Characterization of the bacteriome of water treatment processes with next generation sequencing
Länsivaara, Annika (2020)
Länsivaara, Annika
2020
Master's Programme in Biomedical Technology
Lääketieteen ja terveysteknologian tiedekunta - Faculty of Medicine and Health Technology
This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited.
Hyväksymispäivämäärä
2020-11-12
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202010277525
https://urn.fi/URN:NBN:fi:tuni-202010277525
Tiivistelmä
Background and aims: Wastewater and drinking water treatment are affected by bacteria in water. An optimal treatment result is achieved when the bacteria in water are known, especially the pathogens. If water is not treated properly, a waterborne outbreak might follow. They happen annually in Finland and globally cause around two million deaths and an economic loss of 12 billion dollars per year. The bacteriome of water has been noted to differ between countries. The bacteriome of wastewater and drinking water have not been widely discovered in Finland. Thus, the goal of this study is to discover them. In addition, the aim is to study how effectively water treatment removes bacteria and how the bacteriomes of treatment facilities differ. Seasonality of the bacteriomes and relative bacterial amounts are also studied. Furthermore, pathogens commonly present in waters are screened from the samples to discover which of them are common in Finland.
Methods: 340 water samples were collected from different water processing fractions from 13 Finnish water treatment plants for two years. These samples were concentrated, and DNA was extracted. Relative quantification qPCR was performed to define the bacterial amounts of the samples. Different water processing fractions, treatment plants, and seasons were compared based on their bacterial amounts. Furthermore, 16S V4 hypervariable region targeting NGS was performed to discover the bacteriomes of water processing fractions. These results were also compared through different treatment plants and seasons. In addition, pathogens commonly present in waters were screened from the samples.
Results and conclusions: As expected, the bacterial amount of wastewater was high and that of drinking water low. Out of the drinking water samples, only a few sequences were obtained and thus it was not possible to discover its bacteriome reliably. The bacteriomes of different water processing fractions were unique. The diversity of the bacteriome as well as the bacterial amount reduced during the treatment process. The bacteriomes of Finnish water treatment fractions differed from those of other countries. The different water treatment plants showed differences in their bacteriomes as well as bacterial amounts showing that different treatment methods create differences. Seasonality was seen in both the bacteriome and bacterial amounts possibly due to changing weather and the seasonality of environmental and enteric bacteria. Effluent had mainly opportunistic pathogens. The biggest threat out of pathogens is most likely the genus Legionella as their amount was the highest in effluent and grew during the treatment process. To be able to discover the bacteriome of drinking water, the sample volume should be larger, or biofilm should be used. The discovery of the bacteriome at a more precise taxa level would require a wider sequencing of the 16S gene.
Methods: 340 water samples were collected from different water processing fractions from 13 Finnish water treatment plants for two years. These samples were concentrated, and DNA was extracted. Relative quantification qPCR was performed to define the bacterial amounts of the samples. Different water processing fractions, treatment plants, and seasons were compared based on their bacterial amounts. Furthermore, 16S V4 hypervariable region targeting NGS was performed to discover the bacteriomes of water processing fractions. These results were also compared through different treatment plants and seasons. In addition, pathogens commonly present in waters were screened from the samples.
Results and conclusions: As expected, the bacterial amount of wastewater was high and that of drinking water low. Out of the drinking water samples, only a few sequences were obtained and thus it was not possible to discover its bacteriome reliably. The bacteriomes of different water processing fractions were unique. The diversity of the bacteriome as well as the bacterial amount reduced during the treatment process. The bacteriomes of Finnish water treatment fractions differed from those of other countries. The different water treatment plants showed differences in their bacteriomes as well as bacterial amounts showing that different treatment methods create differences. Seasonality was seen in both the bacteriome and bacterial amounts possibly due to changing weather and the seasonality of environmental and enteric bacteria. Effluent had mainly opportunistic pathogens. The biggest threat out of pathogens is most likely the genus Legionella as their amount was the highest in effluent and grew during the treatment process. To be able to discover the bacteriome of drinking water, the sample volume should be larger, or biofilm should be used. The discovery of the bacteriome at a more precise taxa level would require a wider sequencing of the 16S gene.