Name: KÉZYA CRISTINA FRIZZERA NUNES
Type: MSc dissertation
Publication date: 27/02/2019
Advisor:
Name |
Role |
|---|---|
| SÉRVIO TÚLIO ALVES CASSINI | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| ADRIANA MÁRCIA NICOLAU KORRES | External Examiner * |
| RICARDO FRANCI GONÇALVES | Internal Examiner * |
| SÉRVIO TÚLIO ALVES CASSINI | Advisor * |
Summary: The current scenario of water crisis has increasingly raised the issue of water use. Much has been discussed about water reuse and alternative sources for not-so-noble purposes, a much-used source today is gray water. Gray water is all wastewater from the shower, washbasins, washing machines and tanks, usually water is excluded from the kitchen sink because of the large amount of organic matter present. Water is produced in abundance in a residence, has less organic matter than domestic sewage. Although it has many advantages, gray water must be treated before its reuse since it has a large amount of microorganism present, among them Escherichia coli. Generally, the gray water produced is stored for hours, or even days until its use, with which it can occur increase of the microorganisms present, due to favorable conditions in that environment. The present work aims to analyze the behavior of Escherichia coli isolated from the medium in gray water under different conditions: crude gray water, sterile crude gray water and sterile crude gray water supplemented with nutrients (phosphorus, nitrogen and glucose). Survival / growth curves were plotted for each distinct condition. Assays supplemented with nutrients showed different behavior. Escherichia coli in the presence of phosphorus did not show significant change in behavior, even this nutrient being considered so important in the growth and survival of Escherichia coli. In the presence of nitrogen, even with its toxicity, Escherichia coli presented significant growth, especially when using different amounts of this nutrient. Even using a not recommended carbon source, in the case of dextrose, glucose was shown to be the nutrient with the highest growth value in the samples analyzed. With this it was possible to conclude that even with low amount or excess of nutrients Escherichia coli is able to grow / survive in the medium. Furthermore, in the tests WHERE there is competition of microorganism by nutrients, in the case of raw gray water, the absence (not detectable to the method used) of Escherichia coli was observed possibly due to competition between other microorganisms present in the medium.
