Overview of biological wastewater treatment

Biological wastewater treatment is a process that uses microorganisms to remove pollutants from wastewater. The microorganisms use the pollutants as a food source and break them down into harmless substances. Biological process in a wastewater treatment is a natural process that has been used for centuries to clean water. However, it was not until the early 1900s that scientists began to understand the principles of biological wastewater treatment and develop efficient methods for its application.

Biological wastewater treatment is an important part of wastewater management. It is used to remove pollutants from wastewater and make it safe for reuse or discharge to the environment. Biological wastewater treatment is a sustainable and environmentally friendly process that can help to protect our water resources.

A. Definition of MBBR

MBBR, short for Moving Bed Biofilm Reactor, is a biological wastewater treatment method that utilizes free floating plastic biofilm carriers to provide larger surface area for the growth of microorganisms on it. It is an attached growth process of biological wastewater treatment in which a cluster of microorganisms known as biofilm , breaks down the organic matter and pollutants present in the wastewater resulting in effective treatment.

B. History and Evolution

The concept of using biofilm for wastewater treatment dates back to the early 1980s when Professor Hallvard Ødegaard from the Norwegian University of Science and Technology introduced the MBBR technology. Over the years, MBBR has undergone significant advancements and today, it is considered a robust and reliable solution for various wastewater treatment applications.

C. Introducing MBBR technology

MBBR technology is based on the principle of biofilm growth, where microorganisms attach themselves to the surface of the carrier media. The MBBR carrier, which are designed to provide a large surface area, create an environment conducive to the growth of diverse microbial communities. These microorganisms, including bacteria and fungi, form a biofilm that actively consumes organic matter and nutrients present in the wastewater.

D. Importance of MBBR in wastewater treatment

MBBR process plays a vital role in addressing the challenges associated with wastewater treatment. Its efficiency in removing organic pollutants, nutrients, and contaminants makes it a preferred choice for various industries and municipal wastewater treatment plants. By harnessing the power of biofilm, MBBR provides an effective and sustainable solution for improving water quality and protecting the environment.

How MBBR Works

A. The Core Principles

MBBR operates on the principles of microbial degradation. It can be aerobic, anaerobic or facultative based on the reactor conditions maintained. It relies on the activity of micro organisms to break down organic or inorganic compounds present in the wastewater. These microorganisms form a biofilm on the carrier media, creating a favorable environment for efficient pollutant removal.

B. Components of an MBBR System

To better understand how MBBR works, it’s important to familiarize ourselves with its key components:

1. Biofilm Carriers

Biofilm carriers are the heart of the MBBR system. The carriers can be made of various materials such as plastic, PVC, or polyethylene with a high surface area ensuring a stable environment for microorganisms to thrive. The carriers are kept in constant motion within the reactor tank, ensuring effective contact between the microorganisms and the wastewater.

2. Reactor Tank

The reactor tank holds the biofilm carriers and the wastewater. It is designed to provide optimal conditions for the microorganisms to thrive, such as controlled temperature and pH levels. The movement of the carriers within the tank prevents clogging and allows for efficient treatment.

3. Aeration System

The aeration system supplies oxygen to the reactor tank, creating an aerobic environment that supports the growth of aerobic microorganisms in the biofilm. Proper aeration ensures that the microorganisms have an adequate oxygen supply for their metabolic activities.

4. Clarification Unit

After passing through the reactor tank, the treated water and suspended biomass (biofilm carriers and excess microorganisms) are separated in the clarification unit. Here, the clarified water is collected for further treatment or discharge, while the biomass is recirculated back to the reactor tank to maintain the biological activity.

C. Key Processes in MBBR

1. Biofilm Formation

The microorganisms attach themselves to the biofilm carriers and form a biofilm. The biofilm provides a favorable environment for the microorganisms to thrive and treat the wastewater efficiently. 

2. Substrate Utilization

Once the biofilm is established, microorganisms utilize organic matter present in the wastewater as their energy source. They break down complex compounds into simpler forms, converting them into carbon dioxide and water.

3. Nutrient Removal

It also facilitates the removal of nutrients, such as nitrogen and phosphorus, from wastewater. Specific strains of microorganisms within the biofilm play a crucial role in metabolizing and removing these nutrients, thereby reducing the environmental impact of wastewater discharge.

Advantages of MBBR

It offers numerous advantages over traditional wastewater treatment methods

1. High Treatment Efficiency

MBBR systems have a high treatment efficiency compared to traditional methods. The biofilm carriers in MBBR provide a large surface area for microbial growth, allowing for enhanced contact between microorganisms and wastewater. This results in more effective organic pollutants, nitrogen, and phosphorus removal from wastewater, so that it improves water quality and compliance with environmental regulations.

2. Compact Footprint

MBBR systems have a compact design, requiring less physical space compared to conventional treatment methods. This makes them suitable for both retrofitting existing treatment plants and constructing new ones in areas with limited land availability.

3. Flexibility and Scalability

MBBR systems can be easily adapted and expanded based on the treatment requirements. The modular nature of the technology allows for flexibility in capacity adjustments and future expansion without disrupting the overall treatment process.

4. Reduced Sludge Production

Due to the biofilm-based treatment process, MBBR technology generates less sludge, minimizing disposal and operational costs associated with sludge management.

5. Resilience to Shock Loads

MBBR process demonstrates excellent resilience to variations in wastewater flow and pollutant load. It can handle sudden increases in organic or hydraulic loads without compromising treatment performance. This adaptability makes MBBR ideal for industries with fluctuating wastewater characteristics.

6. Energy Efficiency

MBBR systems can be designed with energy-efficient aeration systems. By optimizing the aeration process, energy consumption can be reduced, leading to lower operational costs and environmental impact.

7. Easy Maintenance

MBBR systems are relatively easy to maintain. The biofilm carriers are self-cleaning, minimizing the need for frequent maintenance and cleaning procedures. This results in reduced downtime and operational disruptions.

8. Versatility

It is versatile and can be applied to various wastewater treatment applications, including municipal sewage treatment plants, industrial effluent treatment, and decentralized wastewater treatment. It can effectively handle a wide range of pollutants and achieve desired effluent quality standards.

Comparison to Other Wastewater Treatment Technologies

A. MBBR vs. Activated Sludge Process

The Activated Sludge Process (ASP) and MBBR are both commonly used wastewater treatment technologies, but they differ in their approach to biological treatment. In ASP, microorganisms are suspended in the wastewater, forming a sludge that requires continuous aeration. This process requires larger tanks and more energy consumption. On the other hand, MBBR utilizes plastic media with a large surface area for biofilm attachment. This biofilm provides a habitat for microorganisms to grow and treat the wastewater. MBBR offers several advantages over ASP

Higher Treatment Efficiency

MBBR typically achieves higher treatment efficiency due to the increased biofilm surface area, allowing for more effective biological degradation of organic matter and removal of pollutants.

Greater Process Stability

The biofilm in MBBR provides a more stable environment for microorganisms, making the process more resilient to fluctuations in wastewater quality and flow rate. This stability reduces the risk of process upsets and enables better treatment performance.

Flexibility and Expansion

MBBR systems are easier to expand or modify compared to ASP. It is possible to increase the treatment capacity by simply adding more plastic media to the existing reactor, whereas expanding an ASP facility often requires constructing additional tanks.


MBBR is an attached growth process while SBR is a variant of activated sludge process in which various steps of treatment are carried out in cyclic mode in a single basin. While both options are effective in treating wastewater, MBBR has some advantages that make it an ideal choice in certain situations.

Process Flexibility

MBBR offers greater process flexibility compared to SBR. In MBBR, the biofilm grows on plastic media, which provides a large surface area for microbial growth. This allows for a diverse and robust microbial community, capable of handling a wide range of wastewater characteristics. SBR, on the other hand, relies on suspended growth, which may limit its performance and adaptability in treating complex or variable wastewater compositions.

Shock and Load Resistance

MBBR demonstrates better resilience to shocks and fluctuations in wastewater composition. The attached biofilm in MBBR can handle sudden changes in organic loads, toxic substances, or hydraulic conditions more effectively. In SBR, the suspended growth system may experience temporary process upsets or reduced treatment efficiency when faced with sudden variations.

Footprint and Expansion Capability

MBBR has a compact design, requiring less space compared to SBR. The use of plastic media allows for higher biomass concentration, resulting in a smaller reactor volume. This compact footprint is particularly advantageous when space is limited or when retrofitting existing treatment plants. MBBR can also be easily expanded by adding more media to accommodate increased wastewater loads, whereas expanding SBR may involve more complex modifications.

C. MBBR vs. Membrane Bioreactor (MBR)

MBBR and MBR are two popular wastewater treatment technologies, but MBBR often offers distinct advantages that position it as a superior choice in certain scenarios.


MBBR generally has lower capital and operating costs compared to MBR. MBR requires expensive membrane filtration systems that can significantly impact the overall project budget. MBBR, with its reliance on biofilm attached to plastic media, eliminates the need for extensive membrane filtration, reducing both capital and operating expenses.

Robustness and Tolerance

MBBR is known for its robustness and tolerance to variations in wastewater composition. The biofilm in MBBR can handle shocks, toxic substances, and fluctuating organic loads more effectively than MBR. MBR, with its reliance on suspended growth and delicate membranes, may be more susceptible to fouling and operational issues when faced with challenging wastewater characteristics.

Retrofitting and Upgrading

MBBR offers easier retrofitting and upgrading options compared to MBR. MBBR can be integrated into existing treatment plants without major modifications, allowing for seamless upgrades and expansions. MBR retrofitting requires substantial changes to accommodate the membrane filtration system, making it more complex and costly.

Overall, MBBR offers several benefits compared to other wastewater treatment technologies. It provides higher treatment efficiency, better flexibility, and lower operating costs, making it a popular choice for various applications, ranging from municipal wastewater treatment plants to industrial processes.

Applications of MBBR - Industries and sectors that benefit from MBBR

mbbr technology for sewage treatment plant

The versatility and effectiveness of MBBR make it a valuable tool for wastewater treatment in various industries and sectors.

A. Municipal wastewater treatment

MBBR is commonly used in municipal wastewater treatment plants to enhance the removal of organic matter, nitrogen, and phosphorus from wastewater. The biofilm carriers in the MBBR provide a large surface area for the growth of microorganisms that break down and remove pollutants effectively.

B. Industrial wastewater treatment

MBBR is widely employed in the treatment of industrial wastewater generated by various industries such as chemical manufacturing, pharmaceuticals, textiles, pulp and paper, and more. It can effectively treat diverse types of industrial pollutants, including organic compounds, toxic substances, and high-strength wastewater

Case Study: Treatment of Soap Producing Unit Effluent Palm Oil Mill Effluent Treatment Treatment of Oleo Chemicals containing effluent

C. Aquaculture and fish farming

MBBR technology is utilized in aquaculture and fish farming for water treatment. The biofilm carriers in the MBBR promote the growth of beneficial bacteria that convert harmful compounds into less toxic forms, ensuring a healthier aquatic environment for the cultured organisms.

D. Food and beverage processing

MBBR systems are beneficial in the treatment of wastewater generated by food and beverage processing facilities. These systems efficiently remove organic compounds, suspended solids, and other contaminants, ensuring compliance with environmental regulations and minimizing the environmental impact of these industries.

E. Upgrading Existing Treatment Plants with MBBR

MBBR process can be retrofitted into existing wastewater treatment plants to enhance their capacity, improve treatment efficiency, and meet stricter effluent standards. By adding MBBR units to the existing infrastructure, treatment plants can increase the biological treatment capacity without requiring significant structural modifications. Its versatility, efficiency, and flexibility make it a popular choice for wastewater treatment where high-quality effluent and regulatory compliance are essential goals.

Considerations for Implementing MBBR

A. Design and engineering considerations for implementing Moving Bed Biofilm Reactor (MBBR) include

1. Sizing and capacity

Properly sizing the MBBR system to meet the desired treatment capacity and hydraulic loading rates.

2. Reactor configuration

Determining the number and arrangement of MBBR tanks based on the treatment requirements and available space.

3. Oxygen supply

Providing adequate oxygen transfer through aeration systems to support microbial growth and biofilm formation.

4. Mixing and agitation:

Ensuring proper mixing within the MBBR tanks to maintain uniform biofilm distribution and prevent settling or clogging.

5. Retention time

Calculating the appropriate hydraulic retention time (HRT) and solids retention time (SRT) to achieve the desired treatment efficiency.

6. Nutrient removal

Incorporating mechanisms for efficient removal of nutrients, such as nitrogen and phosphorus, based on the specific wastewater characteristics.

7. Effluent quality

Designing the MBBR system to meet the required effluent standards and discharge limits.

8. Retrofitting existing infrastructure

Considering the feasibility of retrofitting an MBBR system into an existing wastewater treatment plant.

B. Selecting suitable carrier media

1. Surface area and void fraction

The carrier media used in MBBR provide a substrate for biofilm growth. The media should have a high specific surface area to support a large population of microorganisms. Additionally, the media should have a suitable void fraction to allow for effective wastewater flow and oxygen transfer.

2. Material selection

The carrier media should be durable, chemically inert, and resistant to fouling or clogging. Commonly used media include plastic materials like polyethylene or polypropylene, which are lightweight, have a long lifespan, and offer good biofilm attachment properties.

Levapor has suitable PU Foam MBBR media is an innovative and highly efficient type of MBBR media that offers several advantages over traditional media options. 

C. Maintenance and operational requirements

1. Pre- and post-treatment

Regular monitoring of key parameters such as dissolved oxygen, pH, temperature, and nutrient levels is necessary to ensure optimal reactor performance. Automated control systems can be employed to adjust aeration rates or recycle flows based on real-time data.

D. Integration of MBBR with other treatment processes

1. Pre- and post-treatment

MBBR can be integrated with other treatment processes to achieve comprehensive wastewater treatment. Pre-treatment processes, such as screening or sedimentation, may be necessary to remove larger solids before entering the MBBR. Post-treatment, such as filtration or disinfection, may be required to meet specific effluent requirements.

2. Process optimization

Integration with other treatment processes should be carefully planned to optimize overall system performance. Proper sequencing, hydraulic considerations, and nutrient removal strategies should be evaluated to ensure efficient treatment and resource recovery, if applicable.

Why choose Levapor MBBR Technology ?

While traditional plastic carriers are more popular, they have certain limitations like lower surface area, higher filling ratio required. The plastic carriers can be used with coarse bubble diffused aeration systems only. They don’t offer any adsorption capacity or its surface property modification to make it more suitable for efficient microbial colonization. The inner porosity available in open structure plastic carriers is also a lot lower.

Further, plastic carriers based MBBR are suspected to release micro plastic and certain persistent pollutants which are part of the plastic material. These materials pose serious environmental concern.

While Levapor carriers are made from technical grade reticulated PU foam material which is inert to release of any micro plastic in the environment, the specific properties of Levapor carriers due to activated carbon impregnation offer following advantages making it an ideal choice for MBBR application.

1. Higher volumetric loading rates
2. Lower degree of filling required
3. Light weight material resulting in lower fluidization energy requirement
4. Quicker wetting and faster colonization resulting in faster process startup and recovery from upsets.

Take the first step towards cleaner water by embracing Levapor MBBR technology today for wastewater treatment. Join the sustainable revolution and contribute to cleaner environments and healthier communities. Discover the power of Levapor MBBR and be a part of the solution today!

Author Bio

Amit Christian is a MSc graduate in Environment Science from Middlesex University, London, UK. He has been active in the field of water and wastewater treatment since 1998. He specializes in design, engineering, and management of various biological wastewater treatments such as Activated Sludge Process (ASP), Sequencing Batch Reactor (SBR), Moving Bed Bio Reactor (MBBR), Integrated Fixed Film Activated Sludge (IFAS). He has helped various Industrial and Municipal clients in troubleshooting , optimizing their biological wastewater treatment processes to achieve latest Stringent norms for Ammonia Removal.

Case Studies: Successful Implementation of MBBR

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