Treating mine water to meet stringent EPA standards.
Key Services
Construction
Preconstruction
Self-Perform
Strategic Partnerships
Delivery Method
Progressive Design-Build (PDB)Capacity
68 MGDThe challenge
The Doe Run Company was required to construct five wastewater treatment plants across southeast Missouri to comply with the Environmental Protection Agency’s (EPA) strict regulations under a consent order. With the EPA pressing for rapid compliance, the challenge was to design and build these plants on an aggressive schedule, ensuring Doe Run avoided penalties for non-compliance. Each plant needed to meet stringent requirements for removing heavy metals and contaminants from mining wastewater.

Key Facts
Engineering Excellence Award – American Council of Engineering Companies, Missouri Chapter
Total of five wastewater treatment plants
Challenge met
In response to EPA mandates and tight deadlines, CAS Constructors delivered five wastewater treatment plants for The Doe Run Company through a design-build joint venture. The innovative CoMag System was implemented at all plants to efficiently remove heavy metals and contaminants from mining wastewater, with capacities ranging from 7.2 MGD to 26 MGD..
During the construction of the first plant, the team identified a potential to significantly enhance processing capacity. This led to a reevaluation of equipment and processes, successfully doubling the plant’s capacity without major capital increases. The team extended this forward-thinking approach to prepare the other plants for future scalability.
To address challenging site conditions, including unimproved locations and extensive rock excavation, the team relied on CAS Constructors’ equipment fleet and expertise. These efforts ensured the project stayed on schedule, avoided penalties, and enabled Doe Run to meet EPA compliance standards while supporting sustainable mining operations in southeast Missouri.