Contaminated soil has been a major contributor to a surge in hazardous waste across Australia in the 2020 financial year, according to a report commissioned by the Department of Agriculture, Water and Environment. The report, Hazardous Waste in Australia 2021, highlights that of the 7.4 million tonnes of hazardous waste generated each year in Australia, 35 per cent is from contaminated soil, mostly in Victoria and Queensland. Most of this contaminated soil is removed and then treated at thermal facilities before much of the soil then becomes landfill. Gordon Irons, Enretech’s new Managing Director, suggests there is an alternative and more sustainable approach that could be adopted by the waste management sector. His environmental solutions group is achieving success with bioremediation projects in New Caledonia, Kazakhstan, Vietnam, Micronesia and Japan. He says this alternative approach is also being supported by the Australian Government’s Department of Innovation Industry, Science and Research which acknowledges the use of biotechnology is becoming recognised as a more sustainable and cost-effective soil remediation approach than traditional methods.

Many of Enretech’s bioremediation projects involve treating contaminated soils for mining, oil, and gas or petroleum companies using a sustainable soil remediation solution known as Remediator. This product is made in Australia by Enretech from cotton-waste and is 100 per cent biodegradable. It is a particulate absorbent that contains microbes that remove contamination naturally and quickly from the soil and is also effective in degrading polycyclic aromatic hydrocarbons (PAHs).

“Remediator was successfully used for an in-situ bioremediation project conducted in New Caledonia in a site heavily contaminated with hydrocarbons (190,000 ppm),” says Tony Mozak, Enretech’s General Manager. “As a result, the content of total recoverable hydrocarbons decreased by more than 95 per cent in less than 100 days.”

Onder from Novorem performs bioremediation testing on site.

The Remediator product has been charged with naturally occurring bacteria found in oil-bearing plants and common soils. When given a hydrocarbon food source and kept moist, the bacteria propagate rapidly within the cotton-based fibres and break down the soil contaminants into non-harmful constituents. Gordon says most bioremediation products take multiple uses to see results, however, Remediator can achieve results with just one application. This removes the need for expensive and difficult remote treatments for many bioremediation projects and the potential cost savings can be substantial.

“Many treatment options in the Australian waste management sector are costly, time-consuming, and contribute to further environmental risks,” he says. “Sending contaminated soil to high-temperature thermal facilities or incinerators to be treated contributes to emissions, excavation can lead to further contamination, aeration carries risk of air pollution and letting materials sit in quarantine creates an ever-growing pile of contamination.”

Bioremediation techniques can enable soil remediation to be achieved in-situ and without the need for significant investments being made in waste management facilities. While bioremediation to break down PFAS and/or asbestos is still the subject of further research by Enretech, in conjunction with a number of leading universities and microbiologists, there are some significant benefits for the Australian waste management sector by adopting bioremediation to more effectively manage contaminated soils.

“Based on our international experience in the mining, petroleum and oil and gas sectors, we believe bioremediation in the Australian waste management sector can be achieved more effectively using a sustainable and environmentally-friendly approach,” says Tony.

For example, he explains that for soil contamination up to 40,000ppm of petroleum hydrocarbons, thorough mixing of the Remediator absorbent-microbial blend and maintaining appropriate moisture levels is sufficient for bioremediation to achieve environmental compliance levels in only three-four months. Further, bioremediation has proven to be more successful in contaminated soil that has not been previously treated by other methods. Higher contamination levels in soils however can take up to six months to repair and this depends on the type and age of the hydrocarbons and soil structure. In these circumstances, Tony says Enretech offers clients an additional nutrient mix to enhance hydrocarbon bioremediation based on the soil samples, initial testing, and analysis conducted by Novorem in a purpose-built laboratory in New South Wales.

Enretech’s Remediator sustainable soil remediation solution and bioremediation process has been extensively used for more than 20 years and has been independently verified by governments, universities and research organisations in Australia, Canada, USA, the UK, Japan, Asia and South Africa.