CITY OF PACIFICA
COUNCIL AGENDA SUMMARY REPORT
2/14/2022
1 SUBJECT:
Approval of Purchase Agreement with Polydyne Inc., via sole source, for the supply of Clarifloc WE-2123, the cationic polymer used at the Calera Creek Water Recycling Plant for wastewater treatment.
RECOMMENDED ACTION:
Move to Approve the Purchase Agreement between the City of Pacifica and Polydyne Inc., via Sole Source, for the Supply of Clarifloc WE-2123, Cationic Polymer used at the Calera Creek Water Recycling Plant for Wastewater Treatment in an Amount Not to Exceed $85,000 from February 2022 to June 2022; and Authorize the City Manager to Execute all Necessary Documents.
STAFF CONTACT:
Lisa Petersen, Director of Public Works
(650) 738-3767
[email protected]
Maria Aguilar, Plant Manager
(650) 738-4660
[email protected]
Dave Peel, Assistant Superintendent
(650) 738-4660
[email protected]
BACKGROUND/DISCUSSION:
Cationic Polymers (Polymers) are long-chain organic molecules called “polyelectrolytes” and when mixed with water create a mixture called polyelectrolyte complex (PEC). Polymers are being used at the Calera Creek Water Recycling Plant (Plant) in its gravity belt thickener (GBT) to thicken wastewater sludge.
PEC with its positive electrical charge is mixed with sludge in the GBT to neutralize the negative electrical charge on the sludge particles. Once neutralized, the particles no longer repel each other and can be flocculated, which is the process of bringing together those coagulated particles into a bigger, heavier particle (floc) that is more readily settable. Larger floc allows for better separation between solids and liquids and therefore lowers the amount suspended solids, which can clog the Plant’s pumps. Following this process, the thickened sludge is sent to the digester for further treatment then to the centrifuge for dewatering, ultimately becoming a dryer “biosolid cake”, which is hauled away.
Pacifica City Council 2
February 14, 2022
Up to late 2009, the Plant used various types of Polymers. Some of these Polymers clogged pumps daily causing many hours of maintenance on the pumps at the Plant. Because of this constant equipment breakdown, the Plant became in danger of experiencing other problems that would impact effective Plant operation. These on-going issues prompted staff to invite Polymer manufacturer representatives to run their Polymer products through the Plant’s system for staff observation. Of the various types and brands of polymers, the Zetag 8818 (Zetag) was the most effective, and so the Plant started using Kubwater’s Polymer Zetag which reliably produced excellent sludge without sacrificing pumps and other equipment.
In November 2020, the Plant performed a trial batch with a new Polymer called Clarifloc WE2123 (Clarifloc) manufactured by Polydyne, Inc. that provided good results. In addition, the price of Clarifloc is less than Zetag, allowing for a cost savings. These are the only two Polymer products that have proven to be safe and effective for use at the Plant.
The Plant consumes cationic polymer at about 11,000 pounds a month or 132,000 pounds annually. Polydyne has extended the price of the Clarifloc at $1.40 per pound until the end of June 2022, which is 46% less than Zetag’s price of $2.05 per pound. It is projected that the total cost from February to June 2022 for using Polydyne will be $85,000 in comparison to $124,000 if the Plant uses Zetag, which is in addition to $50,000 already expended this fiscal year under the City Manager’s authority.
For these reasons, the City Manager is recommending the approval, via sole source, of a Purchase Agreement with Polydyne Inc. for the supply of Clarifloc WE-2123 Polymer for the remainder of Fiscal Year 2021-22. Staff will return to the City Council for a new approval of the Plant’s Polymer purchase for Fiscal Year 2022/23 in June 2022.
ALTERNATIVE ACTION:
The Council may choose not to approve the Purchase Agreement with Polydyne Inc. via sole source and direct staff to get at a third quote. However, doing so would delay the treatment of wastewater and is likely to violate the Plant’s National Pollutant Discharge Elimination System (NPDES) permit.
RELATION TO CITY GOALS AND WORK PLAN:
Approval of the Purchase Agreement with Tesco is consistent with the following Council adopted Goals:
• Stewardship of City Infrastructure and Maintaining a Safe Community: This purchase will ensure continuous treatment of wastewater at the Calera Creek Water Recycling Plant and compliance with its NPDES permit.
FISCAL IMPACT:
The total project cost is anticipated to not exceed $135,000 for FY 2021-22 and will be charged on WWTP- Chemical Expense Account Number 18.940741.52342.000.000. No additional budget authority is necessary as sufficient funds have been allocated in the Wastewater Enterprise Fund FY 2021-22 budget to pay for this purchase.
Pacifica City Council 3
February 14, 2022
ORIGINATED BY:
Public Works - Wastewater Division
ATTACHMENT LIST:
PA120303_120304_Polydyne_BS (PDF)