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THE 28 TH CONFERENCE OF THE FEDERATION OF ENGINEERING ORGANIZATIONS CAFEO 28 HANOI VIETNAM, 30 TH NOV. - 2 ND DEC., 2010 TITLE: BIOHYDROGEN PRODUCTION BY ANAEROBIC BAFFLED REACTOR FROM WASTEWATER OF SEASONING SAUCE FACTORY AUTHOR(S)’ NAME(S): Mr.Verapat Rittapirom* and Associate Professor, Doctor Thares Srisatit** ORGANIZATION & DESIGNATION: Department of Environmental Engineering, Chulalongkorn University, Bangkok Thailand. ADDRESS: 359/133 Soi 3 Moo 5 Sub-district Salaya district Puttamonthon Province Nakhonprathom 73170* Department of Environmental Engineering, Chulalongkorn University, Bangkok Thailand.** TEL: 086-5887892* 081-9272352** FAX: 02-2186666** EMAIL: jimmy_jom23@hotmail.com* thares.S@chula.ac.th** Verapat Rittapirom BIOHYDROGEN PRODUCTION BY ANAEROBIC BAFFLED REACTOR FROM WASTEWATER OF SEASONING SAUCE FACTORY Verapat Rittapirom* and Thares Srisatit** Department of Environmental Engineering, Chulalongkorn University, Bangkok Thailand, jimmy_jom23@hotmail.com* thares.S@chula.ac.th** ABSTRACT Hydrogen power has long been heralded as the renewable energy source of the future because of its cost effectiveness and low environmental impact. So, this research it is very interested in hydrogen (H 2 ) gas production by using a three chambered anaerobic baffled reactor (ABR) from wastewater of seasoning sauce factory (the average total COD value was found to be around 14,000-18,000 mg/l and pH~3-4). The reactor was inoculated with thermally pretreated anaerobic sludge (80 °C and 110 °C 30 minutes) compare with non pretreated and operated with constant hydraulic retention time (HRT) of 5 days at room temperature. H 2 is generated under the acidogenesis and acetogenesis phase before transforming to be methane (CH 4 ). While, ABR operation found that inoculated with thermally pretreated at 110°C promoted % hydrogen production in biogas with initial pH 5 showed higher H 2 production of 39-41% of the maximum were reported. The ABR has the potential to provide a higher efficiency at higher loading rates and be applicable for extreme environmental conditions and inhibitory compounds. INTRODUCTION Rising oil prices, finite fossil fuel reserves, environmental degradation, and concerns about looming climatic changes are driving a concerted search for renewable energy sources. A large fraction of current fossil fuel consumption is due to the transportation sector which relies almost exclusively on the use of liquid fossil fuels. Partial or complete replacement of presently used carburants, gasoline or diesel, with a renewable energy carrier is thus key to averting or reducing the impending crisis (Hallenbeck, 2009). The need for alternative energy sources has increased in recent years, due to rapid depletion of fossil fuels. Direct utilization of fossil fuels results in considerable Environmental problems due to CO 2 , SO X , NO X emissions causing air pollution and global warming. Hydrogen gas is a clean fuel with no CO 2 emissions and can easily be used in fuel cells for electricity generation. Besides, hydrogen has a high energy content of 122 kJ/g, which is 2.75 times greater than hydrocarbon fuels. Hydrogen is considered as the major energy carrier of the future. Biomass and water can be used as renewable resources for hydrogen gas production (Argun et al., 2008). Bioprocesses have been given special attention for hydrogen production in the last thirty years due to operation under mild conditions (25–35 o C, 1 atm), the production of bio-hydrogen from renewable sources such as biomass has considerable advantages over other alternatives, Biohydrogen production can be realized by anaerobic (dark fermentation) microorganisms using carbohydrate rich biomass as a renewable resource (Kapdan and Kagi, 2006). This is an experimental research in laboratory, initial screening and optimize of initial pH that significantly influence on hydrogen production from wastewater of seasoning sauce factory in a continuous bio-hydrogen process using anaerobic mixed cultures in the Anaerobic Baffled Reactor (ABR) to study the performance of H 2 production and optimum pH condition on H 2 production . All of experimental study the microbial for H 2 production by temperature control during fermentation for 3 point i.e. at the worst case (%minimum hydrogen production), medium case (%medium hydrogen production) and best case (the optimum which %maximum hydrogen production) using Gas Chromatography-TCD detector(Thermo Finnigan). MATERIALS AND METHODS 1. Anaerobic Baffled Reactor (ABR) The ABR consisted of a rectangular, Plexiglas reactor (inside dimensions: length = 42 cm, height = 35 cm, width = 12 cm) with active volume about 12 L which divided into three compartments. Round openings with a diameter of 2.5 cm from the backside of the Plexiglas sheets separated the compartments. These openings were placed at the bottom to create sufficient contact between biomass and substrate. The flow over the horizontal plane of the reactor was reversed once a week. A weekly change in flow direction was chosen to prevent a pH drop due to VFA build up in the initial compartment and to prevent unequal biomass levels due to anticipated biomass migration between compartments. The samples will be withdraw from the ABR reactor. A structure and schematic of the lab-scale of ABR used in this study is presented in Figure 1. Fig. 1 Schematic configuration of lab-scale ABR . 2. Material - 3 model of lab-scale ABR (12 L active volume follow fig. 1). - 3 of Metering pump. - 3 of Counter gas by using water displacement. - 6 of 15 L Plastic tank. 3. Feed wastewater and mix cultures inoculum preparation Seasoning sauce factory wastewater, which was used in this investigation, was obtained from a local processing plant Bangpu Industrial Estate, Samut Prakan province, Thailand. The raw wastewater contained COD of 14,000–18,000 mg/L, Effluent Tank Total gas Measurement Feeding Tank pH meter Gas sampling 1 2 2 2 3 4 5 ⊗ ⊗ ⊗ BOD of 6,000–10,000 mg/L, total solids (TS) of 10,260-10,752 mg/L, total suspended solids(TSS) of 3,400–4,000 mg/L, total nitrogen (TN) of 14 mg/L, total phosphorus (TP) of 9.68 mg/L ,total volatile fatty acid(VFA) of 1483 mg/L and had a pH of 3.7– 4.0. The reactor was initially seeded with flocculent anaerobic sewage sludge collected from one of the UASB reactor located from fruit juice industry, Nakhonprathom, Thailand and was then introduced uniformly into all three compartments of the ABR. Each 4 L compartment contained 1.2 L sludge. The microorganism seed was heat treated at various temperatures ranging from 80ºC to 110 ºC for 30 minutes to inactivate the non-spore forming methanogens. The heat- treated inoculum (HTI) was spore stained. The harvested spore forming acitogens are used for producing hydrogen from seasoning sauce wastewater. 4. Analytical methods COD, BOD, TSS, TS, pH, and oxidation-reduction potential (ORP) were measured according to standard methods(APHA, 1995). The biogas constituents (H 2 , CO 2 and CH 4 ) were analyzed by a gas chromatogram (GC, Thermo Finnigan) with a thermal conductivity detector (TCD) and shin carbon column packed. The concentrations of VFAs were measured using another gas chromatograph(GC, Agilent 4890D) with a flame ionization detector (FID)and a2 m stainless column packed with Porapak GDX103 (60/80 mesh).COD, pH, biogas volume and ORP were measured or monitored daily.BOD, VFAs, TS, TSS and biogas yield were measured once every 5 days . 5. Operation of anaerobic baffled reactor Barber and Stuckey (1998) had suggested to initially use long detention time (80 h) to startup the ABR and to reduce it in stepwise fashion while maintaining a constant incoming substrate concentration. It provides greater reactor stability and superior reactor performance. The investigation was carried out with a constant hydraulic retention time (HRT) and varying influent COD concentration .The ABR was fed with different concentration diluted seasoning sauce factory wastewater at constant HRT value corresponding to organic loading rate of 1 and 2 kgCOD/m 3 -d, respectively. The experiment in this study consisted of two subsequent [A = initial pH 3-4 and B = initial pH 5] (shown in Table 1). Table 1 The operation parameter of ABR start up. The loading rates were only increased when steady state conditions were obtained for the existing loading condition. In general, a steady state condition was believed to have been reached when a relatively small variation in the levels of determinants of the final effluent for two different samples. The ABR reactor was Operation stage HRT (days) T (°C) Influent pH value Influent COD concentration (mg/L) OLR (kgCOD/ m 3 d) 1st stage 2nd stage 5 5 Room temp. Room temp. A and B A and B 5,000 11,000 1 2 operated continuously until reached constant COD removal during the start-up period. Then it was operated with increasing COD concentrations from 5,000– 5,200 mg/L to 9,000–11,000 mg/L, When effluent COD in the bioreactor became constant, the samples were collected and subjected to the analysis of the following parameters, i.e. feed and effluent COD, effluent total volatile acid; reactor pH, gas production and composition. The experiment in this study consisted of two subsequent [A = initial pH 3-4 and B = initial pH 5], each subsequent were as follow:ABR1 non-treated sludge.ABR2 thermally pretreated anaerobic sludge 80 °C for 30 minutes and ABR3 thermally pretreated anaerobic sludge 110 °C for 30 minutes) by ratio between anaerobic sludge : wastewater = 30% : 70% [shown in Fig. 2] RESULTS AND DISCUSSION 1. COD removal. Feeding was started at a soluble COD feed concentration of 5,000 mg/L at HRT of 5 days (OLR = 1 kg COD/m3d) (Fig. 3A and 3B).From the very decreasing COD removal effluent were in the range of 40-50% of influent COD and after 15 days of startup, feeding soluble COD of 11,000 mg/L until effluent COD of both initial pH 3-4 and 5 have stability of the process. After that operation process was started at 14,000-18,000 mg/l COD concentration of raw seasoning sauce wastewater from data in Fig. 3A and 3B at HRT of 5 days[day 36-60]. Wastewater [A and B] ABR 1 ABR 2 ABR 3 Parameters analysis Fig. 2 Experimental procedure Sludge : Wastewater ratio = 30% : 70% Biogas analysis Effluent analysis - Volume of biogas production - % Hydrogen in biogas - COD - BOD - VFAs - TS & TSS It was operated from day 33 to day 55 at Fig. 3A, Effluent COD of ABR1, ABR2 and ABR3 were 11,979 12,301 and 12,697 mg/L, respectively.It shown that the rate of COD removal were declined from the day 48 to the day 55 and in Fig. 3B shown that COD effluent was declined at the day 34 to the day 60 , Effluent COD of ABR1, ABR2 and ABR3 were 9084 10,612 and 10,723 mg/L, respectively. So, All of COD removal efficiency of Initial pH 5 was generally better than Initial pH 3-4 condition in Table 2. HRT [Days] Seed conditions Influent COD [mg/L] Initial pH 3-4 without pH adjustment Initial pH 5 with pH adjustment Effluent COD[mg/L] % COD removal Effluent COD[mg/L] % COD removal 5 ABR 1 18,000 11,979 33.45 9,084 49.53 5 ABR 2 18,000 12,301 31.66 10,612 41.04 5 ABR 3 18,000 12,697 29.46 10,723 40.43 A 0 5000 10000 15000 20000 0 102030405060 Days COD (mg/L) Inf. COD Eff. COD ABR1 Eff. COD ABR2 Eff. COD ABR3 B 0 5000 10000 15000 20000 0 102030405060 Days COD(mg/L) Inf. COD Eff. COD ABR1 Eff. COD ABR2 Eff. COD ABR3 Fig. 3 ABR performance of influent and effluent COD concentration. Table 2 COD removal with 5 days HRT. 2. Variation of VFA concentrations The profiles of VFAs in different initial pH and microorganism seed conditions are depicted in Fig. 4. It shown that VFAs was generated immediately of acidogenic degradation of seasoning sauce wastewater in the ABR. It is inferred from the Figures 4 that during the initial days, VFAs concentration increased rapidly at the beginning of the operate system [at the day 3- the day 12] and after that VFAs concentration declined until at 2000 mg/L at the day 24. Production of various volatile fatty acids in the acitogenic stage may be the reason for increasing VFAs concentration in the earlier days (Shin, Youn and Kim, 2004). The reduction in VFAs may be due to their conversion into gaseous products. 3. Biogas and %hydrogen productivity Biogas productivity per gm COD removed at the different initial pH [5A initial pH 3-4 and 5B initial pH 5] are shown in Fig. 5A and 5B.Initialy Cumulative gas production of initial pH 3-4 was lower than pH 5 (Fig. 5). The reason for low gas production because of the fermentation are not arrive at acitogenesis and low pH of wastewater . Some fraction of the gas produced solubilized in reactor effluent and escaped from collection. At steady state of fig. 5A, average biogas productions in case of ABR1, ABR2 and ABR3 of 5 days HRTs were 34.88, 33.34 and 28.29 ml/g COD removed, respectively. At steady state of fig. 5B, average biogas productions in case Initail pH 3-4[raw wastewater] 0 2000 4000 6000 8000 10000 0 3 6 9 12 15 18 21 24 Days VFA [mg/L] ABR 1 ABR 2 ABR 3 Initial pH 5 0 2000 4000 6000 8000 0 3 6 9 12 15 18 21 24 Days VFA [mg/L] ABR 1 ABR 2 ABR 3 Fig.4. VFA profiles in different initial pH . of ABR1, ABR2 and ABR3 of 5 days HRTs were 26.92, 29.78 and 26.11 ml/g COD removed, respectively. The high %hydrogen production by ABR in this study could be explained on the basis of least two arguments: [i] has optimum initial pH values was 5.At this pH, both methanogenesis and solventogenesis can be avoided or minimized [both processes would decrease %hydrogen production].In this study, it seems that the initial pH 5 in this study was higher than initial pH 3-4[raw wastewater]Fig.6;[ii] Inoculated with sludge heat-treated at 110 °C for 30 minutes has been reported that the acidogenesis hydrogen-producing consortia are enriched in Clostridium, most being heat resistant. 0 10 20 30 40 50 Initial pH 3-4 Initial pH 5 % Hydrogen in biogas ABR 1 ABR 2 ABR 3 Fig. 6 Performance of % Hydrogen production in biogas. B 0 20 40 60 80 100 0 5 10 15 20 25 30 Days Biogas [ml/g COD removed] ABR 1 ABR 2 ABR 3 A 0 20 40 60 80 100 120 0 5 10 15 20 25Days Biogas [ml/gCOD removed] ABR 1 ABR 2 ABR 3 Fig.5. Biogas production per gm COD removal in different initial pH. The maximum amount of percentage hydrogen in biogas was produced at initial pH 5 among investigated pH values shown in Fig. 6 at pH 5 the maximum %hydrogen production of ABR3, ABR2 and ABR1 reached 39-41%, 26-31% and 23- 27%, respectively. CONCLUSION Both the initial pH [pH 3-4 and pH 5] using the organic fraction of seasoning sauce wastewater seems to be attractive for hydrogen generation, Cause pH conditions effect to acidogenesis process but initial pH 5 experiment was considered better than initial pH 3-4,that enhancing percentage hydrogen production after bacterial stress by using dry heat at 110 °C 30 minutes. REFERANCE Argun, H., Kargi, F., Kaptan, I.K. and Oztekin, R.2008.Biohydrogen production by dark fermentation of wheat powder solution: Effects of C/N and C/P ratio on hydrogen yield and formation rate. Int J Hydrogen Energy , 33: 1813 – 1819. APHA.1998. American Public Health Association Standard Methods for the Examination of Water and Waste Water . 20 th ed. 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