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Aerobic vs Anaerobic Wastewater Treatment

With around 200 - 300L of wastewater being produced per person, per day in Australia (yes, you read that right, per day), wastewater treatment is a big environmental issue across the country (and the world!). With that amount of water making its way from our homes and offices on a daily basis, the types and classes of wastewater treatment arrangements are an important aspect to consider, especially if you are considering installing a system.

Running Tap

We understand that all the information around wastewater, its treatment and the components to different systems can be a little overwhelming, so we have put together some bits and pieces surrounding one particular aspect - aerobic and anaerobic systems. If you would like to know a little more about primary and secondary systems, check out What is the difference between primary and secondary treatment of wastewater?

Wastewater Treatment

Due to the large amounts of wastewater that is produced by homes and offices each and every day, correct and effective wastewater treatment plays a huge role in environmental and personal health. If the wastewater that leaves our kitchen sinks, bath tubs or toilets isn't treated properly, when it is reused for activities such as irrigation it can hurt both the environment and us.

Environmentally Friendly Wastewater Treatment

As such, there are varying styles and types of wastewater treatment arrangements to meet almost every need - from Home Sewage Treatment Plants (HSTPs) to Septic Systems, Aerated Wastewater Treatment Systems (AWTS) to Aerobic Treatment Systems/Units (ATU) and other options in between. Some options use just a primary treatment process, whilst others adopt both a primary and secondary treatment arrangement. These processes contain biological wastewater treatment operations of their own, using naturally-occurring microorganisms to feed on complex organic matter, which transforms them into simpler arrangements. This kind of treatment is separated into two wide-ranging categories: anaerobic and aerobic treatment.

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Anaerobic Wastewater Treatment

Anaerobic wastewater treatment is the treatment of wastewater without the presence of oxygen - or at least very very low levels of oxygen - and is also known as anaerobic digestion. Anaerobic processes use anaerobic bacteria that do not require any oxygen to complete their work - that is, change organic matter into structures that hold large amounts of carbon dioxide and methane gas. Depending on the system, anaerobic wastewater treatment can be used as a pre-treatment step before aerobic treatment begins.

Aerobic Wastewater Treatment

The other component to biological wastewater treatment is aerobic, which requires oxygen to complete. Aerobic bacteria convert organic matter into new biomass and carbon dioxide while air is continuously circulated throughout the tank. The air that is forced into the tank mixes with the wastewater and the microorganisms feed on the waste that is found in the water.

Water Molecule

What is the difference between aerobic and anaerobic treatment?

As you can see above, the major difference between the two types of treatment is the presence of oxygen - aerobic systems require oxygen, whereas anaerobic systems do not. The other differences include :

Aerobic Systems

  • An aerobic system can be a stand alone system, or combined with an anaerobic system
  • Aerobic systems, in isolation, tend to be more expensive than their anaerobic counterparts
  • Aerobic systems need electricity and solids need to be pumped out regularly
  • A qualified professional is required to inspect and maintain the electrical and mechanical components related to the aerobic parts of a system regularly to ensure they are working correctly
  • Anaerobic components also require maintenance, but at a lower level
  • Aerobic systems allow even the strictest of industrial environmental guidelines to be met
  • Anaerobic systems, in isolation, are more environmentally friendly than aerobic systems due to :

    Anaerobic Systems

  • Anaerobic systems generate less sludge
  • Anaerobic sludge can be used for soil enrichment
  • Anaerobic systems have lower sludge-handling costs than aerobic systems
  • There are more chemicals in aerobic systems
  • Anaerobic systems produce biogas that can be used to produce electricity

Both aerobic and anaerobic processes provide crucial components to various wastewater treatment systems and plants, however it is worth noting that the implementation of aerobic wastewater treatment arrangements will usually considerably improve the quality of water being released after treatment.

Your local and reliable wastewater treatment specialists

If you have some questions regarding aerobic or anaerobic wastewater treatment, or think it may be time to introduce a wastewater treatment system to your home or office, get in contact with Express Wastewater today. Give us a call on 1300 722 517 or complete an online job booking form and we can help you with all your wastewater needs.

Department of Environment and Science:


Evoqua :

Environmental Business Specialists (Aerobic) :

Environmental Business Specialists (Anaerobic) :

Aerobic vs Anaerobic Wastewater Treatment Let our experts help you.

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Why Use Express Wastewater Solutions?


    Because we are not a manufacturer and not tied to one particular system we can always offer the best solution for your wastewater needs.


    Because we do this every day we have developed a close knit expert team for every step of the process – from plans and council paperwork to excavations, electrical and plumbing. We handle it all to make the whole process as stress free and quick as possible.


    Most people have never installed a home sewerage treatment plant and don’t know the next step, that is why we offer a free 30 minute phone consult with one of our experts to point you in the right direction.


    We handle your wastewater installation from start to finish we can deal with all the trades, council everything so you don’t have to worry about a thing.


    Have peace of mind knowing that Express are licensed, insured professionals that will do your job right the first time.


    Not sure what system is right for you, or want to know if your system is working properly? Just give one of our friendly wastewater experts a call and they will be more than happy to help.


    We will always look to repair your system rather than replace it if it does not need to be, which will generally save large amounts of money sometimes up to and over $10,000.