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Climate control waste is liquid waste from any heating, cooling, ventilation, air conditioning or refrigeration system consisting of:

  • Waste from cooling towers that are dedicated to and are an integral part of any of these systems, and/or
  • Waste from condensate, de-frost water or chiller water.

Here you will find information about responsibly disposing of commercial climate control waste.

Can climate control waste be discharged to sewer?

Customers may apply for a permit to discharge climate control waste to sewer. Residual sludge from membrane scraping and descaling must not be discharged to sewer. It must be disposed of off-site in accordance with the requirements of the relevant regulatory authority.

Cooling tower waste

Cooling tower water is usually dosed continuously with anti-corrosion chemicals and biocides while the system is operating. Some installations however have a drip feed which means that the chemical is being dosed 24 hours a day, whether the plant is operating or otherwise. Water is fed in automatically (make-up water) to compensate for losses and bleed-off (draining).

Effects of water conditioning

The chemical dosing reduces the risk of corrosion and diseases such as Legionnaires Disease but increases the incidence of scaling, while the bleed-off reduces the scaling but enhances corrosion, disease risk and slime formation within the pipework.

The composition of the chemical formulations varies considerably. Four general groups of anti-corrosion chemical formulations can be identified. These groups are based on chromate, zinc, tannin and phosphate compounds.

Maintaining system water quality

For maintenance purposes and to remove accumulated sludge, cooling tower waste is usually dumped at about 3 monthly intervals but sometimes as frequently as monthly. There's also a small continuous bleed-off to prevent the concentration of scaling materials.

Other waste

Generally, all other waste from climate control systems including condensate, de-frost water and chiller water does not come in contact with chemicals, nor is it dosed with any chemical formulations. This must not be discharged to the sewerage system. 

Permit requirements

Premises wishing to discharge climate control waste to the wastewater system must apply for a trade waste permit.

The application must be accompanied by:

  • Industrial Waste Application Supplement No 9 Commercial Climate Control Waste – Cooling Towers
  • Hydraulic drawing showing how climate control waste is discharged to sewer, and
  • Safety Data Sheets (SDS) for all the chemicals to be used

Customer charges are based on the metering of bleed water, which is mentioned in our typical drawing for cooling tower trade waste. Regardless of the type of metering, meters must be located in accessible and safe areas to facilitate reading by the Corporation.

Commercially confidential proprietary formulations will be processed in the strictest of confidence.

Pre-treatment to reduce chrome and zinc may be required and is determined in accordance with our acceptance criteria.