 | Fishing for indigenous anammox bacteria |
| Expanded Title: | Anammox (anaerobic ammonium oxidizing) bacteria are slow-growing, anaerobic autotrophs that convert ammonium and nitrite to dinitrogen gas. Consequently, these bacteria require 25 % less metabolic energy than the bacteria employed in conventional biological nitrogen removal processes. In addition, these bacteria do not need an organic carbon source and have a low sludge production. Sludge and energy are two major challenges in the operation of wastewater works. The primary aim of this project was to identify and verify the presence of anammox bacteria in samples obtained from various anaerobic habitats in South Africa and to enrich for the organisms. Samples were obtained from anerobic and activated sludge plants from around Cape Town. In addition, sediment mud samples were obtained from the ocean. The results may be summarised as follows:
1) Microbiological techniques demonstrated albeit low levels of anammox bacteria in ocean and wastewater samples.
2) Enrichment proved to be difficult and the research resulted in recommendations for future enrichment studies. Enrichment screening for anammox bacteria in small-volume reactors can be considered ineffective, since oxygen toxicity has a greater impact due to diffusion.
3) The microbiological techniques of FISH, 16S gene sequencing and pyrosequencing were effective to varying degrees in identifying anammox bacteria.
While all objectives were not fully realised due to the sensitivity of the organisms, the benefit of this biological nitrogen removal process remains attractive, and the establishment of viable anammox populations from the environment still remain the most important step in this work. Since the presence of anammox bacteria was demonstrated in natural and man made environments in South Africa, the effective harnessing of these indigenous bacteria to improve wastewater treatment would be an ideal outcome, if this work is further pursued. A key reccommendation for future research is the use of seed anammox bacteria from an existing anammox process or the lengthening of the enrichment period to greater than 2 years. |
| Date Published: | 01/12/2011 |
| Document Type: | Research Report |
| Document Subjects: | Water Resource Management/IWRM - Planning and development, Ecosystem - Resource Economics |
| Document Format: | Report |
| Document File Type: | pdf |
| Research Report Type: | Standard |
| WRC Report No: | 1823/1/11 |
| ISBN No: | 978-1-4312-0209-6 |
| Authors: | Stone W; Wilsenach JA; Mouton M; Botha A |
| Project No: | K5/1823 |
| Originator: | WRC |
| Organizations: | University of Stellenbosch; Virtual Consulting |
| Document Size: | 6 100 KB |
| Attachments: | EXECUTIVE SUMMARY for 1823.pdf
Table of Contents for 1823.PNG
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