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Title:	Thermophilic biohydrogen production using attached biofilm on granular activated carbon as microbial carriers
Authors:	Nur Syakina Jamali (P72362)
Supervisor:	Jamaliah Md Jahim, Prof. Dr.
Keywords:	Fermentation Biofilm Hydrogen Universiti Kebangsaan Malaysia -- Dissertations
Issue Date:	23-Aug-2017
Description:	Production of hydrogen (H2) through anaerobic dark fermentation is an eco-friendly process, and was found as a viable alternative energy to replace fossil fuels. At thermophilic fermentation, this research was aimed to produce hydrogen using attached biofilm by immobilization method on granular activated carbon (GAC) as microbial support carrier. In first objective, the suitability between single culture (Caldicellulorsiruptor saccharolyticus) and mixed culture used for thermophilic biofilm development were evaluated. Factors affecting hydrogen production such as operating pH, operating temperature and sludge percentage were optimized using response surface methodology (RSM). The second objective involved characterization and optimization of GAC prior developing the attached-biofilm. The biofilm was further developed in a sequencing batch through controlled acclimatization condition at optimised GAC conditions. The biofilm was further analysed from 16S rRNA to determine the dominated species found in the biofilm. The attached-biofilm formed was further applied in 16 L fluidized bed reactor (FBR) in third objective. The experiments were started with repeated batch fermentation, followed by sequencing batch fermentation using synthetic medium and palm oil mill effluent (POME) medium at HRT 48, 24, 12, 6 and 3 hour. Lastly in final objective of this research, kinetic study was conducted to determine microbial specific growth rate of attached-biofilm in utilizing optimum amount of sugar. By considering results obtained from FBR fermentation, hydrodynamic study was also conducted in order to investigate the fluidization system in the FBR. In this research, mixed culture was chosen as sludge for biofilm development. From RSM, the empirical model suggested that the optimum conditions for H2 production were at pH 6, temperature 60°C, and sludge percentage of 10%. The optimization of GAC found that, at 0.44 cm3/g was the optimum size and 1 (sludge) to 2 (GAC) in (v/v) was the optimum ratio for biofilm formation. The immobilization was conducted until 60 days to form attached-biofilm on the GAC and found that, the Thermoanaerobacterium thermosaccharolyticum sp. was the dominated species in the biofilm analysed by 16S rRNA. The performance of the attached-biofilm in FBR was revealed that, at HRT 6 h, the maximum HPR of 7.8 mmol H2/L.h was obtained in synthetic medium fermentation. Meanwhile, in POME fermentation, maximum HPR of 5.2 mmol H2/L.h was attained at HRT 12 h. Thermoanaerobacterium sp. was observed as a major microbial component in all HRTs studied analysed by DGGE. The biofilm was investigated on cellulosic degradation performance and found that, the microbes were able to consume more than amount of soluble sugar present in the POME owing of its capability in hydrolyzing polymeric sugar of cellulosic fiber in the POME. Lastly, from Monod kinetic analyses, the maximum specific growth rate (μmax) obtained was 0.31 ± 0.01 h-1 subjected of utilizing an optimum 20 g/L level of sugar. In order for the FBR to be properly fluidized, empirical model of minimum fluidization velocity (Umf) was developed. For adequate fluidization system, the entering fluid's superficial velocity (Uo) was designed to be bigger than the Umf, whereas to avoid washout of immobilised particles from reactor, the maximum fluidization velocity (Umax,f) must always be lowered than the terminal settling velocity of the particles (Ut,s) of 2.11 cm/s as was attained experimentally in this studied. Overall, this study has successfully reached the target goals for the replacement of fossil fuel, and enhancing microbial cell density at high temperature operation in dark fermentation.,Certification of Master's/Doctoral Thesis" is not available
Pages:	255
Call Number:	TJ808.N847 2017 3 tesis
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Engineering and Built Environment / Fakulti Kejuruteraan dan Alam Bina

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