HomeMy WebLinkAboutCC WORKSESSION 12142015
Work Session Agenda
Monday, December 14, 2015
5:30 p.m.
(food available at 5:15 pm)
1. Water Issue. Mark Casey, City Manager Presenting
Closed Session permitted by the attorney-client privilege (Minnesota Statutes, Section
13D.05, subdivision 3(b)) to discuss potential options for responding to 1,4 Dioxane
contamination in groundwater and related legal claims.
2. Undergrounding of Utilities. Todd Hubmer, City Engineer & Mark Casey, City Manager
Presenting
3. Splash Pad. Todd Hubmer, City Engineer Presenting
4. Succession Plan for Police Department. Mark Casey, City Manager Presenting
5. Goal Setting. Mark Casey, City Manager Presenting
6. Adjournment
Next Work Session–
City of St. Anthony
CITY COUNCIL WORK SESSION
City Council Chambers
November 30, 2015
Present:
Mayor & Council. Jerry Faust, Mayor; Hal Gray, Councilmember; Randy Stille, Councilmember; Jan Jenson,
Councilmember and Bonnie Brever, Councilmember.
Absent:
None
Staff:
Mark Casey, City Manager and Shelly Rueckert, Finance Director
Consultants:
Breanne Rothstein, City Planner, WSB
Call to Order:
Meeting called to order by Mayor Faust at 5:30 p.m.
Final Levy & Budget:
Staff presented a memo on the General Fund Budget/Levy, 2016 Proposed Budget PowerPoint and 2016 Budget
Document for Adoption. By consensus of the Mayor & Council, staff was directed to proceed with the proposed
levy increase of 3.76%.
Capital Improvement Plan:
Staff presented the 2016-2020 & 2021-2032 Capital Funds. By consensus of the Mayor & Council, the document
was accepted.
Transfers & Closing Funds:
Staff presented a draft Resolution authorizing the transfers and closing of specific funds and spreadsheet showing
the 2016 phase out options tools, resulting transfers, reversals of negative cash and use of excess fund balance.
Interviewing Commissioners:
Six applicants were interviewed. By consensus of the Mayor and Council, Mark Kalar, Marshall Lichty & Marcey
Westrick will be appointed to the Planning Commission for a three year term effective January 1, 2016. Scott
Bentz and Therese Bellinger will be appointed to the Parks Commission for a three term effective January 1, 2016.
Appoint Chairs and Vice Chairs:
By consensus of the Mayor and Council, Jim Gondorchin will be appointed Planning Commission chair, Dominic
Papatola will be appointed Planning Commission vice-chair and Scott Bentz will be appointed Parks Commission
chair.
Adjourn:
The meeting adjourned at 8:31 p.m.
Minutes respectfully submitted by Mark Casey, City Manager.
1.
W
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St. Anthony Village
3301 Silver Lake Road NE • St. Anthony, MN 55418
December 8, 2015
St. Anthony Village
1,4-Dioxane
City of St. Anthony Village
Hennepin and Ramsey Counties, Minnesota
WSB Project No. 3183-00
FEASIBILITY REPORT
ST. ANTHONY VILLAGE 1,4-DIOXANE FEASIBILITY STUDY
FOR THE
CITY OF ST. ANTHONY VILLAGE, MINNESOTA
December 8, 2015
Prepared By:
WSB & Associates, Inc.
701 Xenia Avenue South, Suite 300
Minneapolis, MN 55416
763-541-4800
763-541-1700 (Fax)
1,4-DIOXANE PROJECT
FEASIBILITY REPORT
CITY OF ST. ANTHONY VILLAGE
WSB PROJECT NO. 3183-00
CERTIFICATION
I hereby certify that this plan, specification, or report was prepared
by me or under my direct supervision and that I am a duly
Licensed Professional Engineer under the laws of the State of
Minnesota.
Greg F. Johnson, PE
Date: December 8, 2015 Lic. No. 26430
1,4-DIOXANE PROJECT
FEASIBILITY REPORT
CITY OF ST. ANTHONY VILLAGE
WSB PROJECT NO. 3183-00
TABLE OF CONTENTS
TITLE SHEET
CERTIFICATION SHEET
TABLE OF CONTENTS
1. EXECUTIVE SUMMARY ..................................................................................................... 1
2. INTRODUCTION ................................................................................................................... 2
2.1 Authorization ................................................................................................................ 2
2.2 City Standards and Objectives ...................................................................................... 2
2.3 Study Scope .................................................................................................................. 2
2.4 Background ................................................................................................................... 2
3. EVALUATION OF OPTIONS .............................................................................................. 4
3.1 Option 1: Blend City Wells .......................................................................................... 4
3.2 Option 2: Construct Deeper Mount-Simon Hinckley Wells ........................................ 6
3.3 Option 3: Purchase Water from Minneapolis Water .................................................... 9
3.4 Option 4: Purchase Water from St. Paul Regional Water .......................................... 12
3.5 Option 5: Implement a Water Treatment System for Dioxane .................................. 13
4. COMPARISON OF OPTIONS ............................................................................................ 19
Appendix A
Preliminary Analysis of Providing Water to Saint Anthony Village Memorandum
Appendix B
St. Anthony Village UV-AOP Pilot Project Trojan UBPhoxTM Advanced Oxidation
System Pilot System Test Report
Appendix C
Evaluation of Hydrogen Peroxide with Ozone and Bioremediation for Treatment of
Dioxane
Appendix D
Cost Estimates
1,4-DIOXANE PROJECT
FEASIBILITY REPORT
CITY OF ST. ANTHONY VILLAGE
WSB PROJECT NO. 3183-00
1. EXECUTIVE SUMMARY
The St. Anthony Village City Council authorized WSB & Associates, Inc. to study the
available options to address 1,4-Dioxane (Dioxane) that has been detected in the City’s
water supply and provide a long term, reliable source of potable water that meets all the
recommended State and Federal health guidelines. This Feasibility Report summarizes
these options. There may be sources of third-party funding to pay for some or all of the
costs associated with remedial action to address the Dioxane contamination. This
Feasibility Report does not attempt to assess the likelihood or scale of such funding, and
does not evaluate remedial options based on funding source or amount.
Dioxane has been detected in the City’s three drinking water wells since March 2015,
likely emanating from the Twin Cities Army Ammunition Plant in Arden Hills (TCAAP).
Dioxane is used to stabilize chlorinated solvents and can be found in personal care
products, laundry detergents, and food in small amounts. TCAAP used Dioxane as an
additive in the solvents used at the facility. Other contaminants from TCAAP have been
detected since the early 1980s in the aquifers supplying groundwater for the City. In
contrast, Dioxane was recently classified as an emerging contaminant by the
Environmental Protection Agency (EPA), and testing for Dioxane in the aquifers below
the City first occurred in March 2015.
This report summarizes five options that were selected for analysis as possible means to
address Dioxane in the City’s drinking water:
• Option 1 – Blend the existing wells;
• Option 2 – Construct deeper Mount -Simon Hinckley wells;
• Option 3 – Purchase water from Minneapolis Water;
• Option 4 – Purchase water from St. Paul Regional Water; and
• Option 5 – Implement treatment to remove Dioxane.
During initial screening, Options 1 and 4 were determined to be either ineffective and/or
clearly inferior to other measures, and were therefore not analyzed in detail. Costs were
evaluated for Options 2, 3, and 5 as these were the options that were determined to be
most feasible. A 3.5% inflation rate was assumed for the O&M costs to match other
programs within the City. The total estimated 20-year capital cost s and operation and
maintenance costs for each of these options is as follows:
Option
Estimated
Capital
Cost
Finance
Cost
(4%
Interest)
Estimated 20-
Year O&M
Cost
(3.5% inflation
rate)
20-Year Cost
of
Purchasing/
Producing
Water
Estimated
Total 20-
Year Cost
2 $7,115,600 $3,356,000 $2,812,300 $4,954,000 $18,237,900
3 $9,480,300 $4,471,200 $4,487,800 $17,472,000 $35,911,300
5 $7,177,600 $3,385,200 $1,080,200 $4,954,000 $16,597,000
1,4-DIOXANE PROJECT
FEASIBILITY REPORT
CITY OF ST. ANTHONY VILLAGE
WSB PROJECT NO. 3183-00 PAGE 1
2. INTRODUCTION
2.1 Authorization
The St. Anthony City Council authorized WSB & Associates, Inc. to study the available
options to address 1,4-Dioxane (Dioxane) that has been detected in the City’s water
supply and provide a long term, reliable source of potable water that meets all the
recommended State and Federal health guidelines. This Feasibility Report summarizes
these options.
2.2 City Standards and Objectives
The City of St. Anthony Village has the following Standards and Objectives as they
relate to providing drinking water for its residents and customers:
1. Provide safe, reliable, and high quality drinking water for its residents and customers
2. Provide adequate quantities of water for fire protection and maximum day demands
3. Provide a robust drinking water system that can withstand the test of time
4. Maintain its own destiny and control
5. Be environmentally responsive
6. Be fiscally responsible
2.3 Study Scope
This report summarizes five options that were selected to address Dioxane in the City’s
drinking water:
• Option 1 – Blend the existing wells;
• Option 2 – Construct deeper Mount-Simon Hinckley wells;
• Option 3 – Purchase water from Minneapolis Water;
• Option 4 – Purchase water from St. Paul Regional Water; and
• Option 5 – Implement treatment to remove Dioxane.
2.4 Background
Trichloroethylene (TCE) has been detected in the City’s water supply since the 1980’s
and this contaminant is currently being treated at the City’s water treatment plant.
Dioxane testing in St. Anthony wells first occurred in March of 2015 by the Minnesota
Department of Health. This testing was initiated in response to the presence of Dioxane
at levels higher than the Health Risk Limit (HRL) in nearby municipal supply wells.
This testing indicated that Dioxane is currently present in the City’s three drinking water
wells. In addition to the MDH testing, the City has been testing for Dioxane monthly
since March of 2015. The results of the Dioxane tests are shown in Table 1.
1,4-DIOXANE PROJECT
FEASIBILITY REPORT
CITY OF ST. ANTHONY VILLAGE
WSB PROJECT NO. 3183-00 PAGE 2
Table 1: Dioxane Concentrations in City Wells
Date Well No. 3 Well No. 4 Well No. 5
March 2015 Not Sampled 0.90 ppb 0.57 ppb
June 2015 0.37 ppb 1.5 ppb Not Sampled
August 2015 0.34 ppb 1.5 ppb 0.99 ppb
September 2015 0.41 ppb Not Sampled (*) 1.0 ppb
October 2015 0.39 ppb Not Sampled (*) 0.94 ppb
November 2015 0.32 ppb Not Sampled (*) 0.99 ppb
(*) Not sampled because well has been shut down
Dioxane is used to stabilize chlorinated solvents and can be found in personal care
products, laundry detergents, and food in small amounts. The TCAAP in Arden Hills
used Dioxane as an additive in the solvents used at the facility and has been identified as
the source of the contamination into the aquifer. The current Dioxane concentration at
TCAAP has recently been detected as high as 60 parts per billion (ppb).
Dioxane is classified as an emerging contaminant by the Environmental Protection
Agency (EPA). Currently, there is not an established Maximum Contaminant Level
(MCL) for Dioxane. However, the EPA has identified thresholds of 3.5 parts per billion
(ppb) to prevent a 1:100,000 increase in cancer risk level and 0.35 ppb to prevent a
1:1,000,000 increase in cancer risk level.
At least one EPA region has recommended 0.35 ppb as the appropriate limit for Dioxane.
At the state level, allowable levels of Dioxane in drinking water have been established.
The Minnesota Department of Health (MDH) has recommended keeping exposures at or
below a health risk limit (HRL) of 1 ppb over a lifetime. Similarly, the states of
California and Massachusetts have established recommendations at 1 ppb and 0.3 ppb,
respectively.
The City currently operates three groundwater wells (Well No s. 3, 4, and 5) to supply the
City’s drinking water. Until the City recently stopped using Well No. 4, t he City was
operating two wells full time with the third well for peaking and back up when one of the
other wells was out of service for repair and maintenance. Having one current well with
high levels of 1,4 Dioxane is now burdening t he City’s daily operations. Test results by
the MDH, independently verified by the City, have shown the presence of Dioxane in the
City’s wells. The concentrations have ranged from 0.35 ppb in Well No. 3 to 1.5 ppb in
Well No. 4. The concentrations detected in Well No. 4 have increased when compared to
the previous test results.
1,4-DIOXANE PROJECT
FEASIBILITY REPORT
CITY OF ST. ANTHONY VILLAGE
WSB PROJECT NO. 3183-00 PAGE 3
3. EVALUATION OF OPTIONS
The City’s ability to operate its municipal drinking water supply system has been
impacted by the presence of Dioxane at levels over 1ppb in Well No. 4. The uncertainty
of future impacts to the remaining two wells by Dioxane has initiated the need for the
City to evaluate alternatives to provide dependable safe supplies of water to the public at
levels less than 1 ppb.
This report summarizes five options that were selected for analysis as possible means to
address Dioxane in the City’s drinking water:
• Option 1 – Blend the existing wells;
• Option 2 – Construct deeper Mount-Simon Hinckley wells;
• Option 3 – Purchase water from Minneapolis Water;
• Option 4 – Purchase water from St. Paul Regional Water; and
• Option 5 – Implement treatment to remove Dioxane.
Descriptions for each option, the benefits and costs are provided below:
3.1 Option 1: Blend City Wells
The first option is to blend the City’s three existing groundwater wells prior to
distribution in an effort to dilute the higher concentrations of Dioxane to acceptable
health levels.
Description
St. Anthony draws its drinking water from three wells, labeled Well Nos. 3, 4, and 5
(Well Nos. 1 and 2 were taken out of service and abandoned). Well Nos. 4 and 5 draw
water exclusively from the Jordan Aquifer, while Well No. 3 is screened to draw water
from both the Jordan and Prairie du Chien Aquifers. To meet the City’s water needs, the
City must have two wells operating at any given time, and sound management also
requires having the third well available as a backup during maintenance of other wells, or
in the event of an emergency.
Historically, the City would rotate usage of the wells. Since the installation of the
Carbon plant , the City has primarily depended on the operation of Well Nos. 4 and 5, as
the operation of Well No. 3 appears to deplete the carbon in the filters at a more rapid
rate than the use of the other two wells
The current wells are not equipped with Variable Frequency Drives (“VFD s”), meaning
that water is drawn at equal flow rates from the two wells that are operating. This limits
the ability of the current operation to blend water from the wells in a controlled and
efficient manner.
1,4-DIOXANE PROJECT
FEASIBILITY REPORT
CITY OF ST. ANTHONY VILLAGE
WSB PROJECT NO. 3183-00 PAGE 4
The concentrations of Dioxane have varied between Well Nos. 3, 4, and 5, with Well
Nos. 3 and 5 staying below 1 ppb, and Well No. 4 exceeding 1 ppb. The City has not
used Well No. 4 since Dioxane levels detected in this well exceeded 1.0 ppb.
Well Nos. 3 and 5 could be blended to reduce the total concentration of Dioxane in Well
No. 4 to below 1 ppb at the point of consumption. The long term viability of blending is
unknown as Dioxane concentrations may increase to levels that prohibits blending.
The City is currently blending Well Nos. 3 and 5 to keep Dioxane concentrations below 1
ppb. However, Well No. 3 is currently in need of rehabilitation, which would require
taking it out of service for a number of months. The City does not currently have a viable
means to blend Wells No. 4 and 5 to keep Dioxane below 1 ppb during the rehabilitation
of Well No. 3. The City may need to add VFDs to the existing wells in order to control
the blending process, provide flexibility in the use of the existing wells, and control the
concentration of Dioxane into the system.
Advantages
This option would provide the following advantages:
1. Minimal additional capital costs and operator training
2. Can be done immediately
3. Addition of variable frequency drives for pumps could provide better blending
4. Buys time while longer -term solutions are evaluated and implemented and MCL
regulations are further updated
Disadvantages
This option would provide the following disadvantages:
1. There is a reasonable likelihood that the Dioxane concentration in the City’s
aquifer could increase over time based on historical concentrations and trends (see
Table 1 in Section 2.4). As stated previously, the concentrations detected at the
TCAAP are as high as approximately 60 ppb and the concentrations detected in
the City wells has increased over the short time period the City has been
monitoring.
2. If the MDH establishes an MCL for Dioxane at or near 1 ppb, the City will be left
without a technology to effectively meet the future regulations. Dioxane is
currently classified as an emerging contaminant, meaning not enough information
is known on the contaminant and an MCL has not yet been established. It is
expected that the EPA will continue to study this contaminant and could set an
MCL at some point in the future. Blending the water could be only a short term
solution depending on a future MCL that could be established by the EPA.
3. The City currently has Well No. 4 shut down because the Dioxane concentration
in this well now exceeds the MDH’s recommended health risk limit . Although it
is unknown until additional sampling and laboratory results become available;
1,4-DIOXANE PROJECT
FEASIBILITY REPORT
CITY OF ST. ANTHONY VILLAGE
WSB PROJECT NO. 3183-00 PAGE 5
there is a reasonable likelihood that the contaminant plume will eventually move
towards Well Nos. 3 and 5 and produce higher concentrations of Dioxane as these
wells are used to pump more water from the aquifer. This condition could also
prohibit blending depending on the concentrations of Dioxane detected over time.
4. Blend ing the well water would not remove Dioxane from the environment like
other treatment options. Blending the well water reduces the concentration at the
point of consumption but the overall concentration within the environment would
remain untreated.
5. The manganese levels in Well No. 3 are the greatest of the three wells. Therefore,
pumping this well at a higher rate to blend and reduce the Dioxane concentrations
in the blended water would increase the manganese levels that are treated by the
water treatment plant. Shorter filter runs would be experienced because of the
higher manganese concentrations. This would require the filters to be
backwashed more frequently and higher chemical dosages would be required to
oxidize and treat the higher levels of manganese at the water treatment plant.
6. Blending the City’s wells could become more complicated in the future when
Well No. 3 requires major rehabilitation. Well No. 3 has been grandfathered-in as
a multi-aquifer well and the DNR no longer allows multi-aquifer wells to be
constructed. The DNR may not allow major rehabilitation or redesign to be done
to this well. T herefore, a new well may need to be constructed that could produce
higher concentrations of Dioxane.
7. Because of aquifer limitations, at least three wells must always be operable to
provide firm capacity and supply adequate volumes of water for the City’s
demands. If one well goes down, with only two wells in service blending could
be prohibited.
Estimated Capital and Long Term O&M Costs
The City well pumps are not equipped with VFDs that would allow the pumping rates to
be varied as needed to optimize blending. The wells can be manually throttled to adjust
the pumping rates, resulting in reduced capacity and consumption of additional energy.
This option does not appear to be feasible as concentrations of Dioxane in the City's wells
are likely to exceed 1ppb at which point blending will no longer provide drinking water
below 1 ppb. Ultimately, this option does not have the ability to reduce Dioxane
concentrations should they increase in the City’s wells in the future. Therefore, estimated
capital and O&M costs to implement Option 1 were not further studied.
3.2 Option 2: Construct Deeper Mount-Simon Hinckley Wells
The second option analyzed was to construct and utilize deeper Mount -Simon H inckley
wells instead of the Jordan Aquifer wells that are currently being used by the City. The
1,4-DIOXANE PROJECT
FEASIBILITY REPORT
CITY OF ST. ANTHONY VILLAGE
WSB PROJECT NO. 3183-00 PAGE 6
City of New Brighton is currently using the Mount-Simon Hinckley Aquifer to supply its
water system.
Description
The Mount -Simon Hinckley Aquifer is the deepest bedrock formation in the Twin Cities
and at a significantly deeper depth than the Jordan Aquifer. This aquifer is confined and
less suscept ible to surficial contaminants such as Dioxane that exists in the Jordan
Aquifer. Options were analyzed to convert the existing wells into deeper Mount-Simon
Hinckley wells or drill new wells into the Mount-Simon Hinckley Aquifer.
New Mount-Simon Hinckley wells can potentially be drilled although it is very
uncommon for the DNR to approve them. The State of Minnesota currently has a
moratorium that restricts the use of the Mount -Simon Hinckley Aquifer in the Twin
Cities Metropolita n Area. Therefore, the DNR does not issue appropriation permits to
cities to pump groundwater from this aquifer.
The City would be required to receive a variance from the DNR before this option could
be fully analyzed. There is no guarantee that the DNR would issue a variance for these
wells to St. Anthony Village. Variances are provided only when no other water supply
options exist for a public water system.
Well No. 4 in St. Anthony Village cannot be converted into a deeper Mount-Simon
Hinckley well because a 10-inch casing would need to be installed inside the existing 18-
inch casing to comply with the Minnesota Well Code. The 10-inch casing would not
allow a large enough well pump to be installed inside the well to produce the needed
capacity to make this option feasible. Well Nos. 3 and 5 could potentially be converted
to Mount-Simon Hinckley wells; however, this option is not cost effective since it would
require the open hole at that base of the existing Jordan wells to be completely grouted.
This is very costly and difficult from a constructability standpoint.
Advantages
This option would provide the following advantages:
1. The Mount Simon-Hinckley Aquifer does not contain any known concentrations
of TCE or Dioxane.
2. The Mount -Simon Hinckley Aquifer is better confined and protected from other
potential contaminants or sources of surface contamination compared to the upper
aquifers (Jordan Aquifer , etc.).
3. The City of St. Anthony would maintain control of its water production and water
rates.
Disadvantages
This option would provide the following disadvantages:
1,4-DIOXANE PROJECT
FEASIBILITY REPORT
CITY OF ST. ANTHONY VILLAGE
WSB PROJECT NO. 3183-00 PAGE 7
1. The Mount -Simon Hinckle y Aquifer is likely to contain concentrations of radium
that exceed the EPA MCL for combined Radium 226+228.
o Radium is required to be removed from drinking water to below the MCL.
The City’s existing treatment system, specifically the greensand filters,
would remove most of the radium.
o Once the radium is removed, it will accumulate on the filter media,
making the media radioactive.
o Radium cannot be effectively backwashed from greensand media, so the
media would need to be replaced on a more frequent basis to reduce the
plant operators’ exposure to the radioactive media.
o Disposal of radioactive media is expensive and very few landfills across
the country will accept the material.
o The water treatment plant HVAC systems would likely need to be
increased in size and modified to provide more air changes throughout the
day as the radium will decay to radon gas.
o The air quality within the treatment facility could be become hazardous
when radon is emitted into the air. This has been found to occur during
filter backwashing when the radioactive filter media is cleaned.
2. The average static water levels in the Mount-Simon Hinckley Aquifer are
approximately 125-feet deeper than the static water levels in the Jordan Aquifer in
the area of St. Anthony Village. As a result, larger well pumps would be required
inside the Mount-Simon Hinckley Wells to pump water from its deeper water
levels. This would increase the City’s electrical utility costs.
3. Constructing and pumping deeper Mount-Simon Hinckley Aquifer wells could
produce groundwater well interference with the City of New Brighton’s water
supply wells. Currently, the City of New Br ighton is utilizing Mount -Simon
Hinckley wells that were constructed before the state moratorium went into effect
for the Mount-Simon Hinckley Aquifer in the Twin Cities. The groundwater
interaction at this aquifer depth was unknown at the time of this study, and
extensive groundwater modeling would be required to predict the potential
interference effects between these wells.
4. It would likely take the DNR at least two years to evaluate and approve the use of
the Mount -Simon Hinckley Aquifer and another one to two years to design and
construct new Mount -Simon Hinckley wells. The City would continue drinking
Dioxane from existing wells during this time.
Estimated Capital and Long Term O&M Costs
Estimated capital and long term O&M costs were based on present worth analysis on the
assumption that the capacity of the Mount-Simon Hinckley Aquifer is less than the
existing capacity of the Jordan Aquifer wells within the City. Therefore, four Mount-
Simon Hinckley wells were assumed to be needed to meet the City’s water demand s.
1,4-DIOXANE PROJECT
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CITY OF ST. ANTHONY VILLAGE
WSB PROJECT NO. 3183-00 PAGE 8
The total estimated cost for Option 2, including contingency and indirect costs, is shown
in Table 2 along with the O&M costs over a 20 year life cycle. A detailed cost estimate
for Option 2 can be found in Appendix D.
Table 2: Option 2 Estimated Costs
Estimated
Capital Cost
Finance
Cost (4%
Interest)
Estimated 20-Year
O&M Cost
(3.5% Inflation
Rate)
20-Year Cost
of
Purchasing/
Producing
Water
Estimated Total
20-Year Cost
$7,115,600 $3,356,000 $2,812,300 $4,954,000 $18,237,900
3.3 Option 3: Purchase Water from Minneapolis Water
The third option analyzed was to purchase water on a wholesale basis and receive treated
water directly from Minneapolis Water through a connection to the City's water
distribution system.
Description
Minneapolis Water treats water supplied from the Mississippi River and distributes
drinking water to the City of Minneapolis and other surrounding communities. This is a
very large and complex water system that dates back to 1867. The main treatment
processes include filtration, disinfection, sedimentation, and filtration. Minneapolis
produces an average of 57 million gallons per day.
Minneapolis Water Pipeline 16 runs from the Hilltop Reservoir along the western border
of St. Anthony Village. This watermain has a capacity of over 40,000 gallons per minute
(gpm) according to Minneapolis Water staff. This pipeline can be connected to the City
of St. Anthony’s water system to meet the City’s water demands.
An interconnection to Minneapolis Water would need to provide adequate fire protection
and meet the City’s maximum day demands. The City’s hydraulic grade line (HGL) and
existing elevated water tower is at least 40 feet higher than the available HGL in the
Minneapolis water distribution system at the interconnection point during static
conditions.
The City’s existing water distribution system is not sized to transmit adequate flow rates
from the Minneapolis water distribution system to the City’s elevated water tower.
Therefore, two water booster stations and two 20-inch wat ermains would need to be
constructed from interconnection points with Minneapolis Water to St. Anthony Village’s
water tower to provide system redundancy in the event that one booster station failed or
one watermain experienced a break.
One watermain would run from the corner of Stinson Boulevard NE along Kenzie
Terrace and north along Silver Lake Road to the water tower at a length of approximately
8,100-feet. The second watermain would run from the corner of Stinson Boulevard NE
1,4-DIOXANE PROJECT
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CITY OF ST. ANTHONY VILLAGE
WSB PROJECT NO. 3183-00 PAGE 9
and Silver Lane NE to 33rd Ave NE and to the water tower at a length of approximately
7,600-feet. Flow meters would need to be installed inside the booster pumping stations to
record the volumes of water purchased from Minneapolis Water. Minneapolis Water
staff studied potential interconnections to its water distribution system and provided a
memorandum that summarizes this study (see Appendix A). The estimated time to
implement this option would be approximately two to three years.
Advantages
This option would provide the following advantages:
1. The City is no longer responsible for treatment and removal of TCE and Dioxane
from the drinking water supply.
2. City residents that currently have home water softeners would save on their
individual water softening costs. Minneapolis Water softens its drinking water to
approximately 80 parts per million (ppm) hardness or about 5 grains. Residential
customers that soften their water may save an average of $6.75 per month in salt
costs.
3. If the ability to draw from the Jordan Sandstone aquifer was retained, connecting
with the Minneapolis system would provide some redundancy in water supplies.
4. Does not rely on groundwater aquifers which are being closely monitored by the
DNR in portions of the Metro Area.
Disadvantages
This option would provide the following disadvantages:
1. The City currently controls its water quality. Purchasing water from Minneapolis
Water would relinquish this control to others while the City would not be able to
address water quality changes.
2. Surface waters, such as the Mississippi River, commonly contain emerging
contaminants’ which could pose a water quality concern if the EPA establishes
MCLs for these constituents within the water. For example, pharmaceuticals are
currently being studied by the EPA and could possibly require further treatment in
the future for drinking water that stems from a surface water supply. This
treatment process may result in an increase in the cost of water.
3. The City would lose control of its water rates by purchasing water from
Minneapolis Water.
4. The water quality of Minneapolis’ drinking water differs in qualit y than that
provided by the City of St. Anthony Village.
1,4-DIOXANE PROJECT
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WSB PROJECT NO. 3183-00 PAGE 10
o Although the concentrations are less than the MCL, Minneapolis’ water
contains higher levels of disinfection byproducts (Haloacetic Acids, Total
Trihalomethanes, etc.) than the water distributed by the City of St.
Anthony Village.
o Minneapolis’ water is supplied from surface water, meaning the influent
water quality has potential to fluctuate throughout the course of a year. In
the spring time during snowmelt and in the summer time during algae
blooms, the water quality within the Mississippi River can produce higher
levels of taste and odor compounds.
5. The potential exists for hazardous materials to spill into the Mississippi River,
either from tanker trucks, rail cars, storm sewers or other sources along the river.
6. The age and redundancy of the Minneapolis Water distribution system is of
concern. The utility contains hundreds of miles of old steel pipe that is yet to be
lined or replaced. These maintenance costs may increase the future cost of
Minneapolis Water.
7. Minneapolis Water most likely has concerns with the long term reliability of the
Mississippi River as its water source. They are currently considering
implementing back-up groundwater wells for its surface water supply. In the
event o f a historic drought or an intentional or unintentional contamination event,
the utility would likely not have enough backup capacity in their groundwater
wells to continue to serve all of its customers.
8. The City’s existing water rates would increase. The City would need to collect
enough revenue from water users in the City to cover the cost of purchasing water
from Minneapolis Water as well as to maintain its own existing water distribution
system (such as the water tower, watermains, hydrants, meters) within the City.
9. At least two watermain connect ions, two booster stations, and 20-inch watermain
would need to be constructed across St. Anthony Village to provide redundancy
in case one of the watermains broke or required maintenance.
10. The City would spend in excess of $17 million over 20 years to purchase water
from Minneapolis Water.
Estimated Capital and Long Term O&M Costs
Estimated capital and long term O&M costs were based on present worth analysis on the
assumption that a new 20-inch watermain would need to be installed from two of the
potential connection points defined by Minneapolis Water to the existing St. Anthony
Village water tower, running approximately 15,000-feet in length.
Due to the difference in the hydraulic grade lines (ground elevation plus water pressure)
between the two water distribution systems, two booster pump stations would be required
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near the connection point s to pump water from the Minneapolis water distribution system
to the elevated water tower and distribution system in St. Anthony Village. These
booster stations would require the acquisition of property for their construction.
The total estimated cost including contingency and indirect costs, is shown in Table 3
along with the O&M costs over a 20 year life cycle. A detailed cost estimate for Option
3 can be found in Appendix D.
Table 3: Option 3 Estimated Costs
Estimated
Capital Cost
Finance
Cost (4%
Interest)
Estimated
Annual
O&M Cost (3.5%
Inflation Rate)
20-Year
Cost of
Purchasing/
Producing
Water
Total 20-Year Cost
$9,480,300 $4,471,200 $4,487,800 $17,472,000 $35,911,300
Current Minneapolis Water Rates
The Minneapolis Water bulk water rate was $2.73 per 1,000 gallons purchased in
2015. The City of St. Anthony Village water rates are in a tiered system ranging from
$2.98 to $4.97 per 1,000 gallons depending on the volume of water used. The City would
need to purchase approximately 320 million gallons per year from Minneapolis Water.
This would add an additional cost to the utility of approximately $873,600 per year or
$17,472,000 over 20 years.
By r emoving the current chemical and pumping costs that are being paid by the City to
operate its existing water treatment facility and wells on a daily basis, the City could save
approximately $39,800 per year in chemical costs, $53,120 in filter media replacement
costs, and $86,990 per year in pumping costs. These cost savings would be minor in
comparison to the costs to maintaining the City’s entire water system. Therefore, the
City would still need to charge its customers about the same current water rates in
addition to paying the Minneapolis bulk water rate while continuing to operate and
maintain its existing water system.
The M inneapolis Water bulk rate includes some funding for future capital improvements
and maintenance. Minneapolis Water uses a 10-year pro forma rate model in which the
rates are set in advance and increased between 2.5 to 4.0 percent annually, depending on
t he timing of the utility’s planned capital improvements. The proposed rate increase for
2016 is 3.99%.
3.4 Option 4: Purchase Water from St. Paul Regional Water
The fo urth treatment option analyzed was to purchase water on a whole sale basis from
St. Paul Regional Water Services (SPRWS) through a connection with the City of
Roseville’s water distribution syst em. The City of Roseville receives its drinking water
from SPRWS through the Dale St. Reservoir.
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Description
Minimal information has been provided by the City of Roseville to analyze this treatment
option. It was unknown at the time of this study if the City of Roseville’s water
distribution system (watermains, booster station, storage, etc.) can supply the required
fire protection and maximum day water demands for St. Anthony Village. However,
enough aspects of the St. Paul Water system were evaluated to conclude that St. Paul
Regional Water Services would have all of the same issues that would be experienced
with Minneapolis Water, and possibly more issues such as Roseville infrastructure
upgrades.
Advantages and Disadvantages
Similar advantages and disadvantages occur with this treatment system as does with the
connection to the Minneapolis Water system.
Estimated Capital and Long Term O&M Costs
It is expected that the costs to purchase water from SPRWS would be as much as, if not
potentially more than, the estimated cost to purchase water from the Minneapolis Water
system. The capital costs required to connect to the Roseville water distribution system
are anticipated to exceed the cost of connect ion to the Minneapolis Water system.
3.5 Option 5: Implement a Water Treatment System for Dioxane
The fifth alternative analyzed is to remove Dioxane to below the recommended health
advisory levels at the existing water treatment plant in St. Anthony Village.
Description
The City’s existing water treatment plant is designed to remove iron, manganese, and
trichloroethylene (TCE) from the City’s three groundwater wells. Greensand filters are
used to filter the iron and manganese and granular activated filters (GAC) are used to
adsorb and remove the TCE. These treatment processes are not capable of removing
Dioxane from the City’s water supplies. The low adsorptive capacity of D ioxane limits
the effectiveness of treatment by GAC according to the United States EPA (Source – EPA
Treatment Technologies for 1,4-Dioxane: Fundamentals and Field Applications).
Conventional treatment methods such as air stripping and reverse osmosis are ineffective
at removing Dioxane due to its low vapor pressure and high solubility. The following
treatment technologies have been evaluated by the EPA at the pilot and full scale levels
for D ioxane:
1) Advanced Oxidation
(a) Ultra -Violet Light with Hydrogen Peroxide
(b) Hydrogen Peroxide with Ozone
2) Bioremediation
After careful review of the ad vantages, disadvantages, and costs for each of the above
treatment processes, Ultra-Violet Light with Hydrogen Peroxide was further evaluated as
the most feasible treatment option to treat Dioxane in the City’s wells. Hydrogen
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Peroxide with Ozone and Bioremediation were not further evaluated but are further
discussed in Appendix C.
Advanced Oxidation with Ultra-Violet Light and Hydrogen Peroxide
Advanced oxidation processes (AOP) are commercia lly available for treating Dioxane in
drinking water. Hydrogen peroxide absorbs ultraviolet (UV) light and produces hydroxyl
radicals that oxidize and breakdown Dioxane to non-toxic compounds consisting of
carbon dioxide, water, and residual chloride.
The typical UV and hydrogen peroxide treatment system can effectively remove Dioxane
from drinking water supplies to levels below the current 1ppb HRL and future levels that
may be considered by the EPA (see Figure 1 ).
Figure 1
UV/Hydrogen Peroxide Treatment System, Trojan Technologies UVPhox
There are currently dozens of surface and groundwater UV-oxidation installations
designed for Dioxane removal in operation today. These installations collectively treat
over 250 million gallons of drinking water each day.
A UV/Hydrogen Peroxide treatment syste m was pilot ed inside St. Anthony Village's
existing water treatment plant with assistance from Trojan Technologies, Inc. on August
27, 2015. Representatives of the Minnesota Department of Health were present to
observe the pilot study. Water was obtained from a sample tap located downstream of the
existing greensand filters and upstream of the existing GAC filters. The pilot water was
spiked with excess D ioxane in concentrations ranging between 169 to 197 ppb at variable
flow rates ranging from 0.5 to 2.0 gpm to simulate and demonstrate the effectiveness of
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the system at removing higher concentrations of Dioxane if they occurred in the City’s
wells in the future.
The removal percentages achieved from the pilot study ranged from 76.56 to 99.96
percent , varying by the concentration of hydrogen peroxide added to demonstrate that a
full scale system could remove Dioxane from the City’s water. The Minnesota
Department of Health did not require any additional testing in addition to the parameters
that were tested in the pilot study. A copy of the pilot study report , as prepared by Trojan
Technologies, is included in Appendix B. A follow-up pilot study is recommended
during the final design phase if this option is selected.
The cost analysis anticipated installing t hree UVPhox units inside a new masonry or
precast concrete building, or WTP addition that would be constructed adjacent to the
existing water treatment plant. Each unit would have a treatment capacity of 1,250 gpm
in which two units combined could treat 2,500 gpm (capacity of two wells pumping) with
the third unit providing redundancy in case one unit fails or requires maintenance.
The new building or WTP addition would include a chemical storage room to contain a
5,000 gallon bulk storage tank, 100 gallon day tank, and chemical feed system for
feeding hydrogen peroxide. The existing effluent piping from the existing greensand
filters would be routed into the new building or WTP addition through a common header
pipe, metered, and connected to the individual treatment units. Automated control valves
would be used to split the flow between the unit(s) that are called for service via an
expanded plant automation control system (PLC/SCADA) to meet the City’s water
demands.
The treated effluent water from the treatment system would be routed back into the
existing pipe gallery of the GAC filter building where the excess hydrogen peroxide
would be quenched and removed by the GAC filters. The estimated time to implement
this option is approximately two years.
Figure 2 shows the location where a full scale UV light and hydrogen peroxide treatment
system could be implemented in the City’s existing treatment process.
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Figure 2 – Existing St. Anthony Village WTP with UV Light and Hydrogen Peroxide
Treatment
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Advantages of AOP Treatment with Ultraviolet Light and Hydrogen Peroxide
This option would provide the following advantages:
1. This treatment option physically destroys and removes Dioxane from the
environment. While the AOP would reduce the concentrations at the point of
consumption, it would also help “clean-up” the Dioxane that exists in the
environment. There are no other contaminates created that require hazardous
disposal.
2. Cleaning up Dioxane from the aquifer would reduce risk to other users of the
aquifer located downstream of St. Anthony Village.
3. The UV and hydrogen peroxide feed system could be implemented with the
existing treatment process that already includes pretreatment for iron and
manganese and downstream GAC filters for removing excess hydrogen peroxide.
4. The City would maintain complete control of its water supply, water quality, and
water rates without being dependent on another water utility.
5. The City would be able to pump each of its wells as needed to meet the City’s
water demands unlike the current condition that requires Well No. 4 to be shut
down.
6. Dioxane could be effectively removed from the City’s water supply ensuring
compliance with the current and future EPA and MDH recommended health risk
limits.
7. Other treatment benefits include enhanced disinfection and removal of TCE and
other volatile organic compounds (VOCs), N-nitrosodimethylamine (NDMA),
endocrine disruptor compounds, and pesticides.
Disadvantages
This option would provide the following disadvantages:
1. Implementing the treatment option would require additional operator training and
time to operate and maintain the treatment system.
2. Treatment would involve a significant up-front capital expenditure.
3. The City would be reliant on a single equipment vendor (Trojan Technologies).
4. Although AOP Treatment with Ultraviolet Light and Hydrogen Peroxide appears
to have robust treatment capability for a wide array of contaminants, the City
would be dependent on the effectiveness of the system in treating other
contaminants that may emerge.
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5. The City would be reliant on a single groundwater source.
Estimated Capital and Long Term O&M Costs
Estimated capital and long term O&M costs were based on present worth analysis. The
total estimated cost for Option 5, including contingency and indirect costs, are shown in
Table 4 along with the estimated O&M costs over a 20-year life cycle. A detailed cost
estimate for Option 5 can be found in Appendix D.
Table 4: Option 5 Estimated Costs
Estimated
Capital Cost
Finance
Cost (4%
Interest)
Estimated
O&M Cost
(3.5% Interest
Rate)
20-Year Cost
of
Purchasing/
Producing
Water
Total 20-Year Cost
$7,177,600 $3,385,200 $1,080,200 $4,954,000 $16,597,000
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4. COMPARISON OF OPTIONS
Table 5 provides a comparison of the advantages and disadvantages of each Dioxane
treatment option while Table 6 provides a comparison of the total 20-year cost of each
Dioxane option.
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Table 5: Comparison of Options
Option 1
(Blend Wells)
Option 2
(Construct Mt. Simon-Hinckley
Wells)
Option 3 and 4
(Purchase Water from
Minneapolis or St. Paul)
Option 5
(Implement Treatment)
Advantages Disadvantages Advantages Disadvantages Advantages Disadvantages Advantages Disadvantages
Low capital and
O&M costs
Does not provide
permanent solution
to meet MDH and
EPA considerations
No TCE in
source water
Radium must be
removed from
source water
No TCE
Vulnerable to
emerging
contaminants
Removes Dioxane
from environment
completely
More operator
training required
for operations
staff
Can be done
immediately
Short term solution
only
No Dioxane
in source
water
Sand filters become
radioactive.
Disposal of
radioactive material
is expensive.
Exposure to staff
will require changes
to plant
No Dioxane Seasonal changes
in water quality
City maintains
control of its water
quality and rates
Increased annual
operating costs
Addition of VFDs
could provide
better blending
Increased
manganese
concentrations
DNR likely would
not allow
Softened
water
Vulnerable to
hazardous spills
Cleaning up the
aquifer of Dioxane
would reduce
liability and risk of
other downstream
users
The City would
be reliant on a
single equipment
vendor
Pumps need to be
throttled or VFDs
installed
Potential
groundwater well
interference
Could serve
as a back-up
source
Age of system
Will remove other
TCE, other VOCs,
and other emerging
contaminants
The City would
be reliant on a
single
groundwater
source
Does not remove
Dioxane from
environment
Higher pumping
costs
Does not
rely on
groundwater
aquifers
Loss of control of
water quality and
rates
Well No. 3 is multi-
aquifer well
Does not remove
Dioxane from
environment
Minimal system
redundancy
Reliant on operation
of all three wells for
blending to occur
Does not remove
Dioxane from
Environment
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TABLE 6 – COMPARISON OF TOTAL COSTS
OPTION 20-YEAR TOTAL COST
2 $18,237,900
3 $35,911,300
5 $16,597,000
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APPENDIX A
PRELIMINARY ANALYSIS OF PROVIDING WATER TO SAINT ANTHONY VILLAGE
MEMORANDUM
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FEASIBILITY REPORT
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Memo - SAV Connection_2015_0818 Page 1 of 3
Public Works - Water Treatment and Distribution Services
Engineering
4300 Marshall St. NE
Minneapolis, MN 55421
Memorandum
To: Glen Gerads
CC: Shahin Rezania
From: Peter Pfister
Date: 8/18/2015
Subject: Preliminary Analysis of Providing Water to Saint Anthony Village
Objectives
1. Identify one or more locations for connection between the City of Minneapolis and Saint Anthony
distribution systems. Factors to consider:
a. Size / capacity of the main to which connection is to be made.
b. Length of required connecting main and other possible indicators of an economical connection.
2. Characterize the approximate static and residual pressures at the potential points of connection, assuming a
maximum steady flow of 3,000 GPM into the Saint Anthony distribution system.
3. Items not in the scope of this analysis include:
a. Research into utilities, geotechnical, or other conditions that may impact constructability or cost.
b. Consideration of siting for pumping station or pressure reducing valves or vaults.
c. Detailed condition assessment of existing water mains under consideration.
d. Detailed hydraulic analysis.
e. Cost estimates
Summary of Findings
The Saint Anthony Village water system is south of the Hilltop finished water reservoirs owned by the City
of Minneapolis. The portion of the Minneapolis Distribution System that abuts the Saint Anthony Village
water system is a boosted pressure zone, called Northeast High Service Area. It is assumed undesirable
from the City of Minneapolis standpoint to connect to mains within the Northeast High Service Area.
However, a major pipeline, Pipeline 16, is located near the border of Saint Anthony Village, an d is not part
of the Northeast High Service Area. Pipeline 16 is provided its pressure by the Hilltop reservoirs.
Minneapolis has a pumping capacity of over 40,000 GPM to maintain the levels at Hilltop, so the 3000 GPM
demand for Saint Anthony Village can be readily accommodated.
Memo - SAV Connection_2015_0818 Page 2 of 3
Two potential options for connection to the City of Minneapolis water system by Saint Anthony Village
were identified for evaluation:
1. Connection to Pipeline 16 at one of several possible locations between 40th Avenue Northeast and
Lowry Avenue Northeast.
2. Providing a connection to the outlet piping of the Hilltop reservoirs at Stinson Boulevard between
45th Avenue NE (County Road E) and 5th Street NW, and routing a new water main South on Stinson,
East on County E, and South on Silver Lake Road and connecting with the existing 12” Saint Anthony
Village water main. This new water main could possibly be combined with a main serving the City of
New Brighton. The length of the main required would be approximately 4,400 feet along this route.
Because of the length of the main and the significance of the roads along the route, this option was
not considered further.
Four potential locations for connection to Pipeline 16 were evaluated, with any number of other locations
potentially being viable for consideration.
Further Discussion of Option 1
Pipeline 16 is a 48-inch welded steel water main constructed 1949-1950, which begins at the Hilltop
Reservoirs. There are a total of four interconnected reservoirs at Hilltop with a total capacity of 72 million
gallons. The pressure for Pipeline 16 under normal operation is controlled by the level in the Hilltop
Reservoirs and regulated by a control valve located downstream where the pipeline runs through the
Columbia Heights treatment campus. The City of Minneapolis has adequate pumping capacity with
sufficient redundancy to be able to continue to maintain sufficient levels in the Hilltop Reservoirs to
accommodate additional consumption as considered in this study. Pipeline 16 is part of the City of
Minneapolis outer transmission main loop and is routed south along Arthur Street, Benjamin Street, and
Stinson Boulevard to Lowry Avenue NE, and continues south. Pipeline 16 was field-lined in 1963 with
cement mortar. Elevations and pressures are as follows:
Hilltop Reservoirs Water Surface Elevation
o Range: 1054 -1074 feet above Mean Sea Level (MSL) (overflow)
Pipeline 16 Control Valve at Columbia Heights Campus
o Outlet Pressure HGL
Approximate Range = 1045 – 1061 feet above MSL
Normal Operation = 1050 feet above MSL
Table 1 lists several possible connection points to Pipeline 16 giving ground elevation at these points, as
well as the corresponding approximate hydraulic grade lines based on the normal control valve outlet
pressure of 1050 feet MSL. Head losses are not included, as the flow in Pipeline 16 is typ ically in the range
of 25-35 MGD and head losses for purposes of this analysis are relatively small. Also included are
approximate distances to potential points of connection to the Saint Anthony distribution system. It is
assumed given the size of the Pipeline 16 that further evaluation of residual pressures is unnecessary at this
time.
Memo - SAV Connection_2015_0818 Page 3 of 3
Table 1 – Summary of Possible connections to Saint Anthony Village Distribution System
Option Connection
Location
(Minneapolis)
Connection Location
(St. Anthony Village)
Ground
Elevation
(ft MSL) at
point of
connection
to MPLS
Approx.
Grade Line
(ft) at point
of connection
to MPLS1
Correspond
ing
pressure
(psi) at
point of
connection
to MPLS
Approx.
Length of
New
Connecting
WM (ft)
1-A Pipeline 16 40th Avenue at Arthur
Place NE (8” Water
Main)
980 70
30 1,100
1-B Pipeline 16 Stinson Boulevard at
27th Avenue NE (8”
Water Main)
918 132 57 50
1-C Pipeline 16 Stinson Boulevard at
26th Avenue NE (north
of intersection) (8”
Water Main)
924 126 55 50
1-D Pipeline 16 Stinson Boulevard at
Lowry Av. NE (10”
Water Main)
932 118 51 450
1 – Based upon “typical” control valve outlet pressure of 1050’ as provided by City of Minneapolis Water
Operations. Ranges of expected pressures may be predicted by varying control valve outlet pressure within
the ranges provided above.
Other Options not Evaluated
Connection to other water mains to the west of Saint Anthony Village was not considered because all of
these mains were within the Northeast High Service area. Northeast High Service Pump Station has a firm
capacity of 2,500 GPM, which is less than the stated maximum demand of 3,000 GPM for Saint Anthony
Village.
APPENDIX B
ST. ANTHONY VILLAGE UV-AOP PILOT PROJECT TROJAN UVPHOX ADVANCED
OXIDATION SYSTEM PILOT SYSTEM TEST REPORT
1,4-DIOXANE PROJECT
FEASIBILITY REPORT
CITY OF ST. ANTHONY VILLAGE
WSB PROJECT NO. 3183-00 APPENDICES
Saint Anthony Village UV-AOP Pilot Project
TrojanUVPhox™ Advanced Oxidation System
Pilot System Test Report
October 16, 2015
Table of Contents
1 INTRODUCTION .............................................................................................................................................2
2 UV-OXIDATION FUNDAMENTALS .............................................................................................................2
2.1 Treatment mechanisms ............................................................................................................................2
2.2 Water quality parameters ........................................................................................................................3
2.2.1 UV Transmittance ..............................................................................................................................3
2.2.2 Hydroxyl Radical Scavenging Demand..............................................................................................3
2.3 The electrical energy per order parameter ............................................................................................3
2.3.1 Parameters affecting E EO ....................................................................................................................4
3 PILOT SYSTEM DESIGN ................................................................................................................................5
3.1 approach to the UV-AOP Study ..............................................................................................................5
3.2 uv-aop pilot system design .......................................................................................................................6
4 UV-AOP SYSTEM TEST PROCEDURES ......................................................................................................8
4.1 UV-AOP Mixing test procedure ..............................................................................................................8
4.2 uv-aop performance test procedure ........................................................................................................8
4.3 sample handling and analysis ..................................................................................................................9
5 RESULTS AND DISCUSSION ......................................................................................................................10
6 FULL-SCALE SYSTEM SIZING ...................................................................................................................17
6.1 Design Criteria ........................................................................................................................................18
7 CONCLUSIONS ..............................................................................................................................................20
i
1 INTRODUCTION
This document describes the work performed to demonstrate the ultraviolet/hydrogen peroxide
(UV/H 2 O 2 ) advanced oxidation process (AOP) for treating various 1,4-dioxane present in the potable
groundwater well of The City of St. Anthony Village, Minnesota water treatment plant. The primary
goals of the study were to demonstrate the ability of the UV/H 2 O 2 process to treat the contaminants in
question and provide the basis to determine the economic costs of implementing and maintaining a
full-scale system. To facilitate these goals Trojan Technologies has supplied, installed and operated a
small pilot-scale UV/H 2 O 2 system. The tests were performed on August 26th and 27th, 2015. This
document provides a brief description of the procedures and results of these tests.
The treatment process at the St. Anthony water treatment plant comprises greensand filtration for iron,
manganese and turbidity removal followed by GAC for 1,4-dioxane and VOC removal. 1,4-dioxane is
very poorly adsorbed by GAC and the required change-out frequency makes it prohibitively expensive
to operate. It is proposed to locate UV/H 2 O 2 AOP upstream of the GAC contactors to allow the
oxidation process to treat 1,4-dioxane and many of the VOCs and allow the GAC to quench the
residual H 2 O 2 leaving the UV reactor and provide a second barrier to VOCs.
2 UV-OXIDATION FUNDAMENTALS
2.1 TREATMENT MECHANISMS
UV-based advanced oxidation processes rely upon the simultaneous mechanisms of direct UV
photolysis and UV oxidation to degrade chemical contaminants in water. UV-photolysis is the process
by which chemical bonds of the contaminants are broken by the energy associated with UV light. UV-
photolysis does not require the addition of H2 O 2. UV-Oxidation systems rely on the in-situ generation of
hydroxyl radicals (•OH) by way of the UV-photolysis of H 2O2 and the subsequent oxidation of chemical
contaminants by those hydroxyl radicals.
Hydrogen peroxide is commercially available as aqueous solutions of varying strength. The solutions most
commonly employed in UV oxidation processes for water treatment are either 35% or 50% by weight and
are certified to meet NSF/ANSI Standard 60 requirements. Hydrogen peroxide is a relatively weak absorber
of UV light having a molar absorption coefficient at 254 nm of 19.6 L mole-1 cm-1. Nevertheless, the
quantum yield of hydrogen peroxide UV photolysis is relatively high. Therefore, the UV/H 2O2 process is
one of the most efficient advanced oxidation processes.
Hydroxyl radicals are extremely reactive, short lived and unselective transient species. The mean lifetime of
hydroxyl radicals in natural water in the presence of natural organic matter (NOM) and alkalinity is
estimated to be in the order of 10 μs (Oppenlander 2002). Therefore, the high reactivity and short life of
these chemical species result in the requirement of in-situ generation of these oxidants. They will not exist
beyond the boundaries of the UV reactor volume.
Hydroxyl radicals can oxidize organic and inorganic compounds by various types of reactions, comprising
electron transfer reactions, hydrogen abstraction and electrophilic addition. In UV oxidation treatment
processes the desired reactions are the oxidation of specific contaminant molecules.
2
2.2 WATER QUALITY PARAMETERS
2.2.1 UV Transmittance
UV transmittance (UVT) is the ratio of UV light transmitted through the sample to that transmitted
through a reference solution. UVT is measured using a UV spectrophotometer. Reagent grade water
is typically used as the reference solution (i.e., UVT = 100%). UV absorbance (A λ )] measures the
amount of light absorbed by a solution over a given path length (l) and at a given wavelength (λ).
UVT and UV absorbance are related by the following equation:
UVT=10-Aλx100
The typical cell pathlength is 1 cm and both transmittance and absorbance values are commonly
reported per cm. A key reference wavelength, and one at which UVT is often reported, is 254 nm.
This wavelength is used because it is the wavelength at which a low pressure mercury UV lamp emits
light. Transmittance decreases in the presence of UV absorbing substances and particles that either
absorb or scatter UV light. This results in a reduction of available UV energy for disinfection and
oxidation. The UV transmittance is the most important water quality parameter used in the sizing of a
UV system. A UV system designer may compensate for low transmittance by increasing the residence
time or the amount of equipment.
2.2.2 Hydroxyl Radical Scavenging Demand
While the desired reaction in UV oxidation systems is between photogenerated hydroxyl radicals and
contaminant molecules the unselective nature of hydroxyl radical reactions result in reaction pathways that
consume hydroxyl radicals by reaction with constituents of the background water matrix. Examples of these
hydroxyl radical scavenging reactions are the oxidation reactions with the natural organic matter (NOM)
present in natural waters or reactions with carbonate and/or bicarbonate ions. Hydrogen peroxide itself will
react with hydroxyl radicals and, therefore, is considered a hydroxyl radical scavenger. All of these
scavenging reactions have the effect of reducing the steady state concentration of hydroxyl radicals in the
water. Since the rate of contaminant degradation is proportional to the steady state concentration of hydroxyl
radicals, these hydroxyl radical scavenging reactions reduce the rate of contaminant degradation. The level
of scavenging reactions associated with a water sample can be quantified and is referred to as the hydroxyl
radical scavenging demand of the water. Trojan routinely determines the scavenging demand of water
samples at its laboratory in London, Ontario.
2.3 THE ELECTRICAL ENERGY PER ORDER PARAMETER
In sizing UV systems for Environmental Contaminant Treatment, a different metric is used than for
UV systems for disinfection. This metric is called Electrical Energy per Order, or E EO (Bolton et al.
1996).
E EO is the electrical energy (measured line power draw) required to reduce the contaminant
concentration by one order of magnitude (one log, or 90%) in one cubic meter (m3) or 1000 gallons
(kgal) of water (depending on the choice of flow units). Typical units are:
•orderkgal
kWh or
•orderm
kWh
3 .
3
E EO is a reactor, contaminant, and water-quality specific metric and the figure of merit accepted by the
Photochemistry Commission of the International Union of Pure and Applied Chemistry for UV-
photolysis/UV-oxidation technologies. It is a measure of the efficiency with which a given
contaminant is treated by UV-photolysis and UV-oxidation. Different contaminants will have
different E EO values in the same UV reactor in water with the same water quality. Different reactors
will have different E EO values as the term measures a UV reactor’s hydraulic, optical and electrical
efficiency (when comparing two reactors treating the same contaminant under the same conditions).
E EO is directly proportional to the required power draw: the lower the E EO , the lower the power
required by the system. The following formula can be used to compute the E EO of a UV treatment
system in units of kWh/kgal/order with flow in gallons per minute (gpm) and power draw in kilowatts
(kW):
××
=
•
C
Cgpmflowrate
kWdrawpowerreactormeasured
orderkgal
kWhE
o
EO
log06.0)(
)(
Where
• 0.06 is a conversion factor that converts minutes to hours and
normalizes the flow rate on a 1000-gallon basis
• C o is the concentration of contaminant at the influent of the reactor
• C f is the concentration of contaminant at the effluent of the reactor
In general, the energy required to reduce the contaminant initially by 90% is the same as the energy
required to treat 90% of the remaining contaminant, for a total of 99% reduction (log-linear kinetics).
In other words, the same energy is needed to reduce 100 units of contaminant to 10 units of
contaminant as is needed to reduce 10 units of contaminant to 1 unit of contaminant.
A related term to E EO is the electrical energy dose (EED) which is determined by dividing the system
power draw (kW) by the flow rate. Typical units of EED are kWh/kgal or kWh/m3.
2.3.1 Parameters affecting EEO
• Reactor design. Different reactors (even those using the same type of lamp) can have
significantly different E EO values for a given water and contaminant. This is due to reactor
characteristics such as lamp spacing, lamp orientation, and location of influent/effluent ports.
Therefore, E EO is a reactor-specific measure. The implications of this are that project
specifications cannot specify design E EO values as they will differ from UV system to UV
system.
• Reactor Lamp Type. Properties of the lamp such as UVC power conversion efficiency and
emittance spectrum can have a significant impact on E EO .
• Water quality. Water quality parameters that impact E EO are:
– UV transmittance (UVT): E EO increases as UVT decreases. That is, as the water
becomes less transmissive to UV light, more power is required to achieve a desired
log reduction in the contaminant concentration.
– Hydroxyl radical scavenging demand: E EO increases as the hydroxyl radical
scavenging demand of the water increases. That is, with greater competition for
4
hydroxyl radicals due to the water matrix, fewer radicals are available to react with the
contaminant.
These water quality parameters impact various reactors and lamp types differently.
• Lamp age. E EO increases as lamps age. That is, more power is required at the end of the lamp
life than at the beginning in order to achieve the same effectiveness. This is because the
lamp’s UVC electrical efficiency decreases over time.
• Flow rate. In general, because E EO is normalized by the flow rate, reactor systems treating
different flow rates can be compared. However, such comparisons should be made cautiously
as empirical evidence and theoretical analysis have shown that the E EO value decreases to an
asymptotic value as flow rate increases. This is due to increases in reactor hydraulic
efficiency with increases in turbulence and mixing at higher flow rates. Reactors must be
specifically designed for certain conditions, including flow rates.
• Hydrogen Peroxide Concentration. E EO is a strong function of H 2 O 2 concentration. The
irradiation of H 2 O 2 produces hydroxyl radicals which accelerate the degradation of
contaminants in the water. The higher the H 2 O 2 concentration the more UV it absorbs and the
more radicals are formed. However, H 2 O 2 itself scavenges hydroxyl radicals. Therefore, the
greater the concentration of H 2 O 2 , the greater the scavenging of hydroxyl radicals. Therefore,
E EO varies inversely with H2 O 2 concentration but this is not a linear relationship.
• Contaminant. Different contaminants will have a different E EO value in the same reactor in
water with the same quality. This is due to differences in the quantum yield, molar absorption
coefficient, and hydroxyl radical reaction rate (i.e., their fundamental kinetic parameters).
3 PILOT SYSTEM DESIGN
3.1 APPROACH TO THE UV-AOP STUDY
While it was the objective of this study to demonstrate the capability of the UV/H 2 O 2 system to treat
1,4-dioxane present in the St. Anthony groundwater, it was decided to inject additional 1,4-dioxane
upstream of the UV reactor. This was done to allow the UV/H 2 O 2 pilot system to demonstrate
treatment of 1,4-dioxane that exceeds 3-log (i.e., >99.9%) reduction.
The primary water quality parameters that influence the efficiency of UV/H 2 O 2 treatment are the UV
transmittance (UVT) of the water and its hydroxyl radical scavenging demand. The UVT of the water
affects the efficiency of delivering the UV photons to the target chemical (i.e., H 2 O 2 ). Similarly, the
hydroxyl radical scavenging capacity quantifies the overall demand for hydroxyl radicals due to all
constituents present in the water.
Trojan received a water sample from St. Anthony in July 2015. The sample was collected upstream of
the GAC filters and is representative of the water that would supply the pilot system. This sample was
evaluated for the water quality parameters that potentially impact the efficiency of UV/H 2 O 2
treatment. Figure 1 presents a summary of the data for the St. Anthony water sample. The key
conclusions from the water quality analysis are that the UVT is very high at 96.3% and the hydroxyl
radical scavenging capacity is moderately high. The moderately high hydroxyl radical scavenging
capacity is due to the relatively high alkalinity and resulting bicarbonate ion concentration. These
results are consistent with the measurement of pH, alkalinity and DOC and together provide a strong
5
indication that UV oxidation should be efficient in this water. The UV absorbance spectrum which is
plotted between 200 nm and 300 nm is consistent with the other measured water quality parameters.
Figure 1: Summary of Filtered St. Anthony Water Quality
3.2 UV-AOP PILOT SYSTEM DESIGN
This document focusses on the UV/H 2 O 2 AOP treatment system design, test procedures and results.
The main components of the pilot system comprise the feed supply, chemical injection and mixing,
flow measurement, the UV reactor with influent and effluent sample ports as well as the GAC
contactor. The UV reactor was a TrojanUVPhox™ A02 system comprising 2 low-pressure high
output amalgam lamps that each draws approximately 100 W of electrical power. The total power
draw is about 200 W.
A photograph of the pilot set-up is shown in Figure 2. Trojan’s UV/H 2 O 2 pilot system was
conveniently shipped in a small crate with pre-assembled UV reactor inlet and outlet piping and
components together with two chemical injection pumps and electrical supply components. The pilot
system is supplied with filtered St. Anthony water. Two chemical injection systems were provided.
One was a hydrogen peroxide injection pump, tubing and nozzle to deliver the required H 2 O 2 dose to
the reactor feed water. A second injection system metered the 1,4-dioxane solution. The H 2 O 2 stock
was injected into the reactor influent stream just upstream of a static mixer. An influent sample port
was located downstream of a rotameter which provided accurate flow measurement. The pipe
transitions from 1” to 3” diameter to match the UV reactor influent flange. The UV reactor itself is 6”
diameter with 3” influent and effluent flanges. The effluent pipe leaving the reactor is immediately
16-Oct-15
Project Name/Site
Sample
Description Sample Date
Saint Anthony Village, MN
e 3&5 te Sa d
Before GAC 07/09/15 Parameter Units Result
pH 7.8
Treatment Objectives 1.50 log 1,4-D alkalinity mg/L as CaCO3 276.2
Sizing 3x2-D72AL75s reactor(s)UVT254nm % transmission 96.3
10.0 ppm H2O2 DOC ppm 1.2
Hydroxyl Radical Scavenging Nitrate ppm as NO3-0.3
Low Scavenging
Environmental Contaminant Treatment
Sample Report- CONFIDENTIAL
Analytical Results
0.000
0.050
0.100
0.150
0.200
0.250
0.300
200 210 220 230 240 250 260 270 280 290 300
Ab
s
o
r
b
a
n
c
e
(
c
m
-1)
Wavelength (nm)
UV Absorbance Spectrum
6
reduced to 1” diameter and exits vertically before turning and continuing on to the GAC vessel. The
effluent sample port is located between the UV reactor and the GAC contactor.
Figure 2: Photo of UV/H 2 O 2 Pilot System
The system performance was determined by collecting pairs of water samples from the UV reactor
influent and effluent sample ports and analysing contaminant concentrations in these samples. In order to
quantitatively determine the system performance it is necessary to have effluent contaminant
concentrations that are above the analytical reporting limit. Therefore, many of the proposed test
conditions were expected to produce water with measurable contaminant concentrations.
Trojan recommended quenching residual hydrogen peroxide and adsorbing residual contaminants
leaving the UV reactor with a granular activated carbon (GAC) contactor. The size of the contactor is
typically defined by the empty-bed-contact-time (EBCT) and a minimum of 2 to 4 minutes is
recommended for quenching most of the H2 O2 . The City of St. Anthony supplied GAC contactor
comprising a 55 gallon drum, shown in Figure 2. The proposed test matrix described below indicates a
flow range between 0.5 and 2 gpm and therefore the EBCTs provided range from about 20 minutes to
about 80 minutes. This should be more than enough to reduce residual H 2 O 2 leaving the UV reactor to
non-detect.
7
It was important to ensure that the samples were collected when the system was operating at steady state
and that the injected chemicals (i.e., 1,4-dioxane & H 2 O2 ) were completely mixed. There are two
alternatives to ensure that the system is operating under steady state conditions prior to sample
collection. The simplest is to wait for at least five hydraulic retention times (HRTs) after a process
change before collecting samples. One HRT is defined as the time required for one system volume to
pass through the system assuming plug flow conditions. In this case, the system volume is defined as the
total water volume between the injection ports and the effluent sample port. Thus, the HRT is calculated
by dividing that volume by the flow rate. A conservative approach to allow for deviations from plug flow
is to allow five HRTs to pass before assuming that the system is at steady state.
4 UV-AOP SYSTEM TEST PROCEDURES
4.1 UV-AOP MIXING TEST PROCEDURE
The mixing test was performed with hydrogen peroxide as the tracer chemical. The hydraulic
residence time distribution within the system, from the H 2 O 2 /1,4-dioxane injection ports to the final
effluent sample port, was assessed, which allowed the equilibration time to be calculated and used for
subsequent tests. This tracer study involved initiating the injection of a known concentration of tracer
compound (e.g., 6 ppm H 2 O 2 ) into the influent stream at time zero with the UV lamps off and
collecting a series of samples at the influent and effluent sample ports. It was recommended that
samples be collected as frequently as necessary to adequately define the tracer curve (i.e.,
concentration vs. time curve). By monitoring the H 2 O 2 level in the effluent samples, the time required
for the system (between injection and effluent ports) to reach steady state was determined. The time
required to reach steady state determined from this test was used to determine run times for the
subsequent performance tests.
4.2 UV-AOP PERFORMANCE TEST PROCEDURE
The UV -oxidation system operating parameters to be investigated during this study included flow and
hydrogen peroxide dose. The flow range for the pilot tests was between 0.5 and 2.0 gpm (0.5, 1.0 &
2.0 gpm). Hydrogen peroxide was dosed into the influent stream at concentrations between 0 and 20
ppm (i.e., 0, 5, 10, & 20 ppm). That provided a test matrix of 3 x 4 totaling 12 unique test runs. In
addition, a run with the UV power off provided a control condition that allowed the sample collection,
handling and analytical procedures to be validated. Other test conditions with 0 ppm H 2 O 2 and
especially with no UV did not need to be performed with all of these conditions. The recommended
test matrix is provided in Table 1. For each run influent and effluent sample pairs were collected and
analyzed for 1,4-dioxane and H 2 O 2 .
8
Table 1: Test Matrix
Test
No. Flow [H 2 O 2 ] UV
Lamps
(gpm) (mg/L) (on/off)
1 0.5 0 off
2 0.5 0 on
3 0.5 5 on
4 0.5 10 on
5 0.5 20 on
6 1.0 5 on
7 1.0 10 on
8 1.0 20 on
9 2.0 5 on
10 2.0 10 on
11 2.0 20 on
Run number 1 was a control run intended to demonstrate that negligible contaminant reduction occurs
in the absence of UV and H 2 O 2 . This test was also intended to validate the integrity of the
contaminant and H 2 O 2 stock injection, sample collection, handling and analytical procedures. Run 2
was with no H 2 O 2 and will demonstrate the level of 1,4-dioxane treatment by direct UV photolysis,
which was expected to be negligible. The remaining 9 test runs cover 3 H 2 O 2 concentrations and 3
flow rates.
Quantitative analysis of the UV AOP system performance is typically based upon measurement of the
contaminant log reduction and the system’s electrical energy per order (EEO ) parameter. These
parameters require measurable levels of contaminants in both the reactor influent and effluent streams.
Therefore, the influent concentration of contaminant must be sufficiently high that the effluent will be
comfortably above the analytical detection limit. The influent concentration of contaminants can be
adjusted based on the analytical detection limits and the expected log reduction provided by the
system. Trojan predicted that up to ~3.5-log reduction of 1,4-dioxane will be provided in Test No. 5.
Given an analytical method detection limit for 1,4-dioxane of 0.07 µg/L Trojan planned for a
maximum influent 1,4-dioxane concentration of about 200 µg/L.
Trojan recommended that a small GAC contactor be installed to both quench residual H 2 O 2 leaving
the UV reactor and to adsorb the low µg/L levels of 1,4-dioxane that are expected in the UV reactor
effluent. St. Anthony provided a 55 gallon Disposorb™ drum of GAC for this purpose that contained
165 pounds of GAC. The empty-bed-contact-time (EBCT) required for quenching residual H 2 O 2 is
approximately 4 minutes or less which would only require about 8 gallons of GAC bed. Therefore,
assuming an apparent density of 0.5 g/cc the GAC bed totals 40 gallons and the associated EBCT at 2
gpm would be 20 minutes which is more than adequate for both peroxide quenching and organic
adsorption.
4.3 SAMPLE HANDLING AND ANALYSIS
The above test matrix presented in Table 1 resulted in the collection of 22 water samples (11 influent
& 11 effluent) for analysis of 1,4-dioxane and H 2 O 2 . All the samples to be analysed for 1,4-dioxane
were sent to Pace Analytical Services, Inc. in Minneapolis at the completion of the tests on August 27th
where they were analysed by EPA method 522 which has an analytical reporting limit of 0.07 µg/L.
9
Trojan measured the concentration of H 2 O2 using the N,N-diethyl-p-phenylenediamine
(DPD)/Peroxidase method based on that described by Bader & Hoigne (Wat. Res., Vol. 22, No. 9, pp.
1109-1115). A Hach DR890 colorimeter was used for this method.
Prior to collecting samples, the sample ports were flushed to waste to ensure that the collected sample
was representative of what was in the adjacent pipe at the time of sampling. The ports were flushed
and samples collected at approximately 200 ml/min to minimize the disruption of flow through the UV
system. Further, the sampling procedure comprised collecting the influent sample first followed
immediately by the effluent sample once the system was at steady state.
5 RESULTS AND DISCUSSION
The results of the tracer test are summarized in Figure 3. This test was performed at 0.5 gpm and
H 2 O 2 injection was initiated at time zero. Influent and effluent samples were subsequently collected
every 5 or 10 minutes and analysed for H 2 O 2 concentration. As Figure 3 demonstrates, the influent
H 2 O 2 concentration climbed rapidly and plateaued between about 6.5 to 7.0 mg/L by slightly more
than 5 minutes after turning the pump on. The effluent H 2 O 2 concentration did not reach the same
level until after 15 minutes and the two sample ports did not reach the same concentrations (i.e., steady
state) until about 30 minutes after beginning the test. To be conservative, it was decided to wait for 40
minutes after adjusting the operating conditions before collecting samples for runs performed at 0.5
gpm. The corresponding times to reach steady state for the 1 gpm and 2 gpm tests were 20 minutes
and 10 minutes respectively.
10
Figure 3: Tracer Test Results Operated at 0.5 gpm
The results of all 11 tests are summarized in Table 2 below. The tests were performed in the order
listed.
Table 1: Data Summary
Figure 4 presents a comparison of the target H 2 O 2 dose and the measured H 2 O 2 concentration at the
UV influent port. It is observed that the measured H 2 O 2 concentration matches the target value
reasonably well. On average, the measured H 2 O 2 dose was 109% of the target value.
Test
No.Flow
Target
[H2O2]
UV
Lamps
1,4-D Log
Reduction
EEO,
kWh/kgal/
order
Influent Effluent Influent Effluent
(gpm)(mg/L)(on/off)(mg/L)(mg/L)
1 0.5 0 off 0.0 191 187 0.01
2 0.5 0 on 0.0 190 159 0.08 86.18
3 0.5 5 on 5.7 1.7 193 2.1 1.96 3.40
4 0.5 10 on 9.9 189 0.082 3.36 1.98
5 0.5 20 on 21.1 6.1 197 0.07 3.45 1.93
6 1.0 5 on 5.5 3.0 172 11.7 1.17 2.86
7 1.0 10 on 10.5 6.0 186 2.3 1.91 1.75
8 1.0 20 on 19.6 192 0.44 2.64 1.26
9 2.0 5 on 6.8 5.4 170 39.6 0.63 2.63
10 2.0 10 on 11.0 8.5 169 17.9 0.98 1.71
11 2.0 20 on 20.1 15.7 170 7 1.39 1.20
1,4-D [H2O2]
11
Figure 4: Comparison of Target and Measured H 2 O 2 Dose
Figure 5 plots the measured influent and effluent 1,4-dioxane concentrations. 1,4-dioxane was injected
at a rate that should provide a relatively constant concentration for all 11 runs. The average influent
1,4-dioxane concentration was 183.5 μg/L and varied from 169 to 197 μg/L. Effluent concentrations
varied widely, as expected based on the varied operating conditions of the tests, and ranged from 187
μg/L for Run 1 to below the analytical method detection limit of 0.07 μg/L for Run 5.
12
Figure 5: 1,4-Dioxane UV Reactor Influent and Effluent Concentrations
Run 1 was a control test that was not expected to provide any treatment of 1,4-dioxane. This was
conducted to demonstrate that the system operation and sample collection, handling and analytical
procedures did not produce anomalous results. As Table 2 and Figure 5 show, the influent and effluent
1,4-dioxane concentrations for run 1 were almost identical. Run 2 was performed to demonstrate that
significant 1,4-dioxane destruction does not occur in the absence of H 2 O 2 . The results demonstrate
that only 0.08-log destruction of 1,4-dioxane occurred and it is possible that a trace of H 2 O 2 may have
been present even though the H 2 O 2 pump was off. For all the other test runs in which both UV energy
and H 2 O 2 were present the 1,4-dioxane reductions were substantial.
Figure 6 presents the log reduction of 1,4-dioxane that was measured for each of the 11 test runs. Log
reduction is calculated by taking the logarithm of the influent 1,4-dioxane concentration divided by the
effluent 1,4-dioxane concentration (i.e., Log(C inf /C eff )). As discussed, the log reduction for runs 1 and
2 were negligible. Referring to the test matrix presented in Table 2, runs 3, 4 and 5 were all performed
at 0.5 gpm with run 3 at 5 ppm H 2 O 2 , run 4 at 10 ppm H 2 O 2 and run 5 at 20 ppm H 2 O 2 . It is observed
in Figure 6 that the log reduction increases as the H 2 O 2 dose increases. Nevertheless, the increase
from run 4 at 10 ppm H 2 O 2 to run 5 at 20 ppm H 2 O 2 appears to be quite low. It is important to note
that, as reported in Table 2, the effluent concentration for run 5 was below the analytical detection
limit of 0.07 µg/L. The corresponding log reduction calculation for run 5 used 0.07 µg/L as the
effluent concentration even though the actual concentration was less than 0.07 µg/L. Therefore, the
actual log reduction would be some value greater than the 3.45-log reported for run 5 and plotted in
13
Figure 6. Similarly, runs 6, 7 and 8 were all performed at 1 gpm with 5, 10 and 20 ppm H 2 O 2 doses
respectively. For these runs we observe that the log reduction values increased from 1.17-log at 5 ppm
to 1.91-log at 10 ppm and to 2.64-log at 20 ppm H 2 O 2 . Runs 9, 10 and 11 were performed at 2 gpm
again with 5, 10 and 20 ppm H 2 O 2 dose targets. The measured 1,4-dioxane log reduction values for
these runs increased from 0.63-log to 0.98-log and to 1.39-log with increasing H 2 O 2 dose. These
results show that by increasing H 2 O 2 dose from 5 ppm to 10 ppm resulted in an average log reduction
increase of 63% while increasing from 10 ppm H 2 O 2 to 20 ppm H 2 O 2 resulted in an average log
reduction increase of 40% (based on runs 7, 8, 10 & 11). This is the expected result in that there is a
diminishing benefit to contaminant log reduction due to H 2 O 2 dose increases. This is because although
increasing the H 2 O 2 concentration increases the rate of hydroxyl radical generation it also increases
the rate of hydroxyl radical scavenging by H 2 O 2 . The results presented in Figure 6 also illustrate that
the measured 1,4-dioxane log reduction increases as the flow rate decreases. Analyzing the data
presented in Figure 6 and Table 2 indicates that reducing the flow rate by 50% results in an average
log reduction increase of 83%. This is also consistent with expectations because it is known that UV
reactor efficiency can decrease at low flow rates due to poor hydraulic flow patterns (i.e., poor mixing)
in the reactor leading to broad UV dose distributions.
Figure 6: Summary of 1,4-Dioxane Log Reduction Data
Another method of describing the treatment performance is to examine the electrical energy per order
(E EO ) parameter for 1,4-dioxane, as described previously. The E EO is calculated by dividing the UV
electrical power by the flow rate and by the 1,4-dioxane log reduction. Therefore, lower E EO values
14
represent more efficient treatment. The E EO is presented for all 11 runs in Table 2 and plotted in
Figure 7 as a function of the measured influent H 2 O 2 concentrations. The first conclusion from
examining Figure 7 is that the E EO decreases as H 2 O 2 dose increases. Also, although the system flow
rate does not have a significant impact on the E EO it does appear that the lowest flow of 0.5 gpm did
result in slightly higher values. This is consistent with our expectations of the reactor hydraulic
efficiency as a function of flow rate. It is also apparent that the correlation between E EO and H 2 O 2
dose is non-linear. This is also consistent with the expected diminishing benefit of increasing the H 2 O 2
dose, as explained above.
Figure 7: 1,4-Dioxane Electrical Energy per Order as a Function of H 2 O 2 Dose and Flow
The same data is examined in Figure 8 which plots the measured log reduction of 1,4-dioxane as a
function of the electrical energy dose (EED). The EED term was introduced in Section 2 and is
determined by dividing the UV system power by the flow rate. This is a measure of the UV energy
provided per unit volume of water treated. As Figure 8 demonstrates, the log reduction of 1,4-dioxane
is proportional to both the EED and the H 2 O 2 dose. Note that the effluent 1,4-dioxane concentration
was below the MDL for the highest EED and highest H2 O 2 dose.
15
Figure 8: 1,4-Dioxane Log Reduction (LR) as a Function of Electrical Energy Dose (EED)
16
6 FULL-SCALE SYSTEM SIZING
This section is intended to describe the basis of sizing the UV/H 2 O 2 AOP System for Saint Anthony
proposed by Trojan Technologies.
Trojan’s general approach to UV oxidation system sizing relies upon the combination of
understanding the fundamental photochemistry of the UV oxidation process together with a thorough
understanding of the hydraulic and optical performance of Trojan reactors, as well as extensive full-
scale experience to provide, with confidence, performance warranties for all Trojan UV oxidation
systems.
Specifically, the sizing method that Trojan typically employs is comprised of the following steps:
1) Through a combination of bench-scale experimentation and literature review determine the
fundamental photochemical kinetic parameters for the specific contaminants that govern the rate
of contaminant destruction by the UV photolysis and UV/H 2 O 2 process. These fundamental
kinetic parameters include the quantum yield and molar absorption coefficient as a function of the
irradiation wavelength which together determine the rate of direct photolysis of the contaminant in
response to a delivered UV dose. They also include the second order rate constant for the reaction
between the contaminant and the hydroxyl radical. The water constituents could undergo
photochemical reactions generating reactive species such as triplet states and radicals which could
affect the contaminant photochemistry/chemistry in that specific water. These parameters and the
role of water constituents on various contaminant structures, including pesticides, algal toxins,
taste-and-odor causing compounds, pharmaceuticals and so on are determined by performing
properly designed collimated beam experiments.
2) Determine the UV transmittance (%T, also abbreviated as UVT) across the radiation wavelength
relevant to the UV application and the hydroxyl radical scavenging capacity of representative
water samples. The water UVT is measured over the wavelength range from 200 to 400 nm using
a calibrated spectrophotometer. The scavenging capacity of the water is determined from a
properly designed collimated beam methodology.
3) Input these parameters together with the system design parameters (flow and treatment goal) into
Trojan’s proprietary mathematical model of the UV photolysis and UV/H 2 O 2 process for the
TrojanUVPhox™ reactor.
4) Trojan’s proprietary model comprises the following system characteristics:
a) It incorporates the photochemical kinetics for direct UV photolysis and hydroxyl radical based
UV-oxidation by modeling the contaminant destruction kinetics for the given water quality
defined by the UVT and the hydroxyl radical scavenging demand.
b) It utilizes computational fluid dynamics (CFD) and UV intensity models to characterize the
product of the hydraulic behavior and the UV intensity gradients within Trojan’s various
reactors. This task requires a detailed knowledge of the internal dimensions and structures of
each possible reactor model together with the lamp spectral power distribution and efficiency,
quartz sleeve UV light transmitting characteristics, and their specific geometric positioning
inside the UV reactor relative to the flow patterns.
c) Specific reactor characteristics used in the modeling have been calibrated and subsequently re-
validated using numerous sets of full-scale, real world results. The TrojanUVPhox design
incorporates the knowledge base accumulated from Trojan’s extensive experience.
5) The model output provides the optimum combination of UV power and H 2 O 2 concentration
resulting in a minimum NPV for the system.
6) Trojan has extensive full-scale experience in applying both the UV direct photolysis and
UV/H 2 O 2 process in various water treatment applications. These full-scale installations comprise
projects treating contaminants including pesticides, industrial solvents, cyanides, taste-and-odor
17
causing compounds, algal toxins, pharmaceuticals and personal care products, endocrine
disrupting compounds, NDMA and 1,4-Dioxane. Numerous systems, including Tucson’s 5,800
gpm airport remediation project utilizing the TrojanUV Phox D72AL75 installation, the 100 MGD
Groundwater Replenishment System in Orange County California and the 50 MGD UV oxidation
system in Aurora, Colorado are designed for low-pressure UV oxidation of various contaminants.
6.1 DESIGN CRITERIA
The full-scale design criteria together with measured water quality are summarized in Table 3.
Table 3: City of St. Anthony Water Village Treatment System Design Specifications
UV SYSTEM DESIGN SPECIFICATIONS
Design Flow 3000 gpm
Average Flow 1250 gpm
Target 1,4-dioxane Log Reduction 2.0-Log
Measured UV Transmittance 96%
The model output for the projected water quality at the peak flow conditions (i.e., 3000 gpm at 96%
UVT) provides an electrical energy per order (E EO ) value of 0.41 kWh/kgal/order for 1,4-dioxane
when 18 ppm of H 2 O 2 is present. This value is associated with the UV output at the end-of-lamp-life
(EOLL) condition as well as an appropriate level of conservatism. Trojan has proposed to reduce 1,4-
dioxane by 2.0-log (i.e., 99.0%) in this stream with 2 parallel trains of 2 TrojanUVPhox™ D72AL75
reactors plus one redundant train. This system is described in a separate proposal.
While Trojan’s preferred approach to sizing UV-AOP systems is to rely upon our proven mechanistic
sizing model, as described above, there are several aspects of the empirical scale-up approach that
should be discussed. Full-scale UV reactors typically have superior treatment efficiency compared
with pilot-scale reactors for the following reasons.
In UV-based AOP systems, most UV photons that are transmitted through the water and reach the wall
of the reactor are absorbed by the wall material and do not contribute to the contaminant treatment
process. This loss of photons at the reactor wall and other surfaces within the UV reactor represents an
inefficiency of the reactor. Conversely, if a large fraction of photons that are emitted by the lamps are
absorbed by constituents in the water, a desired result, then the reactor is said to have high absorption
efficiency. This reactor absorption efficiency can be increased by providing a longer pathlength for the
photons to travel before they reach a surface. Similarly, reactors typically have higher efficiencies
when operated at higher flow rates. This is a result of better hydraulic performance (i.e., mixing) that
better approaches the ideal plug flow behaviour. The result of these phenomena is that the relatively
small pilot reactors operated at relatively low flows generally have a lower efficiency (i.e., higher E EO )
than larger full-scale reactors. It is therefore, not recommended to assume that a full-scale system will
have the same E EO as a pilot-scale system when operated with the same water quality and H 2 O 2 dose.
18
Figure 9: Comparison of Pilot Data and Model Prediction with Full-Scale Prediction
Figure 9 presents the pilot E EO data for 1,4-dioxane from Figure 7 together with the full-scale
model of the E EO for 1,4-dioxane in 2 parallel trains of 2- D72AL75 TrojanUVPhox reactors
treating 3000 gpm of filtered water by 2-log reduction of 1,4-dioxane. The full-scale design at
those peak conditions has an associated E EO of 0.41 kWh/kgal/order at about 18 mg/L of
H 2 O 2 as shown in Figure 9. Also shown in Figure 9 is the model result for the pilot-scale
system at the 2 gpm operating condition. The improved efficiency of the full-scale system
relative to that of the pilot system was explained earlier. This full-scale prediction also
accounts for the lamps operating at their end-of-life condition with an allowance for sleeve
fouling and a safety factor.
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7 CONCLUSIONS
The data generated from operating a TrojanUVPhox™ A02 pilot-scale UV reactor together with H 2 O2
injection at the Saint Anthony Water Treatment Plant has demonstrated that the UV/H2 O 2 AOP is
effective at treating 1,4-dioxane in the filtered Saint Anthony groundwater. Specifically,
• A water sample demonstrated high UV transmittance (>96.3%) making it a very good candidate
for UV/H2 O 2 AOP treatment despite a moderately high hydroxyl radical scavenging demand.
• Greater than 3.4-log (>99.96%) destruction of 1,4-dioxane was demonstrated by the pilot
system.
• 1,4-dioxane log reductions were shown to be proportional to both the H2 O 2 levels dosed and
UV energy delivered (i.e., EED). Therefore, the same log reduction target could be achieved by
increasing H 2 O 2 and reducing power or vice versa. This supports the conclusion that the
process is operationally flexible and able to be optimized to minimize the overall cost of
treatment.
• The EEO values for 1,4-dioxane were shown to vary inversely with the H 2 O2 level dosed. That
is, the E EO decreases with increasing H2 O 2 and vice versa.
• Destruction of 1,4-dioxane was achieved using UV/H2 O2 with relatively low EEO values (~1.2 -
3.4 kWh/kgal/order) depending primarily upon the H 2O 2 dose selected. Full-scale EEOs are
expected to be lower since larger reactors are more efficient than pilot-scale equipment.
• Trojan’s model of the UV/H2 O 2 process was demonstrated to match the pilot data very well.
This same model was adjusted for the full-scale system parameters and provided the basis for
the full-scale system recommendation.
• The proposed full-scale UV/H 2 O2 system comprises three parallel trains of 2-D72AL75
TrojanUVPhox reactors (2 duty trains, 1 redundant train) each with 18 ppm H2 O2 . This system
will treat 3000 gpm of 96%T water by 2-log (i.e., 99%) reduction of 1,4-dioxane.
• The process was demonstrated to be relatively simple to operate. Full-scale system controls
simplify those operations further.
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APPENDIX C
Evaluation of Hydrogen Peroxide with Ozone and Bioremediation for Treatment of Dioxane
1,4-DIOXANE PROJECT
FEASIBILITY REPORT
CITY OF ST. ANTHONY VILLAGE
WSB PROJECT NO. 3183-00 APPENDICES
Appendix C –
Evaluation of Hydrogen Peroxide with Ozone and Bioremediation for Treatment of
Dioxane
Ozone/Hydrogen Peroxide
Ozone with hydrogen peroxide was not piloted or further evaluated for treating Dioxane at the
City's existing water treatment plant for the following reasons:
1. Typically used for high turbidity waters (surface waters) where the Ultraviolet
Transmittance Value (UVT) is too low for UV light to effectively pass through the
water and be absorbed by the hydrogen peroxide. Because the City's water contains
low turbidity, iron, and manganese downstream of the existing greensand filters, the
water produces a very high UVT which is much better suited for UV light with
hydrogen peroxide.
2. This process can form assimilable organic carbon (AOC) byproducts that may require
an additional treatment process to remove them.
3. Generally requires a larger building footprint.
4. Typically higher O&M costs compared to UV/hydrogen peroxide.
Bioremediation
Ex situ bioremediation of groundwater involves putting contaminants in the extracted
groundwater in contact with microorganisms in attached or suspended growth biological
reactors. Ex situ bioremediation was selected to treat Dioxane in groundwater at the Lowry
Landfill Superfund site near Denver, Colorado. Between 1960 and 1980, the site was used for
co-disposal of industrial and municipal solid wastes. Industrial waste liquids that contained spent
solvents including Dioxane were placed in unlined pits and subsequently contaminated shallow
groundwater (Source – EPA Treatment Technologies for 1,4-Dioxane: Fundamentals and Field
Applications).
Ex situ bioremediation was not further evaluated for St. Anthony Village as the treatment process
was determined to be very difficult to pilot and too costly to implement if it was determined to be
an effective treatment technology. In addition, it is possible that the Minnesota Pollution Control
Agency (MPCA) and the MDH would not approve this method. There are no known public
water systems that utilize bioremediation for treatment of Dioxane.
APPENDIX D
Cost Estimates
1,4-DIOXANE PROJECT
FEASIBILITY REPORT
CITY OF ST. ANTHONY VILLAGE
WSB PROJECT NO. 3183-00 APPENDICES
Option 2 Detailed Costs
ITEM NO. UNIT UNIT COST COST
Drill Mount - Simon Hinckley Well 4 Each 350,000$ 1,400,000$
Groundwater Study 1 Lump Sum 75,000$ 75,000$
Misc. DNR Requirements for Approval 1 Lump Sum 50,000$ 50,000$
Pump Houses 4 Each 850,000$ 3,400,000$
HVAC System Upgrade 1 Lump Sum 25,000$ 25,000$
TOTAL:4,950,000$
INDIRECT (25%):1,237,500$
SUBTOTAL:6,187,500$
CONTINGENCY (15%):928,125$
GRAND TOTAL:7,115,625$
ITEM NO. UNIT UNIT COST COST
Hazardous Waste Disposal - Media 1 Lump Sum 50,000$ 50,000$
Media Replacement 1 Lump Sum 1,728$ 1,728$
Additional Well Pump Maintenance 1 Lump Sum 10,000$ 10,000$
Additional Power Usage (Depth)456,375 KWHr 0.0823$ 37,560$
TOTAL ANNUAL:99,288$
PER 20 YEARS: 1,985,753.25$
PER 20 YEARS WITH 3.5% INFLATION RATE: 2,812,253.54$
OPTION 2: MOUNT-SIMON HINCKLEY WELLS
ESTIMATED CAPITAL COST
ESTIMATED ANNUAL O&M COST
Option 3 Detailed Costs
ITEM NO. UNIT UNIT COST COST
20-inch Water Main 15,750 Lin Ft 260$ 4,095,000.00$
Land Acquisition 2 Each 350,000$ 700,000.00$
Booster Pump Station 2 Lump Sum 900,000$ 1,800,000.00$
TOTAL:6,595,000.00$
INDIRECT (25%):1,648,750.00$
SUBTOTAL:8,243,750.00$
CONTINGENCY (15%):1,236,562.50$
GRAND TOTAL:9,480,312.50$
ITEM NO. UNIT UNIT COST COST
Proposed Pumping Costs 1 Per Year 32,434$ 32,434.00$
Demand Charges 1 Per Year 15,036$ 15,036.00$
Replacement Pumps - 2500 gpm 2 Per Year 8,000$ 16,000.00$
Replacement Pumps - 3500 gpm 1 Per Year 5,000$ 5,000.00$
Heat 1 Per Year 4,235$ 4,235.00$
VFD Replacement - 100 HP 2 Per Year 1,910$ 3,820.00$
VFD Replacement - 150 HP 1 Per Year 2,320$ 2,320.00$
SCADA Integrator 1 Per Year 20,000$ 20,000.00$
Building Maintenance 1 Per Year 5,000$ 5,000.00$
Watermain Replacement 1 Per Year 54,600$ 54,600.00$
TOTAL ANNUAL:158,445.00$
PER 20 YEARS: 3,168,900.00$
PER 20 YEARS WITH 3.5% INFLATION RATE: 4,487,843.71$
Individual Water Softening 1 Per Month 6.75$ 6.75$
OPTION 3: PURCHASE WATER FROM MINNEAPOLIS WATER
ESTIMATED CAPITAL COST
ESTIMATED ANNUAL O&M COSTS
Option 5 Detailed Costs
ITEM NO. UNIT UNIT COST COST
General Conditions 1 Lump Sum 651,279$ 651,279$
General Site Work 1 Lump Sum 94,750$ 94,750$
Building and Treatment 1 Lump Sum 4,247,110$ 4,247,110$
TOTAL:4,993,139$
INDIRECT (25%):1,248,285$
SUBTOTAL:6,241,424$
CONTINGENCY (15%):936,214$
GRAND TOTAL:7,177,637$
ITEM NO. UNIT UNIT COST COST
Electrical Costs for Trojan Units 1 Lump Sum 9,884$ 9,884$
Heating Cost 1 Lump Sum 1,750$ 1,750$
Hydrogen Peroxide 1 Lump Sum 25,302$ 25,302$
Additional Power Usage 1 Lump Sum 1,200$ 1,200$
TOTAL ANNUAL:38,136$
PER 20 YEARS: 762,720.00$
PER 20 YEARS WITH 3.5% INFLATION RATE: 1,080,175.50$
OPTION 5: IMPLEMENT A WATER TREATMENT SYSTEM
ESTIMATED CAPITAL COST
ESTIMATED ANNUAL O&M COST
Option 5 Detailed Costs Continued
#ITEM UNIT NO.UNIT COST COST
1 GENERAL CONDITIONS
1.1 General Conditions, building permits, bonds, insurance, mobilization, contractor 1 1 651,279$ 651,279$
project management, construction superintendent, and contractor profit
General Conditions Total Estimated Construction Costs 651,279$
2 GENERAL SITE WORK
2.1 Site preparation and tree removal LS 1 9,000$ 9,000$
2.2 Silt fence LF 150 5$ 750$
2.3 Finish grading and turf restoration LS 1 25,000$ 25,000$
2.4 Site utilities LS 1 50,000$ 50,000$
2.5 Pavement LS 1 10,000$ 10,000$
General Site Work Total Estimated Construction Costs 94,750$
3 BUILDING AND PROCESS EQUIPMENT
3.1 Excavating and backfilling with select granular material CY 1035 20$ 20,700$
3.2 Structural Pilings LF 1080 50$ 54,000$
3.3 Cast-in-Place Concrete (footings and floor slabs)CY 96 600$ 57,600$
3.4 Precast Concrete LS 1 56350.00 56,350$
3.5 Unit Masonry Assemblies LS 1 209300.00 209,300$
3.6 Misc. Metal Work LS 1 46000.00 46,000$
3.7 Rough Carpentry LS 1 6000.00 6,000$
3.8 Building Insulation LS 1 36800.00 36,800$
3.9 Fully Adhered Membrane Roof System LS 1 66700.00 66,700$
3.10 Caulking and Sealants LS 1 29900.00 29,900$
3.11 Door Frames and Hardware LS 1 12000.00 12,000$
3.12 Painting LS 1 24000.00 24,000$
3.13 Process Piping, Fittings, and Valves LS 1 250000.00 250,000$
3.14 Water Quality Analyzers LS 1 15000.00 15,000$
3.15 Trojan Treatment Equipment and Chemical Feed Systems LS 1 2300000.00 2,300,000$
3.16 Chemical Feed System, Piping and Valves LS 1 150000.00 150,000$
3.17 Flow Meters EA 3 10000.00 30,000$
3.18 Overhead Hoist and Beam LS 1 45000.00 45,000$
3.19 Plumbing and HVAC LS 1 104000.00 104,000$
3.20 Electrical General Provisions LS 1 170000.00 170,000$
3.21 Instrumentation and Controls LS 1 250000.00 250,000$
3.22 UV Replacement Lamps EA 296 1,060$ 313,760$
Building and Process Equipment Construction Costs 4,247,110$
OPTION 5: IMPLEMENT A WATER TREATMENT SYSTEM
DETAILED ESTIMATED CAPITAL COST
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Building a legacy – your legacy. 477 Temperance Street
St. Paul, MN 55101
Tel: 651-289-8450
Fax: 651-286-8488
October 26, 2015
The Honorable Mayor, City Council, and Staff
c/o Mark Casey
City of St. Anthony Village
3301 Silver Lake Road NE
St. Anthony, MN 55418
Re: 2017 Street and Utility Improvement Project
Private Utilities – City of St. Anthony Village
WSB Project No: 1626-99
Dear Honorable Mayor, City Council, and Staff:
As requested by the City of St. Anthony Village, WSB & Associates, Inc. has contacted the private utility
companies to determine the costs associated with relocating overhead utilities to an underground
location. Due to the high variance in construction costs with respect to existing utility infrastructure, it
was requested that utilities be looked at on a project-by-project basis. Therefore, the upcoming 2017
Street and Utility Improvement Project planned in the City was given to the utility companies to perform
a cost analysis.
The following table indicates the utility company, contact person, and estimated costs that we have
received for burying the private utilities. Please note that these are preliminary estimates only; the
companies stated that they would not be held to these numbers. Furthermore, this estimate does not
include electric service conversions, system upgrades to meet electrical code, or street light
reconstruction due to utility conversion.
Utility Company Contact Phone No. Estimated Cost
Xcel Energy Wayne Lott 612-630-4409 $400,000
CenturyLink Steve Hoppe 320-291-2852 $60,000
Comcast Eric Rademacher 651-493-5143 $140,000
Total: $600,000
The following table is a summary of the total estimated assessments to benefitting properties for the
proposed 2017 Street and Utility Improvement Project as well as assessments for burying private
utilities (74 properties anticipated to be assessed).
Equal Opportunity Employer
wsbeng.com
K:\01626-990\Admin\Docs\LTR - 2017 Anticipated Assessment (Utility) 102615.doc
Honorable Mayor, City Council, and Staff
October 26, 2015
Page 2
Private Utility
Mainline Bury
Assessment
Private Utility
Service Bury
Assessment
Average Street and
Drainage
Improvement
Assessment
Total Anticipated
Assessment
/ lot / lot / lot / lot
$8,200 $2,000 $6,500-$7,500 $16,700 - $17,700
In addition to these costs, individual properties may need modification at the home to convert from an
overhead mast to an underground connection. Silver Lake Road residents saw these costs range from
$500 to $2,000 when they were converted to underground services.
Please contact me at (651) 286-8465 if you have any questions or comments.
Sincerely,
WSB & Associates, Inc.
Justin G. Messner, P.E.
Attachments
cc: Jay Hartman, Director of Public Works
Todd Hubmer P.E., WSB & Associates, Inc.
Kak/ef
K:\01626-990\Admin\Docs\LTR - 2017 Anticipated Assessment (Utility) 102615.doc
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Building a legacy – your legacy. 701 Xenia Avenue South
Suite 300
Minneapolis, MN 55416
Tel: 763-541-4800
Fax: 763-541-1700
Equal Opportunity Employer
wsbeng.com S:\1Council Worksessions\2015\12142015\MEMO city council water usage 120315.docx
Memorandum
To: Mayor and City Council, City of St. Anthony Village
Mark Casey, City of St. Anthony Village
Jay Hartman, City of St. Anthony Village
From: Todd Hubmer, PE
Date: December 3, 2015
Re: Discussion on Splash Pad Water Usage
WSB Project No. 1626-99
City staff has reviewed the water usage for the splash pads at Emerald and Central Parks in the City of St.
Anthony Village. Based on a review of the 2015 water usage, it was determined that Central Park and
Emerald Park utilize approximately 5% of the total water pumped by the City. Water usage in 2015 can
be broken down as follows:
Central Park Splash Pad 6.9 million gallons
Emerald Park Splash Pad 9.3 million gallons
Total for 2015 16.2 million gallons
Based on this analysis, staff is looking for direction from the City Council in regards to their desire for
evaluating alternatives which may reduce the water usage at the splash pads or allow for recycling and
reuse of splash pad water. Some preliminary alternatives that have been identified include:
1. Treating splash pad water and reusing it as splash pad water
2. Storing and using splash pad water for irrigation
3. Pumping splash pad water back up to water reuse facility
4. Modify hours of operation and/or operational elements of the splash pad to reduce water usage
These are just a few of the options that we have preliminarily identified for discussion at the December
14, 2015 City Council work session. We look forward to discussing this topic with you and to gather
some information in regards to pursuing or not pursuing alternatives to improve the efficiency of these
facilities.
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Notice received of (1)
officer retiring
effective 3/31/16.
Police Department Succession Plan
CURRENT
OFFICERS (17)
EXISTING (14)
NEW (3)
April, 2016
CHIEF
CAPTAIN
LEUITENANT
SERGEANT
SERGEANT
SERGEANT
CAPTAIN
SERGEANT
January, 2016
CHIEF SUBMITS
RESIGNATION
CAPTAIN SUBMITS
RESIGNATION
SERGEANT SERGEANT
SERGEANT SERGEANT
SERGEANT
SERGEANT
SERGEANT
OFFICERS (18)
EXISTING (17)
NEW (1)
SERGEANT
CHIEF CHIEF ON
CALL STATUS
LEUITENANT LEUITENANT LEUITENANTLEUITENANT
All new promotions
take affect and hiring
of officers complete.
Department at normal
operating strength.
OFFICERS
EXISTING (17)
(1) OFFICER
RETIRING EFF
3/31/16
Chief & Captain submit
resignations effective
8/31/16. New officer begins
to replace retiring officer.
SERGEANT SERGEANT
OFFICERS (19)
EXISTING (16)
NEW (3)
OFFICERS (19)
EXISTING (16)
NEW (3)
SERGEANT
NEW CHIEF
NEW CAPTAIN
LEUITENANT
NEW SERGEANT
OFFICERS (19)
EXISTING (16)
NEW (3)
Due to the received and upcoming retirements in the Police Department, over the first eight months of 2016 the City of St. Anthony will
need to execute the following staffing changes: Promote a new Chief, promote a new Captain, promote two (2) new Sergeants and hire
three (3) new sworn officers. (note that this chart assumes internal promotions for supervisory positions)
NEW SERGEANT
June 3, 2016 - August 31, 2016
New officer finishes
field training period.
(2) new officers begin
field training to fill
pending vacancies.
Chief and Captain begin on-call status on 6/3/16.
Pending Chief, Pending Captain and (2) Pending Sergeants
begin eff 6/3/16.
CAPTAIN ON
CALL STATUS
NEW CAPTAIN
PENDING 9/1/16
SERGEANT
NEW CHIEF
PENDING 9/1/16
9/1/2016
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2016 Goal Setting Session
Marriott Northwest - Brooklyn Park
AGENDA
Thursday, January 14, 2016
Invitees:
Mayor & Council
City Manager, Department Heads, Human Resources & City Clerk
Planning Commission – Gondorchin & Parks Commission – Bentz
Consultants – Engineer (Hubmer), Financial (Kvilang), Planning (Rothstein), and Legal (Lindgren)
LMC – Heather Corcoran, Intergovernmental Relations Liaison and Laura Honeck, LMCIT Operations Manager
Metro Cities – Charlie Vander Aarde, Government Relations Specialist
Guest – Kevin McCann, City Administrator, City of Gaylord
Facilitator – Miles
10:00 a.m. to Noon Opening & introductions
Welcome – Mayor
Expectations and session guidelines
Overview of 2015 Strategic Plan
2015 Goals Presentation – Mayor & City Manager
Noon to 1:00 p.m. Lunch
1:00 p.m. to 1:30 p.m. 2018 Comprehensive Plan
1:30 p.m. to 4:00 p.m. St. Anthony’s long term vision/priorities
4:00 p.m. to 4:30 p.m. Staff Reports
Administration Liquor
Finance/HR Police
Fire Public Works
4:30 p.m. to 5:30 p.m. Consultant’s Reports
Engineer Planning
Financial Legal
Group Photo
6:30 p.m. Dinner
Friday, January 15, 2016
Invitees: Mayor, Council, City Manager, Department Heads, Engineer & Facilitator
7:30 a.m. to 8:30 a.m. Open/breakfast on your own
8:30 a.m. to 9:00 a.m. Setting the stage – recap Thursday
9:00 a.m. to 11:00 a.m. Building the Pyramid for 2016
Prioritizing goals and action steps
11:00 a.m. to 11:30 a.m. Connect loose ends and debrief the session
11:30 a.m. Lunch
12:30 p.m. Review session (Mayor, Council, City Manager & Facilitator)