Aerobic and Anaerobic Biological Processes

Anaerobic and aerobic digestion are naturally occurring processes that are harnessed to treat waste, produce biogas, provide heat and produce compost. As wastewater treatment processes each of them, singularly or combined, prevent waterborne diseases stemming from municipal or industrial wastewater

Commonly used for treating these types of wastewater, as well as for sewage water treatment, Veolia Water Technologies South Africa (Veolia) offers biological wastewater treatment using aerobic biological processes and anaerobic biological processes. Aerobic and anaerobic digestion contribute to upgrading the quality of effluent released into the environment. They are considered major components in water recycling from high organic load wastewater.

Veolia relies on a portfolio of 350 proprietary technologies to provide unrivaled flexibility and bring added value to our clients


Veolia's biological processes address the needs of a cross section of industries for biological treatment solutions. Aerobic and anaerobic biological processes used by Veolia for wastewater treatment include:


This process uses BAFF (biological activated flooded filter) for the removal of carbon, nitrification, denitrification and post denitrification in municipal and industrial wastewater applications.


  • Advanced technology
  • Intelligent, compact design
  • Highly efficient
  • Cost-effective
  • Easy to install

For more information on BIOSTYR technology and our other range of technologies contact Veolia South Africa today, or view them here!

Moving Bed Biofilm Reactor (MBBR)

Moving Bed Biofilm Reactor (MBBR) technology offered by Veolia is based on the biofilm principle and uses the advantages of activated sludge and other biofilm systems with none of the disadvantages. Biofilm elements are manufactured from polyethylene and are used for organics removal, nitrification, denitrification and detoxification.


  • Compact & robust
  • Flexible reactor design
  • Ideal for upgrades or new plants
  • Easy to operate & control
  • No clogging
  • No sludge return


  • Food & dairy
  • Pulp & paper
  • Chemical
  • Pharmaceutical
  • Textile
  • Distilling & brewing
  • Oil refineries

For more information on MBBR technology and our other range of technologies contact Veolia South Africa today, or view them here!


This technology is offered by Biothane, a world specialist in aerobic and anaerobic biological treatment of wastewater and part of the Veolia group. Biothane UASB uses an up flow anaerobic sludge blanket and patented double baffle plate three-phase separator to treat different kinds of wastewater.


  • More than 20 years’ experience
  • High volumetric loading rate
  • Compact reactor footprint
  • Stable production
  • Economic operation
  • Low sludge production
  • Major reduction BOD


  • Brewing
  • Chemical
  • Pharmaceutical
  • Fermenting
  • Food & beverage
  • Pulp & paper
  • Sewage

For more information on BIOTHANE UASB technology and our other range of technologies contact Veolia South Africa today, or view them here!


Veolia Water Technologies South Africa uses the innovative, patented BIOSEP process, developed by its parent company Veolia. BIOSEP is a high performance solution that combines aerobic biological treatment using activated sludge and membrane filtration for the treatment of municipal and industrial effluent. The filtration step can use immersed membranes or external, pressurised membrane filtration. The process ensures a high reduction of carbon, nitrogen and phosphorus pollution, as well as exceptional bacterial removal. BIOSEP combines an aeration tank and a membrane system where the membranes are grouped into modules. After treatment, such as screening, raw water enters the aeration tank where carbon, nitrogen and phosphorus are removed.

Membrane filtration then separates the purified water from the activated sludge. Submerged membranes typically deployed in capillary configuration and positioned vertically, with filtrate being drawn through the membranes under slight vacuum. Pressurised membranes, on the other hand, operate on a cross-flow principle. The treated water is pumped out and excess sludge is directly removed from the tank for dewatering.

Benefits over conventional activated sludge:  

  • Exceptional treated water quality
  • Highly compact system
  • No final clarification
  • High COD removal
  • Reduced reagent levels in phosphorus elimination
  • Thickener may also be removed
  • Reduced sludge production

The BIOSEP immersed membrane bioreactor is compact in design and environmentally safe, offers reliable biological treatment and delivers high quality, treated effluent. It has the potential to help Veolia to gain increased market share in the biological treatment of domestic sewage and industrial effluents and will aid the companies in upgrading wastewater for re-use thus bringing long term benefits to the environment.

For more information on BIOSEP technology and our other range of technologies contact Veolia South Africa today, or view them here!

BIOSEP Membrane Bioreactors

A membrane bioreactor (MBR) is a water treatment process that uses both membrane filtration and biological treatment in one step. The process is especially suited to applications such as municipal water treatment, food and beverage production, pharmaceutical manufacturing, paper and pulp, and industrial plants, where effluent with organic pollutants needs to be treated. Typically, the treated effluent must be of a high quality to comply with discharge standards or so that it can be further treated for reuse

For more information on BIOSEP Membrane Bioreactors and our other range of technologies contact Veolia South Africa today, or view them here!



The primary objective of treating wastewater is to dispose of human and industrial effluents without affecting health or causing environmental damage. Biological wastewater treatment introduces contact with bacteria feeding on organic materials in wastewater, which reduces its BOD.

Our engineers understand how to mix aerobic microorganisms, soluble organic compounds and dissolved oxygen for high-rate oxidation of organic carbon.

  • Aerobic biological water treatment
    Aerobic treatment is often used as a secondary treatment process and follows an anaerobic stage. This is because anaerobic treatment is preferred when the dissolved organic concentrations of untreated wastewater are high.

    Aerobic treatment consists of activated sludge processes or aerated pond. The size of these can be reduced and tolerance against fluctuations and toxins can be increased by adding a step with moving bed bioreactors (MBBR) to the active sludge treatment.
  • Anaerobic biological water treatment
    Anaerobic treatment is a slow process and can take up to 3 months, which may be due to septic decomposition. Unpleasant odours may occur in this wastewater treatment process, which Veolia resolves with its sewage treatment processes that include solutions for physical/chemical deodorisation processes and green biological control. 

    Many applications are directed towards the removal of organic pollution in wastewater, slurries and sludges. The organic pollutants are converted by anaerobic micro-organisms to a gas containing methane and carbon dioxide, known as biogas.


Anaerobic treatment

Anaerobic bacteria transforms organic matter in the wastewater into biogas that contains large amounts of methane gas and carbon dioxide.

It is an energy-efficient process often used to treat industrial wastewater that contains high levels of organic matter in warm temperatures.

It can be used as a pre-treatment prior to aerobic municipal wastewater treatment.

Aerobic Treatment

Aerobic processes use bacteria that require oxygen, so air is circulated throughout the treatment tank and aerobic bacteria breaks down the waste in the wastewater.

Some systems use a pre-treatment stage before the main treatment, as well as sanitising prior to release into the environment.

The pre-treatment process: Some systems reduce the solids that the aerobic bacteria could not easily break to reduce the chance of clogging the system.

Main treatment: Treats household wastewater and includes both domestic greywater and blackwater. Forced air from a compressor is mixed with the wastewater where the aerobic bacteria feed on waste in the water and reproduce.

Solid wastes that the bacteria cannot process settle out as sludge. Some aerobic treatment systems include a secondary settling tank to facilitate this process. The sludge is frequently pumped out of the system to reduce opportunities for clogging.

Final Treatment and Disposal: This process prepares the water for return to the environment. It may include disinfection using chlorination or UV light, discharging the water to a soil absorption field, filtering through sand filters, drip irrigation, or evapotranspiration.


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