The illegal discharge of hazardous chemicals into the Cairns sewerage system has on three occasions over the past month compromised the efficiency of two Council wastewater treatment plants.
Residents and businesses are reminded of the importance of properly disposing of hazardous chemicals and oils, with an emphasis on keeping these items out of sewers (toilets, sinks, wash bays and wash tubs etc) and stormwater drains.
Paints, solvents, oils, pesticides, herbicides and fertilisers poured down the drain can cause major contamination of sewers and has the potential to cause damage to the filtration systems that separate the contaminants from the ocean.
Mayor Bob Manning said all wastewater treatment plants in Cairns rely on biological processes to remove harmful nutrients.
"If there is something in the sewage that the bugs don't like they can die easily. Council then has to use vacuum tankers, at significant cost, to bring biological material from another treatment plant to get the process working again," Cr Manning said.
"We are aware of three occasions over the last month where chemical discharges have caused the bugs to die at our wastewater treatment plants."
The Marlin Coast WWTP was impacted by an unknown substance, which entered the treatment plant on 15 May. The Northern WWTP was similarly impacted on 28 May and again on 4 June.
"If you are starting your business back up and discharging wastewater to the sewer, please check that you have a trade waste approval," Cr Manning said.
"If you have any doubts, contact the Council to seek advice on how to safely dispose of harmful wastes."
Council has a process of trade waste approvals for a range of activities, such as laundries, hairdressers and restaurants, that discharge to the sewer.
If discharges occur in compliance with approvals, no harm should come to the biological process occurring at the wastewater treatment plants.
Most forms of household hazardous waste, in domestic quantities of less than 25 litres can be disposed of free of charge at Council's waste transfer stations. This includes paints, solvents, oils and batteries and must be clearly labelled.
