Process Background Introduction-Biofilm Reactor (MBBR)

With rapid industrial development and growing population density, water pollution has become an increasingly pressing environmental concern worldwide. The need for efficient, stable, and cost-effective wastewater treatment technologies has driven the continuous evolution of biological treatment processes.

Currently, two major biological methods dominate the field of sewage treatment: the activated sludge process and the biofilm process. Both have their own characteristics and limitations, which eventually led to the innovation of a hybrid system known as the Moving Bed Biofilm Reactor (MBBR) — a process that integrates the advantages of both to achieve higher treatment performance and operational stability.

Developed in the early 20th century in the United Kingdom, the activated sludge process has become a cornerstone of modern wastewater treatment. It relies on the suspension of microbial flocs in an aeration tank, where organic matter is biologically oxidized.
Over decades of development, this method has evolved into several operating modes and is known for its high treatment efficiency y broad applicability.

However, despite its maturity, the activated sludge process has several limitations:

• Large aeration tank volume y land area requirements
• High construction and operating costs
• Poor adaptability to flow and load fluctuations
• Potential for sludge bulking and unstable operation

These challenges have motivated researchers and engineers to seek more compact and resilient alternatives.

los biofilm process treats wastewater using microorganisms attached to carrier media (such as fixed or moving fillers). These biofilms biologically degrade pollutants as water flows over their surface.
Compared to the activated sludge process, the biofilm method offers several advantages:

• High organic and hydraulic load capacity
• Stable effluent quality under variable conditions
• No need for sludge recirculation
• Compact reactor design with smaller footprint

However, biofilm systems also face challenges:

• Risk of filter media clogging, requiring frequent backwashing
• Difficulty in aeration equipment replacement beneath fixed media
• Limited mass transfer efficiency in dense biofilms

To bridge the gap between the activated sludge and biofilm processes, researchers in Norway developed the Moving Bed Biofilm Reactor (MBBR) in the late 1980s.
The MBBR combines the suspended growth of activated sludge with the attached growth of biofilm, forming a hybrid biological treatment system with exceptional efficiency and reliability.

Core Concept of MBBR

In the MBBR process, suspended plastic carriers (with a density close to water) are added to the aeration tank. These carriers act as mobile surfaces for microbial attachment and growth. As wastewater flows and aeration occurs, the carriers remain in continuous motion, ensuring:

• Excelente oxygen transfer
• Efficient mixing and contact between microorganisms and pollutants
• Automático biofilm renewal without clogging

This moving carrier system eliminates the need for sludge recirculation while maintaining high biomass concentration.

The MBBR system combines the strengths of both traditional methods, resulting in numerous operational and environmental benefits:

1. Compact Design & Small Footprint
   Requires only 20–30% of the space of a conventional oxidation tank under similar load conditions. Ideal for space-limited installations.
2. High Organic Load and Stable Performance
   Capable of treating high-strength wastewater with stable effluent quality, even under shock loads o fluctuating conditions.
3. No Sludge Return or Clogging
   Eliminates the need for sludge recirculation, while the continuous movement of carriers prevents biofilm overgrowth y blockage.
4. Low Energy Consumption and Simple Operation
   MBBR systems have low head loss, minimal maintenance, and can be easily automated for energy-efficient operation.
5. Versatile Applications
   Applicable to both municipal sewage y aguas residuales industriales, including food processing, pulp and paper, oil refining, slaughterhouse, and chemical industries.
6. Scalability and Retrofit Compatibility
   MBBR can be integrated into existing treatment systems to enhance performance or expand capacity with minimal civil modifications.

In the past decade, MBBR technology has proven its reliability through extensive engineering applications across various sectors:

• Pulp and paper mill wastewater – effective removal of high COD and BOD loads
• Food and beverage industry – reduction of organic pollutants and fats
• Slaughterhouse wastewater – treatment of high-nitrogen effluent
• Petrochemical and refinery wastewater – degradation of hydrocarbons and complex organics
• Municipal sewage treatment – stable performance under varying influent conditions

Field data and case studies consistently demonstrate that MBBR offers higher treatment efficiency, lower operational costs, and easier maintenance compared to conventional biological systems.

los Moving Bed Biofilm Reactor (MBBR) represents a major advancement in biological wastewater treatment technology. By integrating the principles of both activated sludge and biofilm processes, MBBR delivers compact, efficient, and robust treatment performance.
Its flexibility, scalability, and operational simplicity make it an ideal choice for both new wastewater treatment plants y upgrading existing facilities.

As environmental standards become stricter and sustainability takes center stage, MBBR technology will continue to play a vital role in achieving high-efficiency wastewater treatment y resource recovery.

MBBR stands for Moving Bed Biofilm Reactor, a biological wastewater treatment process that combines activated sludge and biofilm principles.

Unlike activated sludge systems, MBBR uses mobile biofilm carriers that eliminate the need for sludge return and prevent sludge bulking.

They are typically HDPE plastic media with a high surface area-to-volume ratio, allowing for dense microbial growth.

Yes. MBBR is widely used in food, paper, petrochemical, and municipal sectors, offering stable treatment for high-strength wastewater.

Key benefits include compact footprint, low maintenance, energy efficiency, no clogging, and stable effluent quality.

Xian CHIWATEC Water Treatment Technology es una empresa de alta tecnología especializada en varios dispositivos de procesamiento de agua. Aparte de estos productos individuales, que cubren una serie de tipos y series, también podemos ayudar con proyectos de ingeniería integrales relacionados. Gracias a nuestro arduo trabajo y dedicación desde nuestra fundación, ahora somos uno de los fabricantes de equipos de tratamiento de agua de más rápido desarrollo en el oeste de China.

Otras lecturas:

• ¿Qué es MBBR y su función?
• Planta de tratamiento de aguas residuales de 100m3/día con técnica MBBR
• Planta de tratamiento de aguas residuales MBBR
• Introducción al fondo del proceso: reactor de biopelícula (MBBR)
• MBBR aguas residuales vivas