Why Are Microorganisms Used At A Wastewater Treatment Plant

by Anna

Wastewater treatment is a critical process that plays a pivotal role in maintaining environmental health and ensuring the safety of water resources. One of the key components of wastewater treatment is the utilization of microorganisms. Microorganisms, including bacteria, fungi, and protozoa, are employed in wastewater treatment plants (WWTPs) to break down organic matter, remove pollutants, and enhance the overall efficiency of the treatment process. This article explores the reasons behind the widespread use of microorganisms in WWTPs, shedding light on their indispensable contributions to the treatment of wastewater.


Biological Treatment Processes

Wastewater generated from various sources contains a complex mixture of organic and inorganic pollutants. Traditional treatment methods such as physical and chemical processes alone may not effectively remove these contaminants. This is where microorganisms come into play. Biological treatment processes, such as activated sludge, trickling filters, and biofiltration, harness the metabolic activities of microorganisms to break down and transform pollutants.


Microorganisms, particularly bacteria, are adept at consuming organic matter present in wastewater. They utilize these substances as a source of energy and convert them into simpler and less harmful byproducts. The use of biological treatment processes is environmentally sustainable and cost-effective compared to purely chemical methods, making microorganisms a crucial component of modern wastewater treatment.

Nutrient Removal

In addition to organic matter, wastewater often contains excessive nutrients such as nitrogen and phosphorus, which can lead to eutrophication if not properly managed. Microorganisms play a vital role in nutrient removal processes within WWTPs. In the activated sludge process, for example, specific bacteria are responsible for the conversion of ammonia (NH3) to nitrate (NO3-) and then to nitrogen gas (N2), a process known as nitrification and denitrification. This microbial-driven transformation helps mitigate the environmental impact of nutrient-rich effluents.

Moreover, microorganisms facilitate the removal of phosphorus through the process of phosphorus uptake and storage within their cells. This biological phosphorus removal is an effective and sustainable approach to reducing the discharge of phosphorus into receiving waters, mitigating the risks associated with nutrient pollution.

Pathogen Elimination

Wastewater often contains pathogenic microorganisms that pose significant risks to public health. Microorganisms in WWTPs play a critical role in eliminating or reducing these pathogens through various treatment stages. The biological processes in wastewater treatment create an environment hostile to pathogenic bacteria and viruses, reducing their concentration to levels safe for environmental discharge.

The competition for nutrients and the production of antibacterial substances by certain microbial species contribute to the suppression of pathogenic microorganisms in wastewater. This microbial antagonism, along with other treatment processes like disinfection, ensures that the effluent meets stringent regulatory standards for water quality, safeguarding public health and the environment.

Sludge Treatment and Management

Microorganisms are also instrumental in the treatment and stabilization of sludge produced during the wastewater treatment process. The activated sludge produced in secondary treatment contains a high concentration of microorganisms, organic matter, and nutrients. Through anaerobic digestion, microorganisms break down the organic content of the sludge, producing biogas and significantly reducing the volume of sludge.

Furthermore, the resulting biosolids can be used as a valuable resource for soil amendment and fertilizer, closing the loop on resource utilization. Microorganisms contribute not only to the reduction of sludge volume but also to the transformation of its organic components into a more stable and environmentally friendly form.

Adaptability and Robustness

Microorganisms exhibit a remarkable level of adaptability and robustness in responding to changes in wastewater composition and operating conditions. Unlike some chemical processes, which may be sensitive to fluctuations in input parameters, microorganisms can adjust to varying conditions, ensuring the stability and reliability of wastewater treatment plants.

This inherent adaptability allows WWTPs to handle seasonal variations, industrial discharges, and unforeseen events, making biological treatment processes with microorganisms a versatile and resilient solution for wastewater management.


In conclusion, the use of microorganisms in wastewater treatment plants is fundamental to the success of these facilities in meeting environmental standards and protecting public health. Microorganisms contribute to the breakdown of organic matter, removal of nutrients, elimination of pathogens, and efficient sludge management. The biological treatment processes driven by microorganisms offer sustainable and cost-effective solutions, showcasing the importance of harnessing the power of nature to address the challenges of wastewater treatment. As we continue to advance in our understanding of microbiology and wastewater engineering, the role of microorganisms in wastewater treatment will likely become even more refined and integral to creating a sustainable and resilient water management infrastructure.


You may also like

Copyright © 2023