بررسي فرآيند هضم بي هوازي ضايعات سيب زميني در سيستم دو مرحله اي Mixed-UASB

چكيده انگليسي :

Investigation of Anaerobic Digestion of Potato Leachate in Two Stage Mixed UASB System Behzad Kamiab b kamyab@ce iut ac ir Date of submission March 3 2012 Department of Chemical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Hamid Zilouei hzilouei@cc iut ac irAbstractDeveloping processes of alternative energy for fossil fuel is increasing interest because of both environmental andeconomical aspects Increasing price of fossil based products together with increasing of environmental pollutionare potentials for increasing interest for sustainable and renewable energy sources Among the renewable energytechnologies such as waterfall solar wind and so on biogas production from organic matter present in industrialwastes has had growing attention during last decades Biogas is mainly composed of methane and carbon dioxideproduced as a result of synergistic interaction of bacterial community so called anaerobic digestion Anaerobicdigestion involves the degradation and stabilization of degradable organic materials under anaerobic conditions bydifferent bacterial groups including acidogenesis acetogenesis and methanogenesis bacteria which lead to theformation of biogas and microbial biomass High straight wastewaters from food dairy and beverage industries aswell as agricultural wastes are good options for this purpose Anaerobic digesters often exhibit significant stabilityproblems that may be avoided only through appropriate control strategies Such strategies require in general thedevelopment of appropriate mathematical models which adequately portray the key processes that take place In thisresearch modeling and simulation of a two stage system for anaerobic digestion of potato leachate was performed In order to perform the anaerobic digestion under optimum conditions hydrolysis and acidogenesis steps wereperformed in a mixed reactor followed by methanogenesis in a UASB reactor Known amount of sliced potato wasplaced in a first reactor and after hydrolysis and acidogenesis activities flow rate containing acetate was transferredto second reactor which methane and carbon dioxide were produced under methanogenesis activity Both reactorswere operated under mesophilic temperature at 37 C There were assumed that both mixed and UASB reactorswere completely mixed and no methane was produced in the first reactor The influence of hydraulic retention timeand inlet concentration of wastewater on the response parameters of COD removal efficiency methane productionefficiency concentration of volatile fatty acids leaving the first reactor and concentration of acetate leaving thesecond reactor were predicted and compared with experimental data By increasing the hydraulic retention time upto 4 days removal efficiency of COD was increasing up to 80 65 while removal efficiency of COD was constantat hydraulic retention times more than 14 days Yield of methane production was decreased by increasing hydraulicretention time These results have been observed in experimental data when system has been stabilized with respectto hydraulic retention time after 17 days At hydraulic retention times less than 17 days the concentration of volatilefatty acids especially acetate was increasing in the first reactor which cause inhibitory effects on the methanogenicactivity of the second reactor This shows the importance of control of the two stage anaerobic digestion whichutilization and conversion of acetate in the first reactor is not performed Therefore concentration of acetate and itsinhibitory effect should be monitored After this overload system was checked and stabilized After this time system was working steadily and results of model were comparable to experimental data Keywords Biogas anaerobic digestion UASB reactor potato leachate two stage mesophilic

كامياب، بهزاد

بررسي فرآيند هضم بي هوازي ضايعات سيب زميني در سيستم دو مرحله اي Mixed-UASB

بيوگاز , مزوفيليك , راكتور بي هوازي با بستر جريان رو به بالا , اكسيژن خواهي شيميايي