Real-time control strategies were developed for biological systems requiring exposure to a number of different redox environments. The approach taken was to develop control strategies under static redox conditions, and then merge them into a unified scheme. The anoxic system studied consisted of the removal of oxidized nitrogen by Pseudomonas denitrificans. A control strategy that was based on detecting an inflection point in the transient ORP signal was applied. The inflection point was detected by searching for a minimum in the first derivative. Using this approach, all of the nitrate and nitrite was removed each cycle. Aerobic removal of toluene, performed by Pseudomonas putida, was then studied. In this system, the optimal strategy involved the second derivative of the transient ORP signal, and resulted in toluene removal efficiencies on the order of 95% per cycle. Finally, an attempt was made to automate a process requiring exposure to both anoxic and aerobic environments. In this system, oxidized nitrogen was removed under anoxic conditions, while carbon removal continued under an aerobic environment. Both processes were mediated by Pseudomonas denitrificans. This attempt was only partially successful. While little oxidized nitrogen remained at the end of the anoxic cycle, a significant amount of nitrite reappeared in the medium upon exposure to aerobic conditions. This result served to indicate the importance of the transition zone, and the difficulties associated with controlling sequential environments.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.35681 |
| Date | January 1998 |
| Creators | Brown, Wayne A. |
| Contributors | Cooper, D. G. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Chemical Engineering.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001781028, proquestno: NQ50121, Theses scanned by UMI/ProQuest. |
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