Hanford's 100-HX Pump and Treat Project - a Successful Blend of Science, Technology, Construction, and Project Management - 12412
CH2M Hill Plateau Remediation Company (CHPRC) recently completed construction and start-up of the $25 million 100-HX Groundwater Pump and Treat Project for the Department of Energy (DOE) at its Hanford Reservation site in Washington State. From the onset, the 100-HX Project Leadership Team was able to successfully blend the science and technology of a state-of-the-art groundwater pump and treat system with the principles, tools, and techniques of traditional industrial-type construction and project management. From the 1940's through most of the 1980's, the United States used the Hanford Site to produce nuclear material for national defense at reactor sites located along the Columbia River. While the reactors were operational, large volumes of river water were treated with sodium dichromate (to inhibit corrosion of the reactor piping) and used as a coolant for the reactors. After a single pass through the reactor and before being discharged back to the river, the coolant water was sent to unlined retention basins to cool and to allow the short-lived radioactive contaminants to decay. As a result of these operations, hexavalent chromium was introduced to the vadose zone, and ultimately into the groundwater aquifer and the adjacent Columbia River. In addition, numerous leaks and spills of concentrated sodium dichromate stock solution over the lifetime of reactor operations led to higher concentrations of chromate in the vadose zone and groundwater in localized areas. As a result, the 100 Area was included in the National Priorities List sites under the Comprehensive Environmental Response Compensation and Liability Act of 1980 (CERCLA). The mission of the 100-HX Project is to significantly reduce the concentration of hexavalent chromium in the groundwater by treating up to 3.8 billion gallons (14,300 mega-liters) of contaminated water over its first nine years of operations. In order to accomplish this mission, groundwater scientists and geologists using sophisticated scientific modeling optimized the 100-HX's approximately 0.7 square mile (181 hecto-meters) extraction and injection well field to support continuous operation of a maximum of 800 gallons (3,028 liters) per minute, 24 hours per day, and 7 days per week. The use of traditional resin technology for the plant's ion exchange system required a change out of the resin every 12 weeks and shipment to an offsite facility 1,500 miles (2,414 kilometers) away for regeneration. Instead, the project leadership pursued newer technology with a disposable resin that could be disposed of on-site and would require less frequent change outs, reducing the project's life cycle costs by more than $16 million. Constructing the facility had its own challenges. The well field location overlapped ecologically sensitive lands where bald eagles and native wildlife use the land for their mating habitat for nearly half of the year. Building locations had to be planned around historically and culturally sensitive areas, and around another contractor's remediation work zones. Also, the size of the well field required a transfer (pumping) facility and installation of more than 60 miles (97 kilometers) of high-density polypropylene pipe, 23 miles (38 kilometers) of power cable, and 28 miles (46 kilometers) of control cable. Along with schedule and budget constraints typical of any fast-track project, the project team dealt with severe resource constraints due to competing projects across the Hanford Site caused by the influx of American Recovery and Reinvestment Act stimulus funding. In addition, the project team itself was stretched between completing another $25 million dollar construction project while designing and constructing this project. In order to save money, the project schedule was compressed by three months from the original baseline schedule. This was made possible by the strong use of project management principles throughout the design, construction, and testing phases, as well as implementation of many lessons learned from a similar construction project. In summary, the 100-HX Project truly was a unique blend of science, technology, construction and project management. In summary, Hanford's 100-HX Pump and Treat Project was a successful blend of science, technology, construction, and project management. (authors)