A.G. Vlyssides et al. 57

6 A.G. Vlyssides et al. specific volume, l/hl Volume of processing tank, m3 Figure 4 The effect of size of the storage or processing tanks on the specific volume lt of wastewater /tn of wine produced Reception Must Fermendation Decanting Stabilization Filtration Disposal Figure 5 Wastewater in each stage of wine kg BOD5/m3 wastewater white wine red wine Reception Must Fermendation Decanting Stabilization Filtration Disposal 58 Figure 6 BOD 5 concentration for each stage of wine

7 kg COD/m3 wastewater Reception Must Fermendation white wine red wine Decanting Stabilization Filtration Disposal A.G. Vlyssides et al. Figure 7 COD concentration for each stage of wine Table 4 Characteristics of vinasses produced from distillation of wines and wine lees No Parameter Vinasse from wines Vinasse from wine lees 1. PH Total solids (mg/l) 36, , Total volatile solids (TVS) (mg/l) 32, , Suspended solids (mg/l) 1, , Suspended volatile solids (mg/l) , BOD 5 at 20 C (mg/l) 16,300 67, COD (mg/l) 27, , Total carbon (mg/l) 20,860 84, Total nitrogen (mg/l) , Total phosphorous (mg/l) 65 7, Ammonium nitrogen (mg/l) Organic nitrogen (mg/l) , Sulfates (mg/l) 120 1, Chlorides (mg/l) 420 1, Total carbohydrates (mg/l) 1,560 1, Total lipids (mg/l) , Total proteins (mg/l) 2,750 32, Disolved sugars (mg/l) Potassium (mg/l) Sodium (mg/l) Calcium (mg/l) Magnesium (mg/l) Total iron (mg/l) Copper (mg/l) Lead (mg/l) Zinc (mg/l) The diagrams of Figures 5 7 prove that the processes of must as well as the filtering of wine have the greatest contribution in the wastewater as well as in the pollutant loads of the final wastewater. As far as the characteristics of the wastewater after the distillation of the alcohol are concerned, Table 4 presents their mean values. 59

8 A.G. Vlyssides et al. Conclusions Conclusively, regarding the annual distribution of wastewater in wineries, during the months of September and December when machinery washing is necessary, the greatest percentages of wastewater are observed. In contrast, during the period January to July, when the transportation and disposal of wine takes place, the wastewater is very low as would be expected. The parameters that determine the pollutant load of the final effluent of red wine are obviously higher than those of white wine. Due to this fact, the biological treatment of wastewater from white wines is more efficient than that from red wines. A striking difference is observed in the total phenolic compounds concentration. The mean of this parameter for red wine is 1450 mg/l which renders biological treatment much more difficult. The specific volume was found to be strongly depended on the size of the tanks for the stages that include tanks according to the following equation: specific volume = V x where V is the tank volume in m 3. It was also proved that the processes of must as well as the filtering of wine have the greatest contribution in the wastewater as well as in the pollutant loads of the final wastewater. The parameters that determine the pollutant load of vinasses produced from distillation of wine lees are, as expected, greater than those of wine. References AOAC (1974). Official Methods of Analysis, 10th edition. Association of Official Agricultural Chemists, Washington, D.C. Danilatos N. (1986). Development of Greek wine and wineries. Proceedings in 1st EEC Symposium on Anaerobic Digestion results of research and demonstration projects, Villeneuve-d Ascq, France, 4 6 March, Gaudy, A.F. Jr. (1962). Colorimetric Determination of Protein and Carbohydrate. Ind. Water Wastes, No 1, Standard Methods for the Examination of Water and Wastewater (1989). 17th edn, American Public Health Association/American Water Works Association/Water Environment Federation, Washington DC, USA. 60