Standard Scope of Work • Survey — Including all plat research, existing easement documentation, easement deed and plat development and recordation. • Geotechnical — Rock bores and soils analysis. The town will likely bid all work as unclassified excavation, the geotechnical reports provided will be included in the bid documents to enable an unclassified excavation bid. • Subsurface Utility Exploration (SUE) in support of the preparation of bid documents. • Pretreatment sized for the design flow using a channel grinder or appropriately selected and sized pretreatment. • Structural design of a wet well approximately 20 feet deep. Structural design will include supports for lifting cranes to allow removal of the submersible pumps for replacement. Structural design will include flotation analysis of the proposed wet well with spread bases or rock anchors as needed. All wet well channels and slopes will conform to Hydraulic Institute (HI) standards. • All electrical controls for the channel grinder and submersible pumps. The electrical design will include Variable Frequency Drives (VFDs) to control all pumps, with soft start bypasses of the VFDs to allow VFD maintenance. The electrical controls will also include a permanent backup generator sized to start pumps while running other pumps and ATS. • Instrumentation and Control (I&C) of the VFDs. The I&C will allow flow pacing using the VFDs and will rely on local control of the pumps only utilizing a Programmable Logic Controller (PLC). A flow meter and ultrasonic depth sensors will likely be required to facilitate flow pacing. Full integration of all pump station operations with the town’s existing SCADA system (possibly at the wastewater treatment plant and through mission communications) will be required. • Operational requirements that ensure the pumps operate within HI’s specified Preferred Operating Range (POR) as much as possible, and within Allowable Operating Range (AOR) at all times. The selected consultant will provide affinity curves for different VFD setting with motor horsepower curves, Hydraulic Grade Lines (HGL) of all sewer and force main operational scenarios and recommended ultrasonic depth settings to ensure adequate Net Positive Suction Head (NPSH) for all pumping scenarios. The operational requirements will include evaluation of equalization sites and needs for peak flows.
