The first review of a biosolids application trial at Fosterville Gold Mine (FGM), northeast of Bendigo, has been completed this week – with promising signs so far.
The two-year trial is a joint initiative between Coliban Water and FGM, and is the largest of its size Coliban Water has been involved with to assess whether the application of biosolids on rehabilitated mine land will facilitate the growth of pasture and plants.
General Manager Water Quality Performance and Regulation David Sheehan said the reuse of biosolids is one way of turning a by-product from the wastewater treatment process into a valuable resource for the local region.
“We recognise the environmental value in reusing resources. Biosolids contain nitrogen, trace metals and phosphorus, which are all beneficial for soil conditioning,” said Mr Sheehan.
“We’ve just completed our first review of the four-hectare trial site after the seeds were spread in late autumn. There is plenty of green popping up, so things are looking good so far. This project is a win-win,” said Mr Sheehan.
“It benefits FGM as they have free biosolids to help rehabilitate the land, and it benefits Coliban Water by having a secondary use for the treated biosolids. The pasture growth also helps to reduce dust in the mine vicinity.”
Coliban Water has been active in efforts to increase its biosolids reuse program. The current trial includes four plots – an area with no biosolids, a plot with 20 tonnes of biosolids per hectare, a plot with 50 tonnes per hectare and a plot with 100 tonnes per hectare.
FGM Senior Environmental Adviser Joseph Hughes said the trial area was originally used for flotation mine tailings before the land was capped with oxidised waste rock.
“Now it’s been planted out with native species like rough spear grass, burra weeping grass and salt bush. We opted for native pasture following input from community representatives prior to the trial,” he said.
“There’s so many factors to consider in a trial such as this – the landscape, soil quality and potential rainfall. Eventually, a large portion of the affected land will need to be rehabilitated and the biosolids are obviously helping a lot.
In 2014 a small scale Biosolids Application Trial was carried out, with some success. The trial site used some topsoil in addition to the biosolids, while the current trial is being carried out without topsoil.
“The final land use plan for the entire mine site is to use both pasture and a box iron bark native forest. There is potential to use biosolids more widely in rehabilitated areas of the mine site in the future,” said Mr Hughes.
An Environmental Improvement Plan for the trial was developed in consultation with the Environmental Protection Authority (EPA) and a range of stakeholders.
Information about biosolids is available on the Wastewater page of our website at www.coliban.com.au or contact our Customer Support Team on 1300 363 200.
About biosolids
Biosolids are a by-product of the wastewater treatment process and can be used on farms as a fertiliser or soil conditioner to enhance plant growth.
Biosolids are created when wastewater receives biological treatment and the pollutants in the wastewater are removed by converting them into a fine, fluffy mass formed by the aggregation of bugs and other fine suspended particles. This is called wastewater sludge or biosolids.
Last updated on 08 Jul 2019