Storing chemicals in bulk

If allowed to enter the sewer, chemicals may:

• pose a health and safety risk to sewer workers
• cause sewers to corrode more quickly than usual 
• create an explosive atmosphere in the sewer 
• disrupt the operations of sewage treatment plants
• compromise the quality of recycled water and biosolids produced at treatment plants
• harm the environment.

If direct connections exist from tank farms and other bulk chemical storage areas to the sewerage system, undiluted chemicals can potentially enter the network undetected. This can occur over a long period of time from a slow leak or as a large, one-off volume discharge if a tank is damaged.

Bunds

A bund is an embankment or wall used to contain liquid.

We require all tank farms and bulk chemical storage areas to be bunded. Bunds cannot have drains, with or without valves, or be connected to the sewer.

We might not allow discharge from a bunded area to the sewer if we believe the chemicals stored in there pose an unacceptable risk. If this is the case, then an alternative disposal methods needs to be found.

Requirements for bunds

• The base of the bunded area should be sloped so that it drains to a collection pit or “blind sump”. Rainwater can then be manually pumped out of this area.
• Liquid should only be removed from a bunded area using a manually operated portable or fixed pump.
• If you use a portable pump to remove liquid, remove the pump from the bunded area or tank farm immediately after you’ve finished. 
• If you use a fixed pump to remove liquid, it must be manually operated and have a low-level shut off switch.
• If your tank farm holds large volumes of rainwater that is discharged into our sewer network, you may need a flow metering device to measure the discharge. 
• All tank farm areas must be prepared to clean up spills.

For guidance on bunding construction and sizing, refer to the Victorian Environment Protection Authority (EPA) Bunding Guidelines.

What can be discharged to the sewer? 

Prohibited:

• Product or raw material spills must be stored until they can be processed or disposed of by an industrial waste contractor.
• Unpolluted rainwater must be sent to stormwater drainage. There may be exceptions to this, depending on EPA requirements.

Permitted in accordance with a trade waste agreement:

Slightly polluted water from the tank farm area:

• wash down waters following spill clean-ups
• water from general cleaning and hosing down of tank farm area
• water containing traces of contaminants from minor spills, pump gland leakage or filler point leakage.

Disposal is only allowed if:

• the water complies with the Trade Waste Acceptance Criteria, listed in the trade waste agreement 
• all other requirements in the agreement are met. This may include analysing the composition of the wash water or receiving permission from GWW.

Operational requirements for emptying bund contents

It is your responsibility to make sure that there are processes in place for testing, assessing and disposing of bund water, in accordance with the details on this page and the requirements in the trade waste agreement.

Contact us

Email trade.waste@gww.com.au or call 13 44 99.