Many industrial effluents carry chemical oxygen demand (COD) far above municipal strength — from food and beverage, pulp and paper, and chemical processing. High-COD streams challenge conventional biology because the organic load is heavy and often variable. MBBR is well suited to these streams: biomass is fixed on the carriers, so the process sustains a high organic load and absorbs peaks without the biomass washout that limits suspended-growth systems.
Roughing and Multi-stage Treatment
High-COD streams are frequently treated in stages. A high-rate roughing MBBR removes a large share of the load in a compact reactor, protecting and relieving downstream biology. Additional MBBR stages then drive the biodegradable COD lower. Only the biodegradable fraction can be removed by biology — the inert COD passes through and sets a floor on the achievable effluent, so characterising the COD fractions is essential to setting a realistic target.
Where the COD is very high, anaerobic pretreatment may precede the MBBR to remove bulk organics economically, with the MBBR polishing the remaining biodegradable COD aerobically.
High-COD Design Context (indicative literature ranges — confirm per project)
| Parameter | Typical Value | Unit | Notes |
|---|---|---|---|
| SALR — roughing | > 15 | g BOD/m²·d | Partial COD removal, compact |
| SALR — full removal | 5 – 15 | g BOD/m²·d | Toward the inert-COD floor |
| Effluent floor | inert COD | — | Non-biodegradable passes through |
| Pretreatment | optional anaerobic | — | For very high COD — confirm per project |
Why MBBR Suits High Organic Load
The retained biofilm means the process can be loaded hard without losing biomass, and it recovers quickly from concentration and flow peaks. This robustness, combined with a compact footprint, makes MBBR a common choice for concentrated industrial effluents.
Frequently Asked Questions
How high a COD can MBBR treat?
What is a roughing MBBR?
Why does inert COD matter?
Related Pages
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