This confidential mining company needed a new treatment process to meet more stringent wastewater discharge limit. The water from mine dewatering and ore processing contains heavy metals. After extensive testing, Woodard & Curran delivered a new system using a design/build approach that met the client’s permit limits on schedule and on budget.
FINDING AN AFFORDABLE PROCESS TO ADDRESS WHOLE EFFLUENT TOXICITY
Needing to reduce cadmium, copper, lead, nickel, zinc, and toxicity at an affordable cost, our client brought us in for field tests and an extended pilot study to evaluate several chemistries and processes. The team selected a sulfide and hydroxide precipitation process with ballasted sedimentation (CoMag), which allowed the 4,500 gpm (6.5 MGD) plant to fit on a small site.
INTEGRATED DESIGN-BUILD APPROACH CONTROLS COSTS, SAVES TIME
Our team met with the regulators to expedite permitting of a process new to the agency. We worked with our construction partner and client to find cost savings and ways to meet a tight schedule. Completed on time and on budget, the plant has met its metal limits (average effluent concentrations: cadmium < 0.5 ppb; copper < 4 ppb lead < 1 ppb; zinc < 50 ppb) from the first day of operations. The effluent has passed its toxicity tests, despite influent metal concentrations that were sometimes twice the design basis.