Effect of hydraulic retention time and feeding strategy of a household anaerobic digester treating food waste

Sagor Kumar Pramanik (P90700)

Please use this identifier to cite or link to this item: https://ptsldigital.ukm.my/jspui/handle/123456789/457849

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DC Field	Value	Language
dc.contributor.advisor	Fatihah Suja, Prof. Dr.
dc.contributor.author	Sagor Kumar Pramanik (P90700)
dc.date.accessioned	2023-09-12T09:14:18Z	-
dc.date.available	2023-09-12T09:14:18Z	-
dc.date.issued	2020-03-04
dc.identifier.other	ukmvital:123705
dc.identifier.uri	https://ptsldigital.ukm.my/jspui/handle/123456789/457849	-
dc.description	The improper management and uncontrolled discharge of huge amounts of food waste (FW) has been creating environmental pollution and sanitation related problems. Anaerobic digestion (AD) is considered to be the most attractive and widely applied technique for the treatment of FW since it produces an energy rich gas in the form of methane and minimizes the quantity of waste. The aim of the study was to investigate the effect of hydraulic retention time (HRT) on the process performance and microbial community composition of an anaerobic single-stage household reactor for treating food waste. The effect of feeding mode on process performance and biogas production was also studied. Single-stage semi-pilot anaerobic reactor (160L) was operated with a working volume of 124 L. The reactor was operated upon two phases for a total of 255 days. During the first phase, the reactor was operated over 78 days and FW was fed every 2-3 days. In the second phase, the reactor was conducted over 178 days and FW was fed once-per-day. Results displayed that the performance of single-stage household reactor was clearly influenced by HRT and feeding mode in terms of biogas production rate, biogas yield, methane yield, intermediate metabolism, volatile solids (VS) and chemical oxygen demand (COD) removal efficiency. The maximum average biogas and methane yield of 0.79 0.17 L/g VSadded and 0.55 0.13 LCH4/g VSadded, respectively, were achieved at an HRT of 124 days. When HRT decreased to 62 days, the average volatile fatty acid (VFA) and ammonia concentration increased rapidly whereas the average pH, methane yield, and biogas yield decreased gradually. Daily feeding mode displayed better process performance compared with every 2-3 days feeding mode. The highest biogas and methane yield of daily feeding mode was increased by almost 11 and 15 . respectively, compared with that of every 2-3 days feeding mode. The accumulation of VFA was noticed in both feeding modes but the accumulation of ammonia was only found in every two-three days feeding mode. Higher VS (92.7 ) and COD (95.84 ) removal were observed in daily feeding mode compared to every 2-3 days feeding mode. VS and COD removal efficiency in daily feeding mode increased by 8 and 10, respectively compared with every 2-3 days feeding mode. Four kinetic models-the first-order kinetic model, the modified Gompertz model, the logistic function model and the Cone model -were used to fit the cumulative methane production obtained from the experimental data. The kinetic study showed that the modified Gompertz model for both feeding mode had the best fit (coefficient of determination (R 2) value 0.994 -0.998) with the experimental data out of the four models. Pyrosequencing results displayed significant shifts in the microbial community during operation under decreased HRT. Bacteroidetes and Firmicutes were the most dominant bacterial phyla, while Methanomicrobiales, Methanosarcinales and Methanobacteriales were the most dominant archaeal order during operation under decreased HRT. Hydrogenotrophic methanogenesis was the main pathway to produce methane from hydrogen and carbon dioxide during 124-day HRT, although acetoclastic methanogenesis also contributed. The domain methanogens involved in the anaerobic digestion process are partially washed-out from the reactor during 31-day HRT which could be the cause of process failure. These results indicated the performance of single stage household reactor was significantly affected by HRT and feeding mode. The experimental results would serve as useful information to understand the performance of single-stage household AD system.,Master of Science
dc.language.iso	eng
dc.publisher	UKM, Bangi
dc.relation	Faculty of Engineering and Built Environment / Fakulti Kejuruteraan dan Alam Bina
dc.rights	UKM
dc.subject	Universiti Kebangsaan Malaysia -- Dissertations
dc.subject	Dissertations, Academic -- Malaysia
dc.subject	Hydraulic retention
dc.subject	Feeding strategy
dc.subject	Waste
dc.title	Effect of hydraulic retention time and feeding strategy of a household anaerobic digester treating food waste
dc.type	theses
dc.format.pages	162
dc.identifier.barcode	005774(2021)(PL2)
Appears in Collections:	Faculty of Engineering and Built Environment / Fakulti Kejuruteraan dan Alam Bina

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