Membrane Bioreactor (MBR) Is A Combination Of membrane Processes like microfiltration or ultrafiltration with A Biological wastewater Treatment process, The activated Sludge Process. It Is Now Widely Used For municipal and industrial Wastewater Treatment.^[1] The Two Basic MBR Configurations Are A Submerged Membrane Bioreactor (SMBR), And A Side Stream Membrane Bioreactor.^[2] In The SMBR Configuration, The Membrane Is Located Inside The Biological Reactor And Submerged In The Wastewater, While In A Side Stream Membrane Bioreactor, The Membrane Is Located Outside The Reactor, As An Additional Step After Biological Treatment.

The Basic Membrane Processes Are microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), reverse Osmosis (RO). Separation Ranges For Those Membranes Are As Follows: 100 To 1000 Nm For MF, 5 To 100 Nm For UF, 1 To 5 Nm For NF, And 0.1 To 1 Nm For RO.  For More Than The Last 10 Years MBRs Have Emerged As An Effective Secondary Treatment Technology By Using Membranes In The Range Of MF And UF.

Treatment Process And Basic Design Principles

Membrane Bioreactors Combine Conventional Biological Treatment (e.g. activated Sludge) Processes With Membrane Filtration To Provide An Advanced Level Of Organic And Suspended Solids Removal. When Designed Accordingly, These Systems Can Also Provide An Advanced Level Of Nutrient Removal. In An MBR System, The Membranes Are Submerged In An Aerated Biological Reactor. The Membranes Have Porosities Ranging From 0.035 Microns To 0.4 Microns (depending On The Manufacturer), Which Is Considered Between Micro And Ultrafiltration. 

This Level Of Filtration Allows For High Quality Effluent To Be Drawn Through The Membranes And Eliminates The Sedimentation And Filtration Processes Typically Used For Wastewater Treatment. Because The Need For Sedimentation Is Eliminated, The Biological Process Can Operate At A Much Higher Mixed Liquor Concentration. This Dramatically Reduces The Process Tankage Required And Allows Many Existing Plants To Be Upgraded Without Adding New Tanks. To Provide Optimal Aeration And Scour Around The Membranes, The Mixed Liquor Is Typically Kept In The 1.0-1.2% Solids Range, Which Is 4 Times That Of A Conventional Plant.

 

Membrane

During MBR Wastewater Treatment, Solid–liquid Separation Is Achieved By Microfiltration (MF) Or Ultrafiltration (UF) Membranes. A Membrane Is Simply A Two-dimensional Material Used To Separate Components Of Fluids Usually On The Basis Of Their Relative Size Or Electrical Charge. The Capability Of A Membrane To Allow Transport Of Only Specific Compounds Is Called Semi-permeability (sometimes Also Permselective). This Is A Physical Process, Where Separated Components Remain Chemically Unchanged. Components That Pass-through Membrane Pores Are Called Permeate, While Rejected One's Form Concentrate Or Retentate.
There Are Five Types Of Membrane Configuration Which Are Currently In Operation:

• Hollow Fiber (HF)
• Spiral-wound
• Plate-and-frame (i.e. Flat Sheet (FS))
• Pleated Filter Cartridge
• Tubular

 

2. MBR Applications

MBRs Are Generally A Preferred Option When,

1. There’s Limited Space
2. End User Requires High Quality Treated Water (e.g. For Water Reuse)

Increasingly Tighter Environmental Regulations Together With A Decreasing MBR CAPEX And OPEX Has Led To An Boost In Installations And In Size All Over The World. MBRs Have Now Been Implemented In More Than 200 Countries Worldwide With A Number Of Plants Over 4,200 M³/d In Capacity And Their Growth Rates Of Up To 15% Are Regularly Reported In Various Market Analyses.

Usually MBR Technology Is Applied To Those Wastewaters With A Readily Biodegradable Organic Carbon Content. The Latter Is Especially True When It Comes To The Food And Beverage Sector Which Has Made An Extensive Use Of MBR Technologies.

Wastewaters Markets Which Are Containing Sparingly Biodegradable Content (e.g. Landfill Leachate And Pharmaceutical Effluents) Have Also Seen A Grow Of MBRs Due To The Long Solid Retention Times (SRT) That Allow For An Improved Biological Treatment Over The One From The Conventional Biological Processes.

Waters That Contain Suspended Oil (vegetable Or Mineral) Require Pretreatment (e.g. Plate Separation, Dissolved Air Flotation Or Both) In Order To Protect The Membrane.

Although The MBR Global Market Is Mainly Dominated By A Few Major Companies, The Number Of Technology Suppliers Continues To Grow, With Over 70 MBR Membrane Module Products Available On The Market Today.

In General MBRs Have Been Applied To Treat Effluent In A Number Of Industrial Sectors, Like:

3. What Are The Advantages Of MBRs?

It's Generally Acknowledged That Membrane Bioreactors Have A Number Of Advantages Over Other Wastewater Technologies,

• I.    Independent Control Of HRT And SRT
• II.   High Quality Effluent
• III.  Small Footprint
• IV.  Improved Bio-treatment.
• V.   Independent Control Of HRT And SRT
• VI.  MBR OPEX

Containerized System:

• Fully Equipped MBR
• Pilot Testing Of Industrial Waste Water
• Verification Of Effluent Quality
• Confirmation Of Full-scale Operating Parameters
• Obtaining Regulatory Approval
• Support By Experienced Engineers
• Quick & Easy Onsite Installation