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DATE:
TO:
FROM:
SUBJECT:
Agenda Item #4.0
August 5, 2019
Honorable Mayor and Members of the City Council through City Manager'
Dan St. John, F.ASCE — Director, Public Works & Utilities
Phil Benedetti — Assistant Engineer II, Public Works & Utilities
Resolution Accepting Completion of the Ellis Creek Solids Handling Upgrades
Project C66501305
RECOMMENDATION
It is recommended that the City Council adopt the attached Resolution Accepting Completion of
the Ellis Creek Solids Handling Upgrades Project C66501305.
BACKGROUND
The City's Ellis Creek Water Recycling Facility (ECWRF) has been in operation since early
2009 and currently processes an average dry weather daily flow of 4.8 MGD (million gallons per
day). Since 2010, the plant has experienced increases in organic loading. A large part of this
increased loading is the growth of the City's food processing industries. To understand better the
City's wastewater treatment and reclaimed water needs, the City Council held a workshop on
March 11, 2013, and adopted a goal to: "Focus attention on supporting food and beverage
processing, manufacturing, and alternative energy business clusters." In addition, a review of the
plant was conducted to evaluate loading trends. The plant evaluation resulted in a
recommendation to upgrade the solids treatment system to address wastewater loading increases
while filling the need for redundancy in the plant system by adding a second anaerobic digester
and other ancillary improvements.
The project included adding a second 550,000 -gallon anaerobic digester to mirror the existing
digester. The second digester will provide a factor of safety to the regulatory requirement of a
minimum 15 -day solids detention time where current operation hovers at 16 to 18 days detention
time. These improvements have resulted in modification of the activated sludge process to
reduce oxygen demand and improve aeration. This project also completed the first phase of the
larger Biomass to Biof iel project by providing digester capacity to accept high strength waste
from the City's food and beverage industries. Subsequent phases of this project are currently
under construction at ECWRF and are expected to be completed by October 2019.
Additional upgrades within this project include a second gravity belt thickener, third thickened
waste pump, and related piping, controls, and heating equipment. Additionally, the project
includes replacement of the existing dewatered sludge conveyance system, which has been
problematic, and the addition of a truck scale for the biosolids hauling trucks.
Bids for the construction contract were opened on June 1, 2016, and on July 11, 2016, the City
Council awarded the construction contract to C. Overaa & Co., of Richmond, CA in the amount
of $6,204,000. Construction was substantially completed in September 2018.
The proposed action meets Council Goals: "Our Environmental Legacy, Goal 51- Complete
Biomass to Biofuel project at the City's Ellis Creek Water Recycling Facility."
DISCUSSION
The final construction contract cost is $7,052,428, which included nine change orders. The
change orders are described in the table below:
Change Value
Order #
Summary
I
During construction of Digester #2, the adjacent Sludge Storage Tank was
1 $58,130.00
emptied to eliminate the need for extensive shoring to prevent settlement.
During this time the tank was cleaned and several maintenance items were
addressed.
During construction of the Treatment Wetlands Effluent pipeline, additional
provisions were needed to stabilize the trench due to the presence of
2 $89,795.00
groundwater. During excavation for Digester #2, an electrical ductbank was
discovered in the footprint of the foundation to be installed, requiring
demolition of the ductbank and re-routing of several existing electrical conduits.
During a routine inspection of the ECWRF Outfall pipeline, it was noted that
several sections of the pipe had developed signs of failure and that a possibility
3 $163,914.00
of collapse was high. A temporary bypass system was designed by City Staff and
installed by the contractor as a contingency plan, should the outfall pipe fail and
prevent discharge.
An alternative routing of the dewatered solids cake conveyor system was
devised to allow the use of both truck load -outs. This was facilitated by changing
4 $270,093.00
plans during the design of the High Strength Waste project, which eliminated the
need for a second screw press. This required different conveyors, supports,
electrical equipment, and controls.
During construction of Digester #2, it was determined that the proposed method
of operating the digesters in series configuration via gravity flow would pose
5 $183,751.00
operational issues. A new plan was designed that would allow series operation
of the digesters, utilizing pumped sludge. This required piping changes,
additional electrical equipment, and controls changes.
This credit was received from the Contractor as a result of eliminating the
second digester gas blower from the contract. During the design of the
6 -$261,801.00
CNG/HSW projects, City Staff were able to determine that the dual fuel boilers
would primarily use utility natural gas instead of digester gas. This eliminated
the need for a redundant blower unit.
I
Change Value
Order #
Summary
This change order included numerous additional equipment including piping,
valves, electrical conduit, and equipment supports that were the result of
7 $134,353.00 changes from other change orders. A new bucket was provided for one of the
large chopper pumps that was specified to use an existing bucket with an
undersized motor starter unit. This resulted in a delay of the project addressed
in change order #8.
The delay caused by the bucket replacement described in change order #7
8 $29,056.00 resulted in a delay of 24 working days on the critical path of the project. The
contractor's claim of $109,056 was reduced by City Staff via negotiation for
contractor delays related to the startup of the dewatered cake conveyor system.
The new dewatered cake conveyors selected required different conduit and
conductors than what were described in the original contract. Changes to the
9 $181,137.00 lighting around the digester required additional conduit, conductors and
switches. An additional stainless pipe spool was needed to allow the addition of
High Strength Waste to Digester #1.
Total
Cost of $848,428.00
Changes
FINANCIAL IMPACTS
The total approved project budget (Project Number C66501305) was $9,795,000. With the
design, construction contract, final quantities, contingency, construction management and
inspection, the total revised cost for the project was $9,795,000, as shown in following project
breakdown:
Ellis Creek Solids Handling Approved
Upgrade Project C66501305 CIP Budget
Planning/Environmental
$ 445,000
Design
$ 1,053,000
Construction Contracts
$ 7,001,000
Construction Management
$ 456,000
CIP Overhead/Administration
$ 40,000
Contingency
$ 800,000
TOTAL EXPENSES
$ 9,795,000
FUNDING SOURCES
Wastewater Capital $ 9,795,000
TOTAL FUNDING $ 9,795,000
Revised
Project Cost
$ 84,018
$ 1,130,038
$ 7,202,257
$ 720,400
$ 84,710
$ 573,577
$ 9,795,000
$ 9,795,000
$ 9,795,000
The project is funded through the wastewater capital fund. At project closeout, any remaining
funds will be returned to the Wastewater CIP fund to be used on other future projects. Following
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the acceptance of the project, the City Clerk will file a Notice of Completion with the Sonoma
County Recorder and the Finance Department will release the contract retention account to the
contractor within 60 days.
ATTACHMENTS
1. Resolution
2. Location Map
11
Attachment 1
RESOLUTION ACCEPTING COMPLETION OF
THE ELLIS CREEK SOLIDS HANDLING UPGRADES
PROJECT 066501305
WHEREAS, City staff prepared construction bid documents and advertised for the Ellis
Creek Solids Handling Upgrades Project C66501305 to construct a new anaerobic digester and
install various other solids handling equipment at 3890 Cypress Drive, Petaluma, CA 94954
("the project"); and
WHEREAS, the Project was bid on April 20, 2016, and five (5) bids were received and
opened on June 1, 2016 in accordance with applicable law; and
WHEREAS, the lowest responsible bid for the Project was submitted by C. Overaa &
Co., of Richmond, CA for $6,204,000.00; and
WHEREAS, by Resolution No. 2016-112 N.C.S., adopted on July 11, 2019, the City
Council found the bid of $6,204,000.00 for the project to be the lowest responsive bid, awarded
the Project to C. Overaa & Co., in the amount of $6,204,000.00, conditioned on C. Overaa &
Co.'s timely executing the project contract and submitting all required documents and authorized
and directed the City Manager to sign the project contract on behalf of the City; and
WHEREAS, the following contract change orders (CCO) affecting the Project amount
have been approved:
Proiect (C66501305)
Cost
Change Order #1
$
58,130.00
Change Order #2
$
89,795.00
Change Order #3
$
163,914.00
Change Order #4
$
270,093.00
Change Order #5
$
183,751.00
Change Order #6
$ <261,801.00>
Change Order #7
$
134,353.00
Change Order #8
$
29,056.00
Change Order #9
$
181,137.00
Total Change Orders
$
848,428.00
; and
WHEREAS, the final contract amount, as amended, including all change orders,
overruns and underruns is $7,052,428.00 and is within the approved project budget, and
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WHEREAS, based on the foregoing, staff recommends acceptance of the project on
behalf of the City.
NOW, THEREFORE, BE IT RESOLVED that the City Council of the City of
Petaluma hereby:
The contract titled Ellis Creek Solids Handling Upgrades Project, project no.
066501305, with the final contract amount of $7,052,428.00, is accepted as complete,
subject to the Contractor's continuing warranty and other obligations pursuant to the
contract.
2. The City Clerk is hereby authorized and directed to file a Notice of Completion
concerning the project with the Sonoma County Clerk's Office within 10 days of the
date of this Resolution.
3. Staff are hereby authorized and directed to release all undisputed retention not subject
to pending change orders within 60 days of the date of this Resolution and in
accordance with the terms of the project contract, California Public Contract Code
Section 7107 and applicable law.
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ELLIS CREEK WATER RECYCLING FACILITY
SOLIDS PROCESS UPGRADES
PROJECT NO. 066501305
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Date: June 1, 2015
Attachment 2
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City of Petaluma
PROJECT SITE w E Public Works and Utilities
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