Challenge  The Victorian Government through the Department of Environment, Land, Water and Planning (DELWP) are working with Coliban Water (the regional water authority) to reduce the level of groundwater in old mineshafts and workings under Bendigo. The water has been accumulating since mining operations ceased in 2011, with the rise in groundwater levels impacting on the tourist mineshaft in Central Bendigo, as well as posing the potential for ongoing environmental impact to local waterways.

This high profile project has a technically challenging application where the groundwater contains elevated levels of salinity, arsenic, other heavy metals and hydrogen sulphide gas. A water treatment plant was required that could safely extract 730 megalitres of groundwater each year for a 4 year period.

Solution  Osmoflo designed and built a 2,000 m3/day brackish water reverse osmosis plant for Lendlease as the central process of the plant. Water is extracted from an existing mineshaft, where it is initially pre-treated to remove any suspended matter. It is then treated further to produce water of very high purity using a high-recovery reverse osmosis (RO) system. The purified water is sent via pipeline and blended with existing licensed discharge from the Bendigo Water Reclamation Plant. The small brine volumes from the RO process are pumped to Epsom for containment in specially constructed and lined ponds.

Result  As a ‘fast tracked’ project, Osmoflo designed, fabricated and dispatched the new process units (including RO systems) within 17 weeks. We also provided control and commissioning services, and will provide Operation and Maintenance support services for an initial 6 month period. O&M services will then be handed over for the remainder of the 4 year term to our client, Lendlease.