What Is A Biological Membrane And How Does It Works?

Biological wastewater treatment is one of the processes that use a natural method to help decompose organic substances. However, the process is complex and requires an understanding of biochemistry and biology.


Membrane bioreactors for wastewater treatment combine two processes: a membrane for ultrafiltration (or microfiltration) with a biological process to break down the waste, typically activated sludge. The added step of using membranes is useful in performing the critical solid-liquid separation function. In facilities using only the activated sludge process, this separation is traditionally accomplished using secondary/tertiary clarifiers and filtration.


The two general types of Membrane Biological Reactor (MBR) systems are pressure and vacuum-driven systems. Gravity and vacuum systems are immersed and employ hollow flat or fiber sheet membranes installed in bioreactors or subsequent membrane tanks. Pressure-driven systems are in-pipe cartridge systems located externally to the bioreactor.


How are they used in wastewater processing?

Biological treatments rely on nematodes, bacteria, or other organisms used to break down the organic wastes using normal cellular processes. Household wastewater typically contains organic matter like wastes, garbage, and partially digested foods. Industrial wastewater may also contain toxins, heavy metals, and pathogenic organisms. Depending on the source of the wastewater, chemical contamination may be present as well. Since CWE treats industrial wastewater, the first elements to be removed in the treatment process are the light-ends (solvents like alcohols, ketones, and other quick evaporating hydrocarbons). Next come the long-chain heavy organic molecules, heavy metals, and solids. In CWE’s case these “lights” and “heavies” are removed in our Distillation/Evaporator unit. The final unit in the process is the MBR, which treats the chemical contamination of glycols and long chain alcohols.


The goal of biological wastewater treatment is to create a system that results in decomposition. The matter is then easily collected for proper disposal. Biological treatment is as effective as and more economical than many chemical or mechanical processes.


Biological treatment is usually divided into anaerobic and aerobic processes. “Anaerobic” describes a biological process in which oxygen is absent, while “Aerobic’ refers to the process in which oxygen is present. Scientists can refine and control both anaerobic and aerobic processes to achieve the optimal removal of organic substances from wastewater.


Biological membrane wastewater treatment or MBRs are helpful as a secondary treatment process, meaning the process helps remove the materials remaining after the primary treatment. The process includes dissolved air flotation (DAF). In the primary water treatment process, substances like oil and sediments are removed from the wastewater.


How does a biological wastewater treatment system work?

Depending on the chemical makeup of the wastewater with the effluent requirements, a biological membrane wastewater treatment system comprises numerous types and different processes of microorganisms. It also requires specific operational procedures that vary depending on the environment. The biomass growth rates are optimal for the specific microbial populations.


For example, it often requires adjusting and monitoring aeration to maintain a consistent dissolved oxygen level to keep the bacteria of systems multiplying at an appropriate rate to meet discharge requirements.

What are the advantages of using this method over other filtration methods?

Biological Membrane technology is helpful to remove solids in wastewater treatment. It is usually based on microfiltration or ultrafiltration. The membranes can be introduced into the biological wastewater treatment process either as:

  • Integrated into the biological process, or
  • A separate unit operation downstream of the biological step

Here are a few advantages of the biological membrane filter technique:

  • It is easy to obtain results rapidly compared with conventional methods, typically within 24 hours.
  • The membrane can be transferred from one medium to another to select and differentiate organisms, allowing the isolation of discrete colonies of bacteria.
  • Biological membranes allow large sample/large volume loads.

How CWE helps in wastewater management?

Clean Water Environmental has a state-of-the-art wastewater treatment, disposal, and recycling facility for non-hazardous and hazardous wastewaters. We treat diverse streams of wastewater that come from manufacturing facilities, landfills, refineries, and chemical plants. Our latest expansion and innovations include a dual thermal unit which pairs an Evaporator with a Distillation column for maximum efficiency and a state-of-the-art twin tank Membrane Biological Reactor (MBR) which allows us to process dissolved organics in wastewater.

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