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Liquid Trade Waste

Blayney Shire Council has a number of statutory responsibilities for the approval of liquid trade waste to be discharged to the sewerage system under the Local Government Act 1993. 

Council obligations include risk management, cost recovery, approvals, monitoring and ensuring licence conditions of the Sewerage Treatment Plant are met. Council has developed a Policy for Discharge of Liquid Trade Waste to the Sewerage System which outlines requirements and procedures for the management of liquid trade waste.

What is liquid trade waste? 

Liquid trade waste means all liquid waste other than sewage of a domestic nature. Activities producing liquid trade waste include, but are not limited to:
  • Businesses/commercial premises (e.g. beautician, hairdresser, motel, café, butcher, service station, dentist);
  • Industrial premises;
  • Community/public premises (e.g. school, college, hospital, craft clubs);
  • Trade activities (e.g. mobile carpet cleaners);
  • Saleyards, racecourses, stables and kennels not associated with households; and
Any commercial activity carried out at a residential premises.

Sewer systems are generally designed to cater for domestic waste and liquid trade waste may exert greater demands on sewer. Management of liquid trade waste is required to: 
  • Protect community assets, e.g. sewer mains, pumping stations and sewerage treatment facilities from damage by trade waste;
  • Protect the environment - some substances, such as metals or pesticides may pass through the treatment facility unchanged and accumulate in the environment.  Other substances may adversely affect the biological processes and the quality of the treated effluent and biosolids;
  • Protect public and worker health and safety - people working in and around the sewerage system can be harmed if toxic substances are discharged into the sewer.

Why is liquid trade waste a problem?

The Blayney Shire (Blayney and Millthorpe) sewerage system was designed for domestic sewage.  By contrast, trade waste is generated by businesses or commercial activities and may be quite different to domestic sewage in terms of:
  • Corrosiveness
  • pH
  • Temperature
  • Presence of fats and oils
  • Presence of oil and grease
A person wishing to discharge liquid trade waste to sewer must obtain Council's approval as per Section 68 of the Local Government Act 1993.  This applies to new trade waste dischargers, those whose approval has expired, or where there is a change to operations. In order to assist business, Council is happy to accept some liquid trade waste, subject to conditions.
  • Firstly, the liquid trade waste generating business must obtain Approval to discharge trade waste to the sewerage system. The discharge of trade waste to sewers without this Approval is an offence under the Local Government Act.
  • The Approval usually specifies a pre-treatment device to improve the quality to a level where it can be accepted into the system and treated at the sewerage treatment plant together with all the domestic sewage. One example of a pre-treatment device could be a grease trap in the case of a commercial kitchen to remove fats that would otherwise solidify in the sewers.
  • The Approval specifies the frequency the pre-treatment device(s) is to be serviced.  If not serviced regularly, pre-treatment devices fail to actually pre-treat the trade waste.  
  • Sometimes the trade waste, because of its nature/composition cannot be accepted in the sewerage system no matter what pre-treatment is proposed. An example of this would be flammable fuels, which would create an explosive atmosphere in sewerage pipes, or radioactive wastes.
Council's management of liquid trade waste is overseen by the NSW Office of Water (NOW, formerly Dept. of Water and Energy - DWE) in accordance with the Liquid Trade Waste Management Guidelines and Best Practice Management of Water Supply and Sewerage Guidelines.

Last modified: 19 Oct 2021