Lochbuie Wastewater Treatment Plant Improvements
JVA was hired by the Town of Lochbuie to design an influent pump station (IPS), grit removal and solids dewatering improvements to their existing 2.0 MGD WWTF. The IPS design included the abandonment of an old pump station and construction of a new wet well dry pit influent pump station integrated with preliminary treatment (i.e. grit removal). JVA conducted a detailed hydraulic evaluation to determine the optimum pump capacities for meeting existing minimum, average and peak hourly flow demands as well as sizing the station to ultimately meet buildout flow demands. The IPS was designed for a peak hour capacity of 6 MGD expandable to 12 MGD. This project was delivered as a CMAR with milestone deliverables at the 60 percent design for the CMAR RFP and procurement. This project had very challenging subsurface conditions as well as major existing electrical ductbanks that had to be considered during the CMAR design and constructability phase.
JVA worked closely with the Town and Contractor to reduce the excavation area footprint for the IPS and grit removal to most efficiently shore and dewater during the excavation and concrete work to reduce construction costs by over $50,000. JVA worked with ESC (Electrical Sub- Consultant) to develop an IPS level control system and control narratives to match influent flow with pump speed and capacity for maintaining a user set level in the wet well. With this control scenario, the lead pump never shuts off while maintaining the same level in the wet well 24/7. This dramatically improves the biological treatment process at the WWTP since the delivery of influent to the aeration basins is constant without on / off delivery or rapid change delivery. The project also included the addition of a new vortex grit removal system and grit classifier prior to the IPS. The grit classifier was installed inside the existing Headworks building along with the mechanical fine screen.
Location: Lochbuie, CO