1 AIT Asian Institute of Technology

Anaerobic digestion of municipal solid waste in thermophilic continuous operation

AuthorChea Eliyan
Call NumberAIT Thesis no.EV-07-6
Subject(s)Refuse and refuse disposal--Thailand--Pathum Thani
NoteA thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Environmental Engineering and Management, School of Environment, Resource and Development
PublisherAsian Institute of Technology
AbstractThe process for waste stabilization prior to landfill is very attractive in managing municipal solid waste (MSW). Thus, the main goal of this study is to assess the effectiveness of the anaerobic digestion method as the pretreatment technology of organic fraction of municipal solid waste (OFMSW) prior to landfill. On that account, a pilot study was conducted in inclined type horizontal anaerobic digester. During the initial period of starting up the process, the reactor was operated under mesophilic condition (37°C), and then the system was shifted to thermophilic condition (55°C) by gradually increasing the temperature at the rate of 2°C per day. Result showed there was no any stress situation was found as methane composition in biogas keeps increasing and reached the maximum value of 66% at day 19. The highest volume of biogas production (520 L/ day) was also achieved at the same day. In the second phase of this study, the influence of mass retention time (MRT) on the digestion process with higher organic loading rate was investigated. Two feeding rates of 2 kg VS/m3.day and 2.5 kg VS/M3.day were conducted under draw-feed mode are described with the retention time of 25 and 20 days, respectively. The highest VS degradation yield of around 51%, with a biogas production rate of 245 L/kg VS add were achieved with a retention time of 25 days. However, the methane content of the biogas generated from the reactor was in the range of 30-40%. The problem on the drop of methane concentration was traced on the technical problems on reactor configuration and not with the process. The fate of heavy metals in the digestion process was also investigated. This study confirmed that heavy metals and nutrients concentration of digestate complies with WHO guideline and can be used as fertilizer. The net energy yield from the process was also studied to indicate the energy surplus from the system. Moreover, the digestate from the process was analyzed for its calorific value content. Based on EURITS, the residue might have a potential to be used as a material for refuse derived fuel (RDF) since its calorific value was found to be 11.16 MJ/kg
Year2007
TypeThesis
SchoolSchool of Environment, Resources, and Development (SERD)
DepartmentDepartment of Energy and Climate Change (Former title: Department of Energy, Environment, and Climate Change (DEECC))
Academic Program/FoSEnvironmental Engineering and Management (EV)
Chairperson(s)Visvanathan, C.
Examination Committee(s)Chongrak Polprasert;Chart Chiemchaisri
Scholarship Donor(s)SWEDEN (Sida)
DegreeThesis (M.Sc.) - Asian Institute of Technology, 2007


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