The waste is a mixture of ‘persistent organic pollutants’ banned from use under the Stockholm Convention. The chemicals that make up the waste are a mixture of organo-chlorinated pesticides (OCPs) and metal-based pesticides. These pesticides were used for agricultural purposes, to protect crops from damage by insects and other pests.

The chemical wastes came from farmers and others in the agricultural and veterinary sector. As the Stockholm Convention was being mandated and prior to its formal international adoption in 2001, the Victorian and Commonwealth governments jointly funded the collection of chemicals that had been banned for use. The collection, between 1999 and 2002, included 235 tonnes of wastes including pesticides, fungicides and other veterinary chemicals. 80 tonnes of the wastes were deemed un-treatable as metal based pesticides and organic based pesticides had been mixed together prior to collection.

If consumed, these chemicals have the potential to accumulate in the body, so organisers of the Stockholm Convention sought to have them banned. The Stockholm Convention was formally adopted in 2001 and reviews of pesticides that may be added to the list regularly occur. Further information on the known toxicological effects of persistent organic pollutants can be found on the Stockholm Convention website.

The treatment of organo-chlorinated pesticides and metal-based pesticides separately has well known methods. However, when these chemicals are mixed, a separation process is required to allow for the separate treatment methods to be applied. This separation technique, along with the treatment method, being undertaken at the one location has not been available to a standard suitable to EPA until now. EPA required that this waste be able to be treated in the same location and to best practice standards. That includes ensuring the minimisation of potentially toxic by-products and the minimisation of solid end products, which will need to go to landfill.

The wastes are stored in a chemical storage facility in Laverton, Victoria. The waste was originally placed in metal 44 gallon (~205L) drums. The metal drums have since been encased in UN dangerous goods-approved drums that are sitting on pallets. These drums have been proven safe for transport, including in the event of dislodgement from a secure lodging within a vehicle.

The transport will be in accordance with Dangerous Goods transport regulations, EPA requirements and national requirements.

As Cleanaway is in Narangba, Queensland, EPA will arrange for the drums to be transported via cargo train to the site. The wastes are stored in UN-rated dangerous goods drums, which will be secured within a sealed container (similar to a shipping container yet appropriate for storage on a train). There will be no passengers on the train and safe transport methods will meet Dangerous Goods transport requirements. Transportation of the waste will be safe and bears minimal to no risk to the community.

After the waste enters the system, it will undergo a thermal process to separate the organic components from the metals. The metals will come out as ash and will be chemically immobilised to prevent potential leaching, then solidified to prepare them for disposal in accordance with EPA and Queensland Department of Environment and Health Protection (DEHP) disposal guidelines.

The volatilised organics will be destroyed and by-products treated through a best-practice controlled-emission process. This will include rapid quenching, and passing the emissions through activated carbon or liquid scrubbers.