Representatives from a newly purchased apartment complex engaged Pinyon Environmental, Inc. (Pinyon) to assist with evaluating several activities related to dewatering at a property in Denver, Colorado. There were both compliance and legal issues to address as the previous owner sold the building without disclosing the permit requirements for permanent foundation dewatering.

Compliance with the Remediation Activities Discharging to Surface Waters Permit included groundwater treatment system design, installation, start up, and optimization. The Colorado Department of Public Health and Environment (CDPHE) required that dewatering activities meet specific permit standards, which involved sampling for various contaminants. Metals were identified in historical sampling and required treatment to meet permit standards before discharging the groundwater into the storm sewer system, eventually releasing it into surface waters.
A groundwater treatment system was designed and installed at the site, incorporating a flow equalization tank, automated controls, forwarding pumps, and a programmable logic controller. The system was flexible, capable of increasing the treatment media volume and flowrate to about 30 gallons per minute. Selenium treatment can be expensive to economically manage, therefore, Pinyon provided alternative management strategies for selenium to keep water treatment costs at a reasonable level. Pinyon also provided expert witness services in court in the project included evaluating the options, risks, and costs associated with the treatment system to guide decision-making and achieve the most cost-effective solutions.