HomeMy WebLinkAbout03.a. Review draft Position Paper to authorize the General Manager to amend an existing professional engineering services agreement with Stantec Consulting Services, Inc. to increase the agreement ceiling from $1,540,000 to $3,078,000 for final design of Page 1 of 25
Item 3.a.
CENTRAL SAN BOARD OF DIRECTORS
POSITION PAPER
DRAFT
MEETING DATE: SEPTEMBER 17, 2019
SUBJECT: REVIEW DRAFT POSITION PAPER TO AUTHORIZE THE GENERAL
MANAGER TOAMEND AN EXISTING PROFESSIONAL ENGINEERING
SERVICES AGREEMENT WITH STANTEC CONSULTING SERVICES, INC.
TO INCREASE THE AGREEMENT CEILING FROM $1,540,000 TO
$3,078,000 FOR FINAL DESIGN OF THE FILTER PLANTAND CLEARWELL
IMPROVEMENTS — PHASE 1A, DISTRICT PROJECT 7361
SUBMITTED BY: INITIATING DEPARTMENT:
CHATHURAABEYRATHNA, ASSOCIATE ENGINEERING AND TECHNICAL SERVICES-
ENGINEER CAPITAL PROJECTS
REVIEWED BY: CRAIG MIZUTANI, SENIOR ENGINEER
EDGAR J. LOPEZ, CAPITAL PROJECTS DIVISION MANAGER
JEAN-MARC PETIT, DIRECTOR OF ENGINEERING AND TECHNICAL
SERVICES
ISSUE
Board of Directors' (Board) authorization is required for the General Manager to execute an amendment to
a professional engineering services agreement above ten percent or$200,000, whichever is greater.
BACKGROUND
Central San's recycled water facilities have provided a reliable supply of recycled water to Central San's
wastewater treatment plant (plant) since being commissioned in 1977. In the mid-1990s, Central San
modified these facilities to produce California Title 22 Water Quality Requirements for Recycled Water
(Title 22) and delivery to off-site customers in Zone 1, which was defined under an agreement with Contra
Costa Water District (CCWD).
While Central San remains the largest customer of the Recycled Water Program, some of the recycled
water facilities are nearing the end of their useful lives, which is leading to reliability concerns and the need
to address the critical elements of the Filter Plant and Clearwell Improvements project to proceed at this
time.
Several recent failures, described below, have shaped and focused staff's recommendations for this first
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phase of the project, entitled Phase 1 A. The east Clearwell cover experienced some failures in 2017. In
2018, a high-voltage (12kV) electrical feeder from Substation 82 (Central San's main PG&E electrical
service)to Substation 40 at the Filter Plant failed at a splice box. I n early 2019, Substation 40 experienced
another failure which triggered a cascading series of events that led to a 16-minute, plant-wide power
failure. The cover ripped in July 2019, leading to the east cell decommissioning. Recycled water storage
is now accomplished in the west Clearwell, which was recently cleaned, commissioned with a temporary
cover, and placed in operation. These incidents reflect that, despite staff's good operation and
maintenance practices, the recycled water facilities are showing signs of significant deterioration, which is
starting to impact reliability.
Project History:A Phased Approach with Future Recycled Water Projects
On May 3, 2018, the Board authorized an agreement with Stantec Consulting Services, I nc. (Stantec)to
provide planning and preliminary design of the Filter Plant and Clearwell Improvements, District Project
7361.As part of this agreement, Stantec prepared several technical memoranda that reviewed the
condition of the filter plant, disinfection alternatives, hydraulics, seismic assessment, process and
automation, and alternative filtration technologies.
Staff and Stantec have taken a long-term approach on this project and have evaluated the possible
impacts of future projects, including the Concord Community Reuse Project and especially the Water
Exchange Project. When looking at possible solutions to resolve the aging infrastructure needs for the
recycled water facilities, the team evaluated Central San's immediate needs, which include the most critical
items that require replacement to restore reliability over the next five to ten years, and that would not
conflict with or potentially leave stranded assets when the Water Exchange Project is implemented. Staff
asked the question: If we knew today that a Water Exchange Project was proceeding, would our
recommendation be different?
With that thought in mind, staff developed a recommendation that divides the Filter Plant and Clearwell
Improvements into three phases, with the most operationally critical elements proceeding first.
• Phase 1 A: Electrical improvements, recycled water storage tanks, Clearwell pump renovation, and
rehabilitation of one of the four existing filters.
• Phase 1 B: Rehabilitation of the remaining three filters and Filter Building, other remaining electrical
improvements, upgrades to the Applied Water Pump Station and hydraulic improvements to bypass
the Forebays. This phase would also include the addition of a chlorine contact basin and would
complete the remainder of the renovations to meet the long-term needs of the Recycled Water
Program.
• Phase 2: Improvements to provide additional recycled water supply to CCW D so they can serve the
future Concord Community Reuse Project. (The Phase 2 project, and its associated costs, is not
currently included in the Ten-Year Capital Improvement Plan and budget.)
On May 2, 2019, the Board approved an amendment to the agreement with Stantec to complete the 30-
percent design for the Phase 1 A project.
Shortly thereafter, on June 21, 2019, Central San staff held a Technical Peer Review Treatment Train
Workshop for the Water Exchange Project. The purpose of the workshop was to seek input from technical
experts in the consulting and academic communities on the most optimal treatment train that could produce
both Central San's current and future Title 22 recycled water supply, in addition to refinery-quality recycled
water, while considering Central San's future nutrient removal requirements. There were 32 people in
attendance, including Central San staff, Dr. Glen Daigger(University of Michigan), Dr. David Jenkins
(Professor Emeritus, UC Berkeley), the lead technologists from twelve major wastewater consulting firms,
and representatives of our partner agencies (CCW D and Valley Water). The outcome of the workshop
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was a number of proposed treatment alternatives.
Some of the proposed treatment alternatives included continuing to incorporate process elements of the
Filter Plant; possibly repurposing some of the structures (e.g. Forebays and Filter boxes); or completely
abandoning the Filter Plant and replacing it with membrane technology. However, under all these
alternatives, the need to store and distribute the recycled water to the end users (Central San and Zone 1)
remained unaltered. This review of the potential synergy between current and future recycled water related
projects further confirmed the decision to divide the project into phases and proceed with the Phase 1 A
project.
Phase 1A Project
Staff recommends moving forward with Phase 1 A, which focuses primarily on providing reliable recycled
water storage and distribution to end users. The Phase 1 A project will serve the recycled water facilities
whether or not the future Water Exchange Project is implemented. Phase 1 A would address recycled
water supply reliability(e.g. storage and pumping) and address electrical safety and deficiency concerns.
I n addition, it will include rehabilitating one of the four existing filters. This filter rehabilitation would have a
dual purpose: reliability of production (worst operating filter) and provide the filtration production capacity
needed to meet current demand using new filter media. Central San will benefit from the new filter for a
minimum of five to ten years before the Water Exchange Project is implemented. A more detailed scope
of work for Phase 1 A is provided in Attachment 1.
Business Case Evaluations (BCEs")
Central San performs comprehensive BCEs for every capital project, which includes, but is not limited to,
the following tasks:
• Evaluate specific project needs and drivers.
• Conduct an in-depth evaluation of existing asset condition assessment(s) and determination of
remaining life.
• Evaluate whether to keep the existing assets or replace with in-kind and/or new technology.
• Evaluate current and possible future regulatory drivers or related projects that would impact the
project solutions.
• Preliminary investigation as needed (geotechnical, permitting, environmental, etc.).
• Prepare alternative solutions, which consists of: prepare and estimate costs and related
expenditures; evaluate operations and maintenance impacts; compare pros and cons; and prepare
lifecycle cost analysis for each alternative.
• Prioritize scope or projects based on multiple factors. Sometimes, this may require phasing a
project over time or combining projects into one project.
• Conduct pilot testing of preferred technology when appropriate to validate design criteria and risk.
(i.e. Filter pilot testing completed under Phase 1 A).
• Review and discuss with the Capital Improvement Program Executive Review Committee
(Executive Team) and stakeholders.
Since the last Board update, two BCEs were conducted. The BCEs include disinfection and recycled
water storage. Staff recommends postponing the chlorine contact basin and building two new steel storage
tanks. Details of these BCEs can be reviewed in Attachment 2.
California Environmental Quality Act (CEQA):
At its May 2, 2019 meeting, the Board independently found that the agreement with this vendor (Stantec)
was exempt from CEQA under Central San's CEQA Guidelines Section 15262, since it allowed for
further planning and feasibility studies for possible future actions which Central San has not approved,
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adopted, or funded, and the outcome of these tasks will not have a legally binding effect on later activities.
Central San will conduct an environmental evaluation of any capital project that is proposed in the future as
a result of the tasks authorized herein to determine the need for any additional CEQA documentation.
ALTERNATIVES/CONSIDERATIONS
Other alternatives are set forth below; however, are not recommended by staff.
Alternative 1: Split Phase 1 A into smaller projects and spread the construction over several fiscal years.
While this approach would result in a smaller initial design fee request, administering separate smaller
projects within the same work areas, possibly with overlapping schedules, would be more challenging in
terms of coordination between the designs and potentially multiple contractors, thereby increasing the
overall cost of the project. This alternative would result in higher costs due to the added overhead, cost of
bidding and administering separate projects, staff coordination, and costs for keeping the facility
operational during construction.
Alternative 2: Delay recommended project elements longer or minimize scope and wait to integrate the
solutions to the current problems with the Water Exchange Project. Under this alternative, staff would
proceed with a smaller scope project and postpone some of the needed work to the future, if possible. All
elements suggested as part of Phase 1 A are deemed critical for the reliable operation of the recycled
water facilities and required in the next five years, with electrical and storage needed sooner. The only
scope item that may be considered for postponing is rehabilitating one filter; however, staff is proposing to
list this work as a bid alternate and consider the rehabilitation after receiving the bid.
Alternative 3: Do-nothing to the facilities. Under this alternative, staff would not amend Stantec's
agreement and the existing recycled water facilities would continue operating in its current condition.
Repair of facilities would be done upon failure. This alternative would prevent staff from implementing work
that will maintain a reliable recycled water supply to both Central San's plant and Zone 1 customers.
FINANCIAL IMPACTS
The total anticipated cost for final design for Phase 1 A is $1,538,000, which includes design and bidding
services performed by Stantec. The current Stantec agreement is valued at$1,540,000 and if the final
design is included would result in an agreement valued up to $3,078,000, as shown in the table below.
Services Fees Board Approval
Original Agreement— Planning/Pilot Study $990,000 May 3, 2018
Amendment 1 — Phase 1A Preliminary Design $550,000 May 2, 2019
Current Stantec Agreement $1,540,000
Proposed Amendment— Phase 1 A Final Design $1,538,000 Pending
Total Contract Value with Amendments $3,078,000
The total estimated cost of Phase 1 A is approximately$35.5 million, of which approximately$27 million is
construction costs, as detailed in Attachment 3. The total agreement value with amendments constitutes
about 11.4 percent of the estimated construction cost, which appears high. However, this includes planning
(which applies to all proposed project phases) and pilot testing costs. When compared to the design
costs, the actual percentage ranges between 8-10 percent. This project is complex as it involves multiple
facilities and includes the evaluation of many evolving options and the implication of future projects.
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COMMITTEE RECOMMENDATION
The Engineering and Operations Committee reviewed this subject at the September 17, 2019, meeting
and recommended
RECOMMENDED BOARD ACTION
Authorize the General Manager to amend an existing professional engineering services agreement with
Stantec Consulting Services, Inc. to increase the agreement ceiling from $1,540,000 to $3,078,000 for
final design of the Filter Plant and Clearwell Improvements — Phase 1A, District Project 7361.
Strategic Plan re-In
GOAL ONE: Provide Exceptional Customer Service
Strategy 1 - Build external customer relationships and awareness
GOAL THREE: Be a Fiscally Sound and Effective Water Sector Utility
Strategy 2- Manage costs
GOAL FIVE: Maintain a Reliable Infrastructure
Strategy 1 - Manage assets optimally throughout their lifecycle
GOAL SIX: Embrace Technology, Innovation and Environmental Sustainability
Strategy 1 -Augment the region's water supply, Strategy 3- Encourage the review and testing of technology to optimize
and modernize business operations
ATTACHMENTS:
1. Phase 1 A Scope of Work
2. Business Case Evaluations
3. Total Phase 1 A Cost Estimate
4. Presentation
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Attachment 1
Filter Plant and Clearwell Improvements - Phase 1A, District Project 7361
Scope of Work
Staff recommends the following scope of work for Phase 1A final design:
1. Electrical Replacement and Upgrades:
a. Electrical power distribution to the Electrical Substation 40 will be reconstructed
to remove 2400v equipment and replace with new medium voltage distribution,
step down transformers and 480v equipment.
b. Clearwell Pumping Station Electrical. New 480v electrical switchgears including
new motor control centers (MCC) and variable frequency drives (VFD) for the
Utility Pumps, Backwash Pumps and Recycled Water Pumps for Zone 1.
Equipment to be housed in a pre-engineered electrical building.
2. Recycled Water Storage Tanks Addition:
a. Two new three-million-gallon (MG) recycled above grade water storage tanks
will be constructed to replace the East Clearwell. The new tanks will be
conventional steel tanks with a protective coating inside and out, which is
standard practice for water storage structures.
b. Appurtenances will be added to facilitate operation in series or parallel to
provide chlorine contact time under different operating scenarios for high
recycled water demand in the summer and low demand in the winter.
c. The embankment for the East Clearwell will be partially removed to provide a
site area for the new storage tanks.
d. The West Clearwell will be maintained to facilitate recycled water delivery
during construction and to provide backup storage.
3. Filter Rehabilitation:
a. One filter of the existing four filters will be rehabilitated with new filter media
and underdrains to confirm that the filter can reliably operate at a filtration
capacity of 4.5 MGD/filter (million gallons per day/filter).
b. All filters will receive reliability work to replace aging instrumentation and
restore individual filter effluent turbidity measurement.
c. Shade structures will be added to the filters to control attached algae growth
and improve filter operation, which will reduce maintenance.
d. The chemical feed reliability work will replace aging instrumentation, piping and
valves on the hypochlorite system and update the feed pump motor control
center. The coagulant system will be modified to feed a new filter aid.
4. Clearwell Pump Station (CWPS) Improvements:
a. A new Utility Water pump will be added at the CWPS.
b. The shade structure will be rebuilt to improve reliability of the Utility and
Recycled Water delivery pumps.
c. Replace the three Backwash Pump motors, as needed.
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Attachment 2
Filter Plant and Clearwell Improvements - Phase 1A, District Project 7361
Business Case Evaluation (BCE) - Disinfection and Storage Alternatives
Disinfection Alternatives:
The viable BCE options that were examined for each disinfection alternative were:
• DIS-1: Reinforced concrete partitions to create chlorine contact basins (CCBs)
within the existing Clearwell (in each cell);
• DIS-2: Reinforced concrete CCBs within the existing Forebays;
• DIS-3: Stand-alone reinforced concrete CCBs (adjacent to the existing
Clearwell); and
• DIS-4: New In-Vessel UV (Ultraviolet) Disinfection Facility.
The recommended alternative was DIS-3, stand-alone reinforced concrete CCBs that
would be located south of the existing Clearwell adjacent to the filter effluent (FE)
overflow junction structure. This alternative provides the most cost-effective long-term
approach for disinfection. Other benefits include better maintenance access for cleaning
and storage capacity. While alternative DIS-3 is the best approach, staff recommends
postponing its implementation until Phase 1 B of the project and continue using the FE
pipe as a contact time contactor supplemented by the recycled water storage to fulfill
the Title 22 contact time requirements.
Recycled Water Storage Alternatives:
Since Phase 1A's main focus includes the provisions for safe, reliable storage of
recycled water, another technical memorandum further analyzed various storage
options. Staff prepared and developed BCEs on five alternatives:
• RWS-1: Repair or replacement of existing Clearwell liner and cover;
• RWS-2: Re-purpose the existing Forebays to be used as a Clearwell;
• RWS-3: Provide two new storage tanks using above-ground steel;
• RWS-4: Provide two new storage tanks using above-ground prestressed
concrete; and
• RWS-5: Status Quo, a do-nothing alternative.
The recommendation is alternative RWS-3, to construct two new three-million-
gallon above-ground steel storage tanks instead of replacing the liner and covers on the
Clearwell. These tanks will be located inside the east cell of the Clearwell and
connected to the final effluent overflow junction structure. Benefits of this alternative
include better maintenance accessibility, the Clearwell structure will not be classified as
an off-stream dam under the jurisdiction of the State Division of Safety of Dams, and it
is the most cost-effective compared to the other alternatives. The tank location was
based on the geotechnical site evaluation that revealed hard rock formation under the
existing Clearwell structure, which is surrounded by Bay mud.
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Attachment 3
Filter Plant and Clearwell Improvements - Phase 1A, District Project 7361
Estimated Capital Costs of Recommended Items
Total Construction Total Project
Cost Cost
Project Component
Electrical System Upgrades $7,500,000 $9,900,000
Clearwell Pump Station Renovation $1,700,000 $2,400,000
New Above Grade Steel Water Storage Tanks $15,200,000 $19,600,000
Filter Renovation (Filter No.1) $2,000,000 $2,700,000
Chemical Conditioning System Rehabilitation $600,000 $900,000
Total Capital Costs $27,000,000 $35,500,000
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p Attachment 4
FILTER PLANT AND CLEARWELL
IMPROVEMENTS - PHASE 1A
DISTRICT PROJECT 7361
Engineering and Operations Committee Meeting
September 17, 2019
Jean-Marc Petit, PE
Director of Engineering and Technical Services
s
ORIGINAL PROJECT OBJECTIVES
• Improve reliability and performance of the
Recycled Water Facilities
Electrical Systems
Recycled Water (ReW) storage and
distribution (Central San and Zone 1)
Filtration
o Disinfection
• Maximize asset value of existing facilities
o Rehabilitate and/or repurpose
• Integrate with the Water Exchange Project and
Concord Community Reuse Project (CCRP)
r!2
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DP 7361 : FILTER PLANT AND CLEARWELL
IMPROVEMENTS PROJECT PROGRESSION TIMELINE
Board Authorized BCEs and 30%
Clearwell Cover Agreement with design Requesting
Failure Stantec for Planning Board to
of Filter Plant and authorize
Clearwell Project amendment for
2018 DP 7361 2019 Final Design
Board authorized Stantec Board
Recycled Water submitted authorized
Clearwell Repairs planning amendment for
Contingency level design Preliminary
Project report Design
3
INITIAL PHASED PROJECT APPROACH
Phase 1: (Estimated construction cost at$53 million)
• Replace electrical and distribution (2,400V to 480V)
• Rehab filter diversion structure (or provide an alternative new structure)
• New Applied Water Pump Station (AWPS) (decouple Forebay, eliminate
throttling)
• Filter rehabilitation (two out of four minimum)
• Upgrade chemical conditioning
• Upgrade filter controls
• Perform Clearwell (East and West) recommended improvements
• Chlorine Contact Basins (CCB) (two out of four)
Phase 2: When CCRP: (Estimated construction cost at$35 million)
• Provide booster pumps and additional storage for CCRP project on site,
if needed
• Upgrade remaining two filters
• CCBs (two additional CCBs)
4
CENT AL SAN
2
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MODIFIED PHASE 1
FOCUSING ON CRITICAL ELEMENTS
• Split Phase 1 recommendations:
• Phase 1A: Proceed with final design on elements of the
project that would not be impacted by a future Water
Exchange project
• Phase 1 B: Postpone improvement or rehabilitation of other
elements that could be impacted if a Water Exchange project
was to proceed
• Plan for, but do not include, elements of Phase 2 into
design which would be triggered and coordinated with
CCRP
5
IMPACT AND INTEGRATION OF REFINERY
RECYCLED WATER EXCHANGE PROJECT WITH
RECYCLED WATER PROJECT
Martinez
Refineries
4AA�
Immm*Iiiiiiiii
Contra Costa Transfer-Bethany
Water District Pipeline VQLl2y WO#er
South Bay
(proposed)
Aqueduct
6
CENTRALSAN
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WATER EXCHANGE TREATMENT TRAIN WORKSHOP
HELD ON JUNE 217 2019
•Central San invited some _
of the best and brightest
minds of the wastewater
industry to weigh in on the
most cost-effective = Y r
treatment train(s) to - —
produce Title 22 and
refinery-quality recycled
water supplies
•32 attendees with 13 PhDs
• Representatives from CCWD and Valley Water were
in attendance
oil
CENTRALSAN
WATER EXCHANGE TREATMENT TRAIN WORKSHOP
HELD ON JUNE 217 2019
• Morning session was
j� a
background and
afternoon session
u. included breaking into
four workgroups to
, - develop and present
- �- suggested treatment
f'> trains.
Some alternatives
would rely on the
upgraded filters while
others would favor
membrane
technologies.
I!8
4
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_ Clearwell:
Mechanical,
tructural and Failing
Electrical Equipment and _ East Cell Cleanvell
CVVPS Pu IP Coed Goe and Cover and Liners
S zing
Combined Storage
i' and CIz Contact
Filter Capacity and Basins Efficacy
Condition
Pipeline and Pipe
Electrical Power .
Distribution Voltage Supports Condition
.i and Reliability
..y Water Qualityand
Filler Building Ae® Hydraulic Bottleneck
•-� Condition and Code into Forebays
Upgrades
• Electrical Equipment;and `* Phase 1A
- AWPS Pump Condition and
Sizing
�Y
PROPOSED PHASE 1A SCOPE FOR
RECYCLED WATER PLANT FACILITIES
Upgrade/Replace Electrical Gear
• New CW Electrical Facility
Replace Switchgear 43 to 480V
• Add UW Pump e
• Recycled waterRecycled waterStoragee-
• Two new Above Grade
Steel Storage Tanks 'tl
f
Rehab 1 Filter(q3) R ,
Upgrade Chemical Feed £
Upgrade/Replace Electrical Gear
• New CW Electrical Facility
• Modify Substation 40-2400V
10
CENTRALSAN
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WHY NOW?
Meet Commitment for Recycled Water Service
• Electrical Safety (arc flash protection)
•We are a recycled water purveyor and provider (must
maintain a level of service to plant utility water and Zone 1
customers)
• Reliability of producing recycled water (electrical, recycled
water storage, chemical feed, and filter production)
•Water Exchange Project implementation window is 5-10
years
6and
Phase 1A improvements are required now independently
from the implementation of the Water Exchange Project
Ce
11
MANY CUSTOMERS RELY ON A
RELIABLE REW SUPPLY
• Reliance on Recycled Water by Users
• Utility Water for the Treatment Plant
• Zone 1 customers:
• City of Pleasant Hill _
• CC Golf Course
• Buchanan Field Golf Course ----
• Country Quarry 1 .e•��
• DVC =__
• Veranda,Willows
• Concord Hilton
• Animal Shelter - _ • _ — _-
• CoCo San Sustainable Farm
• Maltby Pump Station
• Auto Truck Fill Station
Residential Fill Stations
Maki a-
12
011ROTHIMT1111W.M6
6
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CURRENT REW VULNERABILITIES
IDENTIFIED RISK OF FAILURES
A. Electrical Power Distribution
B. ReW Storage and Delivery
C. Filter Production
13
CURRENT REW VULNERABILITIES
IDENTIFIED RISK OF FAILURES
A. Electrical Power Distribution
B.
C.
CENTRALSAN
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ELECTRICAL POWER DISTRIBUTION CONCERNS
• Transformers are on the road to failure
based on oil analysis
• Improve arc flash safety for critical gears
to reduce safety risk to electricians -
• Recent failures in 12kV feeder and
Substation 40-2400V buss bar
highlight concerns
• Medium voltage (2400V) power is
obsolete, inefficient and unnecessary for
the motor sizes needed for current and '
future demands
,5
MOTOR CONTROL CENTERS (MCC)
RELIABILITY AND SAFETY
CONCERNS
• MCC needs to be replaced; buss bars I-I
are arcing
• Arc flash protection is a significant
safety concern that must be remedied
• Medium voltage (2400V) power is
obsolete, inefficient and unnecessary
for the motor sizes needed for current _
and future demands
• MCCs for pump station are outdoors
and unprotected, reducing reliability
and making maintenance difficult in
inclement weather
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RECENT EVENTS IMPACTING PROJECT
TIMING AND PRIORITIZATION
1
On January 16,2019,Substation 40
located at the Filter Plant,experienced
On November 13,2018,a high-voltage(12kV) a failure which triggered a cascading
electrical feeder from Substation 82(Central San's series of events that led to a 16-minute,
main PG&E service)to Substation 40 failed. plant-wide power failure.
` 17
CENTRALSAN
PHASE 1A ELECTRICAL IMPROVEMENTS
New CW Electrical Equipment
• Transformer(12kV to 480V)
• MCCs
• VFDs _ _"
n R
a' 6r
Demo—Sub 40-2400V
18
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CURRENT REW VULNERABILITIES
IDENTIFIED RISK OF FAILURES
A.
B. ReW Storage and Delivery
r
J.
19
REW STORAGE/DELIVERY DEFICIENCIES
• East Clearwell cell out of commission due to
liner and cover failure
• West Clearwell cell now in service with a
floating cover system in as a temporary solution
• Currently no redundant storage available to
prevent ReW interruption
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CLEARWELL COVER AND LINER FAILURES
t.
ast Clearwell cell cover triggered
e tears and cover failures in
ber 2017
On July 7,2019,a car hit a Central San recycled
water hydrant on Marsh Drive,which triggered an
unexpected,high-demand on the recycled water
system,drawing the water level in the East Clearwell
cell down rapidly causing the cell cover to rip,
leading to its failure. This revealed excessive wear
on both the cover and liner in the East Clearwell cell. 21
CENTRALSAN
NEW WEST CLEARWELL CELL TEMPORARY
COVER COMMISSIONED ON AUGUST 9, 2019
Sand bags are being used to -
hold the existing liner in place.
22
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BUSINESS CASE EVALUATION (BCE)
AT CENTRAL SAN
• Engineering does a comprehensive BCE(s) on
all capital projects, including Phase 1A
• Since the last Board update, two BCEs were
finalized; these were disinfection and storage
• BCEs are done at a project and scope level
23
CENTRALSAN
EXAMPLE:
BCE FOR REW STORAGE
• RWS-1: Repairs or upgrades to the
existing Clearwell
• RWS-2: Repurpose the existing
Forebays to be used a Clearwell
�• RWS-3: Provide new storage using
two above-ground steel tanks �-
• RWS-4: Provide new storage using
two above-ground prestressed
concrete storage tanks = �`
• RWS-5: Status Quo, do nothing
alternative— Operate West Cell ;_
Clearwell with temporary cover
k24
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BCE FOR REW STORAGE
Alternative RWS-1: Alternative RWS-2:Ell=Alternative RWS-3: Alternative RWS-4: Alternative RWS-5:
r. I E P.r.le E.sli.. Install nevvAl—Grade torage F rebays into Recycled Water
ea (Base Case "eaj
Alternative, Tanks for Storage Storage Tanks
Capital Expenditure
Ca Ex in$M 2019 $9.20 $13.70 $12.60 $14.90 N/A
Least CapEx option Provides two active Provides new storage tanks Maximizes use of existing No CapEx required at this
storage cells and designed specifically to store infrastructure time
additional operational water.Can be isolated for
flexibility. cleaning andarecovered.
Protects the recycled water from
dust,birds,and sunlight,
Pros maintaining water quality.
Eliminates migratory birds
congregation over the Clearwell,
which has used a problem with
both degradation of water
quality and an increased hazard
for the airport.
This option would Clea-11 cells have a None Requires repumping with This option would require
require implementing poor and low CT higher head and energy cost. implementing RWS-2 or
RWS-2 or RWs-3 in the efficiency factor.In RWs-3 in the future and
future which would end order to have increase risk of failure for
up increasing the total redundancy,both cells the Clearwell and reliability
cost for implementing should be upgraded. of the Recycled Water
Cons this alternative by Requires seismic Supply.
about$4.9 M upgrade of divider wall.
Requires construction o
a 1 MG steel storage
tank for construction
sequencing
California Division of
Safety of Dams Hazard YES YES NO NO VES
Safety Required
Viable but not
ended
Staff Recommendation
re eAlternative Recommended Alternative
PHASE 1A REW STORAGE SOLUTION
Recycled Water
Storage Solution:
• Two new above
grade steel t:
Storage Tanks
inside East I
Clearwell cell r'
footprint
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September 17, 2019 EOPS Regular Committee Meeting Agenda Packet- Page 23 of 49
Page 22 of 25
CURRENT REW VULNERABILITIES
IDENTIFIED RISK OF FAILURES
A.
B.
C. Filter Production
27
FILTER DEFICIENCIES
Proceed with rehabilitation of one filter
under Phase 1A
• High solids loading produces short-filter
runs requiring frequent backwashes
and limits production capacity
• Filter production capacity is limited
• Filter media and underdrains need
rehabilitation
• Filter underdrain is outdated and
subject to upsets of the gravel layer,
which must be rebuilt to correct
• Balance between filter production, net --�.
filtration and energy cost
• Filter effluent piping and control valves
are undersized
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September 17, 2019 EOPS Regular Committee Meeting Agenda Packet- Page 24 of 49
Page 23 of 25
TOTAL PROJECT COST - PHASE 1A
TotalProject Component . .
Construction .
]II1111111111111lu Ali
Electrical System Upgrades $7,500,000 $9,900,000
Clearwell Pump Station(CWPS)Renovation $1,700,000 $2,400,000
New Steel Storage Tanks $15,200,000 $19,600,000
Filter • $2,000,000 $2,700,000
Chemical • $600,000 $900,000
Total Capital Costs $27,000,000 $35,500,000
2s
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PROJECT ALTERNATIVES
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September 17, 2019 EOPS Regular Committee Meeting Agenda Packet- Page 25 of 49
Page 24 of 25
PROJECT ALTERNATIVES/CONSIDERATIONS
The Board could consider several alternatives for the Filter Plant
and Clearwell Improvements Project— Phase 1A, as follows:
•Alternative 1: Further split Phase 1A project into three smaller
projects and spread their construction over several fiscal years
•Alternative 2: Proceed with Sub-Project: Construct upgrades to
Clearwell Pump Station and electrical distribution systems,
including conversion from 2400 V to 480 V; remove filters
•Alternative 3: Status Quo - Do Nothing Alternative
• These alternatives are not recommended
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CENTRALSAN
RECOMMENDED BOARD ACTIONS
Staff recommends the following:
• Authorize the General Manager to amend an existing
professional services agreement with Stantec
Consulting Services, Inc. to increase the agreement
ceiling from $1,540,000 to $3,078,000 for final design of
the Filter Plant and Clearwell Improvements - Phase 1A,
District Project 7361
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Page 25 of 25
QUESTIONS
33
BUSINESS CASE EVALUATION AT CENTRAL SAN
The following tasks are performed when preparing a Business Case Evaluation:
1. Evaluate specific project needs and drivers.
2. Conduct an in-depth evaluation of existing asset condition assessment and
determination of remaining life.
3. Evaluate whether to keep, maintain the existing assets, replace in kind,
and/or replace with new technology.
4. Conduct pilot testing of preferred technology when appropriate to validate
design criteria and risk.
5. Evaluate current and possible future regulatory drivers that would impact
the project and identified solutions.
6. Preliminary investigation as needed (geotechnical, survey, permitting,
environmental, etc.).
7. Prepare design alternatives based on prior information.
8. Prepare Capital Expenditure (CapEx)for each alternative.
9. Evaluate operation and maintenance for each alternative.
10. Prepare pro and cons for each alternative.
11. Prepare 20-year net-present value (lifecycle cost analysis)for each
alternative.
12. Present BCE to Executive Review Committee.
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CENTRAL SAN
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September 17, 2019 EOPS Regular Committee Meeting Agenda Packet- Page 27 of 49