ansonia derby interconnection feasiblity study - compiled document

8/20/2019 Ansonia Derby Interconnection Feasiblity Study - Compiled Document

1/168

City of Derby, CONNECTICUT

Water Pollution Control

Authority

Ansonia Derby Interconnection

Feasibility Study

Mr. John Saccu, Chairman

Mr. Lindsay King, WPCF Superintendent

Water Pollution Control AuthorityMr. Richard Bartholomew Mr. Robert Miani

Ms. Carolyn Duhaime Mr. James Gildea

Ms. Marcy McGuire, Administrator

April 2014

Weston & Sampson Engineers, Inc.

273 Dividend RoadRocky Hill, CT 06067

www.westonandsampson.comTel: 860-513-1473

Fax: 860-513-1483


2/168


3/168


4/168

City of Derby, Connecticut

Derby-Ansonia Feasibility Study ii

April 2014

LIST OF FIGURES

Figure 2-1A Ansonia-Derby Interconnection Force Main

Figure 2-1B Ansonia-Derby Interconnection Force Main

Figure 2-2A Ansonia-Derby Interconnection Force Main

Figure 2-2B Ansonia-Derby Interconnection WWTF Upgrades

Figure 2-3 Ansonia-Derby Interconnection East Derby Pump Station

LIST OF APPENDICES

Appendix A Regionalization Letters

Appendix B Ansonia WPCF – UV Hydrualic Failure Information

Appendix C Storage Analysis Data and Results

Appendix D Ansonia-Derby Interconnection Opinion of Probable Costs

Appendix E Ansonia Interconnection Alternatives – UIC Reports

Appendix F Ansonia – Derby Interconnection Meeting Minutes 3-12-2012

Appendix G Ansonia – Derby DEEP Interconnection Meeting Minutes 10-15-2012


5/168


6/168


Derby-Ansonia Feasibility Study 1-3

April 2014

interconnect with the Derby WPCA collection system via an 8-inch forcemain connection but the

allowable pumping rate shall not exceed 800 gpm.

1.3 Regionalization with the Town of Woodbridge

The Town of Woodbridge has expressed no interest in regionalization with the Derby WPCA.

The town is currently a member community of the Greater New Haven Water Pollution Control

Authority. As a member of the GNHWPCA, the town’s wastewater is treated at the East Shore

Water Pollution Control Facility located in the City of New Haven. As such, no flow allocation

has been provided for the Town of Woodbridge.

1.4 Regionalization with the City of Shelton

The City of Shelton recently completed a major upgrade and capacity expansion to its WPCF

and does not have capacity issues within its system. The Derby WPCA expressed an interest in

connecting to the City of Shelton collection system for wastewater treatment and disposal since

the two WPCF sites are located on opposite sides of the Housatonic River at the Route 8

crossing (Commodore Isaac Hull Memorial Bridge). The City of Shelton has indicated on

several occasions that it is not interested in receiving and treating flows from the Derby WPCA

at the City of Shelton WPCF.

1.5 Regionalization with City of Ansonia

The City of Ansonia expressed an interest in interconnecting the City of Derby wastewater

collection system for wastewater treatment and disposal at the Ansonia WPCF since the two

WPCF sites are located approximately 1.5 miles from each other along the Naugatuck River

and the City of Ansonia recently completed a major upgrade of its WPCF, which is permitted for

an annual average flow of 3.5 MGD. Based on the information provided in its 2004 Wastewater

Facilities Plan (prepared by Camp Dresser and McKee) the Ansonia WPCF, is anticipated to

have an annual average flow surplus of approximately 1.3 MGD in 2025, based on the proposed

build out (0.4 MGD). Based on an Analysis Report completed by United International

Corporation (UIC) on behalf of the City of Ansonia, the Ansonia WPCF has a permitted annual

average design capacity of 3.5 MGD and a peak design hydraulic capacity of 12.0 MGD.

Discussions with Ansonia WPCF staff and a review of the failure associated with Module #1 of

the UV system in 2011 indicates a hydraulic bottleneck occurs somewhere between the UV

system and the effluent discharge to the Naugatuck River. Based on a discussion with Ansonia


7/168


8/168


9/168



April 2014

The 20-year build out flows for Ansonia were obtained from information provided within the City

of Ansonia’s 2004 Wastewater Facilities Plan. The information provided in the plan indicates

that additional flows from the City of Derby were neither anticipated nor accounted for as part of

the Wastewater Facilities Plan, nor were additional flows from Derby included in the subsequent

upgrades to the Ansonia WPCF. The combination of the current flows and the 20-year build out

flows are presented in Table 1-2 and Table 1-3.

Table 1-2: Current Flow Conditions Ansonia and Derby combined Flows

Current FlowCondition

AnsoniaFlow (MGD)

Derby Flow(MGD)

Total Flow(MGD)

Ansonia WPCFCapacity (MGD)

Ansonia WWTFExcess Capacity

(MGD)

Annual Average

1.8 1.6 3.4 3.5 0.10

Peak Day 10.5 10.0 20.5 7/12 -13/-8.5

Table 1-3: 20-Year Flow Conditions Ansonia and Derby combined Flows

20-Year FlowCondition

AnsoniaFlow (MGD)

Derby Flow(MGD)

Total Flow(MGD)

Ansonia WPCFCapacity (MGD)

Ansonia WWTFExcess Capacity

(MGD)

Annual Average

2.2 2.4 4.6 3.5 -1.10

Peak Day 7.4 9.5 16.9 7/12 -9.9/-4.90

As shown in Table 1-2, the Ansonia WPCF provides adequate capacity to treat the current

combined annual average flows from both communities. However it does not have capacity to

treat the current combined peak flows from both communities. In addition, the information

presented in Table 1-3 indicates that the Ansonia WPCF does not provide adequate capacity to

treat the combined annual average and/or the combined peak flows from both communities

based on the 20-year build out flows presented in each community’s wastewater facilities plan.

In order to facilitate a possible interconnection between the City of Ansonia and the City of

Derby, the following would need to occur:

• Derby would need to aggressively begin removing I/I. In previous reports, Ansonia has

indicated that Derby needs to reduce the annual I/I component to no greater than 0.50


10/168



April 2014

MGD. This will require the removal of approximately 10 MGD of I/I from the system.

This would require the removal of both cost effective and non-cost effective I/I and may

still not be attainable as the system continues to age.

• Ansonia would need to continue removing I/I. Ansonia has recently completed several

I/I remediation projects. Ansonia would need to continue removing I/I, this would require

the removal of both cost effective and non-cost effective I/I.

• Ansonia would need to upgrade the WPCF to expand capacity. The Ansonia WPCF

does not have adequate capacity for the combined flows from both communities and

would be beyond the statutory 90% flow capacity threshold on an annual average basis

upon completion of the interconnection. Failure to upgrade the WPCF would limit the

growth and economic development in both communities.

• A regional WPCA would need to be created. Each community would relinquish sole

control of its wastewater system. A regional WPCA board comprising members from

each community would be created with each community having an equal say. At a

meeting with CT DEEP, the City of Ansonia has indicated that they are not in favor of a

regional WPCA and that City of Derby would be deemed a paying customer.

1.5.2 Storage Analysis

To determine the storage volume required for the City of Derby, the reported Derby WPCF flow

records for 2011 were analyzed. Using the reported Derby WPCF effluent flows, a requiredstorage volume could be calculated based on a given pumping rate. The required storage

volumes, shown in the Table 1-4, are the result of a two week period in March 2011 during

which three storms occurred. The first storm in March 2011 included an equivalent rainfall of

5.75 inches, which includes snow melt and is slightly higher than a 10-year return interval storm.

Two smaller storms followed within two weeks after the first storm. The results of the storage

analysis are presented below in Table 1-4 and the charts and raw data for the analysis are

included in Appendix C.

Table 1-4: Required Storage Volumes At Various Pumping Rates

Derby PumpingRate (gpm)

Derby PumpingRate (MGD)

Ansonia WPCF PeakCapacity MGD

Storage Volume MG(7 MGD / 12 MGD Capacity)

3,000 4.3 7 / 12 13.1 / 8.1


11/168



April 2014

Derby PumpingRate (gpm)

Derby PumpingRate (MGD)

Ansonia WPCF PeakCapacity MGD

Storage Volume MG(7 MGD / 12 MGD Capacity)

4,000 5.8 7 / 12 11.5 / 3.5

5,000 7.2 7 / 12 6.8 / 1.8

6,000 8.6 7 / 12 5.72 / 0.72

7,000 10.1 7 / 12 5.0 / 0

Since the Ansonia WPCF can be upgrades to attain its design peak hydraulic design capacity of

12.0 MGD and the 20-year design peak flow for the City of Ansonia is anticipated to be 7.4

MGD, the maximum pumping rate that could be used by the City of Derby is 3,200 gpm or 4.6

MGD. Based on the storage analysis presented in Table 1-4, the City of Derby would be

required to store approximately 8,000,000 gallons (assuming the Ansonia WPCF increases the

hydraulic actual peak capacity to the design of 12 MGD) of raw wastewater for storms similar to

those that occurred in March 2011 or storms greater than the 10-year return interval storm

event. Based on the flows experienced at the Derby WPCF over this time period and the

allowable pumping rate, it would take approximately two weeks to pump all of the stored

wastewater volume to the Ansonia WPCF for treatment. The rainfall amount for a 100-year

return interval storm event is 9.4 inches, which would result in an even greater required storage

volume or a higher pumping rate to prevent a bypass or an overflow.

The interconnection concept is not feasible at this time due to the excessive storage volumes

required (8 to 13 million gallons). The City of Derby has indicated that the interconnection

concept will not be feasible until the required storage volume is reduced to 1 million gallons or

less due to odor concerns as well as operations and maintenance concerns associated with the

storage facility. This can be accomplished by a combination of the following:

• Reduction of I/I from Derby

• Reduction of I/I from Ansonia

• Upgrades and expansion of the Ansonia WPCF


12/168



April 2014

2. Ansonia Derby Interconnection Alternatives

2.1 Alternative 1 - Elimination of the Derby WPCF with pumping of flows to the Ansonia

WPCF

Alternative 1 diverts flow from the Derby WPCF to the Ansonia WPCF via a new interconnectingpumping station and force main. Based on discussions with the City of Ansonia, the City of

Derby would need to provide fine screening and grit removal before the interconnection

pumping station since it would function as a satellite headworks for the Ansonia WPCF. To

facilitate operations during construction as well as the fine screening and grit removal systems,

the influent pump station at the Derby WPCF would need to be replaced with a new larger

pumping station, this would also allow for the screening and grit removal systems to be provided

before the wastewater pumps . After passing through the screening and grit removal systems

Derby’s wastewater would be pumped directly into the primary settling tanks at the Ansonia

WPCF. Two four-million gallon storage tanks would need to be installed at the Derby WPCF

(See Section 1.5.1) to accommodate peak flows. Conceptual layouts for the pump station and

force main are shown on Figures 2-1A and 2-1B.

The results of the conceptual interconnection analysis were based on an allowable pumping

rate of 3,200 gpm, which was dictated by the City of Ansonia. The City of Ansonia noted that

the flows from the City of Ansonia combined with the pumping rate from the City of Derby could

not exceed the Ansonia WPCF design hydraulic capacity. An upgrade to the Ansonia WPCF

would be needed in order to increase the current hydraulic capacity (7 MGD) to the design

hydraulic capacity (12 MGD). To achieve the required cleansing velocities while reducing the

friction head within allowable values, a 16-inch diameter force main is recommended. Due to

constructability and underground utility corridor issues, the best force main route from the Derby

WPCF to the Ansonia WPCF is approximately 9,000 linear feet. Based on the static head,

allowable pumping rate, pipe diameter and length of the force main, the wastewater pumps

would pump against approximately 75 feet of total dynamic head. Conceptual estimates

indicate that this would require four 100-horsepower variable speed drypit style wastewater

pumps operating in parallel. Each of the pumps would be provided with a dedicated VFD to

allow for flow fluctuations between the normal and the I/I induced peak flows. To prevent

overflows during events greater than the 10-year storm, Derby will either have to pump at rates

higher than 3,200 gpm or provide greater than 8 million gallons of storage. As previously noted,


13/168


14/168



April 2014

The preliminary opinion of probable costs for interconnection with the City of Ansonia is

approximately $50,000,000 which includes design and a planning level contingency. A

breakdown of the project costs is included in Appendix D. NOTEWELL: The opinion of

probable costs does not include any upgrades to expand the permitted capacity of the Ansonia

WPCF or any of the costs associated with the removal I/I.

If the WPCA were to proceed with the Interconnection, the WPCA estimates that the annual

cost of maintaining the collection system and wastewater pumping stations is $1,860,000. This

annual cost does not include any existing or future capital debt service or wastewater disposal

fees to the City of Ansonia.

2.3 Alternative 3 - Elimination of the Derby WPCF with pumping of flows between the

Ansonia WPCF and Shelton WPCF

As noted in Section 1.4 the City of Shelton has expressed no interest in regionalization with the

City of Derby. The City of Shelton recently completed a major upgrade and capacity expansion

to its WPCF and does not have capacity issues within its system. The City of Derby expressed

an interest in interconnecting with the City of Shelton for wastewater treatment and disposal at

the Shelton WPCF. The City of Shelton and the City of Derby WPCF sites are located on

opposite sides of the Housatonic River at its intersection with Route 8. The City of Shelton has

noted on numerous occasions that it is not interested in receiving and treating flows from the

City of Derby.

Since the City of Shelton is not interested in interconnecting with the City of Derby this

alternative is not viable and was eliminated from consideration.

2.4 Alternative 4 – Alternatives Presented by the City of Ansonia

The following Interconnection alternatives were presented to the City of Derby by the City of

Ansonia through a study conducted by United International Corporation (UIC – now Prime

Engineering). Additional Interconnection Alternatives were also discussed in detail by Ansonia

Mayor James Della Volpe in a press release from September 2013 during his re-election

campaign. A copy of the press release and alternatives are provided in Appendix E.


15/168



April 2014

2.4.1 Option 1 – Storage at Derby WPCF and Off-Peak Pumping to Ansonia

Under Option #1, which was prepared and proposed by UIC on behalf of the City of Ansonia,

the City of Derby would utilize the existing WPCF for preliminary and primary treatment and the

storage of up to 2.0 million gallons of wastewater per day. The storage volume would

encompass the total volume of the City of Derby WPCF aeration basins and secondary

clarifiers. The wastewater would be pumped to the Ansonia WPCF via a 6-inch forcemain from

12 am to 5 am at a rate of 235 gallons per minute. An evaluation of storage and pumping based

on the information provided under this option for a seven-day period is provided in Table 2-1.

Table 2-1: Off Peak Storage and Pumping Analysis

DayVolume Pumped

to Ansonia

(Gallons)

Volume Stored atthe Derby WPCF

(Gallons)

Overflow Volume tobe Treated Onsite

(Gallons)

Derby DailyWastewater

Volume (Gallons)

1 70,500 1,529,500 0 1,600,000

2 70,500 2,000,000 1,059,000 1,600,000

3 70,500 2,000,000 1,529,500 1,600,000

4 70,500 2,000,000 1,529,500 1,600,000

5 70,500 2,000,000 1,529,500 1,600,000

6 70,500 2,000,000 1,529,500 1,600,000

7 70,500 2,000,000 1,529,500 1,600,000

Total 493,500 Note 1 8,706,500 11,200,000

1 – The storage volume of the Derby WPCF is completely utilized within the first two days. Since the storage is never emptied thetanks would remain at 2.0 million gallons until being emptied.

The option presented by the City of Ansonia only accounts for the average daily flow and does

not take into account peak/variable flows. On average, the Derby WPCF currently treats 1.6

MGD which is equivalent to 1,111 gpm. Under this scenario, only 70,500 gallons per day would

be sent to the Ansonia WPCF for treatment. The remaining flow would have to treated at theDerby WPCF, thus the regional concept is not feasible as presented by this alternative, and was

eliminated from further consideration.


16/168



April 2014

2.4.2 Option 2 – Storage at Derby WPCF and Off-Peak Pumping to Ansonia and Additional

Storage within a 15-inch RCP sewer.

Option #2, which was prepared and proposed by UIC on behalf of the City of Ansonia, is similar

to Option #1 with the exception that the 6” forcemain is replaced with a 15-inch RCP gravity

sewer from the Derby WPCF to the Ansonia WPCF. Under this scenario, a second pumping

station is provided at the Ansonia WPCF to lift the flows into the primary settling tanks. The 15-

inch RCP gravity sewer provides an additional storage volume of approximately 74,000 gallons

after the 2.0 million gallons of storage at the Derby WPCF. Based on the information depicted

on existing plans the Derby WPCF is at a site elevation of approximately 10 feet with an influent

24-inch gravity sewer at an elevation of -4.6 feet. The Ansonia WPCF is at a site elevation of

approximately 23 feet with an influent 27-inch gravity sewer at an elevation of 3.5 feet. The

proposed gravity sewer would have to be installed against grade by a minimum of 13 feet for a

distance of approximately 9,000 feet. Like Option #1, Option #2 is not feasible for the reasons

outlined in Option #1 and was eliminated from consideration.

2.4.3 Option 3 – Storage and Pumping at Derby WPCF with conveyance to the Ansonia

WPCF Influent Pumping Station via a 15-inch RCP interceptor.

Option #3, which was prepared and proposed by UIC on behalf of the City of Ansonia, is similar

to Option #2 with the exception of the following:

• The use of the Derby WPCF for preliminary and primary treatment has been eliminated.

• The Derby WPCF Influent Pumping Station is used for pumping of wastewater to

Ansonia,

• The 15-inch RCP gravity sewer connects to the Ansonia WPCF influent pumping station

wetwell rather than the primary settling tanks,

• Three sewer interceptor layouts were provided. The costs for the interceptor layouts

ranged from $8.9 to $5.7 million.

Since proposed pumping information was not provided, a flow and storage analysis for this

alternative could not completed. It should be noted that the cost estimates for each layout

included two (2) packaged pumping stations, neither of which were noted in the discussion of

each option. The City of Derby has noted on numerous occasions to the City of Ansonia that if

the interconnection were to happen a new pumping station would be provided. Due to

construction staging and redevelopment requirements for the Derby WPCF Site, the City of


17/168



April 2014

Derby will not re-use the existing influent pumping station under any interconnection. This

alternative does not include the screening and grit removal systems at the Derby site as

previously required by Ansonia. Also, as noted in the analysis of Option #2, the information

depicted on existing plans, the Derby and Ansonia WPCF’s are at elevations that do not support

the installation of a gravity interconnection.

Options #1 and #2, as described above, were discussed at a joint meeting between the City of

Ansonia and City of Derby which was held on March 12, 2012 at the City Hall of Ansonia. At

this meeting, the City of Derby WPCA noted that each of these options was not viable for the

reasons noted above. The City of Derby also requested information including an acceptable

pumping rate, the capital connection fee, and the anticipated user fee structure from the City of

Ansonia. To date, this information has not been provided to the City of Derby WPCA. A copy of

the meeting minutes from this meeting are provided in Appendix F.

Option #3, was presented to the public on September 3, 2013 by Ansonia Mayor James Della

Volpe as part of a press conference during his re-election campaign. Since no pumping/storage

information was provided, an analysis of this alternative could not be completed. Due to the

discrepancies between the write-up of Option #3 and the cost estimates, it appears as through

Option #3 is Option #2 with several different interceptor sewer routes.

None of the alternatives presented by the City of Ansonia appear to be viable. In addition to the

information provided above, each of the options from the City of Ansonia assumes that the City

of Derby will remove unrealistically high quantities of I/I, thus reducing the annual average daily

flow from 1.6 MGD to 1.2 MGD and the peak flow from 10.0 MGD to 3.2 MGD. Each of the

options presented by the City of Ansonia assume that the Derby collection system has a

combined I/I of 1.4 MGD which is cited from a 2007 I/I study, prepared by Milone and

MacBroom. However, that 2007 I/I study was focused on only the Hawthorne Avenue area and

not the entire collection system. The systemwide I/I value based on actual flow metering data

exceeds 10 MGD.

2.5 Partial “Turnaround” Project

Portions of the Derby collection system are located adjacent to the Ansonia collection system,

making it possible to divert flows from these areas to Ansonia’s collection system. As part of the


18/168



April 2014

future planned upgrades to the collection system, Derby plans to eliminate the inverted siphon

and trunk line that conveys flow from East Derby under the Naugatuck River to the Derby

WPCF. These pipelines present hydraulic restriction points and are maintenance intensive due

to access and flood plain issues. These issues can all be alleviated by installing a new pump

station and force main to eliminate the inverted siphon and trunk line. The new force main route

could be laid out to discharge to Ansonia rather than the Derby WPCF. The peak flow measured

during the flow metering program in East Derby was 4.82 MGD. By installing the force main

from the proposed station to the Ansonia WPCF, a regional solution can be made without

exceeding the peak hydraulic capacities at either WPCF. Approximately 0.22 MGD of peak I/I

would need to be removed from East Derby for this alternative to be effective. The proposed

force main route and pump station location can be seen on Figure 1-3.

In discussions with the City of Derby, the financial impacts to the WPCA associated withmaintaining the system and the WPCF while losing half of the flow would be unsustainable. The

City of Derby WPCA noted that only interconnection options which eliminated the operations of

the WPCF would be considered. As such this alternative was eliminated from consideration.

2.6 Fountain Lake Industrial Park

Over the course of the planning period it is expected that the Fountain Lake Industrial Park will

be expanded from its current location in Ansonia into Derby. Average daily flows of up to

348,500 gpd at maximum build-out have been projected for the industrial park. Over theplanning period it is expected that approximately 25% of the industrial park will be occupied and

contribute an average daily flows of 87,125 gpd. Based on the recommendations in Derby’s

Conservation and Development Plan the flows from the Fountain Lake Industrial Park should be

directed to the Ansonia collection system.

2.7 Alternatives Scoring Matrix for Economic and Non-Economic Factors

A summary of the interconnection alternatives recommendation matrix analysis for

recommendation of a preferred regionalization option is provided in Table 2-2. As noted abovesince the Shelton is not interested in interconnection and the options provided by the City of

Ansonia are not viable they are not been included in the matrix analysis.


19/168



April 2014

Table 2-2: Matrix Analysis – Interconnection/Regionalization Recommendation Matrix

Criteria Alternative #1 –Pump to Ansonia(Section 8.5.3.1)

Alternative #2 – Pump to Ansonia – 36-inch effluent to Housatonic

River (Section 8.5.3.2)

Fountain Lake(Section 8.5.5)

Flow Feasibility 1 1 5

Concept Feasibility 5 5 5

Ansonia WPCFUpgrades requiredfor 20-year + peakflows

1 1 5

Eliminates Ansonia

EffluentPhosphorousRequirements

1 5 1

Required Army Corp/ Rail PermittingIssues

3 2 5

RequiredConnecticut DOTPermitting Issues

3 2 5

Derby’s Ability toControl Costs

1 1 3

Reduced DerbyStaffing

3 3 1

Ability to ImplementPlanned Growth

1 1 5

Allows for Re-Development of

Derby WPCF Site

2 2 1

Requires less than 1MGD in Storage atDerby PS Site

1 1 5


20/168



April 2014

Criteria Alternative #1 –Pump to Ansonia(Section 8.5.3.1)

Alternative #2 – Pump to Ansonia – 36-inch effluent to Housatonic

River (Section 8.5.3.2)

Fountain Lake(Section 8.5.5)

Requires more than

1 MGD of I/IRemoval by Derby

1 1 5

Addresses FutureNPDES PermitRequirements

5 5 5

Total 28 30 51

The ranking criteria range from 5 being excellent to 1 being poor. The interconnection with the

City of Ansonia through the Fountain Lake Industrial Park Development alternative has the

highest overall ranking, and is the only alternative that is feasible at this time.


21/168



April 2014

3. Recommendation

Based on the analysis and discussion above, it is recommended that the City of Derby meet its

wastewater needs by maintaining operations of the Derby WPCF. The Derby WPCF has

capacity to accept additional flow from the Towns of Orange and Seymour. The amount of

additional flow the WPCF can accept will increase after the implementation of an annual I/I

removal program as described earlier in the report. Derby should also pursue regional solutions

with Ansonia as described in the Derby Conservation and Development Plan by directing all

future flows from the Fountain Lake Industrial Park to the Ansonia collection system.

Other options for regionalization with the City of Ansonia do not appear to be an effective

solution at this time due to the limited capacity at the Ansonia WPCF to handle the I/I induced

fluctuation in flows in the Derby collection system or the 20-year planning flows from both

communities. The viability of the interconnection should be assessed again within the next 10

to 15 years, prior to the Phase II upgrades to the Derby WPCF noted herein. Prior to the re-

assessment of the interconnection viability the following actions need to be taken by both

communities:

• The City of Ansonia must assess the upgrades need to the Ansonia WPCF to increase

the permitted capacity to allow for planned growth / economic development within both

the City of Ansonia and the City of Derby.

• The City of Derby must begin a I/I removal program to reduce the peak I/I flow from the

Derby collection system.

The City of Derby met with the Connecticut Department of Energy and Environmental Protection

(CTDEEP), City of Ansonia, UIC, HDR Engineering, Inc., and Weston & Sampson Engineers,

Inc. on October 15, 2012 at the CTDEEP offices to discuss the status of the interconnection

analysis and its feasibility. At the meeting the following was recognized by all parties:

• The interconnection was currently not feasible,

• The interconnection would take a minimum of 15 to 20 years to implement.

•

The City of Derby collection system contains excessive infiltration and inflow volumesand is in the process of conducting an SSES,

• The goal of any I/I project is to remove 50% of the I/I but realistically only 30% of it can

typically be removed,


22/168



April 2014

• Ansonia was not interested in creating a regional WPCA with a WPCA board consisting

of members from both communities, and

• The Derby WPCA would be responsible for maintaining its collection system and would

be a paying customer to the Ansonia WPCA.

At the conclusion of the meeting CTDEEP recommended that the Derby and Ansonia WPCA’s

develop subcommittees to keep open lines of communication regarding the possibility of

regionalizing their wastewater services at some point in the future. CTDEEP also

recommended that the subcommittees meet annually to discuss the status of each system, I/I

removal and to keep lines of communication open regarding the possibility of an

interconnection. A copy of the meeting minutes is provided in Appendix G.


23/168

APPENDIX A

Regionalization Letters


24/168


25/168


26/168


27/168


28/168


29/168


30/168


31/168

APPENDIX B

UV System Hydraulic Issues


32/168


33/168


34/168


35/168


36/168


37/168


38/168


39/168


40/168


41/168

APPENDIX C

Storage Analysis Data and Results


42/168


43/168

0

1

2

3

4

5

6

7

8

9

10

J

a n - 1 1

F

e b - 1 1

M

a r - 1 1

A

p r - 1 1

M

a y - 1 1

J

u n - 1 1

J u l - 1 1

A

u g - 1 1

M I L L I O N S O F G A L L O N S S T O R E D

EQUALIZATION STORAGE EVALUATION - 10 MG

3,000 GPM (4.32 MGD)

4,000 GPM (5.76 MGD)

5,000 GPM (7.20 MGD)

6,000 GPM (8.64 MGD)

7,000 GPM (10.08 MGD)

TOTAL DAILY FLOW

PUMPING RATES


44/168

PUMP RATE 3,000 4,000 5,000 6,000 7,000

REQUIRED

STORAGE (GAL) 8,027,500 3,410,000 1,766,667 715,833 0

2011 FLOW DATA

REQUIRED STORAGE (GAL)

DERBY, CT

DERBY WASTEWATER TREATMENT FACILITY


45/168


46/168


47/168

Quantity Unit Unit Cost Description Cost

9,000 LF $250 Forcemain $2,250,000

2,200 CY $100 Rock Excavation $220,000

2,000 CY $75 Unsutiable Material $150,000

2 EA $500,000 Forcemain Railroad Pipe Jacking $1,000,000

10 EA $15,000 Forcemain Structures $150,000

1 LS $500,000 Ansonia WPCF Primary Clarifier Interconnection Structure $500,000

2,000 LF $10 Cross Country Area Restoration $20,000

7,000 LF $25 Temporary Pavement $175,000

7,000 LF $45 Permanent Pavement $315,000

24,000 SY $20 Milling and Overlay Pavement (1 1/2") $480,000

2,000 HR $65 Traffic Control Allowance $130,000

1 LS $100,000 Concrete Road Base Allowance $100,000

1 LS $250,000 Dewatering $250,000

1 LS $420,000 Contractor Bonds & Insurance (7.5%) $420,000

Forcemain Subtotal $6,160,000

4 EA $60,000 Drypit Wastewater Pumps $240,000

1 LS $200,000 Backup Generator $200,000

1 LS $500,000 Electrical System $500,000

1 LS $350,000 Instrumentation Control System $350,000

1 LS $200,000 Process Piping $200,000

1 EA $350,000 Fine Screen $350,000

1 EA $450,000 Grit Removal System $450,000

1 LS $500,000 Equipment Installation $500,000

2,000 CY $1,000 Cast In place Concrete Drypit/Wetpit (40ft deep) $2,000,000

6,000 SF $250 Pumping Station CMU Operations Building $1,500,000

1,000 SY $45 Paving $45,000

9,000 CY $75 Excavation $675,000

1 LS $500,000 Support of Excavation $500,000

1 LS $250,000 Dewatering $250,000

1 LS $500,000 Site Modifications, Utilities, Piping Modifications $500,000


Pumping Station Subtotal $8,880,000

2 EA $4,000,000 4 MG Prestressed Concrete Tank w/ Mixing/ Odor Control $8,000,000


Wastewater Storage Subtotal $8,600,000

1 LS $3,500,000 Demolition and Removal (existing WPCF) $3,500,000

Derby / Ansonia Regionalization Interconnection

Drypit Wastewater Pumping Station and Forcemain

Engineer's Opinion of Probable Construction Costs

Forcemain

Wastewater Pumping Station

Wastewater Storage

WPCF Demolition


48/168


49/168


9,000 LF $250 Forcemain $2,250,000



2 EA $500,000 Forcemain Railroad Pipe Jacking $1,000,000

10 EA $15,000 Forcemain Structures $150,000

1 LS $500,000 Ansonia WPCF Primary Clarifier Interconnection Structure $500,000







1 LS $200,000 Dewatering $200,000


Forcemain Subtotal $6,075,000

10,000 LF $425 36" PVC $4,250,000



2 EA $500,000 Railroad Pipe Jacking $1,000,000

1 EA $500,000 Flood Dike Pipe Jacking $500,000

1 LS $300,000 Derby WPCF Effluent Interconnection Structure $300,000







1 LS $200,000 Dewatering $200,000


Effluent Modificaitons Subtotal $7,860,000

2 EA $4,000,000 4 MG Prestressed Concrete Tank w/ Mixing/ Odor Control $8,000,000


Wastewater Storage Subtotal $8,600,000

1 LS $3,500,000 Demolition and Removal (existing WPCF) $3,500,000


WPCF Demolition Subtotal $3,763,000

Ansonia WPCF Effluent Modifications


Drypit Wastewater Pumping Station, Forcemain and WPCF Effluent Relocation


Forcemain

Wastewater Storage

WPCF Demolition


50/168



Drypit Wastewater Pumping Station, Forcemain and WPCF Effluent Relocation


4 EA $60,000 Drypit Wastewater Pumps $240,000

1 LS $200,000 Backup Generator $200,000

1 LS $500,000 Electrical System $500,000

1 LS $350,000 Instrumentation Control System $350,000

1 LS $200,000 Process Piping $200,000

1 EA $350,000 Fine Screen $350,000

1 EA $450,000 Grit Removal System $450,000

1 LS $500,000 Equipment Installation $500,000

2,000 CY $1,000 Cast In place Concrete Drypit/Wetpit (40ft deep) $2,000,000

6,000 SF $250 Pumping Station CMU Operations Building $1,500,000

1,000 SY $45 Paving $45,000

9,000 CY $75 Excavation $675,000

1 LS $500,000 Support of Excavation $500,000

1 LS $250,000 Dewatering $250,000

1 LS $500,000 Site Modifications, Utilities, Piping Modifications $500,000


Pumping Station Subtotal $8,880,000

OPC Construction Sub Total $35,180,000

Contingency (20%) $7,036,000

Engineering and Implmentation (20%) $7,036,000

OPC Project Cost $49,252,000

NOTE:1

2

3

This OPC does not include the costs associated with the connection fee to the Ansonia WPCF

This OPC does not include costs for additional upgrades which will be required to the Ansonia WPCF

Wastewater Pumping Station

This OPC does not include mitigation costs for identification and removal Inflow & Infiltration


51/168

Office Account2600-270-0270 Social Security Taxes $56,006200-110-0110 Office Wages $71,666200-110-0112 Employee Secretarial $1,40

6200-110-0110 Part Time Wages $30,006200-150-0150 Office Instruction $946200-150-0152 Accounting $9,50

6200-150-0153 Computer Service $2,506200-160-0161 Town Clerk $2,606200-160-0162 Atty Sheriff Title Search $2,506200-160-0163 Med/Life/Worker Comp Ins $270,006200-270-0270 Insurance $28,206200-270-0271 Postage/Printing $5,506200-270-0272 Birmingham Billing $3,206200-320-0320 Business Forms $2,716200-330-0330 Office Supplies $1,006200-640-0640 Retiree Medical $6,58

Office Accounts Total $494,31

Plant Accounts6200-110-0111 Superintendent $88,29

Mechanic $64,18 Grade 2 $60,38 Grade 2 $60,38 Grade 2 $60,38

6200-120-0120 Overtime Wages $60,006200-150-0151 Operator Instruction $3,006200-160-0164 Vehicle Maintenance $10,006200-220-0220 Electric $70,00

6200-230-0230 Gas Heat $14,006200-230-0232 Water $1,20

6200-400-0430 Special Clothing $3,006200-400-0432 Pest Control $556200-400-0434 Collection System Maintenance $275,006200-400-0435 Collection System Rehabilitation $200,006200-440-0440 Pump Station Maintenance $165,006200-460-0461 BFI Rags Grit Grease $4,506200-480-0484 General Engineer Costs $60,006200-490-0498 Working Balance $85,006200-480-0495 Vehicle Replacement $75,00

Operations Accounts Total $1,359,88

Grand Total $1,854,20

Office Accounts

System Operations Accounts

City of Derby Water Pollution Control Authority

Estimated System Maintenance Budget - Ansonia Interconnection


52/168


53/168

APPENDIX E

Ansonia Interconnection Alternatives – UIC Reports


54/168


55/168

APPENDIX E

UIC – City of Ansonia Interconnection Report

Interconnection Option #1 through #3


56/168


57/168

1

ANALYSIS REPORT

DERBY WPCF, DERBY, CT

The City of Derby, CT has expressed a need to adequately treat the sanitary flows generated

within the sewer system limits without expending a large amount of funds on upgrading the

existing Water Pollution Control Facility (WPCF). In doing so, the City must look at several

options for handling not only the existing sanitary flows, but flows that are projected to increase

over the next twenty years. For the purposes of this report, the option of transferring the City’s

wastewater flows to the Ansonia WPCF will be analyzed.

The primary concern will be the capacity of the Ansonia WPCF to handle the increased flows

from Derby. The Ansonia facility is permitted to handle and treat a design flow of 3.5 million

gallons per day (MGD), with a peak capacity of 7.0 MGD. The Derby WPCF has a design

capacity of 3.5 MGD with a peak flow capacity of 9.1 MGD. Both facilities’ daily flow records

over a three-year period were analyzed to determine an average daily flow and a maximum

daily flow. This information is presented in Table 1.

Table 1. Daily Flows from Plant Data

Derby WPCF – design flow capacity 3.5 MGD, peak flow capacity 9.1 MGD*

Year Average Daily Flow (MGD) Maximum Daily Flow (MGD)

2009 2.21 6.41

2010 3.01 8.08

2011 2.91 5.30*Data taken from Facilities Planning Study, 1997.

Ansonia WPCF – design flow capacity 3.5 MGD, peak flow capacity 7.0 MGD

Year Average Daily Flow (MGD) Maximum Daily Flow (MGD)

2009 1.72 5.08

2010 2.25 5.73

2011 1.80 3.50

As can be seen, the maximum daily flows from Derby WPCF, in addition to the Ansonia flows,

will exceed the Ansonia WPCF peak flow capacity. Therefore, the flows from Derby must be

restricted in some manner so as not to exceed the capacity of the Ansonia facility. This can be

accomplished by releasing the flows from Derby at a controlled rate which will not adversely

affect the treatment capacity at Ansonia. There are several options to consider:

Option #1: Store the Derby sanitary flows at the Derby WPCF and pump them through a

force main to Ansonia at a controlled rate. The existing treatment structures would be usedas storage/equalization basins. Storing the sanitary sewage at Derby would entail removing

the treatment equipment from the existing Primary Settling tanks, Aeration Basins, and

Clarifiers and using these structures strictly for storage/equalization. Two (2) Primary

Settling Tanks have a combined volume of 215,424 gallons, 3 Aeration Basins have a

combined volume of 1.34 million gallons (MG), and 2 Clarifiers have a combined volume

of 423,000 gallons. The total volume of daily sewage that can be stored is nearly 2 million

gallons. Attachment 1 presents an overhead image of the existing WPCF showing the

locations of these structures. Some form of primary treatment, such as bar screens or

comminutors, would be required to prevent the entry of larger solids through the

equalization facilities. This treatment is capable of removing approximately 60% of the


58/168

2

solids in the influent stream. The sewage could then be pumped via force main at a

controlled rate to the Ansonia facility. The length of the force main, approximately 8,000

linear feet between the facilities, would require sewage lift stations along the route to

maintain system pressure. A 6-inch, poly-vinyl chloride force main could pump the sewage

to Ansonia and release the flows at approximately 235 gallons per minute. The pumping

from Derby could be timed such that during low treatment flow periods, 12AM to 5AM for

example, the Ansonia WPCF would not be overburdened by the additional sewage flows in

terms of capacities and biological loadings.

Option #2: Install a sewer connector between the Derby and Ansonia WPCFs. A 15-inch

or larger reinforced concrete sewer interconnect of approximately 8,000 linear feet could

serve as a storage facility, storing at least 74,000 gallons of sewage until it can be released

into the Ansonia facility. The flow would be a controlled release to minimize the influent

affect on the Ansonia facility. This option could reduce the need to store as much flow in

the Derby facility and allow some form of primary treatment, such as settling, to occur

before the flows are pumped to Ansonia. The Primary Settling Tanks can remove as much

as 65% of suspended solids in the influent. In doing so, the treatment load at Ansonia could

be reduced. The interconnect system may require a pumping station at the Derby WPCF to

pump the sewage through the interconnect, with lift stations to maintain the flow within the

pipe. An alternative would be to install a pump station to pump the sewage from the Derby

facility, install the interconnect with sufficient slope to maintain flow, and construct a liftstation just prior to the Ansonia facility to pump flows into that WPCF.

Each of the previous options is based on the assumption that infiltration and inflow into the

Derby sewer system contributes to the maximum daily flow rate. Infiltration into a sanitary

sewer system occurs when rainfall events introduce storm water into the system through

deficiencies in piping, structures, and connections. Inflow into a sanitary system is due to

improper connections of roof drains, yard drains, etc., that are connected to the sanitary

system. Inflow connections introduce storm water into the sanitary system that should

otherwise be directed through the storm sewer systems. In many municipalities across the

country, these connections are illegal. An infiltration/inflow (I/I) analysis is discussed later

in this report. Option #3 addresses the actions necessary to reduce I/I in the Derby system.

Option #3: To reduce I/I in the Derby sanitary system and thus reduce the maximum flows

that occur during wet weather events, the entire sanitary sewer system should be replaced or

lined with cured-in-place (CIP) pipe linings. The areas of the sanitary system that have not

been studied should be included in a broad program using closed-circuit televising (CCTV),

smoke testing, and dye testing to identify sources of inflow and infiltration. CCTV will

identify those segments of sewer pipe and structures (e.g. manholes) that must be replaced

due to condition, and those segments that are candidates for CIP lining. Both methods will

significantly reduce infiltration into the system. Smoke and dye testing will identify

sources of inflow that should be removed from the sanitary system. A comprehensive

program to eliminate I/I sources would reduce the maximum flows in the system by at least

60%. Once the flows have been significantly reduced, then an analysis of the total flows

required to be treated by the WCPF will be significantly low.

Implementing a comprehensive I/I reduction program, removing inflow sources and

replacing and/or rehabilitating the system piping, will reduce the capacity required for

storage/equalization and reduce the sanitary flows to Ansonia WPCF. Other advantages

include reduced capacity loads on Ansonia WPCF with reduced operating, maintenance,

and replacement costs at both WPCFs.


59/168


60/168

4

development/redevelopment occur as planned, will be 2.38 MGD. Any improvements or

modifications required to direct sanitary flows to the Ansonia WPCF must include the

projected sanitary flows in the design to provide sufficient capacity for growth.

Conclusions/Recommendations

The flow data from the two WPCFs indicates that, if the flow from Derby is taken to

Ansonia without a controlled equalization process and flow rate, the combined flow for 180

consecutive days will exceed 90% of the present average design flow rate of Ansonia

WPCF. This will trigger a requirement for the Ansonia WPCF as stated below:

Section 4(L) of Ansonia WPCF’s NPDES Permit issued on June 27, 2001states:

When the arithmetic mean of the average daily flow from the POTW for the previous 180

days exceeds 90% of the design flow rate, the permittee shall develop and submit for the

review of the Commissioner within one year, a plan to accommodate future increases in

flow to the plant. This plan shall include a schedule for completing any recommended

improvements and a plan for financing the improvements.

Additionally, the treatment processes at the Ansonia facility may not be able to support

untreated sanitary flows from Derby. Therefore, a process step of equalization, along with

primary treatment, must be instituted to allow the processes at Ansonia to effectively treatthe increased sanitary flow. Using the existing treatment structures as storage/equalization

basins, while removing all treatment equipment from these structures, will allow the City of

Derby to appreciably reduce operating costs for this facility. Although minimum operations

would still be required at Derby WPCF, for example, monitoring of pumping and screening

operations, the City of Derby can budget for lower operating costs and lower maintenance

costs for this plant.

An active program to reduce the I/I contributing to the Derby sanitary sewer system should

be implemented throughout the entire system. This program could reduce the I/I

contributions by at least 60%, thereby significantly reducing the flows from the City of

Derby to the Ansonia WPCF.

Feasibility Study

If the project as described is approved, the City of Derby should initiate and complete a

comprehensive feasibility study, or a preliminary engineering report, to analyze each option

as presented for practicality, cost/benefit, constructability, and socio-economic impact. The

purpose of such a study is to analyze all options to determine the best in terms of how much

will it cost to construct, what will be the long term benefits, how will the option affect

future growth, and which will provide the best results. In order to accomplish such a study,

the data collection effort should include the following:

1.

Site investigation. Site investigations will include a site visit by the design team,

interviews with personnel familiar with the project, and an understanding by the designteam of the client’s requirements. The site visit will provide the design team with an

assessment of the existing conditions for each option, the limitations and constraints of

each option, valuable information from the owners/operators of each WPCF, and

background information to provide an overall scope of the project design. Site

investigation will also include:

geotechnical investigations to determine the composition and stability of the

existing soils,

topographic surveys to provide a visual picture of the land surface, existing utilities,

structures, appurtenances, and other possible impediments to each option,

right-of-way and utility easement surveys,


61/168

5

obtaining and reviewing existing utility plans,

closed-circuit televising of existing sewer segments,

manhole and structure investigations,

smoke and dye testing.

2.

Environmental investigation. The environmental phase of the feasibility study will

address cultural, historic, and environmental factors in the design process. Following

the guidelines as set forth in the Connecticut Environmental Policy Act (CEPA), each

option will be assessed as to its impact on local and state environmental, archeological,

cultural, and historical assets for both the City of Derby and City of Ansonia. CEPA

provides for specific guidance on for conducting Environmental Impact Evaluations

(EIE), which are investigative documents that look at how the project will affect the

local and state environmental resources, air and water quality, noise, socio-economic

assets, historical/archeological and national landmarks, and cultural impacts. The EIE

process also provides the public with a vehicle for commenting on the project and

having their concerns taken in account prior to construction. The Consultant should

research all available federal, state, and local regulatory data concerning both WPCFs’

operations, permitting, violations, and corrective actions, if taken.

3. Concept design investigation. The concept design investigation phase begins with a

detailed analysis of all available historical documentation, plant flow data, treatmentand laboratory data, as-built drawings, previous studies, and engineering reports

concerning the existing facilities. At this stage of the feasibility study each option is

thoroughly examined in regards to size, equipment, location, materials, constructability,

and probable cost estimates.

4. Report phase, conclusions/recommendations. Once the design investigation is complete,

all the data collected will be compiled and designed into a feasibility report for

presentation to the client. The report will detail all actions taken from each

investigation phase and present findings and conclusions, and a preferred option, giving

the relevant justification for and against each option. The preferred option will be

recommended based on costs, benefits, ease of construction, limited impact on the

community and environmental resources, and value.

Att (3): 1. Figure 1. Aerial View of Derby WPCF

2. TECHNICAL MEMORANDUM, Wastewater Facilities Plan, Weston &

Sampson Engineers, Inc., September, 2011.

3. Data Correlation Table for Rainfall and I/I, Derby WPCF


62/168

6

List of References

1. Technical Memorandum to the City of Derby Water Pollution Control Authority,Weston & Sampson Engineers, Inc., Sept. 2011.

2. Influent and Effluent Qualitative Data Sheets, January 2009 through February 2011,

Derby WPCF, City of Derby, Conn.

3. Sanitary Sewer System Infiltration/Inflow Analysis, Hawthorne Avenue Watershed.

Milone & MacBroom, Inc., MMI #2165-01-12, July 2007.

4. Facilities Plan, Wastewater Treatment Plant and Sanitary Sewerage System. City of

Derby, Connecticut Water Pollution Control Authority, Semi-Final Draft. Cascio

Bechir Engineers. July 1997.

5. Construction Plans. City of Derby, Alterations and Additions to the Water Pollution

Control Plant Pump Stations and Sanitary Sewerage System. Cascio Bechir Engineers.

August, 1998.

6.

Influent and Effluent Qualitative Data Sheets, January 2009 through April 2011,Ansonia WPCF, City of Ansonia, Conn.


63/168

Attachment 1

Figure 1. Aerial View of Derby WPCF


64/168

AERATION BASINS

CLARIFIERS

PRIMARY

SETTLING

TANKS


65/168

Attachment 2

TECHNICAL MEMORANDUM, Wastewater Facilities Plan, Weston & Sampson Engineers, Inc.,

September, 2011.


66/168


67/168


68/168


69/168


70/168


71/168


72/168


73/168


74/168


75/168


76/168


77/168


78/168


79/168


80/168


81/168


82/168


83/168


84/168


85/168


86/168


87/168


88/168


89/168


90/168


91/168


92/168

Derby

WPCF

Flow

and

Rainfall

Data

Rainfall

Mon/Yr Max Min Avg inches*

for Stevensen Dam rain gage 5.5 mi. WNW o

Jan

09 4.10 0.80 1.72 1.74

Feb

09 3.60 0.70 1.77 1.05

Mar

09 3.40 0.80 2.40 1.41

Apr

09 6.40 0.80 2.10 2.79

May

09 7.50 0.60 1.98 3.95Jun

09 8.90 0.70 3.09 6.57

Jul

09 9.80 0.70 2.57 6.22

Aug

09 7.00 0.60 2.25 4.17

Sep

09 3.40 0.40 1.47 2.07

Oct

09 8.10 0.50 2.31 6.65 Exceeds Derby WPCF design f

Nov

09 7.30 0.80 1.92 2.22 Exceeds Derby WPCF peak flo

Dec

09 7.40 0.90 2.93 5.37

Yr

Avg 6.41 0.69 2.21

Jan

10 6.40 0.80 2.44 2.75

Feb

10 10.00 0.80 4.69 3.24

Mar

10 10.00 1.30 8.10 8.39

Apr

10 10.00 0.70 6.10 1.16

May

10 7.10 0.50 1.54 2.69

Jun

10 5.70 0.30 1.28 3.46

Jul

10 7.80 0.10 1.35 4.82

Aug

10 7.50 0.20 1.41 4.1

Sep

10 8.10 0.30 1.88 2.5

Oct

10 9.30 0.70 2.42 5.87

Nov

10 7.30 0.70 2.38 3.29

Dec

10 7.70 1.00 2.54 4.94Yr

Avg 8.08 0.62 3.01

Jan

11 3.10 0.90 2.04 3.3**

Feb

11 7.50 0.80 3.78 3.67**

Yr

Avg 5.30 0.85 2.91

Design 6.59 0.72 2.71

Avg

Flow

(MGD)

*taken from NCDC rainfall data


93/168

Rainfall

Monthly

Totals

Mon/Yr inches*

Jan

09 1.74

Feb

09 1.05

Mar

09 1.41Apr

09 2.79

May

09 3.95

Jun

09 6.57

Jul

09 6.22

Aug

09 4.17

Sep

09 2.07

Oct

09 6.65

Nov

09 2.22

Dec

09 5.37 Exceeds

Derby

WPCF

design

flow

capacity

of

3.5

MGD

Exceeds

Derby

WPCF

peak

flow

capacity

of

9.1

MGD

See

Table

1.

Derby

WPCF

Flow

Data

Table

Jan

10 2.75

Feb

10 3.24

Mar

10 8.39

Apr

10 1.16

May

10 2.69

Jun

10 3.46

Jul

10 4.82

Aug

10 4.1

Sep

10 2.5

Oct

10 5.87Nov

10 3.29

Dec

10 4.94

Jan

11 3.3**

Feb

11 3.67** **Regional

Climate

Center

state

totals

*taken

from

NCDC

rainfall

data

for

Stevensen

Dam

rain

gage

5.5

mi.

WNW

of

Derby/Ansonia


94/168

APPENDIX E

UIC – City of Ansonia Interconnection Press Release

Interconnection Option #4


95/168


96/168

STATEMENT OF MAYOR DELLA VOLPE - SEPTEMBER 5, 2013

I am announcing today my plan to call upon the State of Connecticut and the City of Derby to

work with Ansonia in creating a regional wastewater treatment system that will protect our

environment and save millions of dollars for our ratepayers in both communities.

Within the last few years, Ansonia successfully completed a $50 million upgrade to its water

treatment facility that eliminated excessive pollutant emissions into the Naugatuck River. These

emissions eventually made their way into the Naugatuck river then to the Housatonic and finally

to Long Island Sound. Along the way, they caused harm to fish and wildlife and reduced the

quality of our environment. The Ansonia plant had long exceeded its expected life span and we

were under an order from the state to compete the expensive upgrade which we did. Each

household unit is paying $270 annually to pay down the bonds needed to repay the State of

Connecticut over a 20 year period. Businesses are paying a greater cost for their share of the

bonds.

It is very likely that Derby may be required to undergo a similar challenge in the coming years at

a great cost to the hard working people in that community. I have asked our engineers to examine

the possibility of using the Ansonia treatment facility for the wastewater flows in both

communities.

Their preliminary analysis indicates that this could be accomplished with certain flow mitigation

procedures for infiltration and inflow I/I in derby and the construction of a pumping station and

8000 linear foot pipe carrying the flow from Derby to Ansonia.

The Ansonia wastewater treatment facility has a design flow of 3.5 million gallons per day with

a peak capacity of 7.0 million gallons per day (MGD).

During the 3 years from 2009 through 2011 Ansonia’s average daily flow (ADF) ranged from

1.72 MGD to 2.25 MGD while Derby’s ranged from 2.21 MGD to 3.01 MGD. The maximum

flows were 8.08 in Derby and 5.73 in Ansonia which would overburden the Ansonia plant on

maximum flow days.


97/168

However, a good portion of the Derby maximum flow is due to particular challenges with

infiltration and inflow I/I which could be mitigated by at least 60% with a successful remediation

program.

Upon completion of such a program, the State of Connecticut could create financial incentives

for the two towns to “hook up” their systems so that the necessity of eventually rebuilding or building a brand new plant in Derby could be avoided. Instead, by using a combination of I/I

mitigation in Derby, storage of flow at the Derby plant and controlled flow timing during the late

evening or early morning hours, the flow from that city could be treated n Ansonia.

This could create enormous benefits for the residential and business ratepayers in both

communities:

• The staffs and workers of both WPCAs could be protected with job security and through

the use of eventual retirement attrition savings could be realized over the long term

•

Each community would retain its separate functions of rate setting and collections andDerby could make semiannual payments to the Ansonia WPCA for use of its treatment

facility

• The people of Derby would avoid the long term cost of building a new plant and the

people of Ansonia could see their $270 annual capital fee reduced by as much as 50%

• Our environment and rivers would be protected for generations by the elimination of

harmful water pollution

• The approach could serve as the model for future collaboration in two small neighboring

communities that are attempting to reinvent their local economies for a brighter future

• The State of Connecticut could use this approach in smart regionalism to save millions of

dollars in bonding costs for our two communities while using it as a model for similarapproaches elsewhere in the future.

I call upon the Department of Energy and Environmental Protection (DEEP), with the

encouragement of our two legislators, Senator Crisco and Representative Gentile, to immediately

begin a comprehensive feasibility study to carefully examine this proposal with an eye to the

economic and environmental benefits to our region and state.

The feasibility study would consider both economic and non-economic factors in arriving at the

most desirable alternative for implementation. A present worth economic analysis would be

performed as part of the evaluation. The economic analysis would incorporate capital, operationand maintenance cost estimates developed for each alternative.

By working together as neighboring communities with a long history of cooperation and with the

state, we could use smart regionalism to protect our future and reduce the cost of living and

doing business in each of our communities.

Thank you very much.


98/168

ANSONIA-DERBY

INTERCONNECTOR

Preliminary

Analysis

A. Ansonia-Derby Interconnector

As shown

on

the attached map, the

following three

alternative routes were analyzed

for

routing the

interconnector. Each route connects the ef{luent from the Influent

Pump

Station of the Derby

V/ater Pollution Control Facility

(V/PCF)

to the

wet

well of the

Influent Pump

Station

at the Ansonia

\I"PCF.

'Ihe

proposed

routes

of

the

server

interconnector

are

presented

as follows:

Option #l:

The

route

for Option

#1

proceeds

&orn the Derby W?CF Influent Punp

northo

crossing

unclemeaih the existing

railroad

immediately

north of

the

WPCF,

continuing north

along the

east

side of Caroline St., crossing

under

Main St., then

continuing norlh

along

Caroline

St.

until

turning

northeast at

Cottage

St.

From this

point,

the

route

continues

through a

vegetated

area untii

reaching

Route B,

rvhere

it

will

cross

under

this

road, then continue norlheast along the west side of

Pershing

Dr. until

r'eaehing

the Ansonia

llv?CF, r,''here

it

will

turn east,

crossing under

Pershing

Dr.

and then under another

railroad,

and

conlinuing to the

ilfluent

*'et

well for Aasonia WWTP. The route

will

take

the sewer

through

several

commercial/industrial

areas

with

paved

parking

areas. The

sewer

is

to be iS-inch

reinforced

concrete

pipe (RCP)

with an

approximate length of

8,000 linear

feet

(LF).

Option

#2:

The rsute

for

Opticn

#2 proeeeds

from

the

Derby

WPCF

Influent

Pump

east,

crossing under

Route 8,

then continuing

east uritil turning north

approximately

550 feet

east of

the

WPCF.

The

route

crosses

under an

existing railroad, contiluing

ncrth

through a vegetated area,

crossing under

Main St. east of the

intersection

with

Route 8, then

conlinues north,

following an

existing

railroad,

crossing

underneath

Division

St., continuing to

the

Ansonia W"CF,

This

se:*er

route

will

pass

through

several commereiallindustrial areas

with

par,ed

parking

lots, and may require right-

of-way

acaess

ficm

fhe

or*'ner

of

the existing railroad. The se*'er

is to be i5-ineh

RCP with

an

approxirxate

length of 8,000 LF.

Option

#3:

The route for Option

#3

proceeds

east from the

Derby WPCF

Influent

Pump,

crossing

under Route 8, continuing

east

approximateiy 800 feet until turning

north. The route crosses under

an existing

milroad,

proceeds

north crossing under

Main St. west

of the

intersection

with

Derby Ave.,

then

continues nonh follorving

the Derby

Greenway to Division

St.. crosses under

Division St." then

proeeeds

along N. Division

St.

until turning west

into

Ansonia

WPCF.

This route

takes the

sewer through

predominately

vegetated area until

reaching

the

Divisicn

St.

crossing, then

the route

encounters an

industrial

area west of N. Division St" The

sewer

is

to

be

1

5-inch

RCP installed

at an

approximate length of 8,500 LF.

Parametric Constructicn

Cosf Estirnates

Option #l: The

preliminary

cost estimate for Option #1. including

materials,

labor,

and contingencies

is

$8,900,000.

Option

#2:

The

prelimilary

cost

estimate

for Option

#2,

including

materials,

labor,

and contingencies

is

$7.300,000.

Option

#3:

The

preliminary

cost estimale

for Option #3, including

materials, labor,

and

contingencies

is

$5,700,000-


99/168

B.

Water

Pollution Control

Facilify

(WPCF)

Flow Data Analysis

The

influent flor,r.s

to

l)erby

and

Ansonia

WPCFs

rvere

provided

for

the time

period

January ?009 to February

201

1.

The

monthly

average

flows

from the

limited data

were

analyzed and

are

presented

as

fsllows:

Derby

WPCF

-

design

flow capacity

3.5

MGD,

peak

flow

capacify 9.1

MGD*

Year

2009

2010

201 I

Year

2009

20

l0

201

l

2.21

3.01

2.91

6.4i

8.08

5.30

Average

Daily

Flow'

(MGD)

Maxirnum

Daily

Fiow

{MGD)

*Data

taken from Faoilities

Pianning

Study,

1997.

ln the analysis

period,

the

1VPCF

exceeded its

peak

flow

capacity 5 times,

July

?009,

February

2010,

March

20i0, April

2010" and October

?010.

reaching

a

high

peak

flou'

of

10

MGD

for

the

three months

February to April 2010. The

plant

exceeded its

design

florr

capacity 4 times. Februarv ?010,

March

2010,

April

2010, and F'ebruary

201

1.

Ansonia WPCF

-

design flow

capacity

3.5 MGD,

peak

flow

capacit-v

7.0

MGD

Average

Daily Fiow

(MCD)

Maximum Daily Flow

(MGD)

5.08

5.73

3.50

1.72

2.25

1.80

In

the

analysis

period,

the WPCF exceeded

its

peak

flow

capacity

4

times,

June

2009,

July

2009,

]v{arch

?010, and April

2010.

The plant

exceeded

its design

{low

capacity

in

March

2010.

C. lnfilfratian/Inflow

(I/I)

A comparison was made belween

the

peak

flows to Derby WPCF and

historical rainfall

data

for the

same

period

to

see if

a correlation

could be

established

between

high

peak

flows and above normal rainfal]

eyents.

This

correlation rvould be useful in

determining

if infiltrationjinflow

into Dertry's

u'aste*,ater

sewers

is eontributing

to high

peak

flows to the

plant. For lhe months

analyzed

where

the

plant's

peak florv capacities

r.vere

exceeded, rainfall records

shorv that for June and July 2009, aad March

2010, the

rainfail totals

exceeded

the arca

averages

by over

509/o. The

high minfull

amounts

might indicate that high

I/I

rates were

a contribuling

factor

in

the

plant's

peak

capacify

being

overtaxed. Table

1

provides

the average

WPCF

plant

inflow

data and rainfall

amounts for Derby.

An

Ir'I sfudy produced

for

&e

City

of

Derby

inZAAT shorred that

I/I

volumes

into

the

sanitary sewer system

can be as

high as

1.4

MGD. Reducing

60%

of the I/l

into

the

system

s'ould

resu

b

average

daily

flows approaching

1.2

MGD

and

peak flows

nearing

3.2

MGD. lt

is

our

understandilg

that the City of Derby

is currently

conducting

an

I/I

study of

the

sanitary

sewer systern. Once

the

results of

that study

are

published,

the

correlations

between

sanitary florvs and rainfall

events can

then

be

reevaluated

and

more accurats

measurements of average

and

peak

flows

can

be

obtained.


100/168


101/168

E. List

of References

l.

Influent and Effluent

Qualitative

Data Sheets, January 20S9 through February 2011,

Derby WPCF,

City

of

Derby, Conn.

2. Sanitary Sewer

System

Infilrratian/Inflow

Analysis,

Haytthorne Avenue

Watershed.

Milone

&

MacBroom.

Lnc.,

MMI

+t2165-01-12,

July

2007.

3. Facilities Plan,

Wastew*ter

Tr€atffient

Plsnt

and. Sanitary

Eewerage

S1xtern. Cig

of

Derby, Connecticut Water

Pollution Confrol

Authoriry*, Semi-Final

Drafi.

Cascio

Bechir Engineers. July' i997.

4-

Construction

Plans.

Ci*,

af

Derby, AJterqtions and Additians

to

th,e Wafer

Pallution

Control

P[ant

Pump Statians

and Sanitary

Sewerage System. Cascio

Bechir

Engireers.

August,

1998.

5.

Influent

and

Effluent

Qualitative

Data

Sheets,

January 2009

through April

2011,

Ansonia WPCF,

City of

Ansonia,

Conn.

6.

I;acilities

Planning Study, Cily

of Ansonia, Connecticut Water Pollution

Control

Authority.

United International Corporation.

Jul;r

20S4"

7.

Seuter

System Evslusti{}n Sarve , Pkase

I

stzd Ph#se

-II

City of Ansonia,

Connecticut

Water

Pollution Control Authoritl.

United Intemational Corporation.

June

2000.

8. Infiltration/Infiov, Study. Cif of

Ansonia, Connecticut Water

Follution

Control

Authority.

United Intemational Corporation.

September 1 996.

9.

Consfruction

Plans. C/ry of Ansania, Connecticut,

Water

Pollutian Control

Facility

Upgrode. Camp,

Drssser

&McKee,

Inc.

November 7A07.


102/168

N

&i

34

a9

(.'o

5(,

n>

di

-1

>o

'Ee

6'i

6x

;o

o3

q

gE

-gx

6E

^9q

[[

utJ

dd

F3

&g

oo

ao

EU

{J

C}

o{}

u

EU

.

t:.-

'.WIC

ila;,i

j':kt

,,:a..

:i:'t;ifr

"F:,'st

'))'-3,

:

t")ry.

#Hj,

t::

o4#

F

E

.l

-i -l

"

" -r*iut

+

..i ct

.,;

'ri "iffiFi

di

+

+

N

*ri

,'i

+ ; :

(s

{3

(t

.E

(f

3

-9

tl

TJ

3

L

o

df,

*i

=

F

d or:.0.:6:


103/168

or(.oc{-.^r*ol\t 1I

I I

(O

$

eO

t:

-l

CO

r

Cn ;;

|-* F-

H

ni.ri+$e"lu^i di cf ;Hi;

-

C)Cf,

(OOOooOnl

^ ^

^Ln

C)OlnOr{

Ot

i

..{

ansonia derby interconnection feasiblity study - compiled document

Documents