Understanding the requirements for oil water separators

Cleanawater on 11 November 2019

Starting or buying a business in Australia can be a stressful process. There are so many things to consider–from the financial viability to marketing and staff management. But before you get too involved in the finer details, you'll want to make sure your office's wastewater meets Australia's discharge regulations. 

Oil (and hydrocarbons) are two of the most common contaminants in wastewater. There is a long list of industries that might be at risk of oil contaminants in their wastewater, including mining, car washing services, mechanic workshops, and service stations. 

Cleanawater supplies oil water separators designed to keep your wastewater compliant to Australia's discharge regulations. 

The Environmental Protection Authority (EPA)

The EPA is the primary environmental regulator in Australia. Its role is to protect the environment as well as to prevent, control, and reduce pollution and damage to the environment.

Some of the functions of the EPA include the following:

  • Conducting environmental impact assessments
  • Preparing policies and guidelines
  • Licensing of businesses
  • Compliance and enforcement

Who are the local water authorities?

oil separators suppliers

Discharges to the municipal wastewater network are managed by local water authorities. Their requirements differ according to the specific challenges of the area. For example, they might assess and monitor:

  • The spare capacity in wastewater treatment plants
  • The contaminants present in the wastewater and the overall loading of those contaminants in the system
  • The history of environmental compliance of the business concerned

Each local water authority generates a specification for the wastewater discharged to their sewer network.

How to comply with the standards?

The specs set by local water authorities include an upper limit for oil or hydrocarbons. For many businesses, the only way to adhere to this standard is to use an oil water separator to pre-treat the water discharge.

Some local water authorities actually make this a requirement before issuing a permit to discharge. They may also specify a servicing schedule and maintain a list of approved separators for installation.

The permit to discharge sets the quality parameters and cost structure of wastewater discharge. If you don't comply with the conditions on the permit, you're at risk of being issued a warning or a fine. In extreme cases, your site might even get shutdown until the conditions are rectified.

Cleanawater oil water separators

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Cleanawater is a leading supplier of oil water separators in Australia. We have two main options–a coalescing plate separator and a hydrocyclone separator.

Coalescing plate separators

These are typically used in for smaller applications like car washes, which generate between 1,000 and 3,000 litres per hour of wastewater. Coalescing plate filters can also be installed in pigeon pairs. This means adding two separators together, which can give a flow rate capacity of up to 10,000 litres per hour.

How they work

Coalescing separators use media packs to allow the free oil molecules to bind together and then float to the surface of the water. Oil is then removed from the surface, and the water is then disposed of according to regulatory requirements. Using this technology, oil content in wastewater can be reduced down to 10 parts per million (ppm).

It's important to remember to:

  • Service the media packs within the separator. Sludge can accumulate in these units, which greatly reduces their efficiency.
  • Use quick break detergents when you operate your business.

Quick break detergents quickly release oil molecules from suspension allowing them to coalesce in the separator. If oil remains as an emulsion it will not separate from the water and will be discharged with the wastewater causing environmental incidents. This can happen when detergents used do not have quick break properties. 

Hydrocyclone separators

These are typically used in larger applications like the mining sector where flow rates can be anywhere from 10,000 to 50,000 litres per hour.

Hydrocyclones use centrifugal forces to separate the oil molecules from water. Because water is heavier than oil, the water is pushed to the outer edges of a vortex and oil collects in the centre. Using this technology oil content in wastewater can be reduced down to 5 ppm.


Cleanawater has developed a range of resources to help you understand the risks of oily wastewater in your industry. Some of the highlights related to oil water separators are:

  • Industry and product brochures
  • Site layout diagrams
  • Operations and maintenance manuals
  • FAQs

Accessing our document centre is a great way to get up to speed on oil water separators and how they can help you meet the discharge regulations in Australia.

Contact Cleanawater 

Contact Cleanawater for all your wastewater advice and oil water separator needs. We have more than 20 years of experience in the Australian market and can help you navigate the regulatory requirements.

Contact Cleanawater to find out more about oil water separators.