Treatment process
Membrane bioreactor
Activated sludge combined with membrane filtration in place of a settlement tank, producing a much higher quality effluent in a much smaller footprint.
Key facts
- Scale
- Municipal
- Treatment stage
- Advanced wastewater treatment
How it works
Micro- or ultrafiltration membranes are immersed in or coupled to the aeration tank, separating treated water directly from the biomass. Because settling is no longer the constraint, biomass concentration can be far higher.
What it removes — and what it does not
| Row | Removes | Does not remove |
|---|---|---|
| 1 | Suspended solids essentially completely | Dissolved salts |
| 2 | Bacteria and protozoa | Most micropollutants and PFAS |
| 3 | Biochemical oxygen demand to very low levels | Nutrients, without a designed nutrient removal stage |
| 4 | Produces effluent suitable for reuse with limited further treatment | — |
Trade-offs
- Higher energy and capital cost than conventional activated sludge
- Membrane fouling requires regular cleaning and eventual replacement
- Compact footprint makes it valuable on constrained urban sites and for water reuse schemes
Related intelligence
Reverse osmosissame topicChlorinationsame topicGranular activated carbonsame topicCombined sewer overflowsame topicIon exchange softeningsame topicUltraviolet disinfectionsame topicCoagulation and flocculationsame topicActivated sludgesame topicRapid gravity filtrationsame topicChloraminationsame topicDistillationsame topicSlow sand filtrationsame topic
Sources
- World Health Organization — Guidelines for Drinking-water Quality. Public but restricted · CC BY-NC-SA 3.0 IGO
- NSF International / American National Standards Institute — NSF/ANSI drinking water treatment unit standards. Public but restricted · Publisher terms — public access, reuse not clearly granted
- American Water Works Association — AWWA standards, water audits and utility benchmarking. Public but restricted · Publisher terms — public access, reuse not clearly granted