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Membrane Filtration Wastewater Treatment How It Works

Water and wastewater treatment uses membrane filtration extensively because it outperforms traditional water technologies in terms of performance and economy. Microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), and reverse osmosis are the four fundamental membrane processes (RO). These membranes’ separation ranges are as follows: For MF, the range is 100–1000 nm; for UF, 5–100 nm; for NF, 1–5 nm; and for RO, 0.1–1 nm. Using membranes in the MF and UF range, MBRs have become an efficient secondary treatment technology over the past ten years or so.


  • The main application of a membrane bioreactor (MBR) is wastewater treatment (WWT), where microfiltration (MF) or ultrafiltration (UF) are combined with a biological process, such as a suspended growth bioreactor. A clear and pathogen-free product is produced by using the membranes as a filter to remove the solids produced during the biological process. The next step illustrate of an immersed MBR (iMBR) provides a visual illustration.
  • To remove large objects that could harm the equipment downstream, the wastewater is passed through a fine screen. Following an Aerobic Zone where microorganisms with the aid of the oxygen coming out of the FBD will digest the organic matter in the wastewater and clump together as they do so, producing a sludge, the wastewater then enters an Anoxic Zone for the treatment of nitrogenous matter and phosphate. The membrane in the Immersed Membrane Bioreactor will separate the water from the solids and microorganisms as this sludge enters it.
  • In the traditional activated sludge (CAS) system, the settlement tank for solid/liquid separation is essentially replaced by a membrane bioreactor. The MBR provides the user with enhanced process control and a significantly improved product.
  • When compared to the traditional activated sludge process, the MBR process operates over a significantly wider range of parameters.


SRT 20-30 days for an MBR and 5-20 days for a conventional system

F/M 0.05 to 1.5 days for conventional systems and less than 0.1 days for MBR

MLSS 5,000–20,000 mg/L for MBR and 2,000–4000 mg/L for conventional process


MBRs typically feature three different membrane configurations multitube, flat sheet (FS), and hollow fibre (HF) (MT). Different configurations of the MBR membrane: A Hollow Fiber, B Multitube, and C Flat Sheet

Applications MBR

MBRs are typically the best choice when,

  • There is not much room.
  • High-quality treated water is required for the end user (e.g. for water reuse)
  • An increase in installations and in size across the board has been brought on by tightening environmental regulations combined with falling MBR CAPEX and OPEX.
  • High-quality treated water is required for the end user (e.g. for water reuse)
  • Global installations and size have increased as a result of tightening environmental regulations and declining MBR CAPEX and OPEX. MBRs have been put into use in more than 200 nations around the world. A number of these plants have a capacity of over 4,200 m3/d, and various market analyses regularly report growth rates of up to 15%.
  • Typically, MBR technology is used with wastewaters that contain an easily biodegradable amount of organic carbon. The latter is particularly accurate in the case of the food and beverage industry, which has extensively utilised MBR technologies.


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