HomeMy WebLinkAbout07. Authorize the General Manager to execute a proessional engineering services agreement with Hazen and Sawyer not to exceed $2,000,000 for final design services for Secondary Clairifier and Channel Improvements DP 100047Item 7.
BOARD OF DI RECTORS
POSIT ION PA PER
M E E T ING D AT E:F E B R UA RY 22, 2024
S UB J E C T: A UT HO R I Z E T HE G E NE R A L MA NA G E R TO E X E C UT E A P R O F E S S I O NA L
E NG I NE E R I NG S E RV I C E S A G R E E ME NT W I T H HA Z E N A ND S AW YE R I N
A N A MO UNT NO T TO E X C E E D $2,000,000 TO C O MP L E T E F I NA L D E S I G N
S E RV I C E S F O R T HE S E C O ND A RY C L A R I F I E R A ND C HA NNE L
I MP R O V E ME NT S, D I S T R I C T P R O J E C T 100047 (P R O J E C T ); A ND F I ND
T HE P R O J E C T I S E X E MP T F R O M T HE C A L I F O R NI A E NV I R O NME NTA L
Q UA L I T Y A C T (C E Q A)
S UB M I T T E D B Y:
MI C HA E L C UNNI NG HA M, A S S O C I AT E
E NG I NE E R
I NI T I AT I NG D E PART M E NT:
O P E R AT I O NS-P L A NT O P E R AT I O NS-
P R O C E S S C O NT R O L
RE V IE WE D B Y:NI T I N G O E L , O P E R AT I O NS O P T I MI Z AT I O N D I V I S I O N MA NA G E R
G R E G NO R B Y, D E P UT Y G E NE R A L MA NA G E R - O P E R AT I O NS
R oger S . B ailey
General Manager
IS S UE
T he B oard of D irectors’ (Board) authorization is required f or the General Manager to execute prof essional
engineering services agreements in an amount greater than $200,000.
B AC K G RO UND
C entral San’s secondary process is essential f or maintaining National P ollutant Discharge E limination
System regulatory compliance. T he secondary process has three main areas: aeration blowers which
supply air to activated sludge, aeration tanks where activated sludge consumes organic pollutants to
improve water quality, and secondary clarifiers where activated sludge is separated f rom secondary
ef f luent and recycled to aeration tanks as returned activated sludge. Secondary effluent is conveyed to
ultraviolet (UV) disinfection before being discharged to S uisun Bay or further treated f or recycled water
use.
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T he S team and A eration B lower S ystems Renovations, District P roject (D P) 7349 (Steam P roject)
completed condition assessments and comprehensive asset evaluations of the secondary process. T he
findings f rom these evaluations are being addressed in subsequent capital projects.
One overarching goal is to evaluate potential nutrient removal during design to avoid stranded assets if
C entral San were required to meet f uture nutrient limits.
T he recently completed Treatment Plant Piping Renovation - P hase 10, D P 7369 addressed immediate
needs on secondary clarif iers by replacing inlet gates and f ailed scum piping in clarifier feed channels. T he
Electric B lower I mprovements, D P 100015 (construction nearing completion) is adding electric blowers to
provide full redundancy to the existing steam blowers. T he Aeration Basins Diffuser R eplacement and
Seismic Upgrades - Phase 1, D P 100019 (in construction) will replace diffusers and complete mechanical
rehabilitation/replacement, concrete repairs, seismic upgrades, and structural repairs. T he Secondary
C larif ier and Channel I mprovements, D P 100047 (P roject) will extend the remaining useful lif e of the
secondary clarif iers and f eed/effluent channels by addressing aging infrastructure challenges identif ied in
the S team Project. F urthermore, the P roject will evaluate opportunities to improve resiliency, evaluate
potential nutrient removal opportunities during design to avoid stranded assets in the future, and optimize
performance and hydraulic capacity.
T he secondary clarifiers were built during the S tage 5A of the Treatment Plant Expansion, D P X3760 in
1973 and last rehabilitated as part of the S econdary C larif ier I mprovements, D P 7089 in 1998. T he
clarifier drives, which slowly rotate pipes to collect returned activated sludge at the bottom of the clarifier,
have wearable components that require the equipment to be rebuilt or replaced every 20 to 30 years. T he
measurements taken annually during preventative maintenance work suggest that the drives need to be
rebuilt or replaced in the near-term or continued operation could impact performance. T his Project will
rebuild or replace clarifier drives, repair concrete and coatings, replace drain gates and scum piping, etc.
Additionally, the f eed and effluent channels to each set of f our clarif iers will be inspected and rehabilitated.
Hazen and S awyer will complete the following evaluations to identify opportunities for improvements and
optimizations bef ore completing the f inal design:
C larif ier hydraulics and process optimization to develop options to improve the efficiency and
maximize the hydraulic capacity of existing clarif iers. T he overall goal is to match the wet weather
capacity of the new UV process (140 million gallons per day). UV D isinf ection Replacement and
Hydraulic I mprovements, D P 100012 is in final design. Models developed f or the evaluation will also
assist with clarif ier shutdowns required during inspection. To avoid stranded assets, potential
upgrades will also be modeled under a scenario where Central S an removes nutrients.
Split treatment evaluation to determine the role of existing clarifiers if Central S an installs nutrient
removal infrastructure in the existing UV channels after the completion of the new UV process.
Equipment and resiliency evaluations to compare options for improving the seismic resiliency of
clarifiers and upgrades to improve maintenance staff access to equipment.
C onsultant S election:
On S eptember 28, 2023, a request for proposal was publicly advertised and two consulting firms
responded with proposals. A f ter evaluating the proposals based on qualifications and scope, staf f invited
both the consulting f irms to participate in interviews on November 30, 2023. T he two consulting f irms were
C arollo Engineers and Hazen and S awyer. After the conclusion of the interviews, Hazen and Sawyer was
selected and scored as the top proposer and is, theref ore, recommended for the P roject.
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Project Tasks:
1. C omplete evaluations prior to the f inal design for hydraulic capacity, process optimization, split
stream, and equipment/resiliency improvements. T hese evaluations will develop a strategy to
optimize performance and avoid stranded assets if C entral San is required to remove nutrients.
2. F inal design will address aging inf rastructure challenges, improve reliability, and extend the useful lif e
of high value assets. I t may also include improvements identif ied in the evaluations.
C alifornia E nvironmental Quality Act (C E Q A)
Staf f has concluded that the Project is exempt f rom C E Q A under Central S an’s C E Q A Guidelines
Section 15301, since it involves repairs, maintenance, and minor alterations to an existing sewage facility
with no increase in capacity; and Section 15302, since it involves replacement of existing public facilities at
the same location and with the same purpose. Any capacity increases are f or non-growth inducing, wet
weather purposes. Approval of this P roject will establish the Board's independent f inding that this P roject
is exempt f rom C E Q A.
ALT E RNAT I V E S /C O NS I D E RAT IO NS
1. T he B oard may elect to postpone the P roject to a f uture fiscal year. However, this is not
recommended as various components of the secondary clarif ier equipment require rehabilitation or
replacement. T his alternative would delay opportunities to rehabilitate equipment to extend the usef ul
life. T his alternative is not recommended.
2. T he B oard may elect to only perform rehabilitation and repair and not evaluations or optimizations
prior to the f inal design. T his alternative may lead to a missed opportunity to improve clarif ier capacity
and performance during rehabilitation and replacement and could lead to stranded assets if C entral
San were required to remove nutrients. T herefore, this alternative is not recommended.
F I NANC IAL I M PAC T S
T he total estimated cost for the f inal design for the P roject is $2,300,000 which includes consultant
services for $2,000,000, staf f time, and contingency. Engineering services during construction is not
currently budgeted under this agreement. C entral San will negotiate the engineering services during
construction services with Hazen and S awyer when the P roject is awarded and request approval f rom the
Board as the P roject progresses. T he total estimated project cost listed in the budget book is
$10,000,000 and will likely increase as clarifier feed and ef f luent channels have been added to the Project
scope along with potential hydraulic capacity, process efficiency, and seismic resiliency improvements.
T here are adequate funds within the current budget and f uture budget for the f inal design of this Project.
C O M M I T T E E RE C O M M E ND AT IO N
T he E ngineering and Operations Committee reviewed this matter at its meeting on F ebruary 7, 2024 and
recommended approval.
RE C O M M E ND E D B O ARD AC T I O N
Staf f recommends the following B oard actions:
1. Authorize the General Manager to execute a professional engineering services agreement with
Hazen and S awyer in an amount not to exceed $2,000,000 f or the final design services f or the
Secondary Clarifier and C hannel I mprovements, D istrict Project 100047; and
2. F ind that the project is exempt f rom C E Q A.
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Strategic Plan Tie-I n
G O A L TW O: Environmental Stewardship
Strategy 1 - Achieve compliance in all regulations
G O A L S I X: I nfrastructure Reliability
Strategy 1 - Manage assets optimally, Strategy 2 - Execute long-term capital renewal and replacement program
G O A L S E V E N : I nnovation and Agility
Strategy 2 - I mplement organization-wide optimization
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