Tesis doctoral de Anna MontrÁ s Boet
Melissa (micro ecological life support system alternative) is the system developed by the european space agency (esa) and the melissa consortium in the field of life support for long term manned missions in space. Based on the principle of an aquatic ecosystem, melissa was conceived as a tool to develop the required technology for a future biological life support system. Its final aim is the production of food, fresh water and oxygen from the organic wastes of a crew. to achieve this goal, the melissa concept is based on the use of five interconnected compartments colonised by several microorganisms and higher plants. This thesis is focused on the third compartment of the melissa loop, in which ammonium is converted to nitrate, the most suitable nitrogen source for the growth of the bacteria and higher plants colonising the photosynthetic compartment. The biological oxidation of ammonium to nitrate, which consists of two successive reactions carried out by two different bacterial strains, takes place in a packed bed biofilm reactor. Nitrosomonas europaea and nitrobacter winogradskyi are immobilised on a polymeric support, with air flowing cocurrently with the feed medium. the pilot-scale reactor of compartment iii (ciii) had been in operation in the melissa pilot plant for several years before the start of the present work. The main contributions of this thesis are in increasing the understanding of the reactor performance by studying the nitrifying biofilm in depth, and by developing a mathematical model that allows the effects of different operational parameters on the process and on the biofilm structure, to be studied. Moreover, continuous monitoring of the nitrifying efficiency will be improved by installing the necessary on-line equipment to experimentally measure the concentrations of all the nitrogen species in the liquid phase. The additional knowledge achieved on the reactor performance via this work will finally lead to re-design the reactor hardware for optimal performance in the melissa pilot plant.
Datos académicos de la tesis doctoral «Mathematical modelling and molecular analysis of a nitrifying packed bed biofilm reactor«
- Título de la tesis: Mathematical modelling and molecular analysis of a nitrifying packed bed biofilm reactor
- Autor: Anna MontrÁ s Boet
- Universidad: Autónoma de barcelona
- Fecha de lectura de la tesis: 24/04/2009
Dirección y tribunal
- Director de la tesis
- Francesc Godia Casablancas
- Tribunal
- Presidente del tribunal: max Mergeay
- cristian Picioreanu (vocal)
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- (vocal)