HomeMy WebLinkAbout5.A.6. Extension Agreement for Lift Station L-16 Emergency Operating PlanTO:
FROM:
SUBJECT:
DATE:
INTRODUCTION:
BACKGROUND:
CITY OF SHAKOPEE
Memorandum
Mayor & City Council
Mark McNeill, City Administrator
Bruce Loney, Public Works Director
Authorize an Extension Agreement for Lift Station L -16
Emergency Operating Plan
December 20, 2010
SR ,
C 7 r
Attached is an extension agreement from WSB & Associates, Inc. for Lift Station L -16
Emergency Operating Plan.
The City of Shakopee obtained ownership of a major lift station (L -16) from the Metropolitan
Council approximately three years ago. This lift station has been operated by MCES since 1971.
Earlier this year, staff reviewed the Emergency Operating Plan for L -16 lift station and
concluded this plan needed updating. Updating of this operating plan was included in the
sanitary sewer utility budget.
The reasons for updating the Emergency Operating Plan is due to changes in personnel, both
City and contractors and response time due to Rahr Malting coming off of the system. Other
items in the proposal would be to provide a large scale drawing for emergency operations on the
operation of the lift station and to evaluate the Supervisory Control and Data Acquisition
( SCADA) and flow meter. The SCADA system is to report above conditions in a timely manner
for emergency responses.
Finally, an evaluation of a comminutor to reduce pump plugging and an evaluation of demolition
of the old lift station building is included in the proposal.
The cost of the proposal is not -to- exceed $16,568.00 for all eight tasks and to be paid out of the
Sanitary Sewer Fund.
The Emergency Operating Plan and evaluation of other components of this lift station will assist
staff in managing this critical facility and for preparation of possible emergency situations.
ALTERNATIVES:
1. Authorize the appropriate City officials to execute the extension agreement for Lift
Station L -16 Emergency Operation Plan at a cost not -to- exceed of $16,568.00 and to be
funded out of the Sanitary Sewer Enterprise Fund.
2. Do not authorize this agreement.
3. Table for additional information.
RECOMMENDATION:
Staff recommends Alternative No. 1.
ACTION REQUESTED:
Authorize the appropriate City officials to execute the extension agreement for Lift Station L -16
Emergency Operation Plan at a cost not -to- exceed of $16,568.00 and to be funded out of the
Sanitary Sewer Enterprise Fund.
ENGR/2010- PROJECTS /2010- COUNCIUEXTENSION- AGREEMENT -L-16
nice Loney,
Public Works Director
WSB
& Associates, Inc.
Infrastructure ® Engineering ® Planning ® Construction
December 13, 2010
Mr. Bruce Loney, PE
Director of Public Works /City Engineer
Public Works Department
400 Gorman St.
Shakopee, MN 55379
Re: Proposal for Lift Station L16 Emergency Operating Plan
Sincerely,
WSB & Associates, Inc.
Thomas A. Roushar, PE
Senior Project Manager
Minneapolis • St. Cloud
Equal Opportunity Employer
701 Xenia Avenue South
Suite 300
Minneapolis, MN 55416
Tel: 763-541-4800
Fax: 763 - 541 -1700
Dear Mr. Loney:
WSB & Associates, Inc. (WSB) is pleased to submit this proposal to prepare an emergency operating plan for Lift
Station L16. As prime consultant, WSB will subcontract with Paul Kaeding, PE, of Barr Engineering. Paul will
evaluate the reliability of the electrical and control equipment including the motor control center, standby generator,
and the pump control system. He will provide recommendations to increase reliability if the existing equipment is
found lacking desirable reliability features. Paul will also evaluate upgrading of the station's SCADA system.
Attached to this letter is Exhibit A - Scope of Work which provides background information, WSB's understanding of
the emergency operating plan project, our approach to the project, and the work scope to be completed.
Compensation for services to complete the emergency operating plan will be in accordance with the hour estimates
outlined in Exhibit B, and according to WSB's agreement for professional services with the City of Shakopee.
WSB Project Team
Tom Roushar, PE - Project Manager
Joe Ward, PE - Project Engineer
Barritt Lovelace, PE - Structural Engineer
Paul Kaeding, PE - Electrical Engineer (Barr Engineering)
Merle Jewell - CAD Technician
WSB proposes to complete work on the Lift Station L16 emergency operating plan within 60 days of authorization to
proceed. This letter proposal represents our understanding of the project scope.
The City of Shakopee agrees to reimburse WSB & Associates, Inc. for these services in accordance with Section IV of
the Agreement for Professional Services. If this agreement meets your approval, please sign below and return one copy
to our office. Thank your for your consideration.
City Administrator
City Clerk
Mayor
Date
Mr. Bruce Loney, PE
December 13, 2010
Page 2
EXHIBIT A
SCOPE OF WORK
BACKGROUND INFORMATION
Station History
The City of Shakopee owned and operated a wastewater treatment facility (WWTF) from the early 1960s to 1971.
Many of the buildings and facilities of the WWTF, which was located at the end of Marschall Road, still exist and are
now owned by the Shakopee Valley RV Park. In 1971, the South Suburban Sanitary District constructed an interceptor
sewer from Shakopee to the Blue Lake WWTF and the City's WWTF ceased operating. The WWTF lift station was
retained by the sanitary district.
The Metropolitan Council was created by the state legislature in the late 1960s and subsequently acquired the assets of
the South Suburban Sanitary District which ceased to exist. From 1971 to 1998, the Metropolitan Council owned and
operated the Shakopee interceptor including the old lift station. Then, in 1998, the Metropolitan Council constructed a
new lift station —Lift Station L16 as it currently exists, which operated from 1998 to approximately three years ago
when they transferred ownership of the Shakopee interceptor to the City of Shakopee. In addition to Lift Station L16,
the Metropolitan Council also transferred ownership of the old lift station to the City.
Existing Station
Lift Station L16 is a modem, submersible lift station that is in good condition despite the fact that it has been in service
for 12 years. The major components of the lift station include:
• Wet well with three 2,200 gallon - per - minute (gpm), 125 horsepower, submersible sewage pumps
• Valve vault below the control room that contains the pump discharge header and the check valves and shut -off
valves for each of the three pumps The vault also contains an ultrasonic flow meter to measure the flow that is
being pumped.
• Control room that houses the motor control center including variable frequency drives (VFDs) and across -the-
line bypass starters for each of the pumps.
• Generator /equipment room that houses the standby generator, generator switchgear, and the HVAC equipment
for the station.
The old lift station is immediately north of Lift Station L16. No mechanical or electrical equipment is housed in it.
The old lift station's only remaining function is to provide emergency storage, should an emergency interrupt pumping
by Lift Station L16. A 24 -inch diameter overflow line runs from the wet well of Lift Station L16 to the old lift station.
If the level in the wet well should rise to the invert elevation of the 24 -inch overflow line, wastewater would be
diverted to the old lift station for temporary storage.
Downstream from Lift Station L16, the Shakopee interceptor consists of approximately 8,700 linear feet of single 16-
inch diameter PVC force main which discharges to a 36 -inch and 42 -inch diameter RCP gravity interceptor. The
gravity interceptor conveys Shakopee's wastewater from the force main to the Blue Lake WWTF for treatment. The
PVC force main, which was constructed during the period 1993 to 1997, is approximately 15 years old. The gravity
interceptor downstream of the force main was rehabilitated before ownership was transferred to the City. So, both of
these facilities are believed to be in good condition.
PROJECT UNDERSTANDING
Reliability Discussion
As noted above, Lift Station L16 has three 2,200 gpm pumps. On an average day, the lift station pumps approximately
800,000 gallons, which equates to approximately 550 gpm. During the recent flood, the lift station pumped a
maximum day flow of 2,000,000 gallons which equates to approximately 1,400 gpm. So, even under maximum flow
conditions, a single 2,200 gpm pump was adequate. Therefore, with three 2,200 gpm pumps, the lift station has
redundant pumping capacity and should be considered to be reliable from a pumping capacity standpoint.
The lift station has two electrical feeds - normal power from the Shakopee Public Utilities and an emergency on -site
standby generator. The standby power system includes an automatic transfer switch that continuously monitors the
Mr. Bruce Loney, PE
December 13, 2010
Page 3
normal power. Should normal power fail, the transfer switch will start the standby generator and transfer the station
operation from normal to standby power. Because of the dual power system, the lift station should be considered to be
electrically reliable.
Despite having redundant pumping capacity and two sources of power, the lift station pumps into a single discharge
header and then through a single force main. Should either the discharge header or force main fail, the lift station could
not pump wastewater flow. Eventually wastewater would either flow onto the ground surface or would back -up into
the lowest -lying basements. It is likely that wastewater would back -up into basements because the lowest lying
manholes have bolt -down, gasketed covers.
In addition to either discharge header or force main failure, a natural disaster such as a tornado could render the lift
station inoperable for an extended period of time.
Existing Deficiencies
WSB has identified the following existing deficiencies that diminish the reliability of the lift station:
• SCADA system doesn't always accurately report alarm conditions
• Pumps that are prone to plugging
When the Metropolitan Council owned and operated Lift Station L16, it was monitored by their SCADA system.
However, the lift station is no longer monitored by the Metropolitan Council system because the City has assumed
ownership and operation. The City's current SCADA provider is Omni which, in essence, is a cell phone system that
relies on cell phone technology. Alarm conditions aren't always being reported and the on -call person is not always
alerted.
Although there are three pumps in the lift station that provide redundant pumping capacity, the pumps often operate
partially plugged which reduces their pumping rate. The pumps are being plugged with rags that resemble disposable
pads. The City should attempt to identify the source of the rags and work with the responsible property owners to
eliminate them at the source. If the source of the rags cannot be identified, the City should consider installation of a
basket to catch the rags or a comminutor to grind the rags into pieces that the pumps will pass if found to be cost
effective and the plugging problems persist.
Although it doesn't affect the reliability of the lift station, another deficiency is related to the superstructure of the old
lift station. The superstructure of the old lift station which dates back to the early 1960s is in poor condition. The
masonry has started to spall, steel lintel plates are corroding, and the doors and windows are in poor condition. Because
the superstructure serves no useful purpose, it should be demolished. In conjunction with the demolition, the open
stairwells from the ground floor level to the lower level should be closed in with hatches.
Another deficiency of the lift station that doesn't affect its reliability is the ultrasonic flow meter. The rate of flow
reported by the meter is often erratic. Because the total volume of flow is calculated based on rate of flow, the daily
volume pumped readings may be inaccurate.
In addition to these existing deficiencies, other deficiencies may be identified during the course of developing the
emergency operating plan.
Scope of Emergency Operating Plan
WSB will evaluate emergency conditions and existing deficiencies that could affect the ability of Lift Station L16 to
pump wastewater. We will then develop an emergency operating plan to prevent or minimize service disruption during
each of the specific emergencies. Emergency conditions that will be evaluated include:
• Discharge header failure
• Force main failure
• Natural disaster such as a tornado that would take the lift station out -of- service for an extended period
• Pump control system failure
Mr. Bruce Loney, PE
December 13, 2010
Page 4
Existing deficiencies that will be evaluated include:
• Inadequate SCADA system
• Pump plugging
• Deteriorating old lift station superstructure
• Inaccurate ultrasonic meter
The emergency operating plan will address both flooding and non - flooding conditions of the Minnesota River.
APPROACH TO PROJECT
The Metropolitan Council prepared a detailed Operation and Maintenance (O &M) Manual for Lift Station L16. The
O &M manual is divided into three volumes as follows:
• Volume I - Facility Management, Operations & Maintenance
• Volume II - Manufacturer's Equipment Manuals
• Volume III - Programmer's Manual
Volumes II and III should be current because there have been no changes in equipment or method of operating. The
one exception to this statement may be the pump control system because it appears as if an ultrasonic system has been
installed to replace the bubbler system furnished at the time the station was constructed. Also, an ultrasonic flow meter
has been installed.
Volume I of the overall O &M manual is divided into three chapters as follows:
• Chapter 1: Facility Management
— Section 1.0 - Introduction
— Section 2.0 - Personnel
— Section 3.0 - Records
— Section 4.0 - Spill Reporting
— Section 5.0 - Response Times
— Section 6.0 - Emergency Response Program
— Section 7.0 - Safety
— Section 8.0 - Utilities
• Chapter 2: Operations
— Section 1.0 - Introduction
— Section 2.0 - Project Design Criteria
- Section 3.0 - Collection System
— Section 4.0 - Lift Station
— Section 5.0 - Force Main
• Chapter 3: Maintenance
— Section 1.0 - Introduction
- Section 2.0 - Maintenance Management
— Section 3.0 - Equipment Maintenance Requirements
- Section 4.0 - Valve, Gate, Other — Exercise Schedule
- Section 5.0 - Spare Parts
— Section 6.0 - Lubricants
— Section 7.0 - Painting
Mr. Bruce Loney, PE
December 13, 2010
Page 5
WSB has reviewed each of these chapters. Our comments follow.
Chapter 1: Facility Management
Section 2.0 - Personnel is out -dated because the City of Shakopee now owns and operates the lift station. This section
should be replaced with an updated one. The revised personnel section should also list the contact information of local
contractors or vendors who agree to be on -call for emergency repairs.
Section 5.0 - Response Times is also out -dated because Rahr is no longer on the system and, as evidenced by the recent
flood, 11I and peak flow rates have been reduced. Rahr leaving the system and the reduced I/I flow have increased
response times. Also, the River Interceptor system has been replaced with larger pipe with greater storage capacity.
This section should be revised.
Section 6.0 - Emergency Response Program is very general in nature and is totally out - dated because the Metropolitan
Council no longer owns and operates the lift station. Replacement of this section with a detailed, implementable
emergency operating plan will be the thrust of this project.
Chapter 2: Operations
Section 1.0 - Introduction includes a schematic of the lift station influent piping, the overflow piping from the wet well
to the old lift station, and the discharge force main. Neither the record drawings of the lift station construction nor this
schematic adequately show the piping. WSB recommends that a drawing be developed for the piping at the lift station.
The drawing should be complete with pipe size, direction of flow arrows, and invert elevations. A laminated copy of
the drawing should be hung on the wall of the lift station control room for reference, particularly during emergencies.
Section 2.0 - Project Design Criteria includes Table I -2 -2 -2 that provides a summary of collection system flows, but is
now outdated due to Rahr leaving the system, the reduction of I/I, and replacement of the River Interceptor system.
Although this table could be revised to reflect current conditions, the new values will appear in the revised response
time table of Chapter 1, Section 5.0. Therefore, it should not be necessary to revise this section.
Section 3.0 - Collection System also includes an outdated flow summary that could be revised, but as noted above, it is
not necessary to do so.
Section 4.0 - Lift Station is current because, with the exception of the flow meter and possible exception of the pump
control system, the equipment remains the same as originally installed.
Chapter 3: Maintenance
Section 2.0 - Maintenance Management references the Metropolitan Council maintenance management system.
Consequently these references are out - dated. However, the remainder of this section and the remainder of this chapter
are still appropriate maintenance procedures for maintaining the lift station.
WSB has not reviewed Volume II - Manufacturer's Equipment Manuals or Volume III - Programmer's Manual of the
overall O &M manual. However, with the exception of the flow meter and possible exception of the pump control
system, the equipment is the same as originally furnished. Consequently, with these exceptions, these volumes should
still be current.
SCOPE OF WORK
As discussed in the previous section, the following tasks will be completed in conjunction with the emergency
operating plan project. WSB's intention is to revise or replace the existing lift station O &M manual sections with the
new, updated information.
Task 1: Replace Volume I, Chapter 1, Section 2.0 - Personnel
This section will be replaced to reflect that the City of Shakopee personnel are now responsible for operating and
maintaining the Shakopee Interceptor. WSB's opinion is that the City should make arrangements with local contractors
and vendors for assistance with emergency repairs. If the City agrees with this approach, the contact information for the
Mr. Bruce Loney, PE
December 13, 2010
Page 6
contractor personnel should also be listed in this section. WSB will contact local underground contractors for
emergency force main repair. In addition, we will contact the following:
• Emergency Pumping: Northern Dewatering, Rain for Rent and Other Firms Identified
• Temporary Rental Generator Set: Zeigler, Inc.
• Electrical: Local Electrical Contractors
• SCADA: Servocal, Total Control and Other Firms Indentified
Task 2: Revise Volume I, Chapter 1, Section 5.0 - Response Times
As previously discussed, the response times presented in the current O &M manual are no longer accurate because Rahr
is off the system and I/I rates have been reduced. Also, the River Interceptor system has been replaced with larger pipe
that provides more system storage. WSB will work with the City to determine the elevation of the lowest lying
basements. We will then calculate the system storage below that elevation. The system storage and the maximum flow
rate during flood stage will then be used to determine the minimum response time. The maximum day flow during the
recent flood was 2,000,000 gallons. WSB will utilize that flow after correcting it for higher peaks such as those that
occur in the early morning and at dinner hour to determine minimum response time. An accurate determination of
minimum response time is important because it will define the time available to implement the emergency measures to
be undertaken.
Task 3: Replace Volume I, Chapter 1, Section 6.0 - Emergency Response Program
This section of the O &M manual is totally outdated and will be replaced in its entirety. WSB will work closely with
City staff to determine staff capability to deal with specific emergency conditions such as a break in the lift station
discharge header or the force main. For those emergencies that are judged to be beyond staff capability to deal with,
WSB will contact local vendors and contractors to determine what their response time would be and their willingness to
be on -call for such emergencies.
This section will contain detailed procedures for dealing with each of the emergency conditions identified during the
course of this project which on a preliminary basis include; discharge header failure, force main failure, natural
disaster, and pump control system failure.
The emergency operating plan will address both flooding and non - flooding conditions of the Minnesota River.
Task 4: Supplemental Drawing for Volume I, Chapter 2, Section 1.0 - Project Design Criteria
As noted, an accurate large -scale drawing of the lift station piping system would be beneficial during emergency
operations. WSB will develop the drawing with help from the City's engineering staff who will be asked to confirm
invert elevations.
Task 5: Evaluate Lift Station Electrical, New SCADA System and Flow Meter
WSB will evaluate the Lift Station L16 electrical and pump control systems. In addition we will evaluate a new
SCADA system. Because the lift station operates unattended, a SCADA system that accurately reports alarm conditions
in a timely manner is critical. If the alarm condition is not promptly reported to the correct person, response time will
be reduced. A worst case scenario would be no response time. The result could be an environmental spill or a claim
for property damage. As part of the emergency operating plan project, WSB will evaluate the existing SCADA system
to confirm that the existing system needs improvement to make it more realiable in detecting and reporting alarm
conditions. If improvement is found to be desirable, we will contact Omni to determine if the existing system can be
modified. We will also evaluate a new SCADA system for the lift station. WSB will make recommendations whether to
continue with the Omni system or replace it with a new system. We will prepare cost estimates for the
recommendations made.
The ultrasonic flow meter will also be evaluated to determine the cause of the erratic rate of flow readings. WSB will
evaluate the meter installation to determine whether it was installed in accordance with the manufacturer's
recommendations. Also, we will evaluate the instrumentation wiring to determine if it complies with the
manufacturer's recommendations. If the installation is found to be correct, WSB will rcommend that a service company
be hired to repair the meter.
Mr. Bruce Loney, PE
December 13, 2010
Page 7
Task 6: Evaluate Comminutor
Because of redundant pumping capacity in the lift station, the pump plugging problem is not as critical as the SCADA
system problem. However, the simultaneous plugging of pumps during a peak pumping time such as a flood event
could impact the lift station's capability to pump the peak flow. Also, when operating partially plugged, the pumps
consume additional power because of the reduced pumping rate. WSB will estimate the cost of staff time that is being
expended to pull and clear partially plugged pumps and the additional power consumption. Also we will prepare a cost
estimate for installation of a comminutor in the structure that receives flow from the East and West River Interceptors
and determine its operation and maintenance (O &M) cost. The cost of the additional staff time and power for the
existing situation will then be compared to the installation and O &M costs of the comminutor.
Task 7: Evaluate Old Lift Station Superstructure Demolition
WSB will also prepare a cost estimate for demolishing the old lift station superstructure and enclosing the existing
stairwell openings with hatches.
Task 8: Final Report
WSB will prepare a fmal summary report of the emergency operating plan, including recommendations and cost
estimates.
The emergency operating plan may make recommendations such as:
• Installation of suction piping in the wet well and a coupling on the piping in the air release manhole just outside
of the lift station to permit bringing in a portable pump to completely bypass the station. This measure would be
implemented in the event of discharge header break or the station being out of- service as the result of a natural
disaster such as a tornado.
• Installation of couplings in the air release manholes to allow for installation of temporary piping to pump around
a force main break.
• Keeping repair materials for the force main on hand, such as repair clamps, additional PVC pipe and couplings.
WSB will prepare cost estimates for all such measures recommended by the emergency operating plan.
Also, the final summary report will include recommendations and cost estimates to correct each of the following lift
station deficiencies:
• Inadequate SCADA system
• Pumps prone to plugging
• Deteriorating control building superstructure
• Inaccurate ultrasonic meter
The final summary report will address both flooding and non - flooding conditions of the Minnesota River.
Deliverables
The deliverables for the emergency operation plan project will include:
• Revised O &M Manual Sections:
— Volume I, Chapter 1, Section 2.0 - Personnel
— Volume I, Chapter 1, Section 5.0 - Response Times
— Volume I, Chapter 1, Section 6.0 - Emergency Response Program
• Lift station piping drawing to supplement Volume I, Chapter 2, Section 1.0 - Introduction.
• Final Report
Mr. Bruce Loney, PE
December 13, 2010
Page 8
WSB's fee estimate appears on the attached spreadsheet.
EXHIBIT B
FEE ESTIMATE
Task
Description
Labor Category and Estimated Hours per Task
Total Labor
Cost
Project
Manager
Project
Engineer
Structural
Engineer
Electrical
Engineer
CAD Tech
Clerical
Total
Hours
1
Replace Volume I, Chapter 1, Section 2.0 -- Personnel
4
8
4
16
$ 1,520.00
2
Revise Volume I, Chapter 1, Section 5.0— Response Times
2
8
4
14
$ 1,268.00
3
Replace Volume I, Chapter 1, Section 6.0 -- Emergency Response Program
8
40
16
64
$ 5,840.00
4
Lift Station Piping Drawing
2
8
10
$ 800.00
5
Evaluate Lift Station Electrical, New SCADA System and Flow Meter
2
4
10
16
$ 2,336.00
6
Evaluate Comminutor
2
8
2
4
16
$ 1,664.00
7
Evaluate Old Lift Station Demolition
2
8
10
$ 1,260.00
8
Final Report
4
4
16
24
$ 1,880.00
Total Estimated Hours
24
74
8
12
12
40
170
Hourly Billing Rate
$ 126.00
$ 96.00
$ 126.00
$ 170.00
$ 76.00
$ 62.00
Total Cost by Labor Classification
$ 3,024.00
$ 7,104.00
$ 1,008.00
$ 2,040.00
$ 912.00
$ 2,480.00
$ 16,568.00
Total Estimated Fee
$ 16,568.00
ESTIMATE OF HOURS AND COST
PROFESSIONAL SERVICES TO COMPLETE
LIFT STATION L16 EMERGENCY OPERATING PLAN
SHAKOPEE
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