What is liquid trade waste?


The Local Government (General) Regulation 2021 defines 'liquid trade waste' as 'all liquid waste other than sewage of a domestic nature'.

All business activities generating liquid trade waste must have current Council approval and maintain the appropriate equipment necessary to treat any liquid waste before it enters our sewerage system.

Shoalhaven Water regulates liquid trade waste discharges in order to:

  • Protect the health and safety of our staff, the public, and the environment
  • Protect wastewater system infrastructure, assets, and sewerage treatment processes to protect the effluent and biosolid quality for facilitation of recycling
  • Reduce maintenance costs and odour complaints

This includes liquid waste generated from:

  • Industrial premises
  • Businesses and commercial premises such as hotels, motels, restaurants, takeaway stores, butchers, service stations, mechanical workshops, vehicle wash facilities, supermarkets, dentists
  • Community and public premises such as pools, schools, colleges, education facilities, hospitals and nursing homes
  • Any of the above activities carried out at residential premises
  • Septic tank waste, marine pump-out facilities and established sites for the discharge of chemical toilet or pan contents from mobile homes, caravans or portaloos

If your business falls into one of these categories, you will be required to pre-treat your liquid trade waste prior to discharging into our sewerage system.

What is pre-treatment?

Pre-treatment is achieved by using a device or piece of equipment to treat the liquid trade waste prior to discharging into the sewerage system. The type of pre-treatment device required is dependent on the nature of the activity and the volume and strength of the liquid trade waste it generates.

Typical pre-treatment devices used for the treatment of liquid trade waste include but are not necessarily limited to the following:

  • Grease arrestor (grease trap)
  • Basket arrestor with fixed screens (dry basket arrestor)
  • Fixed or removable screens
  • Coalescing plate interceptor (CPI oil separator)
  • Vertical gravity separator (VGS separator)
  • Hydrocyclone separation system (HSS separator)
  • Cooling pit
  • Balancing, averaging, neutralising pit/tank
  • Solids settlement pit/silt arrestor
  • Plaster arrestor

Shoalhaven Water’s pre-treatment requirements are in accordance with the Liquid Trade Waste Regulation Guidelines 2021 and our Liquid Trade Waste Policy.

Frequently asked questions

I operate a food business, do I need a grease arrestor?

The answer is usually yes! Most food businesses will need to have a 1000L capacity grease arrestor (grease trap) or larger installed to pre-treat the liquid trade waste prior to discharge to the sewer.

The size is determined by a number of factors, such as available seating or kitchen fixture units, and is individually assessed according to the NSW Liquid Trade Waste Regulation Guidelines in force at the time.

Council’s Liquid Trade Waste Discharge policy outlines the type of food businesses that require, and those that may not require, the installation of a grease arrestor.

If you are considering starting up or purchasing a food business, it is important to understand the type of cooking, preparation and serving you will be doing, to determine if a grease arrestor is required. 

If a grease arrestor is already installed on the premise, you need to consider if it is the correct size and in good condition. If there is none at the property, you will need to contact a licensed plumber for advice and a quote. They can also check if there are any installation issues (e.g. due to lack of space).

What are my requirements if I operate a mechanical workshop?

Liquid trade wastes that are discharged from mechanical workshops and vehicle wash businesses are required to be pre-treated using an oily water separator and associated collection pits and pumps. Separators, pits and pumps need to be sized properly for the activity and amount of waste generated. The minimum size for oily water separators is 1000L/hr.

Double and triple interceptor pits and general-purpose pits are no longer appropriate pre-treatment equipment on their own. If liquid trade waste is to be discharged to sewer, the pre-treatment system will need to be upgraded to include an oily water separator.

An alternative is to operate as a dry workshop. This is only appropriate where a very small amount of liquid trade waste is generated.  Any pits need to be disconnected from draining to the sewer. Any waste liquids collected on site need to be removed by a contractor.

Liquid trade wastes collected from service station covered forecourts and other refuelling locations are not permitted to discharge to sewer and will need to find alternate methods of waste water disposal.

Shoalhaven Water’s Regulatory Unit is available to provide advice and assistance to understand the particular liquid trade waste requirements for your business.

Land owner consent

If you are leasing a property to conduct your business activity you must obtain land owner consent prior to submitting an application.

Please note: An application cannot proceed without the consent of the land owner.

How to provide consent

The land owner can provide consent using our submit land owners consent online application form. In doing this, the land owner acknowledges the business activities proposed for their land, and accepts responsibility for ongoing liquid trade waste charges.

On submission of the consent form, the land owner will receive a PDF copy of their consent which can be forwarded to their property managing agent, or to the person requesting consent.

Land owners consent must be provided as support to an application requesting approval to discharge liquid trade waste into Council's sewerage system.

Submit land owners consent

Why do I need approval?

Business activities can produce large amounts of solids, oil, grease, and other substances which if discharged directly into the sewerage system can overload the system or cause blockages.

Shoalhaven Water must regulate the discharge of liquid trade waste in order to:

  • Protect the health and safety of our staff, the public, and the environment
  • Protect wastewater system infrastructure, assets, and sewerage treatment processes to protect the effluent and biosolid quality for facilitation of recycling
  • Reduce maintenance costs and odour complaints

Approval to discharge liquid trade waste into Council's sewerage system is a requirement under Section 68 of the Local Government Act 1993. Failure to obtain approval or failure to comply with the conditions of an approval, may lead to prosecution under Section 626 and 627 of the Local Government Act 1993.

How do I get approval?

To obtain approval, customers must submit the relevant online application based on the business activity which may include providing information such as a site plan and/or drainage diagram.

Approval requirements and applications

To make application or to find out more about the types of pre-treatment equipment required for a business activity, click on the links below:

Business activities exempt from obtaining Council's written approval but must still meet standard requirements include:

  • Hairdresser/beautician
  • Dental technician/doctor surgery (no x-ray)
  • Jeweller/optometrist
  • Florist
  • Bed and breakfast

If your proposed business activity is not on our list, contact us to find out more. Alternatively, you can view our liquid trade waste policy and our liquid trade waste policy supplement.

Discharger categories

Activities that generate and discharge liquid trade waste will fall into one of the following discharger categories:

Low Risk

  • Category 1A: Nil or minimal liquid trade waste pre-treatment equipment required (eg hairdresser, florist, beautician)
  • Category 1B: Still low risk but require more sophisticated prescribed liquid trade waste pre-treatment equipment (eg vehicle wash, laundry activities)

Medium Risk

Require prescribed liquid trade waste pre-treatment equipment (eg. Grease arrestor for restaurant or cafe, oily water separator for a mechanical workshop).

  • Category 2A - The prescribed pre-treatment equipment is installed and maintained to Council’s requirements (eg correct type and size grease arrestor pumped out to Council’s set frequency)
  • Category 2B - The prescribed pre-treatment equipment is not installed or is not appropriate or is installed but not maintained to Council’s requirements.
  • Category 2S - Dischargers of pan contents, septic wastes, chemical toilet waste and ship-to-shore pump-outs into the sewerage system. Includes septic tank pump outs and septage transported and discharged directly to a sewerage treatment plant. 

High Risk

Referred to as Category 3A or 3B (depending on the complexity of the pre-treatment system) and includes:

  • Industrial dischargers
  • Large volume (greater than 20kL/d) dischargers
  • Dischargers that do not fall into Category 1 or 2 above
  • Contaminated groundwater or stormwater

Ongoing fees and charges

Best practice pricing is implemented to ensure dischargers bare a fare share of the cost of providing sewerage services and to facilitate appropriate pre-treatment waste minimisation and water conservation.

Liquid trade waste fees and charges are in addition to non-residential sewer usage charges and are issued on the landowners quarterly water account. They include:

  • Annual service charge to help recover costs incurred by council for ongoing administration and scheduled inspections, and to ensure that the discharge complies with the approval conditions.
  • Usage charge is a price per kilolitre applied to the volume of wastewater discharged to the sewerage system. The discharge amount is based on a percentage of the amount of incoming water. The usage charge will depend on the charging category and the business activity.