Nyrstar Port Pirie Smelter
BlueSphere completed a large scale environmental site assessment, remedial options assessment and implementation of remedial measures at the Nyrstar Port Pirie Smelter site (178 ha) over several years. The assessment was subject to a Site Contamination Audit and focused on the delineation of the nature and extent of groundwater contamination in three shallow aquifer units – an anthropogenic fill sequence comprised entirely of slag material with an aerial extent of~65 ha underlain by a natural sedimentary sequence. Groundwater was contaminated primarily with metals (including Cd, Pb and Zn) but also hydrocarbons, acids and landfill related contaminants.
A large, multi-layered numerical flow and solute transport model was configured and used in remedial planning and optimisation.
Remedial phases included bench scale treatability studies of Permeable Reactive Barriers (PRBs), in which a number of reactive treatment media were evaluated, including carbons substrates (emulsified vegetable oil), carbon (wheat husks), zero valent iron (ZVI) and zeolite.
The project included multiple presentations to the SA EPA and other stakeholders.
The project team developed a Conceptual Site Model (CSM) that resolved a very complex flow system, including strong tidal interaction with the Port Pirie River and numerous anthropogenic sources and sinks. The CSM substantially updated the understanding of the hydrogeology of the Site and culminated a quantitative human health and ecological risk assessment.
Due to environmental risks being identified at a number of key boundaries, hydraulic interception schemes were designed and optimised using the groundwater model and successfully implemented. Site risks were addressed on a priority basis, while contamination source reduction and longer-term objectives such as passively controlling watertable elevations were ongoing.
The project team ultimately secured the endorsement of the appointed Site Contamination Auditor for the key milestone assessment documents – the Detailed Risk Assessment (DRA) and Remedial Options Assessment (ROA).
Benefits to Client
- Management of key environmental, regulatory and other corporate risks at a critical time of change at a site with a prominent public profile.
- Rationalisation of monitoring to key areas of importance.
- Modified assessment approach allowed focus on major issues, thus avoiding major lower priority investigation costs and time loss.
- Enhanced relationship with EPA.