Potomac Pumping Station Rehabilitation Phase 3

The Potomac Pumping Station Rehab Phase 3 was one of the most challenging projects ACE has encountered. This project was located at a massive 460 MGD pump station and required the phased replacement of major equipment in the basement and wet wells of the pump station. Equipment to be replaced included eight each 54" cast iron motor operated gate valves, four each 35' tall mechanical bar screens, and fourteen each large stainless steel motor-operated sluice gates, along with supporting electrical and control equipment. There was no crane access to the work areas so all hoisting had to be custom engineered and constructed in place. This job required the most complicated and difficult rigging that ACE has had to perform.

The ACE team brought two essential characteristics to this project: planning and perseverance. The great majority of the work on this project was performed during limited outage periods. This meant that it was critical that our work during these periods be performed efficiently and correctly. If we demolished existing equipment and then were unable to return the new equipment to service, that would create significant problems for the client, DC Water. Our superintendent, Russell Chunn, spent countless hours planning the work and then performing numerous test operations to insure the plan would work. We custom-designed rigging frames for hoisting valves and carts for moving valves around the pump station, and we performed a variety of test rigging operations. This enabled us to work efficiently and productively during the outage periods. All of Russ' plans worked to perfection and the equipment was installed flawlessly.

Unfortunately, this project was subject to a variety of delays throughout the project. The most significant was due to the requirement to clean the 108" sewer main coming into the pump station under a separate contract. This required our project to be shut down for 6 months while another contractor performed the line cleaning. Other delays were due to force main repairs and pump failures. In the end, the project was delayed nearly 700 days. Our team persevered through these delays and stayed focused and ready to perform work when available. In the end, the same project team stayed on the job for nearly four years, an impressive display of dedication.

The planning and perseverance exhibited by our project team delivered a very complex project for DC Water under tough conditions. Due to our detailed planning, we were able to complete all of our outages within the prescribed limits to keep DC Water in compliance with EPA requirements. The perseverance exhibited by our team was critical to project success. This was a very unique project, and it would be inordinately difficult to introduce a new superintendent or project manager and have them learn all of the complicated details involved. Because our team stuck it out for the duration of the project, we maintained the continuity of performance and were able to deliver the same high level of service throughout the project.
Everyone involved with the project has been amazed by the execution of our project team. We have received kudos from the client, the design engineer, and onsite inspectors. Probably the most impressive comment we heard was from one of the inspectors who advised that he didn't think it was actually possible to install the 54" gate valves in the basement and had no idea how we were going to execute the work. The pictures from one of the valve installations show it can be done.