Fungal Bioremediation of Mining Waters Through the Use of Woodchip Bioreactors

The MycoMetals Remediation Group has developed a system to address the third task of the 2025 WERC Environmental Design Contest, which focuses on the use of fungi to treat mining-influenced water (MIW). A goal of 90% metal removal by a group’s system was outlined by WERC in their request for proposal (RFP). A major environmental and health concern MIW is its concentration of heavy metals. When not treated correctly, high concentrations of heavy metals in water can directly affect human health, such as causing liver and kidney damage, and environmental health, including toxicity to aquatic life and a decrease in aquatic plant growth. When conducting our background research, potential options that showed promise for decreasing high levels of heavy metals in MIW varied from implementing different lakes, tanks, and different bioreactors. A woodchip bioreactor that utilizes three fungal strains, Aspergillus niger, Phanerochate chrysosporium, and Pleurotus ostreatus, was chosen as our proposed solution. This treatment provides a high contact time and is passive, meaning that maintenance and human intervention is relatively minimal over the lifetime of the project. The use of these fungi in the filtration of MIW does not lead to unintended pollution of water and does not require licensing unless excess fungi grow in sensitive habitats. From the bench tests results, the scaled-down woodchip bioreactor removed 86.2% of MIW metals over a 24-hour period; we anticipate that scaling up to a field-relevant scale would increase this removal effectiveness. These results show promise that a full-scale woodchip bioreactor can serve as an effective solution to treat MIW through the use of fungi, while having a minimal effect on public or environmental health.