9.3. SR 01-21-2014 �i
EOty lk Request for Action
River
To Item Number
Mayor and City Council 9.3
Agenda Section Meeting Date Prepared by
Work Session January 21, 2014 Justin Femrite, P.E. City Engineer
Item Description Reviewed by
Discuss Wastewater Treatment Expansion Gary Leirmoe, Chief Operator
Matt Stevens,Lead Operator
Reviewed by
Cal Portner, City Administrator
Action Requested
Discuss current facility expansion design status and cost estimates.
Background/Discussion
Work continues on the final design of the Wastewater Treatment Facility (WWTF) expansion.
A number of conditions have changed with respect to options available to process and dispose of
biosolids since first discussing the project. These conditions have driven our team to look at different
options for biosolids processing and handling.
Our consultant will give an overview of the project,liquid stream design update, evaluation of biosolids
disposal options and discuss the updated cost estimate.
Financial Impact
The consultant will have an updated project cost estimate to review at the meeting.
Attachments
■ None
p 0 W I R I I a
ATURE
C icy of
r
Wastewater Treatment Facility
Update
January 21 , 2014
BCQLTON M P=
Consulting Engineers & Surveyors
Summary
• Overview of Original Project
• GRE Discussions
• Revised Liquid and Biosolids Options
• Revised Cost Estimate
BCC LTC::>N 8, M I N K , I N C®
Consulting Engineers & Surveyors
2
Original PrJ' ect
o
• Cost Estimate
— Liquid Stream = $ 10. 619 million
— Biosolids Stream = $0. 675 million
• Total Project Cost = $ 11 . 294 million
BC)LTC::>N 8, M I N K , I N C®
Consulting Engineers & Surveyors
3
GRE Discussions
• Met multiple times with GRE to discuss
options for biosolids treatment/disposal
• Four options evaluated
— Injection of biosolids into boiler (liquid and cake
product)
— Injection of biosolids into ductwork following
combustion chamber (liquid and cake product)
— Use liquid biosolids as makeup to bottom ash
system
— Deposit biosolids on ash conveyor or ash pile
BOLTON 8, MENK , INC.
Consulting Engineers & Surveyors
4
GRE Options
• Injection of biosolids into boiler
— Determined not feasible due to air permitting issues and
minimal energy benefit
• Injection of biosolids into ductwork following
combustion chamber
— Determined not feasible due to air permitting issues and
minimal energy benefit
• Use liquid biosolids as makeup to bottom ash system
— Determined not feasible due to potential health and
processing concerns
• Deposit biosolids on ash conveyor or ash pile
— Not feasible due to long term hauling costs for the City
BOLTON 8, M B N K , I NC®
Consulting Engineers & Surveyors
5
Revised Liquid and Bisofids
Options
• Abandoning GRE option impacts both liquid
and biosolids stream options
• Liquid stream changes
— All extended aeration facility ( larger tankage)
— Eliminate primary clarifiers and convert to selector
basins
— Eliminate trickling filters
— All other processes remain the same
BOLTON 8, MENK , INC.
Consulting Engineers & Surveyors
6
Biosofids Stream Options
• Liquid stream changes impact biosolids stream
• All aerobically digested for new process
• Land application options
— Liquid, cake or dry solids
• Liquid application is current method (3%
solids)
• Cake solids (screw press or centrifuge — 18%)
• Dry solids (dryer — 98%)
BOLTON 8, MENK , INC.
Consulting Engineers & Surveyors
7
Biosofids Options
• Cake Solids (approx. 18%)
— Screw press or centrifuge
— Reduce volume by 86% (compared to liquid )
— Range of costs - $2 .85 - $3 .7 million
• Dry Solids (approx. 98%)
— Dryer
— Reduce volume by 97% (compared to liquid )
— Range of costs - $7.7 - $11.0 million
BOLTON 8, MENK , INC.
Consulting Engineers & Surveyors
8
Revised Cost Estimate
• Liquid stream = $ 12 . 55 million
• Biosolids stream
— Cake solids = $2 .85 - $3 .7 million
— Dry solids = $7.7 - $11.0 million
• Total Project cost = $ 15 .40 — $23 . 55 million
BOLTON 8, MENK , INC.
Consulting Engineers & Surveyors
9
Phosphorous Grant
• Point Source Implementation Grant
• Grant only for phosphorous related items
• City awarded a $3 million grant ( max. )
• Grant is reduced by Essential Project Component
( EPC)
— Calculation of current loading divided by future loading —
ranges from 47% to 61%
• Reduces grant amount to approx. $2 . 3 to $3 .0 million
— Dependent on option chosen
• Final grant amount determined after bidding
BCC LTC::>N 8, M I N K , I N C®
Consulting Engineers & Surveyors
10
Recommendations
• All extended aeration facility
— Greater operational flexibility
— More consistent effluent
• Aerobically digested biosolids
• Cake solids ( 18%) processing
— Less product to haul/land apply (86% reduction )
— Greater operational flexibility
• Drying option ?
BOLTON 8, MENK , INC.
Consulting Engineers & Surveyors
11
Schedule
• Submit P/S to MPCA - March/April 2014
• Bid Opening - May/June 2014
• MPCA certify project by June 30, 2014
• Construction start - July 2014
• Construction complete - June 2016
BOLTON 8, MENK , INC.
Consulting Engineers & Surveyors
12