Identify the actual level of replacement
Distinguish replacement of elements, modules, cassettes and complete blocks. State whether the existing frame, diffusers and manifolds remain. Two solutions can occupy the same tank while requiring very different work. Draw the supply boundary and assign each component to the owner, installer or supplier before comparing quantities and committing to an intervention date or outage duration.
Prepare an inventory by train, including references, installed membrane area, age and the reason for replacement. Add daily and peak production, seasonal temperature and sludge condition to define the required duty. If the aim is capacity recovery, distinguish membrane deterioration from limitations in screening, biological treatment and pumping so that the intervention addresses the underlying restriction.
Check the tank, supports and withdrawal route
Survey actual tank dimensions, operating levels, supports, anchors, guides and clearances between blocks. Check side and overhead access for withdrawing each assembly. Extraction weight can include retained water and sludge: use the product's defined maintenance weight and lifting points when planning lifting equipment, rather than relying on the empty shipping weight or an estimate from a visually similar cassette.
Consider access after installation as well. The replacement frame should allow connection inspection and diffuser maintenance without making every intervention a whole-plant shutdown. Use the selected model's drawing to define attachment and removal arrangements, checking for clashes with existing pipework, walkways, covers and neighbouring equipment. Identify the components that must be disconnected for each maintenance intervention before fabrication begins.
Retain existing aeration only after reviewing its duty
Scouring air is part of the module's physical cleaning system. Compare required flow, pressure, distribution, diffuser position and continuous or pulsed operation for the proposed assembly. Check the blower at its actual operating point and determine how air reaches each block. Total plant air capacity does not establish adequate delivery or distribution beneath the membranes being replaced.
When reviewing controls, distinguish membrane scouring from the biological process oxygen demand and evaluate both under the expected train conditions. An air-saving claim needs a complete comparison basis: active units, normalised air flow, net production and electrical consumption. The replacement review should leave operations with a defined setpoint and a practical measurement method for checking performance after the intervention.
| System | Replacement check | Documented result |
|---|---|---|
| Tank and frame | Dimensions, supports, levels and withdrawal | Installation drawing |
| Filtrate | Connections, losses, venting and pump | Hydraulic arrangement |
| Air scour | Diffusers, blower and distribution | Aeration conditions |
| Operation | Filtration, relaxation and cleaning | Updated sequence |
Review filtrate hydraulics, cleaning and controls
Check manifold diameters and materials, flexible connections, valves, vents and the filtrate pump curve. Compare available pressure and module limits at minimum and maximum tank levels. Establish whether suction or gravity operation is retained and how flow is controlled by train. Include access to the connections that must be disconnected when a block is removed for maintenance.
Filtration, relaxation, backwash where applicable and chemical cleaning must suit the new membranes. Update level, pressure and air alarms and interlocks. Check the materials and condition of seals and tubes proposed for reuse. Identify components renewed during each intervention and their part references in the materials list so that subsequent maintenance can reproduce the approved installation accurately.
Plan staged replacement and measurable acceptance
Calculate capacity with one train isolated and adjust the programme, storage or plant production to match demand. Prepare materials and adaptations before removing existing equipment. Where the proposal introduces significant changes, an initial stage can verify installation, filtrate quality and operating behaviour before the remaining trains are converted, using criteria and a duration already agreed in the supply scope.
Set a review point at the end of the first stage: confirm installation, stable operation and agreed results before intervening on the next train. Record net flow, TMP, temperature, sludge conditions, air and quality together with the final configuration. Operators should receive a procedure that they can carry out and maintain, alongside updated drawings of the installed assembly.
Common questions
Can the existing frame be retained?
Review supports, membrane spacing, connections, aeration and extraction access. The integration drawing identifies which components remain.
Will more membrane area increase MBR capacity?
Review sustainable flux, pumping, air, screening and biological capacity together. Additional membrane area is one part of an expansion.
What information starts a replacement assessment?
Module reference and quantity by train, tank and frame drawings or dimensions, connection photographs, production and filtrate and aeration operating data.