ITEM 3.11 Amending Otsego Wastewater Master PlanOtSTY
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DEPARTMENT INFORMATION
Request for
City Council Action
ORIGINATING DEPARTMENT
REQUESTOR:
MEETING DATE:
Administration
City Administrator/Finance Director Flaherty
June 10, 2019
PRESENTER(s)
REVIEWED BY:
ITEM #:
Consent
Utilities Manager Neidermeier
City Engineer Wagner
Scott Schaefer, AE2S
3.11
STRATEGIC VISION
MEETS:
I THE CITY OF OTSEGO:
Master Plan.
Is a strong organization that is committed to leading the community through innovative
communication.
H
Has proactively expanded infrastructure to responsibly provide core services.
No
Is committed to delivery of quality emergency service responsive to community needs and
expectations in a cost-effective manner.
The City adopted the Wastewater Master Plan in January 2018. After the Plan was adopted, City staff
Is a social community with diverse housing, service options, and employment opportunities.
Priority List (PPL). In January 2019, the City approved the Preliminary Design Agreement with AE2S for the
Is a distinctive, connected community known for its beauty and natural surroundings.
AGENDA ITEM DETAILS
RECOMMENDATION:
City staff is recommending that the City Council approve a resolution amending the Otsego Wastewater
Master Plan.
ARE YOU SEEKING APPROVAL OF A CONTRACT?
IS A PUBLIC HEARING REQUIRED?
No
No
BACKGROUND/JUSTIFICATION:
The City adopted the Wastewater Master Plan in January 2018. After the Plan was adopted, City staff
submitted the Plan to the Minnesota Pollution Control Agency (MPCA) for project scoring on the Project
Priority List (PPL). In January 2019, the City approved the Preliminary Design Agreement with AE2S for the
East Wastewater Treatment Facility Solids Phase 1 Project (the Facility), as outlined in the Plan.
Scott Schaefer with AE2S presented to the City Council on May 28, 2019 an update regarding the design
progress of the Facility. The MPCA PPL was a topic of discussion during that presentation.
The attached Facility Plan amendment is intended to provide additional detail to the Plan to show the link
between the Facility project and the liquid treatment system, which is needed to appropriately score the
project with the PPL. MPCA had initial rejected the link, but further discussion has resulted in MPCA
allowing the link following a Facility Plan Amendment. This improvement in the score is anticipated to put
the project into the fundable range for a State Revolving Fund loan. The reduced interest rate loan is
anticipated to save Otsego ratepayers in excess of $1 million, even after accounting for slightly increased
project capital costs due to additional project requirements. A related letter to place the project on the PFA
Intended Use Plan has already been sent, and is attached to this packet.
SUPPORTING DOCUMENTS ATTACHED:
• Technical Memorandum —Wastewater Master Plan Amendment
• Resolution 2019-33
• Letter to MN Public Facilities Authority— Intended Use Plan
POSSIBLE MOTION
PLEASE WORD MOTION AS YOU WOULD LIKE IT TO APPEAR IN THEM I NUTES:
Motion to approve Resolution 2019-33, Amending the Otsego Wastewater Master Plan.
BUDGET INFORMATION
FUNDING: BUDGETED:
Fund #602 — Sanitary Sewer Utility Yes
0
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Technical Memorandum: Facility Plan Amendment
Otsego East WWTF Biosolids Facility
To: Kurt Neidermeier
Utility Manager
City of Otsego
From: Scott Schaefer, PE
AE2S
Date: June 3, 2019
Project No: P05409-2017-003
1 SUMMARY
The intent of this technical memorandum is to amend the Otsego Wastewater Master Plan (2018)
to provide additional detail for elements of the East Solids 1 (ESI) project related to control of
recycled phosphorus. This control will provide the operational tools to minimize the impact of
recycled phosphorus on the liquid treatment system's Biological Nutrient Removal (BNR)
system.
Facility Plan Amendment
City of Otsego, MN P05409-2017-003
Think Big. Go Beyond.) A www.ae2s.com
2 PROBLEM
Mechanical dewatering of waste activated sludge (WAS) will "recycle" dissolved phosphorus
(primarily phosphate) in the dewatering centrate. This phosphorus will be returned to the
beginning of the liquid treatment train and will shift the readily biodegradable biological oxygen
demand (rbBOD) to phosphorus ratio. Recycled phosphorus loads have long been recognized as
an issue for biological phosphorus (bio -P) removal systems ("True Confessions of the Biological
Nutrient Removal Process", S. Jeyanayagam, Florida Water Resources Journal, January 2005).
The rbBOD is needed to drive the bio -P, and too much phosphorus compared to the available
rbBOD will result in degraded bio -P performance. The performance of the system will be very
important in the future as load limits, coupled with growth, will reduce the effective effluent
concentration limit to approximately 0.2 mgTP/L (Master Plan Figure 3.2, Page 106, included
below).
3
25.0
to
no
20.0
10.0
REGULATORY LIMIT PROJECTIONS -EAST WVVTF
35
3.0
25
2.0
15
1.0
.0 .` -- -- — 05
5
- - -
0 S,DDO 10,0DD 15,000 20,ODD 25,0D0 30,000 35,000 40,000 45,060
Population
"BOD (Dec-Prtar), mg/L
TP (Jun -Sep, Seascnal RES), mg/L
TSS , mg/L
TP (LakePepin TM DL), mgfL
Ammcn is (Dec4.Iar), mg/L
Additionally, the phosphorus from the West WWTF will be "imported" to the East WWTF with
the hauled thickened WAS (TWAS). Chemically binding the dissolved phosphorus prior to
recycling the centrate will provide for improved bio -P operation, as well as, allowing for
economical use of chemical.
3 ADDITIONAL PROJECT ELEMENTS
Facility Plan Amendment
City of Otsego, MN P05409-2017-003
Think Big. Go Beyond. A AE www.ae2s.com
Jeyanayagam mentions three main ways to combat the influence of recycled phosphorus on
bio -P systems:
• "Equalizing recycle flows
• Scheduling sludge pro cessing/conditioning operations, and
• Treating the sidestreams"
Several approaches were considered for enhanced recycled phosphorus control. Scheduling of
sludge processing is the least likely scenario as this would require a major change to the
operational scheduling of the Otsego utilities staffing, which is currently weekday operation with
remote monitoring. Equalization and/or treatment of the recycle sidestream was the focus of
options. Struvite precipitation, similar to the St Cloud WWTF system, was considered, but the
WAS and/or TWAS is not anticipated to have sufficiently high levels of ammonia to allow for
struvite precipitation. Supplementing rbCOD was considered, but chemicals would need to be
added that are not currently used at Otsego's WWTFs. Alum or ferric will precipitate dissolved
phosphorus, and ferric is already in use at the East WWTF. Ferric dosing equipment will be
added to the project. The dosing equipment will either be added to the chemical room with the
polymer system, or site piping will be run across the East WWTF site from the existing ferric
area to the new Biosolids Building to allow for a consolidated ferric storage and pump location.
An additional operational feature will be added to manage the centrate. A centrate holding tank
will be added below the new Biosolids Building, which will allow for enhanced operational
control of the centrate recycle. The centrifuge system is planned for operation during regular
weekday shifts. The centrate holding tank will allow for centrate recycle to be evenly distributed
across time during a calendar day or even distributed across weekdays and into the weekend. The
centrate holding tank will also provide a location for chemical dosing, mixing, and reaction to
minimize the dissolved phosphorus recycle.
The Biosolids Building is planned to have the building structure constructed in a single phase
with equipment installation spread over multiple phases. The centrate tank will be underneath the
building and will be constructed in the initial phase. Ferric dosing will be included in the initial
phase for operational flexibility in the near term.
4 CONCLUSION
Recycled dissolved phosphorus can lead to effluent limit violations if not managed. The Otsego
ESI project will create a recycled phosphorus stream that has not previously existed, and current
and future effluent limits will require the mechanism(s) to manage the recycled phosphorus. A
ferric dosing system for the centrate recycle and a centrate holding/equalization tank are
recommended for inclusion in the project. Additional details of the layouts and configuration will
be further examined during preliminary design.
Facility Plan Amendment
City of Otsego, MN P05409-2017-003
Think Big. Go Beyond. A www.ae2s.com
CITY OF OTSEGO
COUNTY OF WRIGHT
STATE OF MINNESOTA
RESOLUTION NO: 2019-33
AMENDING THE OTSEGO WASTEWATER MASTER PLAN
WHEREAS, the Otsego City Council on January 22, 2018 held a Public Hearing and heard all persons
desiring to be heard on the matter and fully considered the same and subsequently adopted the Wastewater
Master Plan; and
WHEREAS, the City has submitted the Wastewater Master Plan to the Minnesota Pollution Control Agency
for project scoring and inclusion on the Project Priority List; and
WHEREAS, in order to improve the project scoring and fundability it is necessary to amend the Wastewater
Master Plan to show the link between the East Wastewater Treatment Facility Solids Phase 1 Project and the
liquid treatment system; and
WHEREAS, the Otsego City Council has reviewed the amendments to the Wastewater Master Plan.
NOW, THEREFORE, BE IT RESOLVED BY THE CITY COUNCIL OF THE CITY OF OTSEGO,
MINNESOTA:
The Otsego Wastewater Master Plan is amended to show the link between the East Wastewater
Treatment Facility Solids Phase 1 Project and the liquid treatment system.
2. That City staff with assistance from Advanced Engineering and Environmental Services, Inc.
(AE2S), are authorized to proceed with submitting the amended Wastewater Master Plan to the
Minnesota Pollution Control Agency, and that the Mayor and City Administrator are authorized to
execute the same.
ADOPTED by the Otsego City Council this 10th day of June, 2019.
ATTEST:
CITY OF OTSEGO
Jessica Stockamp, Mayor
Tami Loff, City Clerk
MOTION made by Council Member and SECONDED by Council Member
IN FAVOR:
OPPOSED:
CITY OF
Oi_ue
MINNESOTA
June 10, 2019
Ms. Kathe Barrett
PFA Loan Officer
MN Public Facilities Authority
1St National Bank Bldg., Suite W820
322 Minnesota Street
St. Paul, MN 55101-1378
RE: 2020 Clean Water Revolving Fund (CWRF) Intended Use Plan
Biosolids Building Project — City of Otsego, Minnesota
Dear Ms. Barrett:
Please accept this letter intending the City of Otsego as officially requesting replacement on the 2020
Intended Use Plan (IUP) as administered by the Minnesota Public Facilities Authority (PFA) in conjunction
with the Minnesota Pollution Control Agency. An application was previously sent to the MPCA for
placement on the 2020 Project Priority List (PPL) for the above referenced Project.
Project Description
The project is comprised of the East Solids 1 (ESI) project for design and construction at the Otsego East
Wastewater Treatment Facility (WWTF) as described in the Otsego Wastewater Master Plan (2018). The
project components are intended to expand the biosolids processing capability of the East WWTF as well as
for treatment of the biosolids from Otsego's West WWTF. The project components are described in detail as
follows:
• Biosolids processing and handling equipment/facilities with full redundancy
o Centrifuges (selected via piloting in late 2018)
■ Two of four units installed in ES 1(1 duty plus 1 redundant; 3 duty plus 1 redundant
at buildout)
o Half of chemical stabilization equipment installed with ES 1
o Full stabilized biosolids loadout garage
o Associated ancillary chemical systems (lime silos, polymer dosing equipment)
• Truck bay for interior unloading of West WWTF thickened waste stream (TWAS)
• Centrate and TWAS storage tanks and pumping
• Storage and maintenance garage
• Locker room with showers
• Break room / office -controls space
• SCADA (controls) upgrades
• Odor control (Biosolids Building and equipment replacement at Pretreatment)
• Electrical/HVAC/Plumbing
• Civil/site work
City of Otsego 113400 90th Street NE, Otsego, MN 55330 1 Tel. (763) 441-4414 Fax (763) 441-9163
Project Cost Estimate
The opinion of probable total project cost follows:
Mobilization / General Conditions
$737,000
Site Worl</ Civil Work
$862,000
Landscape Architectural
$190,000
Dewatering Equipment
$1,055,000
Chemical Stabilization Equipment
$2,015,000
Pumps, Piping, Conveyance
$478,000
Odor Control
$190,000
Structural/Architectural Building System
$3,751,000
Electrical/Instrumentation and Controls
$1,199,000
Mechanical $795,000
SUBTOTAL00i
Tax* $282,000
Construction Contingencies $1,127,000
CONSTRUCTION SUBTOTAL12,681,000
Engineering, Legal, Admin $2,254,000
pgrade to Geothermal
Pretreatment Odor Control Replacement** $145,000
*Tax is estimated based upon total project; biosolids equipment is
exempted, but other materials are still taxed.
**Separated due to anticipated cost through Reh;
31acement Fund.
The project is currently in the preliminary design phase, and project elements are being adjusted with the
intent of reducing the total project cost. The City of Otsego is respectfully requesting a loan in the total
amount of the project. The current opinion of total probable project cost is approximately $15,000,000, but
actual project costs will be dependent on future bid prices.
This is a very important project for the City of Otsego's wastewater system, and the City is committed to
securing any required funding. A low interest loan through the PFA would help mitigate the needed
wastewater rate increase and keep access affordable to the residents of Otsego.
City of Otsego 113400 90`j' Street NE, Otsego, MN 55330 1 Tel. (763) 441-4414 Fax (763) 441-9163
Project Schedule
The anticipated project schedule follows:
Activity
Date
■ Preliminary Design
Early 2019
■ Final Design
Late 2019
■ Bid Opening
February 2020
■ Initiate Construction Project
Spring 2020
■ Operational Completion
Late 2020*
■ Substantial Completion
Spring 2021
■ Final Completion
Summer 2021
* Completion dates will be set once design has progressed to a point that the difficulty of construction
can be more accurately gauged to determine completion dates.
On behalf of the City, I appreciate your consideration of this important project for the City of Otsego.
Should you have any questions or comments regarding either this request for placement of the project on the
2020 IUP or the project in general, please contact Kurt Neidermeier, Utilities Manager, (763) 428-9215, or
Scott Schaefer, Project Manager for AE2S, (763) 463-5036.
Sincerely,
Jessica Stockamp
Mayor, City of Otsego
c: Adam Flaherty, City Administrator / Finance Director
Kurt Neidermeier, Utility Manager
Scott Schaefer, P.E., AE2S
Gabriel Posteuca, P.E., MPCA
City of Otsego 113400 90' Street NE, Otsego, MN 55330 1 Tel. (763) 441-4414 Fax (763) 441-9163