Renovation of a civil project in Richmond, Virginia. Completed plans call for the renovation of a water / sewer project.

The Wastewater Treatment Plant (WWTP) Main Pumping Station Improvements Project will involve a major refurbishment of the 65-year-old Main Pumping Station that will replace pumps, valves and electrical equipment all while maintaining the operation of the WWTP. The overall summary scope of work for construction of the Project consists of engineering design and professional consulting services. The City requires improvements to Main Pumping Station at the Wastewater Treatment Plant ("WWTP"). The treatment works consists of a sanitary sewer and combined sewer collection system, in-line CSO retention facilities, sanitary and combined sewage pumping stations, and one wastewater treatment plant. Together, they discharge treated effluent to the James River and land applying Class B biosolids through a third-party vendor. A. Replace the existing four (4) wastewater pumps with six (6) new vertical centrifugal pumps. 1. Four (4) pumps will be sized for a design flow rate of 75- MGD. 2. Two (2) pumps will be sized for a design flow rate of 50- MGD. B. The pump station will be designed in one of two ways to convey a total flow of 140-MGD to the WWTP: 1. a combination of two (2) 50-MGD pumps and one (1) 75-MGD pump OR 2. two 75-MGD pumps. C. The pumps will be provided with new ductile iron suction and discharge piping. A 48" check valve and 48" electrically (or hydraulically) actuated plug isolation valves. The existing suction and discharge connections will be used for all six (6) pumps. D. Replace the electric actuators on the two (2) wet well isolation gates, with new Rotork electric actuators wired into the Rotork Pakscan communications loop. E. A new seal water system will be provided to support the new wastewater pumps. The seal water system will connect to existing potable water supply piping in Main PS. No additional water service lines will be constructed as part of this upgrade (including both potable and plant water). The new seal water system will be installed on the top floor of Main PS. F. A physical model of the pumping station will be created to better understand the impacts of the existing structure on flow through the station. The model will include the 96" pipe between Grit No. 1 and the pump station, the influent bar racks, wet well, and terminate in the suction side of each pump. Different modifications will be modeled to improve the hydraulics of the existing structure and improve pump operations. G. If justified based upon further evaluation, replace the two (2) existing climber screens at Grit No. 1 with two (2) new multi-rake coarse bar screens. The existing rock trap upstream of each screen will be abandoned, allowing the new screens to be installed at a 30- degree angle relative to the influent flow. Bar spacing on the screens will be reduced from four (4) inches on the existing screens to three (3) inches on the new screens. H. A new screening conveyance system will be provided to bring collected screenings to a central dumpster location. The conveyance system will be protected from freezing with heat tracing where necessary. I. The new screens will extend from the base of the channel all the way to the ground surface. Additional supports will be designed to provide intermediate supports to the new screens. J. A washer/compactor will not be provided in the screenings conveyance system. The nature of the collected debris and screenings from a CSO system is not conducive to operation of a washer/compactor. K. The clamshell bucket and gantry crane will be inspected during the 30% design phase to determine the expected remaining service life of the equipment. Recommendations will be provided to the City for improvements. Should the City want to include upgrades to the grit clamshell bucket or the gantry crane, a change order will be prepared to include additional design into the Work. L. Develop a detailed specification for bypass pumping requirements during construction activities.