When the Queensland Government introduced new rules to track industrial waste there was one notable loophole.
If waste was being transported “to a farm for use as a soil conditioner or fertiliser” it was exempted from state regulations.
The Queensland laws, which mainly benefit the $1.3 billion sugar industry, best illustrate the strange contradictions that apply to waste when it suddenly becomes an agricultural product.
Pollution expert Professor Ian Rae, from Melbourne University, says firms who dispose of their waste in agriculture can also avoid reporting it to the national pollution database.
The database, the National Pollutant Inventory, was set up three years ago by state and federal governments and is supposed to be a comprehensive picture of 92 separate toxins emitted by industry.
But, it seems that if a waste suddenly becomes a product, there is no need to report it.
Professor Rae, who conducted a recent review of the database, says: “If waste was being diverted into agriculture it probably wouldn’t be considered a waste, that’s right.
“We flirted with the idea initially of putting agricultural chemicals on the list – things used in pesticide and fertilisers – and in the end we were more or less directed not to include it because another approach was going to be taken.”
Many of the substances recorded by the NPI include compounds found in some industrial wastes being recycled into agriculture. They include arsenic, mercury, manganese, chromium, nickel, sulfuric acid and flouride.
In Queensland, sugar mills emit a variety of wastes in their production processes, such as boiler ash from the combustion process, and dunder, the waste residue from the distillation process.
Both are classed as regulated waste under the Queensland EPA’s stated objective of following the path of potential environmental hazards from “cradle to grave”.
But if a company decides to recycle them back into the cane fields, they are no longer considered regulated waste. The loophole saves companies the higher disposal costs and farmers are happy because they are getting a cheap fertiliser.
The rules allow a variety of industrial wastes to be used in the Queensland sugar industry.
Suzanne Berthelsen from the CSIRO, which has been testing a variety of products for the Cane Growers Association, says: “The mill ash has shown very good results, but it has to be used close to the mill because you have to put it on at a great tonnage.”
Other products being tested include waste plasterboard and a calcium-silicate industrial slag imported from the United States.
“We wouldn’t use any of the product commercially or on a larger scale without first checking them thoroughly in the laboratory for possible negatives,” Ms Berthelsen says. “And that has been a reason why we have rejected some wastes without ever trying them.
“Some of your fly ash from your coal mines [by-products from coal burning power stations] would have high levels of elements that you wouldn’t want added.”
The principal scientist at the Bureau of Sugar Experiment Stations, Dr Graham Kingston, says the bureau was also experimenting with wastes from the steel industry and cement making.
He said some of the waste show “minor evidence” of potentially dangerous heavy metals, but none had been declared hazardous by the Queensland EPA.