CITY OF SAN MATEO
CITY OF SAN MATEO
Agenda Report
City Hall
330 W. 20th Avenue
San Mateo CA 94403
www.cityofsanmateo.org
Agenda Number: 5 Section Name: {{section.name}} Account Number: 72-4671 File ID: {{item.tracking_number}} TO: City Council
FROM: Alex Khojikian, City Manager
PREPARED BY: Public Works Department
MEETING DATE: January 21, 2025
SUBJECT:
Wastewater Treatment Plant Digester 2 Cleaning — Agreement RECOMMENDATION:
Adopt a Resolution approving an alternative purchasing procedure to award an Agreement to Bristola, LLC for Wastewater Treatment Plant Digester 2 Cleaning services in the amount of $364,100, with a contingency in the amount of $36,000; and authorize the Public Works Director to execute the agreement in substantially the form presented and approve change orders within the approved contingency amount.
BACKGROUND:
The Clean Water Program (CWP) includes several capital improvement projects intended to upgrade or rehabilitate aging infrastructure in the City’s sewer collection system and Wastewater Treatment Plant (WWTP) to maintain plant operations, minimize service disruptions and safeguard public health. As part of the CWP, the WWTP Annual Major Components Project captures several repairs, rehabilitations, and efforts required to keep the portions of the existing WWTP that will remain after commissioning the new WWTP operational and forecast future needs. The WWTP Annual Major Components Project aims to enhance the ongoing improvements to the two digesters, which are used to break down solids in the wastewater treatment process. The WWTP operates two egg-shaped digesters in parallel and can operate with one digester but at limited capacity and with risk and cost to operations and maintenance. Cleaning of the digesters ensure reliability and safe operations of the digestion process and breakdown of sludge for safe disposal.
Digester 2 is currently offline due to failure of the mixer and draft tube in 2022. Services to repair the mixer and draft tube are currently in process. During the process of repair, it was observed that cleaning would be required to conduct the digester repairs properly and allow for reliable start-up and operations of the digester. Additionally, digester cleaning, which helps maintain capacity, effectiveness, and asset lifespan, has not been performed since 2010. To facilitate the repairs and cleaning, City WWTP operations and maintenance staff purged the digester of gas and liquid, and remaining materials include large solids, rags, grit, and struvite build-up. The City has been able to maintain operational capacity by operating only Digester 1; however, the inability to operate both digesters creates a larger volume of sludge (due to an increased liquid content) to be off-hauled, increasing disposal costs by $26,000 per month. Getting both digesters fixed and operational is essential for keeping disposal costs to a minimum. Furthermore, allowing Digester 2 to be cleaned, come online, and operate reliably will allow for inspection of Digester 1. The inspection of Digester 1 is scoped under the WWTP Biogas and Biosolids Evaluation, which was awarded to a consultant by City Council on November 18, 2024.
Staff initiated the process of obtaining a contractor for cleaning of Digester 2, which at the time was thought to be approximately $80,000. However, as staff started to solicit bids, the cost to clean was substantially higher due to the complexity and procedures to access and clean egg-shaped digesters. Egg-shaped anaerobic digester systems are not very common in the Bay Area and therefore, many companies don’t have experience cleaning this type of digester or capability to meet the repair and start-up schedule. The digester needs to get cleaned prior to reinstalling the mixer, which is
CITY OF SAN MATEO
currently scheduled to arrive in April 2025.
Staff requested three quotes from Synagro, Pipe and Plant Solutions, and Bristola, LLC (“Bristola”). Synagro declined to provide a quote due to specialization of the egg-shaped digesters. Pipe and Plant Solutions and Bristola provided cost proposals. Staff assessed both proposals and had virtual discussions with each vendor. Staff reviewed and negotiated a proposal with Bristola for $364,100 and determined it to be appropriate for the scope of work, expertise required, and timely need, and recommends Council approve an agreement with Bristola. Additionally, the costs associated with the cleaning can reduce the concurrent Biogas and Biosolids Evaluation Project scope and cost by coordinating the timing for the joint work of the scaffolding required for both projects.
Agreements that exceed $100,000 typically require an invitation-for-sealed-bids process. San Mateo Municipal Code Section 3.60.070(h)(3) authorizes the City Council to approve an alternative purchasing procedure when it finds doing so is in the best interest of the City. Because of the unusual egg-shaped digesters, only few companies have the capability to provide the cleaning services the City requires. In addition, the time it would take to go through a sealed bids process would not meet the timeframe needed to have the digester cleaned prior to the arrival of the repaired mixer and would not allow for the coordinated efforts of the Biogas and Biosolids Evaluation. Therefore, staff recommends for Council to award an agreement with Bristola since it is one of few companies that is able to provide the requisite cleaning services, will allow for Digestor 2 to be appropriately cleaned prior to completion of the repairs, ensure reliable start-up, and to meet the timeline for Biogas and Biosolids Evaluation.
Staff further recommends that $36,000 be authorized as a contingency amount for any potential changes that may arise due to the nature of this repair and investigation work.
BUDGET IMPACT:
There are sufficient funds available in the budget for WWTP Annual Major Components Project (46t090) to award this agreement and fund the contingency amount.
ENVIRONMENTAL DETERMINATION:
This project is categorically exempt from CEQA as an “existing facility,” in that the cleaning of Digestor 2 consists of the operation, repair, or maintenance of an existing public structure, facility, or mechanical equipment involving negligible or no expansion of existing or former use. (CEQA Guidelines Section 15301.)
NOTICE PROVIDED
All meeting noticing requirements were met.
ATTACHMENTS
Att. 1 – Proposed Resolution
Att. 2 – Agreement
STAFF CONTACT
Thomas Ruark, Senior Project Manager
[email protected]
650-522-7280
Deryk Daquigan, Deputy Director of Public Works
[email protected]
(650)522-7287
Matthew Fabry, Director of Public Works
[email protected]
(650)522-7303