Mesophilic anaerobic digestion conducted in single unit reactor at increasing ammonia concentrations
2011 (English)Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE credits
Student thesis
Abstract [en]
The use of mesophilic anaerobic digestion for treatment of organic wastes is a growing biotechnology for sustainable energy supply. Ammonia inhibition is a major problem in anaerobic digestion mainly when digestion of nitrogen-rich substrates such as livestock wastes and manure occurs. This paper provides a summary of research conducted on ammonia inhibition of the anaerobic process. An experiment with mesophilic digestions of swine manure was conducted in single unit reactors, which were controlled under different ammonia concentrations by addition of NH4Cl in different amounts. From the experimental results, it was shown that NH4Cl could be an effective chemical agent for removing foam and scum in the digester. Methane production was decreased with the increasing NH4Cl addition until a collapse was observed between 11.2 g NH4+-N/l and 13.2 g NH4+-N/l. Contrary to the findings in thermophilic digestion, a dysfunction of acidogenesis was also observed since both gas and methane production was delayed with increasing NH4Cl addition. These findings suggest different ammonia inhibition principles in mesophilic and thermophilic digestion. It was further indicated that methanogenesis could produce a high percentage of methane although gas production was inhibited.
Place, publisher, year, edition, pages
2011. , p. 35
Keywords [en]
biogas, mesophilic digestion, ammonia inhibition, methane
National Category
Renewable Bioenergy Research Environmental Sciences related to Agriculture and Land-use
Identifiers
URN: urn:nbn:se:hh:diva-16920OAI: oai:DiVA.org:hh-16920DiVA, id: diva2:480552
Subject / course
Environmental Science
Presentation
2011-09-12, N-236, Halmstad University, Halmstad, 15:15 (English)
Uppsok
Agriculture, Veterinary Medicine, Forestry
Supervisors
Examiners
2012-01-272012-01-132018-05-23Bibliographically approved