What is an MBR Membrane?

An MBR (Membrane Bioreactor) membrane is used in wastewater treatment plants to separate clean water from biological sludge using hollow fiber filtration instead of a traditional clarifier.

It combines:

• Biological treatment (aeration tank)
• Membrane filtration (solid-liquid separation)

Step-by-Step: How MBR Membrane is Used

1. Pre-Treatment (Very Important)

Before using an MBR membrane, proper pre-treatment is required to avoid damage and fouling.

Includes:

• Screening (coarse & fine screen)
• Grit removal
• Oil & grease trap

👉 Why?
MBR membranes are sensitive — large particles can choke or damage fibers.

2. Biological Treatment Tank (Aeration Tank)

Wastewater enters the aeration tank where:

• Air is supplied using diffusers
• Microorganisms break down organic matter (BOD/COD)

Typical Parameters:

• MLSS: 3000–12000 mg/L
• DO: 2–4 mg/L

3. Membrane Tank (MBR Section)

MBR membranes are installed inside a tank (submerged type).

How It Works:

• Membranes are dipped in mixed liquor
• Suction pump pulls clean water through membrane pores
• Solids, bacteria, and sludge are retained

Flow Concept

$Q=A\times J$

Where:

• $Q$ = Permeate flow
• $A$ = Membrane area
• $J$ = Flux (LMH)

4. Permeate Collection

Filtered water (permeate) is collected and can be:

• Reused (gardening, flushing, cooling)
• Sent to RO for further purification

5. Air Scouring (Critical Step)

Air is continuously supplied below membranes using diffusers.

Purpose:

• Prevent fouling
• Clean membrane surface
• Increase membrane life

6. Backwashing & Cleaning

a) Physical Cleaning:

• Backwash every 10–30 minutes
• Relaxation cycle (stop suction briefly)

b) Chemical Cleaning (CIP):

• Sodium hypochlorite (for organic fouling)
• Citric acid (for scaling)

Operating Parameters (Important for Clients)

Installation Guidelines

Do:

✔ Install vertical and properly aligned
✔ Ensure uniform air distribution
✔ Use proper suction pump (low pressure)
✔ Maintain equal flow across modules

Don’t:

✘ Don’t run membrane dry
✘ Don’t allow large particles inside
✘ Don’t exceed recommended suction pressure

Common Problems & Solutions

1. Low Permeate Flow

• Cause: Fouling
• Solution: Cleaning / backwash

2. High TMP

• Cause: Membrane choking
• Solution: Chemical cleaning

3. Fiber Damage

• Cause: Poor pre-treatment
• Solution: Improve screening

Advantages of Using MBR Membrane

• High-quality treated water
• No need for clarifier
• Compact system
• Better sludge control
• Ideal for reuse applications

Where MBR Membranes Are Used

• STP (Sewage Treatment Plant)
• ETP (Effluent Treatment Plant)
• Textile & pharma industries
• Hotels & commercial buildings

Pro Tips (Very Important for Performance)

• Always maintain proper MLSS
• Never skip air scouring
• Monitor TMP regularly
• Clean membrane periodically
• Use good quality diffusers