Site work for a civil project in Windsor, California. Completed plans call for site work for a water / sewer project.

The work consists of dewatering the Water Reclamation Facility's aeration basin, further excavation and installation of a new concrete aeration basin facility with a flow splitting structure, air lines, diffusers, a mixing system, a surface wasting pumping system, and a high flow return pump connected to the adjacent high flow storage pond. In conjunction with the new aeration basin, a new blower building with internal blowers will be constructed with a separate electrical control building. Additional work includes a separate carbon feed building with internal tanks and chemical metering pumps, a below grade secondary clarifier weir flow splitting structure, and relocation of a concrete sand filter high flow diversion structure. Questions regarding the plans and specifications shall be addressed to Garrett Broughton by email at bids@townofwindsor.com. The last day for questions is February 12, 2026. The Work to be performed under these Contract Documents is generally described as follows: 1. Existing Headworks Facility- the existing headworks facility consists of one mechanical bar screen, one vortex grit removal chamber, a Parshall flume to measure influent flow, and two channels to send flow to the two aeration basins. Modifications to the existing headworks structure include: a. Existing headworks effluent yard piping will be modified outside of the Facility to connect to the new BNR facility. b. Piping from Pond 2 Return Pump Station will be rerouted to connect upstream of mechanical bar screens into the existing headworks structure. c. No improvements to the actual existing headworks facility components are included. 2. New BNR Flow Splitting Structure - a new cast-in-place concrete BNR flow splitting structure will be constructed integral to the new BNR facility to ensure even distribution of screened and degritted raw influent and return activated sludge (RAS) for three aeration basin treatment trains. 3. New BNR Basin -The new BNR aeration basin design includes: a. Cast-in-place concrete tanks. Three trains are expected to be constructed within the footprint of existing Aeration Basin A and a portion of Pond 2. BNR Basins will be partially buried. b. New mechanical piping to provide equal flow split and capacity between discharge of basins and connection to existing secondary clarifiers. c. All basin internals including internal mixed liquor return pump systems, fine-pore diffusers, membrane aerated biofilm reactor (MABR) cassettes, large bubble mixing piping system, miscellaneous piping, instrumentation and monitoring. 4. New Secondary Clarifier Flow Splitting Structure - A new cast-in-place concrete secondary clarifier flow splitting structure will be designed to provide an equal split to the two secondary clarifiers. 5. Existing waste activated sludge (WAS) Pump Station and return activated sludge (RAS) Pump Stations A and B - The changes to WAS and RAS Pump Stations include: a. New WAS pumps with variable frequency drives (VFDs) that are sized to meet system design conditions. b. New above ground piping, valves and instrumentation associated with WAS pumps. Buried WAS suction and discharge piping is not expected to be replaced c. RAS pumps shall remain with minor improvements including new flow meters, instrumentation, and piping. d. New electrical feeds and controls for WAS pumps. 6. New Blower Building - A new pre-cast concrete building will be constructed in accordance with local building codes. Building will house equipment for aeration blowers, MABR blowers and compressor system for the compressed air mixing (CAM) system. 7. New Electrical Building - A new pre-cast concrete building will be constructed in accordance with local building codes. Building will be constructed to house the new electrical equipment required for the project. The new building will have space for electrical to be installed in the future for two additional BNR trains, their associated components, and associated blowers. 8. New Supplemental Carbon Storage and Feed Building - A supplemental carbon storage and feed building will be required to ensure adequate carbon supply is available for the BNR system. The design of the new supplemental carbon storage and feed building includes: a. A new pre-cast concrete building will be constructed in accordance with local building codes. b. Concrete building will be constructed with secondary containment, sized in accordance with local fire codes. c. Building will include storage tanks and chemical feed pumps with instrumentation, controls, chemical feed piping, and appurtenances. 9. Pond 2 Return Pump Station - The existing Pond 2 return pump station will be demolished, and new pump station constructed integral with the BNR Basins. The new Pond 2 return pump station shall include new pumps, piping, instrumentation, and appurtenances for conveyance to the existing Headworks facility. 10. Existing Pond 1 - A temporary earthen berm will be required to be installed in Pond 1 and utilized for construction vehicle site access. This temporary berm will be removed and restored to original conditions once the BNR system is commissioned. 11. AWT Filter Diversion Structure - Demolish and design a new structure in a location adjacent to the existing location. 12. The treatment plant must be kept in operation at all times. Sequencing and coordination with Operations staff will be required. The BNR basin and other facilities must be constructed while flow is maintained through Aeration Basin B. Work for certain portions of the project will be restricted during the Dry Season as detailed herein. Question Deadline 02/12/2026