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Wastewater odor control and chemical treatments are crucial for any facility or plant handling waste and producing effluent. But what exactly are these wastewater microbes, and how do they work in the process of water treatment?
Read on as we explore this in more detail.
The Huge Variety of Microbes in Wastewater
It has long been understood that many different microbes are present in wastewater samples and that these microbes play an important role in treating these samples. However, what is not understood is just how many different types of microbes there are in wastewater.
It’s very easy to identify a microbe. In the wastewater treatment process, a sample is taken from activated sludge, and microbes are extracted. The DNA sequence of the microbes within this sample can quickly tell us which microbes are present. To confirm the presence of a specific microorganism, this DNA sequence must be checked against a reference database — which is where the identification process can break down. If the microbe is not already listed in an existing database, there is no reference point for identification. Scientists believe that many microbes — or even a majority — go undetected as a result.
Scientists working on wastewater samples in Denmark have developed a potential solution. They have created a new database — known as the Microbial Database for Activated Sludge, or MiDAS — that maps many previously undetected DNA sequences. Along with the database, they have developed a new taxonomy of microbes so that newly discovered microorganisms within a sample can be quickly identified and added to the database. This should help increase the scientific understanding of microbes within wastewater facilities worldwide.
General Categories of Microbes in Wastewater Treatment
While there are a great many different types of microbes in wastewater treatment, they can be broken down into three main categories;
- Aerobic Wastewater Microbes
Aerobic microorganisms require a source of oxygen to function, which means the wastewater will need to be aerated for these microbes to fulfill their roles effectively. Oxygen may be added to the wastewater intentionally to support microbes and their reactions.
This type of wastewater microbe uses the matter within the wastewater as a food source. The microorganism consumes the matter and converts it into the energy it needs to survive and reproduce to form a larger colony. This process is very useful in wastewater treatment, as it means that pollutants are removed from the water and converted into energy and less harmful by-products. As the wastewater itself provides the fuel, facility staff simply need to ensure that oxygen levels remain high within the water.
- Anaerobic Wastewater Microbes
Anaerobic microorganisms also use the pollutants and suspended matter within the wastewater to provide fuel, which is converted into energy for growth and reproduction. This means they are also helpful in reducing the level of pollutants within the water during treatment. The key difference is that these microorganisms do not need an external source of oxygen to drive their internal chemical reactions.
While anaerobic microorganisms still use oxygen in chemical reactions, they derive this by breaking down the pollutants and matter within the water. As a result, facility teams do not need to aerate the wastewater or add oxygen by another means, making the microbial treatment largely self-sustaining, even over long periods.
In fact, anaerobic microorganisms actively produce methane gas due to their reactions. If this gas can be harnessed, it can be used to generate energy through biogas processors, increasing the sustainability and environmental viability of the plant. In addition, this category of microbes is also helpful for removing other contaminants from the water, such as phosphorus.
- Facultative Wastewater Microbes
Not all microorganisms fit so neatly into the two categories listed above. For example, some microbes will instead exist as aerobic or anaerobic microorganisms depending on their environment. These microbes are classed as facultative.
This doesn’t make much of a practical difference to managing the water treatment process. In most cases, the facultative microbes will behave as aerobic as long as they have access to oxygen within the water. If there is not enough oxygen for them to process, they will switch to anaerobic chemical reactions to derive energy from the fuel. However, if the treatment plant relies on methane gas released from anaerobic microbes, they will have to ensure that the water oxygen levels do not get too high.
Generally, facultative microbes will act as aerobic microbes when enough oxygen is available. This means they may be less effective when forced to operate anaerobically.
The Role of Microbes Within Wastewater Treatment
Microbes fulfill a number of different roles within the wastewater treatment process, some of which we’ve touched on already.
- Microbes reduce the volume of pollutants and contaminants within the water, making other forms of treatment more effective.
- As the volume is reduced, other filters don’t need to work quite so hard, and microbial treatments can minimize wear and tear on components, reduce energy costs, and extend equipment lifespans.
- Some microbes can actively reduce the odor produced by wastewater. Using microbes for wastewater odor reduction makes treatment sites and their surroundings safer, healthier, and more pleasant for employees and the general public.
- Some forms of microbes can remove chemical contaminants that are difficult to filter, such as phosphorous.
- Anaerobic microbes can produce methane gas or biogas, which can be harnessed to provide power to the treatment plant or facility.
- Microbial chemical reactions tend to be a greener, more sustainable option than other forms of water treatment. While the microbes may not be 100% effective by themselves, a microorganism treatment strategy can decrease reliance on less sustainable forms of treatment.
There are many different aspects to successful wastewater treatment. Any facility engaged in this treatment must adopt a multifaceted approach to ensure wastewater effluent adheres to all state and federal standards. However, microbe treatment is a crucial part of the process and should not be overlooked. By supporting other forms of treatment with microbial reactions, facility teams are helping to reduce costs, improve energy efficiency, and protect local ecosystems and communities.