A retrofit MBBR system upgrades a plant that already exists. By adding carriers to an existing aeration basin — as an MBBR or as an IFAS hybrid alongside suspended sludge — the biomass in the tank increases without enlarging it, which can raise capacity or add nitrification within the current footprint. It is a targeted way to meet growth or tighter consents without a full rebuild.
What a retrofit involves
Typical scope includes carriers, retention screens on the outlets and an aeration grid adapted to move the carriers and transfer oxygen. In an IFAS configuration the existing sludge process is retained and carriers are added to boost treatment; in a full MBBR conversion the process moves to fixed film. Which approach fits depends on the existing plant, its loading and the treatment goal.
Our dedicated retrofit resources cover the specific cases — capacity upgrades, nitrification upgrades, footprint-limited sites and activated-sludge conversion — in more depth.
Retrofit MBBR — Configuration Choices (project-specific — confirmed per project)
| Parameter | Typical Value | Unit | Notes |
|---|---|---|---|
| Approach | MBBR or IFAS | — | Full conversion or hybrid |
| Goal | capacity / nitrification | — | Within existing footprint |
| Scope | carriers + screens + aeration | — | Added to existing tank |
| Suitability | per existing plant | — | Load + tank assessed |
| Sizing basis | flow + load | — | Set during engineering review |
Frequently Asked Questions
What is the difference between MBBR and IFAS retrofit?
Can a retrofit increase capacity without a bigger tank?
Will my existing aeration work?
Related Pages
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Tell us about your wastewater, flow and treatment objectives. We will identify a suitable MBBR configuration and the next engineering step.