MBR Plant in Bangladesh

It depends on what you need from the water. An MBBR with a clarifier and a polishing filter costs less to build and is simpler to run, and it is enough when discharge limits are basic and space is available. An MBR folds the clarifier and the filter into one membrane step, so it gives clearer water in a smaller footprint and a cleaner feed for RO. Choose MBR when you plan to reuse water, space is tight or limits are strict. Choose MBBR when budget and simplicity matter most.

The usual causes are oil and grease, hair and fibres, running above the design flux, very high sludge concentration and sudden temperature swings. Pilot studies have linked temperature shocks to faster fouling. Prevention is mostly design and discipline: fine screening, oil removal, equalisation, steady flow, air scouring, regular backwash and a scheduled chemical clean-in-place. Keep the flux within the supplier's rating.

Neither is better everywhere. Hollow fibre packs more membrane area into a tank and can be backwashed, but long fibres and hair can tangle and clog bundles. Flat sheet is mechanically rugged and tolerant of fibres, but needs more space per square metre of membrane. Published comparisons also suggest that overall plant design and control affect energy use more than membrane shape does. Tell us your wastewater and we will recommend a type.

Optimised full-scale municipal MBRs report roughly 0.5 to 0.65 kWh per m3 treated, and one audit measured 0.64 kWh/m3 against 0.3 kWh/m3 for conventional activated sludge. Most of the extra energy goes to air scouring that keeps the membrane clean. Add cleaning chemicals, operator time and eventual membrane replacement. Ask any supplier for a guaranteed kWh/m3 and the air-scouring strategy.

Textile wastewater needs fine screening for lint and fibre, oil and grease removal, equalisation and cooling, because membranes have a rated temperature range (flat-sheet PVDF modules are often rated about 15 to 40 degrees C). An MBR holds back bacteria and solids and cut COD and BOD strongly in a Dhaka bench trial, but it does not remove dissolved salts and may not remove all colour. For reuse, add RO or an oxidation step.

Often yes. A common route is to replace the clarifier with a membrane tank and raise the biomass in the existing aeration tank. An engineer must check aeration capacity, available tank volume, fine screening, power supply and the sludge handling you already have. Send us your tank drawings and wastewater data and we will assess whether a retrofit or a new plant makes more sense.

MBR membranes are a physical barrier and remove most bacteria. A full-scale MBR with 0.04 micron membranes removed about 4 to 5.5 log of adenovirus and norovirus, but reported virus removal ranges from roughly 0.5 to 6 log depending on membrane, design and operation, and one cold-climate pilot achieved only 1.8 to 3.0 log. For hospitals and reuse, keep a disinfection step and follow the rules for your reuse application.

Start-up is gradual. The tank is seeded with activated sludge and the biomass builds towards the design level over several weeks, with flow raised step by step while the membranes run. Day-to-day operation is largely automated, but a trained operator must watch transmembrane pressure, flux, air scouring, dissolved oxygen and the cleaning schedule. We commission the plant and train your team.