CITY OF PACIFICA
COUNCIL AGENDA SUMMARY REPORT
8/22/2022
1 SUBJECT:
Purchase Agreement between the City of Pacifica and De Nora Water Technologies, LLC for the purchase of ControlLogix System and Blower Unloading Valve in connection to the Calera Creek Water Recycling Plant Sand Filter Upgrade Project.
RECOMMENDED ACTION:
Approve Purchase Agreement between the City of Pacifica and De Nora Water Technologies, LLC, via sole source, in the amount of $131,000.00 for the purchase of ControlLogix System and Blower Unloading Valve in connection to the Calera Creek Water Recycling Plant (CCWRP) Sand Filter Upgrade Project; approve budget authority in the amount of $151,000.00 which includes 15% contingency in the amount of $20,000.00; authorize the City Manager to execute all documents related to the project.
STAFF CONTACT:
Dave Peel, Assistant Superintendent
(650) 738-4660
[email protected]
Maria Aguilar, Plant Manager
(650) 738-4660
[email protected]
Lisa Petersen, Director of Public Works
(650) 738-3767
[email protected]
BACKGROUND/DISCUSSION:
During the FY 2022-23 Capital Improvements Program (CIP) budget approval process, the Council approved funding for the Calera Creek Water Recycling Plant (CCWRP) Sand Filter Upgrade Project. Purchase of a new programmable logic control system and blower uploading valve was included in the funding approval for the CCWRP Sand Filter Upgrade Project.
CCWRP utilizes five U.S. Filter (now De Nora Water Technologies) sand filters to remove solids from the CCWRP (Plant) primary effluent. After the water flows through the sand filters it becomes final effluent, which is treated water being discharged from the Plant into Calera Creek. The removal of suspended solids allows the last process before discharge, ultra-violet disinfection, to be efficient and cost effective. It also allows the City to stay within the National Pollutant Discharge Elimination System (NPDES) permit guidelines for maximum total suspended solids that can discharge to the final effluent. During large storm events, the sand filter operation is critical to allow water out of the Plant so it can receive high storm flows.
Control of the sand filters is automated and utilizes an Allen Bradley PLC5 programmable logic controller system (PLC) that has been produced for over 30 years. Staff received notice from Allen Bradley that this controller would be phased out. This end-of-life announcement means Pacifica City Council 2
August 22, 2022
there will no longer be any support for parts and repair of PLC 5 components, although the Plant has spare back-up parts that have been purchased.
When a particular brand of PLC is specified upon initial construction of a project, the architecture of that project becomes very specific. To change brands of PLCs within a Plant can be very involved. Different cabinets, wiring, software, programming, training, etc. can exceed the cost savings of a different brand of PLC. Fortunately, Allen Bradley has deemed its ControlLogix line of PLCs as a direct replacement for the PLC5.
De Nora Water Technologies (DNWT) has developed several improvements to filter operations in the past 15 years that will allow much more flexibility in the operation at CCWRP. One of the improvements is DNWT’s proprietary and patented Speed Bump technology. The Speed Bump (Bump) has two purposes. One is to release gasses that form biologically and accumulate in the filter media that can impede filtration. The second purpose allows the redistribution of solids within the media bed to increase filter runtimes. The Bump is commonly used during high filtration rate periods to maintain filtration through the filter system. The Bump technology will redistribute the solids within the beds during high flow events to maintain filtration rates, minimizing the possibility of disruption to the Plant during storm events.
Thus, a benefit of replacing the existing PLC5 with the ControlLogix is that it allows for the Speed Bump technology to be added to the automation of the sand filter operation. ControlLogix adapters will allow the use of the existing PLC 5 wiring harnesses, plugs, rack locations, and cabinets, to accomplish the processor retrofit. By using these adapters, downtime for the filter system and installation costs will be minimized. In addition, DNWT proposed the purchase and installation of the Blower Unloading Valve, which is a component used to meter the blower air with the proposed Bump feature. This will reduce the initial air surge into the filters increasing the longevity of the filter system. It also allows for easier blower starts, thereby reducing initial back pressure on the blower and wear on the blower.
The following are reasons purchase of ControlLogix System and the Blower Unloading Valve from De Nora have been determined to be Sole Source commodities and benefits the City:
• DNWT is the design owner of the sand filter system at CCWRP. • DNWT’s familiarity with CCWRP’s sand filter system enables them to provide the highest standard of responsiveness and reliability.
• The original commissioning DNWT engineers are available, thereby reducing any timeconsuming learning curve to understand the existing system and perform proper upgrade.
• DNWT has priority right to the Speed Bump that is designed to redistribute the solids within the sand filter bed during high flow events to maintain filtration rates. • DNWT has the expertise to program the new ControlLogix System and Blower Uploading Valve for the Speed Bump to be integrated in the automation of the sand filter system and the new system is compatible with the existing wiring harnesses, plugs, rack locations, and cabinets.
For these reasons, the City Manager is recommending the approval of the Purchase Agreement between the City of Pacifica and DNWT, via sole source, in the amount of $131,000.00 for the purchase of a ControlLogix System and Blower Unloading Valve in connection to the CCWRP Pacifica City Council 3
August 22, 2022
Sand Filter Upgrade Project.
ALTERNATIVE ACTION:
The Council may choose not to approve the Purchase Agreement with De Nora Water Technologies via sole source and direct staff to issue a Request for Proposal (RFP). However, doing so will delay project delivery, will likely increase project cost, will subject us to parts procurement problems during failures, and possibly violate the Plant’s National Pollutant Discharge Elimination System (NPDES) permit.
RELATION TO CITY GOALS AND WORK PLAN:
Approval of the Purchase Agreement with De Nora is consistent with the following Council adopted Goals:
• Stewardship of City Infrastructure: The Project will ensure continuous treatment of wastewater at the Calera Creek Water Recycling Plant and compliance with its NPDES permit.
• Maintaining a Safe Community: The Project will ensure continuous treatment of wastewater at the Calera Creek Water Recycling Plant and compliance with its NPDES permit.
FISCAL IMPACT:
The cost of purchasing the ControlLogix System and Blower Unloading Valve is $131,000. City staff recommends including a 15% contingency for any additional parts or services needed to complete the project. The Source and Use of Funds spreadsheet is shown below.
Total Use of Funds
Purchase Agreement $ 131,000
Contingency (15%) $ 20,000
Total Cost $ 151,000
Total Project Source
Enterprise Fund (Fund 34) $ 209,000
Account No 34.900000.52800.P044.000
Estimated Project End Balance $ 58,000
No additional budget authority is necessary as sufficient funds have been allocated in the Wastewater Enterprise Fund FY 2022-23 budget for this project. The total cost of $151,000.00 is within the project budget of $209,000.00 allocated for the CCWRP Sand Filter Upgrade Project.
ORIGINATED BY:
Public Works - Wastewater Division
ATTACHMENT LIST:
Pacifica City Council 4
August 22, 2022
PurchaseAgreement_Denora_CCWRP Sand Filter Upgrade_Final (PDF)