What is MBBR Technology in an Sewage Treatment Plant

2026-01-28 | by Joydip Manna

Moving Bed Biofilm Reactor (MBBR) technology is an advanced biological wastewater treatment process that uses thousands of free-floating plastic media (carriers) within an aeration tank to support biofilm growth. It is a biological sewage treatment process where bacteria grow on floating plastic media instead of floating freely like in activated sludge. That one shift—attached media instead of loose sludge—clears out many daily operational problems operators keep fighting on site.

MBBR today is almost the default choice for compact STP plants, especially apartments, hotels, hospitals, IT parks, and industrial townships. Space is tight, load keeps changing, and discharge norms are getting stricter every year, so systems that forgive mistakes survive.

Why MBBR Even Exists

Conventional Activated Sludge Process (ASP) struggles badly in India and surrounding regions. Influent quality changes day to day, power cuts happen without warning, operators are not always trained, and land availability is never enough. Sludge bulking, foaming, washout—these are daily site problems, not theoretical concepts.

MBBR got adopted because:

• It does not depend on MLSS control like ASP
• It tolerates shock organic and hydraulic loads
• It works where land is expensive
• It gives stable BOD, COD, and ammonia removal even when flow is uneven

That is why consultants and regulators keep pushing MBBR for decentralized STPs now, especially in regions demanding industrial water and wastewater treatment solutions in India.

What Is MBBR?

As per accepted design practice followed under CPCB and referenced in WHO biological treatment frameworks:

MBBR is an attached-growth aerobic biological process where microorganisms grow as biofilm on high-surface-area plastic carriers, kept in suspension by aeration or mixing, treating wastewater through biodegradation.

Bacteria remain attached—they do not wash out easily. That is the core engineering logic.

How MBBR Actually Works

Not brochure version, real operation.

• Pre-treated sewage (after screening + equalization) enters the MBBR tank
• Tank is filled around 40–70% with bio-media (HDPE carriers)
• Air diffusers keep media moving continuously
• Bacteria grow inside media pores, protected from shear and shock loads
• Organic matter and ammonia are consumed by biofilm
• Media stays inside using retention sieves
• Treated water flows to secondary clarifier or tube settler
• Sludge generation is low and easier to handle

No sludge return pumping. No MLSS calculations. Operators finally breathe.

Key Components in an MBBR-Based STP

• MBBR Tank – RCC or FRP, properly aerated
• Bio Media – 500–1200 m²/m³ specific surface area
• Fine Bubble Diffusers – oxygen supply + media movement
• Media Retention Screens – SS wedge wire or HDPE
• Secondary Clarifier – solids separation
• Disinfection Unit – chlorine or UV depending on reuse norms

Performance Numbers

When designed correctly and not value-engineered blindly:

• BOD: < 10 mg/L
• COD: < 50 mg/L
• TSS: < 10 mg/L
• Ammonia-N: < 5 mg/L(achievable only with proper nitrification design)

These numbers meet CPCB norms for inland discharge and reuse.

MBBR Technology Advantages

• Runs with minimal maintenance
• Natural, stable biological process
• Compact layout requiring less space
• Resilient to toxic shock
• Generates low sludge

MBBR Technology Disadvantages

• Requires periodic manual monitoring
• May attract insects if housekeeping is poor

Why MBBR Is Preferred in Eastern India

STP sites in these states deal with real-world issues every day — limited space, changing loads, power cuts, and operator gaps. MBBR simply handles these conditions better than older ASP systems and has become a core part of industrial sewage treatment systems in eastern India.

• Cities like Bhubaneswar, Ranchi, Jamshedpur, Patna, and Kolkata have tight footprints
• Flow varies in apartments, hostels, hotels — MBBR stays stable
• Easier operation with no MLSS control
• Biofilm survives power cuts better
• Meets strict BOD/COD/ammonia norms set by Odisha SPCB, JSPCB, BSPCB

That’s why MBBR has become the go-to STP choice across Odisha, Jharkhand, Bihar, and West Bengal.

Flaws

• Media quality matters — cheap media collapses in 2–3 years
• Aeration energy slightly higher than ASP
• Not suitable for high-TDS industrial wastewater
• Poor screening causes media choking

Design shortcuts fail fast. Media selection and aeration design are non-negotiable.

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Frequently Asked Questions

Q1. Is MBBR approved by CPCB for STP plants?

Yes. CPCB accepts MBBR as a standard biological treatment technology if outlet norms are met.

Q2. Does MBBR need sludge recycling like ASP?

No. That is one of its biggest advantages.

Q3. Can MBBR handle shock hydraulic loads?

Yes. Attached biofilm resists washout much better than suspended systems.

Q4. Is MBBR suitable for reuse applications?

Yes, when followed by tertiary treatment like PSF, ACF, UV, or RO depending on reuse requirements.

Q5. What is typical media life?

5–8 years if genuine HDPE media is used and screens are properly designed.

MBBR is practical, not new. It survives poor influent, imperfect operators, and regulatory pressure—this is why it dominates modern STP design today.

Plizma Technology works with MBBR regularly because it performs predictably, handles load variations, and meets compliance norms without operators firefighting every morning.

— Plizma Technology, engineering-led water treatment company in India.

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Last updated on: 2026-01-28