The growth of heterotrophic microbes in water distribution systems causes deteriorations in the quality of drinking water and increases corrosion of pipelines. Microbial growth in drinking water can also be prevented by efficient removal of nutrients required for microbial growth. The limiting nutrient for microbial growth in drinking water is supposed to be organic carbon or phosphorus. In central Europe and Northern America, microbial growth is generally limited by organic carbon, especially by a fraction called Assimilable Organic Carbon (AOC)
The AOC test was first proposed by Van der Kooij, the water samples are collected in very clean, AOC-free glassware, and then heated to kill the indigenous bacterial population and inoculated with one or more test organisms. The sample is incubated, and growth of the test organisms is monitored. The stationary-phase level (Nmax) of bacteria is proportional to the amount of limiting nutrient in the water. The nutrient level in a sample is converted into carbon equivalents with an empirically derived yield coefficient of the organism for a selected growth substrate. Cell yield with may vary different carbon compounds.
The time needed to perform the assay islimited by the incubation temperature, the inoculum density and sample volume. Therefore, the purpose of this study is to investigate the optimum conditions of AOC analysis to minimize the analytic time. Through this study, the results show that the optimum temperature is 20 ¢J, the optimum inoculum density is 400-500 CFU/mL, Biodegradable Total Organic Carbon (BTOC) and Biodegradable Organic Carbon (BDOC) test made AOC test without the need for plate count and increase the accuracy of AOC analysis.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0630108-125546 |
| Date | 30 June 2008 |
| Creators | Cheng, Yu-Ning |
| Contributors | Shui-Jen Chen, Wen-Chien Kuo, Jie-Chung Lou |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0630108-125546 |
| Rights | withheld, Copyright information available at source archive |
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