The City of Sunnyvale is seeking proposals from licensed Engineering firms to provide professional services for design and preparation of bid documents and construction support for improvements to the aged primary effluent pipeline at their Water Pollution Control Plant (WPCP). The primary scope of work includes design and bidding/construction/commissioning support. Ancillary work includes the following: • Project management • Conducting workshops • Preparing NEPA and CEQA documentation • Preparing permit application(s) • Performing geotechnical investigation and interpretation • Construction cost estimating • Schedule development • Design and construction phase site visits • Inter-project coordination meetings with Construction Manager and ESD Currently, all primary effluent flows to the oxidation ponds by gravity. Primary treated effluent is conveyed from the newly constructed primary sedimentation tanks, constructed as part of Project 1.1.2, via a new 66-inch HDPE pipeline along the northern boundary of the WPCP. Flow then transitions to an existing 60-inch welded steel siphon and 66-inch diameter aboveground reinforced concrete pipe (RCP) that carries primary effluent to the oxidation pond circulation channel for secondary treatment. As part of Project 1.1.2, a cross fitting and 48-inch HDPE pipe segment was constructed, connecting to the existing pond return pipeline at the tank drainage pump station. This modification provides WPCP staff the flexibility to bypass and redirect flow from the existing PEP to the oxidation ponds via the pond return pipeline. Following completion of Project 2.2.2 Secondary Treatment Stage 1 (CAS-1), a portion of primary effluent will be treated by the new CAS-1 facilities, while the remainder continues to be sent to the ponds. The purpose of this Project 2.1.3 is to ensure the Primary Effluent Pipeline (PEP) can continue to reliably convey primary treated wastewater to the oxidation ponds. A secondary objective of this project is to provide future operational flexibility for the WPCP once construction of Secondary Treatment Stage 2 (CAS-2) has been completed. The Master Plan currently includes a project to construct a diurnal equalization and emergency storage facility (expected construction starting 2032), which would require two-way flow through the PEP, under pressure in one direction. The City has a preferred alternative that addresses their operational objectives. The Consultant will be responsible for validating this alternative during Conceptual Design. The preferred alternative includes the following: • Replace the above-grade section of the PEP with a floating pipeline located in Cargill Channel o Clean the existing above-grade section of the PEP (from Manhole 4 (MH-4) to MH-5) and leave in place for emergency use. o Remove and replace MH-4 and MH-5. • Rehabilitate the upstream siphon crossing Moffett Channel by conducting spot-repairs to the existing coal-tar epoxy lining within the siphon. • Rehabilitate existing MH-3. • Replace the downstream siphon with a new outfall to the Pond Recirculation Channel. Clean the existing downstream siphon and abandon in place. • Install gated connections to the PEP at MH-4 and MH-5 to allow the existing RCP PEP to be placed in service during emergency conditions. This does not include rehabilitating the existing aboveground RCP PEP.
