MBR Process Flow Diagrams
Standard P&ID templates and conceptual flow diagrams for typical MBR configurations. These diagrams illustrate common equipment arrangements, piping layouts, recycle paths, and control points for submerged, external, nutrient-removal, reuse, anaerobic, and staged MBR systems.
Design boundary: These are conceptual reference diagrams, not construction drawings. Confirm hydraulic profile, membrane supplier requirements, controls, chemical compatibility, redundancy, safety, and local permit conditions during detailed design.
Municipal · decentralized · reuse01. Submerged municipal MBR
The membrane modules are immersed in the aerobic or dedicated membrane zone. Permeate is withdrawn through the membrane headers while air scour and mixed-liquor circulation control solids accumulation around the modules.
flowchart LR
A[Influent] --> B[Fine screening]
B --> C[Anoxic zone]
C --> D[Aerobic / MBR tank]
D --> E[Immersed membrane cassettes]
E --> F[Permeate extraction]
F --> G[Discharge or reuse]
D --> H[Internal recycle]
H --> C
D --> I[WAS wasting]
J[Blower and air-scour header] --> E
Key Components and Design Notes:
1
Influent and screening: Removes debris and protects downstream equipment.
2
Immersed membrane zone: Combines biological treatment, separation, and air-scour protection.
3
Permeate and sludge paths: Separates treated water from recycle and waste-sludge flows.
Best fitMunicipal sewage, resorts, campuses, and compact reuse systems.
Key design checkMembrane air scour, cassette spacing, mixing, and peak-flow train availability.
02. Industrial MBR with pretreatment
Industrial applications usually need a stronger pretreatment and equalization boundary than domestic sewage. The actual sequence depends on screening, grit, oil and grease, toxicity, temperature, and the need for pH or alkalinity correction.
flowchart TB
subgraph P["Pretreatment and load equalization"]
A[Industrial influent] --> B[Coarse screening]
B --> C[Equalization and mixing]
C --> D[Fine screening and grit]
D --> E[FOG or solids pretreatment]
end
subgraph Bio["Biological treatment and membrane separation"]
F[pH or alkalinity correction] --> G[Anoxic or selector zone]
G --> H[Aerobic MBR tank]
H --> I[Membrane separation]
I --> J[Permeate]
H --> K[WAS and sludge handling]
end
E --> F
L[Rejects and return streams] --> C
Key Components and Design Notes:
1
Pretreatment and equalization: Buffers variable industrial loads and protects the biological and membrane stages.
2
FOG and solids control: Reduces carryover that can cause fouling, foaming, and dewatering problems.
3
Biological and membrane train: Provides the treatment barrier after source-control and conditioning steps.
Best fitFood, beverage, dairy, commercial kitchens, and other variable-strength wastewaters.
Key design checkPeak pollutant loads, FOG carryover, equalization time, toxicity, and cleaning compatibility.
03. Nutrient-removal MBR
This arrangement separates anoxic and aerobic functions and uses internal mixed-liquor recycle. Carbon availability, alkalinity, oxygen transfer, SRT, and membrane-zone aeration must be considered together rather than sized as isolated units.
flowchart LR
A[Influent] --> B[Anoxic zone]
B --> C[Aerobic nitrification zone]
C --> D[Membrane zone]
D --> E[Permeate]
C --> F[Internal nitrate recycle]
F --> B
B --> G[WAS]
H[Supplemental carbon if required] --> B
I[Alkalinity dosing if required] --> C
J[Membrane air scour] --> D
Key Components and Design Notes:
1
Anoxic zone: Supports denitrification when biodegradable carbon and recycle are adequate.
2
Aerobic and membrane zones: Provide nitrification, oxidation, and membrane separation.
3
Recycle and alkalinity: Must be balanced with cold-weather SRT, oxygen, carbon, and alkalinity demand.
Best fitProjects with ammonia, total-nitrogen, or nutrient limits.
Key design checkCold-weather SRT, anoxic volume, recycle ratio, carbon balance, and alkalinity.
04. Reuse-oriented MBR
MBR permeate is a strong upstream barrier, but reuse design still needs a defined end use, post-treatment objective, monitoring plan, storage strategy, and contingency route. The diagram shows common polishing functions without implying that every project needs every unit.
flowchart LR
A[Biological MBR] --> B[Permeate tank]
B --> C[UV disinfection]
C --> D[Chlorination or residual control]
D --> E[Optional carbon / polishing]
E --> F[Reuse storage]
F --> G[Non-potable reuse]
F --> H[Controlled discharge / bypass]
I[Online quality monitoring] --> B
I --> D
Key Components and Design Notes:
1
Permeate barrier: Provides a low-turbidity upstream barrier for reuse treatment.
2
Disinfection and polishing: Selected according to the end-use water-quality objective.
3
Storage and monitoring: Provides residual control, quality verification, and controlled bypass.
Best fitToilet flushing, irrigation, cooling, industrial reuse, and other defined non-potable applications.
Key design checkEnd-use criteria, disinfection credit, residuals, storage retention, and failure response.
05. Side-stream MBR
In a side-stream arrangement, mixed liquor is circulated through external membrane modules and returned to the bioreactor. This can provide module access and a distinct hydraulic environment, but pumping energy, shear, heat, and membrane cleaning requirements become important design variables.
flowchart LR
A[Biological reactor] --> B[Mixed-liquor feed pump]
B --> C[External membrane module]
C --> D[Permeate]
C --> E[Concentrate return]
E --> A
F[Air or cross-flow support] --> C
G[Cleaning / backwash connection] --> C
Key Components and Design Notes:
1
Mixed-liquor feed pump: Provides the external circulation needed by the membrane module.
2
External membrane module: Allows direct access but introduces cross-flow and pumping requirements.
3
Concentrate and cleaning paths: Must respect OEM pressure, shear, and chemical limits.
Best fitSelected industrial or specialized applications where external access is valuable.
Key design checkCross-flow velocity, recirculation power, shear sensitivity, heat, and module pressure limits.
06. Anaerobic MBR
An anaerobic MBR can recover biogas while separating solids and treated liquid through membranes. It often requires careful gas handling, sulfide and odour management, membrane fouling control, and a defined downstream polishing or disinfection strategy.
flowchart LR
A[High-strength influent] --> B[Screening / equalization]
B --> C[Anaerobic bioreactor]
C --> D[Biogas handling]
C --> E[Anaerobic membrane module]
E --> F[Permeate]
E --> G[Concentrate / solids return]
G --> C
F --> H[Optional aerobic polishing]
H --> I[Discharge or reuse]
Key Components and Design Notes:
1
Anaerobic bioreactor: Converts high-strength organics with potential biogas recovery.
2
Biogas handling: Requires gas-tight design, odour control, and hazardous-area safety.
3
Permeate polishing: May be required before discharge or reuse, depending on the objective.
Best fitHigh-strength industrial wastewater where energy recovery is valuable.
Key design checkBiogas safety, sulphide, temperature, membrane fouling, and permeate polishing.
07. Staged or two-pass treatment
A second treatment barrier may be selected when the final water-quality objective, source variability, or reuse risk requires targeted polishing. The second pass should be justified by a mass balance and monitoring plan rather than added automatically.
flowchart LR
A[Screening and biological MBR] --> B[Primary permeate tank]
B --> C[Pass-one quality monitoring]
C --> D[Targeted second pass or polishing]
D --> E[Final disinfection]
E --> F[Reuse or discharge]
B --> G[Controlled bypass / reject route]
H[Chemical or carbon polishing] --> D
Key Components and Design Notes:
1
Primary MBR barrier: Provides the first biological and membrane treatment step.
2
Targeted second pass: Should be justified by contaminant basis, recovery, and reject handling.
3
Final monitoring: Confirms final quality and defines bypass or contingency response.
Best fitProjects with stringent reuse, trace-contaminant, colour, or source-variability objectives.
Key design checkContaminant basis, recovery, reject handling, monitoring, and whole-life cost.