How are microorganisms used in sewage treatment? - Proseptic

How are microorganisms used in sewage treatment?

2020 septic tank regulations

When we covered in detail what a small sewage treatment plant was, we touched on the role of bacteria in the process.

In fact, microorganisms play an important part in sewage treatment, from smaller domestic properties to multiple occupancy buildings and workplaces.

And while it’s understandably tempting to think ‘out of sight, out of mind’ once the toilet has been flushed, what happens to our waste is a current hot topic.

How are microorganisms used in sewage treatment?

The pollution of the UK’s water courses has come under understandable scrutiny recently, largely due to discharges from chemical and agricultural business.

But when it comes to sewage waste, the unsung heroes helping to avoid a similar national outcry are acting at a microscopic level. 

As local authorities have raised the environmental standards required for sewage treatment, these microorganisms have come into their own – and they include:

  • Naturally occurring bacteria
  • Fungal organisms
  • Single celled organisms known as ‘protozoa’
  • Multicellular rotifers
  • Other organisms such as tardigrades

And while googling any of these doesn’t result in a particularly attractive gallery, all of them have a vital thing in common – they help to digest waste.

The vast majority of this process is carried out by bacteria, both aerobic and anaerobic types, that are found in wastewater during sewage treatment.

Aerobic bacteria

Once the solid and liquid parts of sewage have been separated, the wastewater (sometimes known as sludge) is aerated.

Oxygen loving bacteria can then thrive and begin to digest the organic material in the sludge, in order to reproduce.

The ammonium present is oxidised into nitrite and nitrate, in a process known as nitrification.

Anaerobic bacteria

As the name suggests, these organisms don’t need oxygen to thrive, meaning they are used to digest solid waste.

This is particularly useful in systems or tanks where separation has meant that a liquid layer prevents oxygen from reaching the solid waste below.

Sometimes anaerobic bacteria can be introduced to waste both before and after the aerobic digestion phase in order to achieve more pure results.

And often, the resulting methane gas that is generated as a by-product can be collected and used or sold.

Do I need a sewage treatment system that uses microorganisms?

In any septic tank, cesspit or small sewage treatment plant, there will be countless naturally occurring microorganisms digesting the contents.

But there are obviously varying degrees of efficiency and environment friendliness available. If you’d like to talk to a helpful professional about how to get the best performing system for your property, please get in touch.

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