Role of Micro-organism in Biological Treatment

Introduction

Biological treatment plays a crucial role in environmental engineering, particularly in the treatment of wastewater and industrial effluents. This process utilizes micro-organisms to break down organic matter and remove contaminants, resulting in cleaner water that can be safely discharged into the environment. The role of micro-organisms in biological treatment is essential, as they are responsible for carrying out the necessary biochemical reactions that facilitate the treatment process.

Key Concepts and Principles

Micro-organisms involved in biological treatment can be classified into different types, including bacteria, fungi, and protozoa. These micro-organisms possess unique metabolic capabilities that enable them to degrade organic compounds and convert them into simpler forms. The microbial metabolism is a key factor in the treatment process, as it determines the efficiency and effectiveness of the treatment.

There are several key processes involved in biological treatment:

1. Aerobic treatment: This process utilizes oxygen to break down organic matter and convert it into carbon dioxide and water. It is commonly used in municipal wastewater treatment plants.

2. Anaerobic treatment: In this process, micro-organisms break down organic matter in the absence of oxygen, producing biogas (methane and carbon dioxide) as a byproduct. Anaerobic treatment is often used in the treatment of industrial wastewater.

3. Nitrification: This process involves the conversion of ammonia into nitrate by nitrifying bacteria. It is an important step in the removal of nitrogen from wastewater.

4. Denitrification: Denitrifying bacteria convert nitrate into nitrogen gas, completing the nitrogen removal process.

5. Phosphorus removal: Certain micro-organisms have the ability to accumulate phosphorus from wastewater, aiding in its removal.

Microbial activity in biological treatment is influenced by various factors, including temperature, pH, nutrient availability, and oxygen concentration. Optimal conditions must be maintained to ensure the growth and activity of the micro-organisms.

Step-by-Step Walkthrough of Typical Problems and Solutions

In biological treatment, various problems can arise that affect the microbial activity and overall treatment efficiency. Two common problems include insufficient microbial activity and excessive microbial growth.

When there is insufficient microbial activity, the treatment process may not effectively remove contaminants from the wastewater. This can be addressed by adjusting the environmental conditions to optimize microbial growth. Factors such as temperature, pH, and nutrient availability can be modified to create a more favorable environment for the micro-organisms. Additionally, the addition of microbial cultures or bioaugmentation can help introduce specific micro-organisms that are capable of degrading certain contaminants.

On the other hand, excessive microbial growth can lead to system overload and reduced treatment efficiency. To control microbial growth, environmental conditions can be adjusted to limit the availability of nutrients or oxygen. Biomass control strategies, such as wasting excess biomass or implementing sludge retention systems, can also help manage excessive microbial growth.

Real-World Applications and Examples

Biological treatment is widely used in both municipal wastewater treatment plants and industrial wastewater treatment facilities.

In municipal wastewater treatment plants, micro-organisms play a crucial role in removing organic matter and nutrients from the wastewater. The treatment process typically involves multiple stages, including primary treatment, secondary treatment (biological treatment), and tertiary treatment. Examples of biological treatment processes used in municipal wastewater treatment include activated sludge process, trickling filters, and sequencing batch reactors.

In industrial wastewater treatment, micro-organisms are employed to treat specific contaminants that are present in the effluents. Different industries generate wastewater with varying characteristics, requiring tailored treatment approaches. For example, in the food and beverage industry, anaerobic treatment may be used to treat high-strength organic wastewater, while in the pharmaceutical industry, aerobic treatment may be employed to remove organic compounds and pharmaceutical residues.

Advantages and Disadvantages of Biological Treatment

Biological treatment offers several advantages compared to other treatment methods:

1. Cost-effectiveness: Biological treatment is often more cost-effective than other treatment methods, such as chemical or physical processes. It requires less energy and fewer chemicals, resulting in lower operational costs.

2. Environmental sustainability: Biological treatment is considered environmentally sustainable as it relies on natural processes and does not generate harmful byproducts. It reduces the need for chemical usage, minimizing the environmental impact.

3. Versatility: Biological treatment can be applied to a wide range of contaminants, making it a versatile treatment option. Micro-organisms can adapt to different types of wastewater and effectively remove various pollutants.

However, there are also some disadvantages associated with biological treatment:

1. Reliance on specific environmental conditions: Microbial activity in biological treatment is highly dependent on specific environmental conditions, such as temperature and pH. Any fluctuations or deviations from the optimal conditions can affect treatment efficiency.

2. Potential for system upsets: Biological treatment systems are susceptible to upsets, which can lead to fluctuations in treatment efficiency. Factors such as toxic substances, shock loads, or changes in influent characteristics can disrupt the microbial activity and compromise the treatment process.

Conclusion

Micro-organisms play a vital role in biological treatment, enabling the removal of contaminants from wastewater and industrial effluents. Understanding the role of micro-organisms and the key processes involved in biological treatment is essential for effective environmental engineering. By optimizing the environmental conditions and implementing appropriate strategies, biological treatment can be a cost-effective and sustainable solution for wastewater treatment.

Summary

Biological treatment is a crucial process in environmental engineering, particularly in wastewater and industrial effluent treatment. Micro-organisms, such as bacteria and fungi, play a key role in breaking down organic matter and removing contaminants. The microbial metabolism and various processes, including aerobic and anaerobic treatment, nitrification, denitrification, and phosphorus removal, are essential for effective treatment. Factors like temperature, pH, nutrient availability, and oxygen concentration influence microbial activity. Problems like insufficient microbial activity and excessive microbial growth can be addressed by adjusting environmental conditions and implementing biomass control strategies. Biological treatment finds applications in municipal wastewater treatment plants and industrial wastewater treatment, with examples of processes used in each. Advantages of biological treatment include cost-effectiveness, environmental sustainability, and versatility, while disadvantages include reliance on specific environmental conditions and potential system upsets. Understanding the role of micro-organisms in biological treatment is crucial for efficient wastewater treatment.

Analogy

Biological treatment can be compared to a team of specialized workers in a factory. Each worker has a specific role and skill set, contributing to the overall production process. Similarly, micro-organisms in biological treatment have unique metabolic capabilities that enable them to break down organic matter and remove contaminants. Just as the workers rely on a suitable working environment and coordination with other team members, micro-organisms require optimal environmental conditions and interaction with other micro-organisms to carry out the treatment process effectively.