Adit 93 Remediation Project

The Adit 93 Remediation Project, located in the Buhovo ore field near Buhovo, Bulgaria, was implemented to treat acid mine drainage (AMD) generated from historic uranium mining operations. The AMD from Adit 93, with a throughput of 720 m³/day, contained dissolved uranium, elevated concentrations of heavy metals, and high sulfate levels, presenting significant environmental risks to downstream water bodies.

The treatment process began with an ion exchange system for the selective recovery of uranium from the acidic mine water, producing uranium as a marketable by-product. The water then underwent hydroxide precipitation for removal of heavy metals such as iron and manganese, followed by solid-liquid separation. To address elevated sulfate concentrations, the partially treated water was directed to a barium salt precipitation unit, where insoluble barium sulfate was formed and removed through clarification and filtration — ensuring the final effluent was free of uranium and compliant with heavy metal and sulfate discharge limits.