WASTEWATER MANAGEMENT FOR A SOFT DRINK INDUSTRY

Transcription

1 Proceedings of the 9 th International Conference on Environmental Science and Technology Rhodes island, Greece, 1 3 September 25 WASTEWATER MANAGEMENT FOR A SOFT DRINK INDUSTRY S. Oktay, G. Eremektar, F. Germirli Babuna, G. Kutluay and D. Orhon Istanbul Technical University, Civil Engineering Faculty, Environmental Engineering Department, 3449, Maslak, Istanbul, Turkey geremektar@ins.itu.edu.tr EXTENDED ABSTRACT Current understanding of an appropriate industrial wastewater management mainly focuses on a twostage approach; where the first stage is allocated to apply the inplant control alternatives (such as waste minimization, reuse, water use reduction etc.) and the next step is devoted to endofpipe treatment to meet the effluent discharge standards. Assessment of the potential for recovery and reuse is among the priority issues of industrial pollution control and therefore must be considered as an inevitable part of a sound wastewater management. Soft drinks industry is among the industrial sectors where inplant control measures can be successfully applied to get an overall sustainable water management. The reuse strategies such as reuse of wastewaters obtained from treatment plant effluents; recovery and reuse of sugar from certain segregated wastewater streams by employing different technologies (i.e. membrane filtration, ion exchange etc.) is stated to yield satisfactory results for soft drinks industry. The key issue in such recovery and reuse practices is the degree of contamination of different segregated wastewater streams. Water reuse from wastewater streams having low to medium pollutant concentrations as well as sugar recovery from highly concentrated streams are of concern. On the contrary when inplant control alternatives are not considered, costly endofpipe treatment alternatives (i.e. combinations of coagulation flocculation and activated sludge systems; anaerobic followed by an aerobic process) must be encountered. In this study wastewater management options were investigated in terms of sustainability for an industry manufacturing tons of energy drinks daily. A two stage management approach covering both inplant control and endofpipe treatment was adopted for the industry under examination. The characterization of segregated wastewater streams was evaluated in a way to define the pollution profile and possible reuse alternatives. When reuse practices were not employed a wastewater having an organic content of 3 mg/l of COD must be treated. Whereas if wastewaters originating from filter cleaning operations were segregated from other wastewater sources and passed though a suitable system such as a membrane process, a valuable sugar byproduct can be obtained and the rest of the wastewaters did not require any type of treatment to meet the discharge standards as they contain only 25 mg/l of COD. It is recommended to run a feasibility study to assess whether these effluents can be reused after treated with a membrane system. Key words: Energy drinks industry, industrial wastewater, inplant control, pollution profile, reuse, recovery. Α1131

2 1. INTRODUCTION Appropriate management of industrial wastewaters involves a twostage approach. The first stage must be attributed to inplant control alternatives such as waste minimization, reuse, water use reduction etc. The next step must cover the application of endofpipe treatment to meet the effluent discharge standards. Since a management strategy that skips the first stage is stated to increase the financial burdens enormously [1] especially for some industrial premises, possible inplant control applications must be considered as an inevitable part of a sound wastewater management. Currently assessment of the potential for recovery and reuse is among the priority issues of industrial wastewater management [2]. In this respect industries manufacturing soft drinks need special attention as inplant control measures can be successfully applied to get an overall sustainable water management. The reuse strategies cover a wide range of applications from reuse of wastewater treatment plant effluents to recover and reuse of certain segregated wastewater streams by employing different technologies such as membrane filtration, ion exchange etc [3, 4, 5]. In soft drinks industry the segregated wastewater streams can be subjected to various recovery and reuse practices by evaluating their level of contamination. Water reuse from wastewater streams having low to medium pollutant concentrations as well as sugar recovery from highly concentrated streams is of concern [] yielding suitable options in terms of financial aspects. On the other hand costly endofpipe treatment alternatives such as combinations of coagulation flocculation and activated sludge systems [7] or anaerobic followed by an aerobic process [8] must be encountered when inplant control alternatives are not considered. This study deals with the management options of wastewaters originating from a soft drinks industry having a daily production capacity of tons of energy drink. The segregated wastewater streams are characterized to define possible reuse alternatives, and the pollution profile together with the effect of such inplant control measures on the endofpipe treatability is determined. 2. MATERIALS AND METHODS All analyses in terms of conventional parameters apart from COD are performed on grab and composite samples as defined in Standard Methods [9]. COD has been measured according to the procedure defined by ISO [1]. Filtrates of samples subjected to vacuum filtration by means of Millipore membrane filters with a pore size of.45 µm are defined as soluble fractions. The Millipore AP glass fiber filters are used for suspended solids (TSS) analyses. Absorbance measurements are conducted on samples filtered from.45 µm membrane filters, at 3 different wavelengths, namely 43, 525 and 2 nm. Pharmacia LKB Novaspec II model spectrophotometer is used for this purpose. All experiments are conducted at room temperature. Each data point in the study is calculated as the mean of three replicate measurements. 3. PROCESS DESCRIPTION AND WASTEWATER SOURCES The industry investigated currently manufactures canned energy drink with a daily production capacity of 1 tons, however as an enlargement that will take place within months to elevate the production capacity to tons/day is planned, all the data presented in this paper corresponds for the future situation. According to the general process flow scheme shown in Figure 1, the investigated plant has a mix tank where all the ingredients such as fructose, acidulants, vitamins, aromating agents, caffeine etc. are added together with treated water previously obtained from tap water; a filter; a gas tank; and a packaging unit. Α1132

3 Tap Water Resin Active Carbon Water Treatment Unit Fruktoze,Acidulants, Colors, Vitamins, Caffein, Aromatic Agents Mix Tank CO 2 Tank Filling Gas Gas Introduction Product Figure 1: Schematic Flowchart of the Production Processes The water treatment unit consists of a resin filter used for water softening, another filter and an activated carbon tank. After the addition of treated water, fructose and acidulants to the mix tank a pasteurization process takes place at 75 C for 2 minutes. When the temperature is cooled down to C other ingredients are introduced. The tank contents are then passed through a filter to get rid of possible residues. In the subsequent filling unit the prepared energy drink is canned with CO 2 introduction. Only cleaning and subsequent rinsing operations applied to all the units previously mentioned generate the wastewaters as outlined in Table 1. A wastewater of 45 m 3 is originated from the water treatment unit once in every 4 months. Whereas the mix tank cleaning operations take place in every 3 weeks producing a wastewater volume of 3 m 3. cleaning is applied in every 3 days creating a wastewater of 12 m 3 and lastly gas tank is cleaned once a week by the use of m 3 of water. In the cleaning operations special cleaning agents are used where after rinsings with water are employed. 4. WASTEWATER GENERATION AND POLLUTION PROFILE Conventional wastewater characterization indicates generation of a wastewater that can be classified as strong nature, having a total COD of 3 mg/l as tabulated in Table 2. Higher COD concentrations than given in literature for soft drinks industry [11] (approximately mg/l) is obtained due to the fact that this industry produces energy drink with elevated organic matter content. Apart from membrane technologies, as high organic content is involved and the soluble COD accounts for over 8% of the total COD for the wastewater, anaerobic processes can be applied to meet the sewer discharge limitations of 8 mg/l COD. Α1133

4 PROCESSES Water Treatment *Cleaning I *Rinsing I *Cleaning II *Rinsing II *Cleaning III *Rinsing III Premix Tank *Cleaning IV *Rinsing IV *Cleaning V *Rinsing V *Cleaning VI *Rinsing VI *Rinsing VII *Rinsing VIII Table 1: Wastewater Generation Added Ingredients Wastewater Generation Brand Name Purpose m³ Discharge Frequency TITAN 15 TITAN 475 TITAN 389 TITAN 15 TITAN 475 TITAN 389 Alkaline Cleaning Acidic Cleaning Disinfection Alkaline Cleaning Acidic Cleaning Disinfection Once in 3 days Once in 3 days Gas Tank *Rinsing IX Once in a week Table 2: Wastewater Characterization of the Investigated Industry Parameter Value Total COD (mg/l) 3 Soluble COD (mg/l) 27 TKN (mg/l) 54 Total P (mg/l) 2.5 TSS (mg/l) 25 ph 5.4 The pollution profile of the industry can be summarized as 7. m 3 /day or 25.4 l/ton product of wastewater generation, 851 kg of COD per ton product or 255 ton COD/day. Detailed information on pollution profile can be seen from Table 3. The wastewater characterization of segregated wastewater streams originating from each source for the investigated plant is given in Table 4. The most striking feature about the characterization of segregated streams is the high organic content of two wastewater sources, Rinsing VII and Rinsing VIII originating from filter cleaning operations, namely. Therefore adopting a wastewater management strategy that segregates these streams having a COD of approximately 87 mg/l and a volume of 3.2 m 3 /day from the rest of the wastewaters will be necessary. As stated in literature [11], a valuable sugar byproduct can be obtained by passing the mentioned wastewater streams through a membrane process as a reuse alternative. Apart from this advantage according to the data tabulated in Table 5, an untreated effluent COD concentration of 25 mg/l is obtained indicating that the wastewater does not need any treatment to comply the effluent limitations of 8 mg/l COD. Besides this wastewater seems to be reusable after being directed to a suitable treatment. Therefore it is recommended to perform a feasibility study on this issue. Α1134

5 PROCESSES Water Treatment *Cleaning I *Rinsing I *Cleaning II *Rinsing II *Cleaning III *Rinsing III Premix Tank *Cleaning IV *Rinsing IV *Cleaning V *Rinsing V *Cleaning VI *Rinsing VI *Rinsing VII *Rinsing VIII Table 3: Pollution Profile of the Investigated Plant WASTEWATER COD lt/day lt/ton product mg/l kg/ton product kg/day Gas Tank *Rinsing IX PROCESSES Water Treatment *Cleaning I *Rinsing I *Cleaning II *Rinsing II *Cleaning III *Rinsing III Premix Tank *Cleaning IV *Rinsing IV *Cleaning V *Rinsing V *Cleaning VI *Rinsing VI *Rinsing VII *Rinsing VIII Table 4: Characterization of Segregated Wastewater Streams ph COD (mg/l) COLOR Turbidity ABSORBANCE (NTU) PtCo 43nm (cm 1 ) 525nm (cm 1 ) 2nm(cm 1 ) Gas Tank *Rinsing IX DISCUSSION AND CONCLUSION According to the results obtained in this study that investigates the wastewater management for an industry producing energy drink; the importance of inplant control covering especially Α1135

6 reuse is emphasized. When inplant control practices are not considered, an endofpipe treatment scheme consisted of either anaerobic treatment or membrane processes is Table 5:Effect of Wastewater Management Options on Effluent COD, Wastewater Generation Options COD Wastewater Generation (mg/l) m 3 /day l/ton product without any inplant control with inplant control required to control the wastewaters with a strong nature in terms of organic matter. Such an application will surely exert an additional financial burden to the industry. On the other hand if the appropriate way of managing the wastewaters with the aid of two stage approach covering first inplant control and then endofpipe treatment is adopted, two wastewater sources with very high organic contents can be identified: i) filter cleaning operation Rinsing VII having a total COD of 1582 mg/l; ii) filter cleaning operation Rinsing VIII having a total COD of 32 mg/l. Sugar recovery and reuse can be applied to these waste streams by passing them through a membrane process. By doing so a valuable sugar byproduct and a wastewater that does not necessitate any endofpipe treatment to comply the effluent limitations can be achieved. Apart from canceling the treatment requirement for the effluent, such an inplant control application can generate wastewaters that are reusable in nature. Therefore it is recommended to find out reuse potential of these wastewaters by running a feasibility study. REFERENCES 1. Erdogan, A. O., Orhon, H. F., Dulkadiroglu, H., Dogruel, S., Eremektar, G., GermirliBabuna, F. and Orhon, D. (24). Feasibility analysis of inplant control for water minimization and wastewater reuse in a wool finishing textile mill. Journal of Environmental Science and Health Part A (in press). 2. Dulkadiroglu, H., Eremektar, G., Dogruel, S., Uner, H., GermirliBabuna, F. and Orhon D. (22). InPlant Control Applications and their Effect on Treatability of a Textile Mill Wastewater, Water Science and Technology, Vol. 45(12), Visvanathan, C. and Hufemia, A. M. M. (1997). Exploring zero discharge potentials for the sustainability of a bottle washing plant, Water Science and Technology, Vol. 35(9), Miyaki, H., Adachi, S., Suda, K. and Kojima, Y. (2). Water recycling by floating media filtration and nanofiltration at a soft drink factory, Desalination, Vol. 131, Tay, J. H. and Jeyaseelan, S. (199). Membrane filtration for reuse of wastewater from beverage industry, Fuel and Energy Abstracts, Vol. 37(1), 59.. Chemiel, H., Kaschek, M., Blöcher, C., Noronha, M. and Mavrov, V. (22). Concepts for the treatment of spent process water in the food and beverage industries, Desalination, Vol. 152, Tebai, L. and Hadjivassilis, I. (1992). Soft drinks industry wastewater treatment, Water Science and Technology, Vol. 25(1), AustermannHaun, U. and Rosenwinkel K. H. (1997). Two examples of anaerobic pretreatment of wastewater in the beverage industry, Water Science and Technology, Vol. 3 (23), Standard Methods for the Examination of Water and Wastewater (1998). 2th edn, American Public Health Association/American Water Works Association/Water Environment Federation, Washington DC, USA. 1. ISO (198). Water QualityDetermination of the Chemical Oxygen Demand. Ref. No. ISO Guyer H. H. (1998). Industrial Processes and Waste Stream Management. John Wiley & Sons Inc., 592 pages, Canada. Α113