The bacterial community in wastewater is influenced by the population of microbial predators. This explains how seasonal changes in the microbial population affect how effectively water is treated. This is the result of a study conducted by Nils Heck and PD Dr Kenneth Dumack from the University of Cologne’s Institute of Zoology.
The study has been published under the title ‘Microeukaryotic predators shape the wastewater microbiome’ in the journal Water Research.
In wastewater treatment facilities, a carefully orchestrated interplay of several microorganisms occurs to efficiently treat wastewater. However, very little is known about the majority of the microbes used in water treatment.
Many of the predators of the helpful bacteria that clean wastewater are also present in the bioreactors along with the beneficial bacteria themselves. However, it is unclear at this point if and how much these predators have an impact on wastewater treatment.
The bacterial community in wastewater and, consequently, the effectiveness of water treatment are influenced by the seasons, as has been recognized since the development of wastewater treatment plants.
But why is this so? After all, bacteria do not possess an inbuilt sense of time. Given that a number of causes contribute to seasonal fluctuations, this is by no means a simple question. Temperature and lighting conditions are without a doubt the most well-known parameters.
We found that the community of microbial predators, such as amoebae, ciliates, and also rotifers, can explain the composition of the bacterial community to a certain extent. These predators are in turn dependent on the ambient temperature. Thus, the temperature factor represents an indirect influence on the bacteria through the community of predators.
Nils Heck
The chemical makeup of the wastewater, the amount of precipitation, and many other things, however, also change throughout the year.
So which of these factors causes the bacterial community to change over the seasons? PD Dr. Kenneth Dumack, the leader of the study, explained, “We found that seasonal variation in ambient temperature cannot explain the variation in the bacterial community. This surprised us, so we looked for another factor that could explain the variation in the bacterial community.”
Nils Heck, first author of the study, added, “We found that the community of microbial predators, such as amoebae, ciliates, and also rotifers, can explain the composition of the bacterial community to a certain extent. These predators are in turn dependent on the ambient temperature. Thus, the temperature factor represents an indirect influence on the bacteria through the community of predators.”
The latest research advances our knowledge of the so-called ‘black box’ of wastewater treatment, assisting us in preventing potential health concerns associated with insufficient wastewater treatment, among other things.
