WASTEWATER 199
Project Financial Summary
Project Costs Revenues Operating Costs
Prior Actual 651,625 - -
2024-25 876,160 - -
2025-26 1,137,820 -
2026-27 570,000 - -
2027-28 - - -
2028-29 - - -
2029-30 213,849 - -
2030-31 776,757 - -
2031-32 - - -
2032-33 - - -
2033-34 - - -
2034-35 247,910 - -
2035-36 1,191,618 - -
2036-37 - - -
2037-38 - - -
2038-39 - - -
2039-40 287,395 - -
2040-41 1,334,612 - -
2041-42 - - -
2042-43 - - -
2043-44 - - -
2044-45 333,170 - -
20 Year Total 6,093,132 - -
Grand Total 7,620,917 - -
Project Description/Scope/Purpose
This project focuses on the repair, replacement, and rehabilitation of storm drain pipes and related infrastructure, such as manholes, catch basins, outfalls, and pump station forebays. The City maintains over 320 miles of storm lines ranging from 6 inches to 84 inches in diameter, many of which are over 50 years old. The project identifies and addresses necessary repairs based on condition assessments or the Wastewater Master Plan’s Capital Improvement Program (CIP).
To ensure the most efficient and effective solutions, various technologies are evaluated for each location such as open-trench replacement, trenchless pipe-bursting or replacement, and pipe-lining. Since storm systems generally endure less severe conditions than sewer systems, they tend to have a longer lifespan.
Project Scope:
o Repair, replacement, or rehabilitation of associated stormwater conveyance components, such as outfalls, pump station forebays, manholes, catch basins, grates, and lids.
o A recent example includes the Remington Court storm drain outfall into Stevens Creek. Design of the Remington Court storm drain outfall into Stevens Creek was completed in 2021, with construction of the outfall repairs completed in December 2022. The project’s environmental subconsultant has determined that the required environmental mitigation associated with the project has not yet been successful. As a result, the post-construction report to the Regional Water Control Board cannot be completed. The estimated cost to complete the necessary mitigation efforts, which include one year of plant maintenance and submission of the project completion report to the Water Board, is $44,000. o Installation of new storm drain pipes and manholes to reroute approximately half the flow of an existing 30-inch storm drain that currently enters a 27-inch sanitary sewer.
o Cured-in-place pipe (CIPP) lining to rehabilitate a damaged storm drain along Borregas Avenue. o A study to identify and prioritize sources of stormwater inflow into the sanitary sewer system is being finalized. This study will guide future capital improvement projects.
o Activities such as condition assessments, cleaning, debris removal, and flow monitoring are conducted to diagnose structural or performance issues.
o Video inspections are commonly used to identify locations needing replacement or rehabilitation.
Project Evaluation and Analysis
This project is essential to maintain effective stormwater conveyance and reduce the risk of system failures that could lead to flooding and property damage. Delaying or defunding this project could result in costly emergency repairs due to aging infrastructure.
Fiscal Impact
This project is primarily funded by the General Fund. $450,000 is funded by the Wastewater Management Fund to cover 50% of a project that reduces stormwater inflow into an existing sanitary sewer.
Funding Sources
General Fund and Wastewater Management Fund
Plans and Goals
EM - Environmental Management - EM-9: Adequate Storm Drain System 825362 - Replacement/Repair/Rehabilitation of Storm Drain Originating Year: 2019 Project Type: Wastewater Department: 270 - Environmental Services Planned Completion Year: Ongoing Category: Infrastructure Project Manager: Richard Chen Project Financial Summary
Project Costs Revenues Operating Costs
Prior Actual 17,640,392 - -
2024-25 1,800,000 - -
2025-26 1,880,000 -
2026-27 2,165,000 - -
2027-28 2,250,000 - -
2028-29 - - 280,000
2029-30 - - 280,000
2030-31 - - 280,000
2031-32 - - 280,000
2032-33 - - 280,000
2033-34 - - 280,000
2034-35 - - 280,000
2035-36 - - 280,000
2036-37 - - 280,000
2037-38 - - 280,000
2038-39 - - 280,000
2039-40 - - 280,000
2040-41 - - 280,000
2041-42 - - 280,000
2042-43 - - 280,000
2043-44 - - 280,000
2044-45 - - 280,000
20 Year Total 6,295,000 - 4,760,000
Grand Total 25,735,392 - 4,760,000
Project Description/Scope/Purpose
The Water Pollution Control Plant (WPCP) Biosolids Processing project was initiated in 2009 to address the accumulation of biosolids (sediments) on the bottom of the WPCP Secondary Treatment Oxidation Ponds. This project provides funding for the removal, processing, and disposal of accumulated sediments from the Plant's Oxidation Ponds.
The WPCP Biosolids Processing project also provides funding for the dewatering and beneficial reuse of anaerobically digested biosolids from the Plant's solids handling process until new solids dewatering facilities are constructed as part of the ongoing Sunnyvale Cleanwater Program (projected completion
2028).
The Biosolids Handling scope of work provides for the removal of pond solids by dredging and preconditioning before sending those biosolids to a centrifuge and belt press for dewatering. The WPCP Biosolids Processing project also provides funding for the dewatering and disposal of biosolids generated by the WPCP Anaerobic Digesters. After dewatering, those concentrated solids are hauled off-site for land application (beneficial reuse).
Funding can also be used to clean digesters when the same contractor provides one or both of the previously mentioned services (pond and/or digester solids processing). This is a cost and logistical advantage for the City as much of the same equipment is used in the cleaning process.
Project Evaluation and Analysis
The WPCP is a heavily regulated wastewater treatment facility with strict effluent discharge requirements. The ammonia concentration in the WPCP final effluent is one of the plant effluent limits. Reduced volumetric treatment capacity within the Oxidation Ponds due to solids accumulation can directly affect the ammonia removal ability of the ponds and, if not addressed, may increase the concentration of ammonia in the effluent.
Over the last decade, the WPCP held several technical meetings with scientists and engineers to determine the best course of action to minimize the chance of process failure of the Secondary Oxidation Ponds. During those meetings, it was concluded that dredging the ponds at a rate faster than accumulation is the most prudent approach.
The rate of capacity restoration of the ponds is slow and needs to be spread over several years. The anaerobic digestion of wastewater solids provides fuel for power generation and volumetric reductions of plant-generated solids. Both save operating costs associated with purchasing power, handling, and disposal of plant-generated biosolids.
Fiscal Impact
The project costs are reflected in the agreement with the current contractor providing the handling, processing, and disposal services. $280,000 impacts in wastewater operation budget have been added to cover the ongoing hauling and disposal costs related to biosolids dewatering and disposal after 2027, once a new Thickening and Dewatering Building has been constructed.
Funding Sources
Wastewater Management Fund
Plans and Goals
EM - Environmental Management - EM-7: Effective Wastewater Treatment 825521 - WPCP Biosolids Processing
Originating Year: 2006 Project Type: Wastewater Department: 270 - Environmental Services Planned Completion Year: 2027/28 Category: Infrastructure Project Manager: Xi Jiang Attachment 2