SOLUTION
The city selected Burns & McDonnell, in partnership with Garney Construction, to provide design and construction services for the new 15 MGD Westminster Northwest WTP.
RESULTS
The water treatment plan increased allowable flux of membrane units by 50 percent by adding pretreatment. The project resulted in a reduced unit price, and the design allowed for future expansion. In 2012, the city increased capacity by 5 MGD, making it a 20 MGD WTP to surpass the overall demand of 63 MGD.
DESIGN SPECIFICS
- The design included enhanced conventional water treatment with plate settlers followed by microfiltration membrane units. This method increased the membrane units’ allowable flux capacity by 50 percent.
- The plant piping is organized with flexibility to bypass pretreatment and use raw water pressure for direct microfiltration during periods of low turbidity in raw water.
- The membrane system was designed to use one skid for secondary recovery or to recycle membrane backwash water to the pretreatment process, allowing for flexible operation in high recovery or higher process flow modes.
- The design included a 2 MG clearwell with a 15 MGD high service pump station (expandable to 20 MGD).
- Sizing the plant with a hydraulic capacity of 20 MGD accommodated future process equipment. The membrane system design included eight units with 82 microfiltration modules per unit (656 total). Additional space allowed for three more racks (246 modules), which were installed in 2012.
