1. INTRODUCTION Hydrogen production in an upflow anaerobic sludge blanket treating brewery wastewaters A.A Mendez-Revollo*, T.R. Chaparro** *Sanitation Laboratory, Civil Engineering Department, Military University email: u1100853@unimilitar.edu.cou1100853@unimilitar.edu.co cra 11 No 101-80, Bogotá, Colombia ** Sanitation Laboratory, Civil Engineering Department, Military University email: adela.rodriguez@unimilitar.edu.co,adela.rodriguez@unimilitar.edu.co cra 11 No 101-80, Bogotá, Colombia The hydrogen is a clean fuel, which generates in its combustion, water as a unique product and has 2.75 times more potential energy than hydrocarbons [1]. [2] indicates that the production of hydrogen from dark fermentation has gain much attention, mainly because there are a wide range of substrates that can be converted in hydrogen without additional energy. Substrates that most are being studied include the sewage of industrial origin with high content of carbohydrates. However, it is important to mention that one of the major disadvantages of dark fermentation for the production of hydrogen is the presence of microorganisms consumers of H 2, which quickly converted to acetate, propionate and methane [3]. In this sense, to avoid the presence of H 2 consuming bacteria and increase production, it is important to develop methods that inhibit the activity of H 2 consuming microorganisms. According to [4], [3], [5], the procedure that has shown better results is to implement pre-treatment to the inoculum. Based on this, the objective of this study was to evaluate the production of hydrogen applying a heat shock pre-treatment (90°C/15 min) to the inoculum in an Upflow anaerobic sludge blanket reactor (UASB) treating wastewater of a brewery Industry. METHODS DISCUSSION In this study was evaluated the feasibility to produce hydrogen by the anaerobic process treating real wastewater from a Brewery Industry. Although the production of H 2 was low, only 21%, the results are promising once that permits demonstrate that is possible use real wastewater to produce clean energy using the Upflow Anaerobic Sludge Blanket. Despite of the control of the pH to improve the production of gas hydrogen, close to 5.5, also was observed the presence of gas methane. Hence, it is inferred that the pH is not determinant to optimize the H 2 production. The pretreatment of the inoculum applying heat shock does not improve the production of H 2. It is important to remark that to produce H 2 with real wastewater is necessary to do more studies that include for the example the configuration of the reactors, the toxicity of the wastewater and take into account that this type of water has a high variability in its composition due to its process of production. CONCLUSIONS inspiring change Highligths As shown in Figure 1 and Figure 2, there was presence of hydrogen treating brewery wastewater. However, the production as cited in the literature was not stable,. Authors like [9] and [10] indicated that the production of H 2 begins to decrease from the day 25 of operation. The maximum value was 21% and from this peak the hydrogen decay concomitantly with the decrease og the total volatile acids (VFAs). It is to be highlighted that there was not a remarkable production of volatile acids, probably due to that the raw wastewater already contains an important content of these compounds and the production of acids that is typical in an anaerobe process not occurred in a regular form. Authors like [11] mentioned that the oxidation of reduced components such as Long Chain Fatty Acids to VFAs reduce the production of the hydrogen because the reaction is thermodynamically unfavorable. Was observed gas methane during the operation. One possible explanation of this phenomenon is that the heat shock applied to the inoculum was not sufficient to inactivate the H 2 consumers. Similar results have been cited by [12]. Also we can say that an inadequate manipulation of the inoculum could have supressed the activity of the microorganism producers of H 2. Unfortunately, we can not measured the composition of the VFAs. This could have shown the patterns of intermediates like acetate, butyrate and ethanol Authors like [13] with Brewery waste mentioned that at pH or below the major by-products are acetate and butyrate and also indicate that the effects of the pH on the hydrogen production is related not only with the metabolic patways but also with the changes in the microbial communities. Finally, we observed that 2 hours of HDT is not enough in an UASB reactor to optimize the H 2 production. Based on our observations we guess that the major challenge in this type of reactors is to promove the granulation Acknowledgement: This work was carried out as a part of major research project sponsored by the Military University and Colciencias. The authors would like to thank to Sanitation Laboratory and Water Quality Laboratory of the Military University for the technical support. References:[1] CHEN, C., LIN, C.Y., CHANG, J.S. Kinetics of hydrogen production with continuous anaerobic culture utilizing sucrose as the limiting substrate. Applied Microbiology Biotechnology, 57, 56-64, 200.[2] KAN. E. (2013). Effects of pretreatments of anaerobic sludge culture conditions on hydrogen productivity in dark anaerobic fermentation. Renewable Energy, 49, 227-231, 2013.[3] OH. S., GINKEL. SV. LOGAN. B.E. The relative effectiveness of pH control and heat treatment for enhancing biohydrogen gas production. Environmental Science and Technology, 37 (22), 5186-5190, 2003. [4] WANG. J., WAN. W. (2008). Comparison of different pretreatment methods for enriching hydrogen-producing bacteria from digested sludge. International Journal of Hydrogen Energy, 33(12), 12, 2934-2941. [5] CAI, M., LIU,J. WEI. Y. Enhanced biohydrogen production from sewage sludge with alkaline pretreatment. Environmental Science and Technology, 38 (11), 3195-3202. 2004. [6] APHA. Standard Methods for the Examination of Water and Wastewater. 21th ed. American Public Health Association/American Water Works Association/Water Environemnt Federation, Washington, USA. 2005. [7] PEIXOTO, G. Producao de hidrogenio em reator anaerobio de leito fixo e fluxo ascendente a partir de agua residuaria de industria de refrigerantes. Dissertacao (mestrado). Universidade de Sao Paulo, 2008. [8] Ripley. L.E., Boyle, W.C., Converse. J.C. (1986). Improved alkalimietric monitoring for anaerobic digestion of high-strength wastes. Journal of Water Pollution Control Federation, 58(5), 406-411. [9] FONTES, D. M., ZAIAT. M. The influence of the degree of back-mixing on hydrogen production in an anaerobic fixed-bed reactor. International Journal of Hydrogen Energy, 9630-9635, 2012. [10] PENTEADO, E.D., ZAMPOL C., KIMIKO I., ZAIAT M. (2013). Influence of seed sludge and pretreatment method on hydrogen production in packed-bed anaerobic reactors. International Journal of Hydrogen Energy, 38, 6137-6145, 2013.[11 GUO. X., TRABLY.E., LATRILEE.E., CARRERE.H., STEYER.J. (2010).Hydrogen production from agricultural waste by dark fermentation: a review. International Journal of Hydrogen Energy, 35, 10660-10673. [12] OH. S.E., IYER,P., BRUNS, M.A., LOGAN, BE. Biological hydrogen production using a membrane bioreactor. Biotechnology Bioenginnering, 87 (1), 119-127., 2004. [13] FAN.K. KAN.N., LAY.J. (2006). Effect of hydraulic retention time on anaerobic hydrogenesis in CSTR. Bioresource Technolog, 97(1), 84-89. RESULTS The Table 1 show the main characteristic of the brewery wastewater. This type of wastewater has a good biodegradability, a high concentration of carbohydrates and nutrients as the nitrogen and phosphorous. This wastewater has a considerable content of volatile acids. www.iwahq.org Wastewater of Brewery Industry Raw material H2 HDT : 2 hour ORL: 9,41 gCOD/L.day Operation time: 62 days Source of inoculum: UASB from Brewery Wastewater Plant Pre-treatment of the inoculum: 90°C/15 min [4] Mineral medium: [7] Adjustment of pH in the influent : 5,5 Which were the operational conditions? ParametersReference pH, COD, BOD 5, [6] TSS, Sulfates, TP, TN Chlorides ParametersReference pH, COD, TSS, Flow[6] Total Alkalinity, TVA [8] Biogas compositionGC Agilent 7890A Carbonplot column 1010 Carrier Flow (He): 1.5 mL/min What was measured? How was characterized the BWW? Brewery wastewater plant (BWWP) Scheme of the UASB reactor UASB Reactor Dark fermentation ParametersUnitMean±S.D CODmg/L868±174 pHUnits7±1,1 TAmg/L1628±492 TVA mg/L1720±317 TSS mg/L356±40 PO 4 mg/L76±43 TNmg/L32±10 SO 4 mg/L97±61 Cl-mg/L144±37 Table 1. Main characteristics of the Brewery Wastewater Figure 1. Hydrogen and methane production (%) In the UASB reactor Figure 2. Hydrogen vs pH in the effluent The Figure 1 and Figure 2 show the production of gas hydrogen during 62 days of continues operation. The production was not stable. The maximum value of H 2 was 21%. The pH in the effluent was constant and close to 5.5. The gas methane appears during the entire operation time. There was not observed granulation of the sludge. Was observed small particles of colour grey and white inside the reactor.