Alder Valley Water Treatment Plant*

The district's existing slow-sand filters were reaching the end of their service life and could no longer meet summer demand. A new plant had to be built on a constrained 11-acre site adjacent to the existing intake, with the old plant in full service until the day of cutover.

Membrane modules and UV reactors carried 52-week lead times, and the district's SRF loan required all iron and steel to meet American Iron and Steel requirements.

Under progressive design-build, our team and the engineer jointly developed the process layout, and we procured the membrane racks and UV reactors at 40 percent design, saving eight months of schedule. A 3D model of yard piping caught 63 conflicts before a single trench was opened.

We staged tie-ins to the raw-water and distribution mains as 11 discrete events, each with a written shutdown plan, bypass arrangement and chlorination and pressure-test sequence signed by district operators. An AIS compliance coordinator tracked every pipe, valve and fastener on the project.

The plant started up 71 days ahead of the original schedule, and all 11 tie-ins were completed inside their planned shutdown windows with no customer outages. Final cost came in $2.8 million below the GMP.

The district's operators were trained over 400 hours before substantial completion, and the plant passed its state health department performance test on the first attempt. The project recorded 0 lost-time incidents over 538,000 hours worked.