Naugatuck Valley Council of Governments

Regional Wastewater Treatment Consolidation Study – Phase 2Workshop #3 – Screen-out Long List; Identify Short List Regional Alternatives

25 June 2020

Agenda

2

Introduction & Roles

Phase 1 - Long List Regional Alternatives

Develop & Screen Out Evaluations - Long List

Next Steps

Aggressive I/I

Conveyance Corridors

Plant Process and Site Layouts

Introduction & Roles

3

- NVCOG

- Black & Veatch

- Participating Communities

- OPM, DEEP

Phase 1 - Long List Regional Alternatives

4

Phase 1 – Long List Regional Alternatives

5

No. Alternative Description

1 Beacon Falls to Naugatuck

2 Beacon Falls to Seymour

2a Beacon Falls to Seymour, I/I Reduction

3 Derby to Ansonia

3a Derby to Ansonia, I/I Reduction

4 Derby to Ansonia, Effluent Pumped to Housatonic River

4a Derby to Ansonia, I/I Reduction, Effluent Pumped to Housatonic River

5 Derby and Seymour to Ansonia

5a Derby and Seymour to Ansonia, I/I Reduction

5b Derby and Seymour to Ansonia, Effluent Pumped to Housatonic River

5c Derby and Seymour to Ansonia, I/I Reduction, Effluent Pumped to Housatonic River

No. Alternative Description

6 Derby to Seymour and Ansonia

6a Derby to Seymour and Ansonia, I/I Reduction

8 Ansonia to Derby

8a Ansonia to Derby, I/I Reduction

9 Seymour and Ansonia to Derby

9a Seymour and Ansonia to Derby, I/I Reduction

10 Seymour to Ansonia, Part of Ansonia to Derby

10a Seymour to Ansonia, Part of Ansonia to Derby I/I Reduction

11 Beacon Falls and Seymour to Ansonia, Part of Ansonia to Derby

11a Beacon Falls and Seymour to Ansonia, Part of Ansonia to Derby, I/I Reduction

12 Beacon Falls, Seymour, and Ansonia to Derby

12a Beacon Falls, Seymour, and Ansonia to Derby, I/I Reduction

Methodology

Regional Alternatives were developed and screened out in a progression of three major steps (i.e. assessments):

1. Aggressive I/I Evaluation

• Review of extraneous flow reduction and feasibility of such measures

2. Conveyance Corridors Evaluation

• Feasibility of pipeline routes between communities

3. Plant Process and Site Layout Evaluation

• Treatment process upgrade and space requirements of regionalized plants

6

Aggressive I/I Evaluation

7

- I/I Programs – Overview

- I/I Programs Enacted at the Study Communities

- Aggressive I/I Programs – What Can Be Achieved?

- Regional Alternatives Screen Out

I/I Overview

• What is I/I and levels of control

• Identifying I/I

1. Flow monitoring

2. Major inflow sources

3. Infiltration sources

4. Sewer system evaluation surveys

8

Typical Sources of Inflow & Infiltration (I/I)

Wastewater Flow Analysis

Identifying Inflow Sources

I/I at the Study Communities

12

Derby Ansonia Seymour Beacon Falls Naugatuck

SSES (2016 – 2017)

No city-wide I/I program in

over 15 years

No city-wide I/I program in over

15 years

No need for aggressive I/I

SSES (2015 & 2017)

Phased I/I control plan (2019- Present and

beyond)

Re-procuring professional

O&M services (includes capital to

control I/I)

Derby Plant Flows 2015 – 2020

13

0.0

2.0

4.0

6.0

8.0

10.0

12.0

Jan-15 May-15 Oct-15 Feb-16 Jul-16 Dec-16 Apr-17 Sep-17 Jan-18 Jun-18 Nov-18 Mar-19 Aug-19 Dec-19

Flo

w R

ate

(MG

D)

Date

MAX

MIN

TOTAL

Ansonia Plant Flows 2015 – 2020

14

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

Jan-15 May-15 Oct-15 Feb-16 Jul-16 Dec-16 Apr-17 Sep-17 Jan-18 Jun-18 Nov-18 Mar-19 Aug-19 Dec-19

Flo

w R

ate

(MG

D)

Date

MAX

MIN

TOTAL

Seymour Plant Flows 2015 – 2020

15

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

Jan-15 May-15 Oct-15 Feb-16 Jul-16 Dec-16 Apr-17 Sep-17 Jan-18 Jun-18 Nov-18 Mar-19 Aug-19 Dec-19

Flo

w R

ate

(MG

D)

Date

MAX

MIN

TOTAL

Beacon Falls Plant Flows 2015 – 2018

16

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

May-15 Jul-15 Sep-15 Nov-15 Jan-16 Mar-16May-16 Jul-16 Sep-16 Nov-16 Jan-17 Mar-17May-17 Jul-17 Sep-17 Nov-17 Jan-18 Mar-18

Flo

w R

ate

(MG

D)

Date

MAX

MIN

TOTAL

Naugatuck Plant Flows 2015 – 2020

17

0

5

10

15

20

25

30

Jan-10 Sep-10 May-11 Jan-12 Sep-12 May-13 Jan-14 Aug-14 Apr-15 Dec-15 Aug-16 Apr-17 Dec-17 Aug-18 Apr-19 Dec-19

Flo

w R

ate

(MG

D)

Date

MAX

MIN

TOTAL

Aggressive I/I and Regional Alternatives Screen Out

Standard I/I Management

• Target reduction of peak flows

• Inflow and rapid infiltration are priority

• Point repairs or limited extents

• Focus on known/identified sources

Aggressive I/I Removal

• Target reduction of peak and average flows

• Comprehensive rehabilitation

• Removal of private I/I sources

18

Rehabilitation/Replacement Methods

Managing I/I from Private Laterals

Phase 1 – Long List of Regional Alternatives

21

No. Alternative Description

1 Beacon Falls to Naugatuck

2 Beacon Falls to Seymour

2a Beacon Falls to Seymour, I/I Reduction

3 Derby to Ansonia

3a Derby to Ansonia, I/I Reduction

4 Derby to Ansonia, Effluent Pumped to Housatonic River

4a Derby to Ansonia, I/I Reduction, Effluent Pumped to Housatonic River

5 Derby and Seymour to Ansonia

5a Derby and Seymour to Ansonia, I/I Reduction

5b Derby and Seymour to Ansonia, Effluent Pumped to Housatonic River

5c Derby and Seymour to Ansonia, I/I Reduction, Effluent Pumped to Housatonic River

No. Alternative Description

6 Derby to Seymour and Ansonia

6a Derby to Seymour and Ansonia, I/I Reduction

8 Ansonia to Derby

8a Ansonia to Derby, I/I Reduction

9 Seymour and Ansonia to Derby

9a Seymour and Ansonia to Derby, I/I Reduction

10 Seymour to Ansonia, Part of Ansonia to Derby

10a Seymour to Ansonia, Part of Ansonia to Derby I/I Reduction

11 Beacon Falls and Seymour to Ansonia, Part of Ansonia to Derby

11a Beacon Falls and Seymour to Ansonia, Part of Ansonia to Derby, I/I Reduction

12 Beacon Falls, Seymour, and Ansonia to Derby

12a Beacon Falls, Seymour, and Ansonia to Derby, I/I Reduction

Conveyance Corridors

22

- Reviewed Phase 1 Conveyance Corridors

- Initial Route Feasibility Review

- Developed Routes

- Evaluated Routes

Initial Route Feasibility Review

• Phase 1 routes were aligned along major infrastructure ROWs for ease of implementation

• ROW access almost impossible to obtain

23

Pipeline Routes Developed

• Development

• Routes were defined and analyzed using:

• Satellite Images

• Connecticut GIS Data

• Parcel Data

24

Physical Constructability Environmental

Length Topography Wetlands

Pipe Size Geology Flood Zones

Pump Stations Easements Protected Open Space

Beacon Falls to Naugatuck

25

ROUTE 1 ROUTE 2

Total Length (ft) 28,100 16,500

Pipeline10” to 12” gravity and force main

10” to 12” gravity and force main, and tunnel

Number of Pump Stations

5 3

Easements ~65% route along Naugatuck State Forest

~65% route along Naugatuck State Forest

Beacon Falls to Seymour

26

ROUTE 1 ROUTE 2

Total Length (ft) 31,000 26,500

Pipeline10” to 12” gravity and force main

10” to 12” gravity and force main, and tunnel

Number of Pump Stations

6 4

Easements ~5% route crosses private parcels

~45% route crosses private parcels

Seymour to Ansonia

27

ROUTE 1 MAIN ATTRIBUTES

Total Length (ft) 14,200

Pipeline14” to 18” gravity and force main

Number of Pump Stations

2

Easements ~10% route crosses private parcels

Ansonia to/from Derby

28

DERBY TO ANSONIA

ANSONIA TO DERBY

Total Length (ft) 8,100

Pipeline18” force main 16” to 18” gravity

and force main

Number of Pump Stations

1

Easements ~20% route crosses private parcels

Alternatives Screen-Out Based on Conveyance Corridors

29

No. Alternative Description

1 Beacon Falls to Naugatuck

2 Beacon Falls to Seymour

3 Derby to Ansonia

4 Derby to Ansonia, Effluent Pumped to Housatonic River

5 Derby and Seymour to Ansonia

5b Derby and Seymour to Ansonia, Effluent Pumped to Housatonic River

6 Derby to Seymour and Ansonia

8 Ansonia to Derby

9 Seymour and Ansonia to Derby

10 Seymour to Ansonia, Part of Ansonia to Derby

11 Beacon Falls and Seymour to Ansonia, Part of Ansonia to Derby

12 Beacon Falls, Seymour, and Ansonia to Derby

Plant Process and Site Layouts

30

- Plant Treatment and Process Evaluation:

1. 1. Flows and Loads Update

2. 2. Treatment Capacity Assessment

3. 3. Site Layouts

Flows and Loads Update – Derby, Ansonia & Seymour

• Flows and loads through design (2040) were updated from Phase 1

• Daily MOR (2018 through March 2020) was used

31

Design Flows Derby Ansonia Seymour

Annual Average (MGD) 1.9 1.9 1.3

Max. Month (MGD) 3.0 3.3 2.6

Peak Day (MGD) 5.5 5.0 4.5

Treatment Capacity Assessment

• Evaluated existing plants to handle individual and combined flows

• Assessment focused on:

• Footprint intensive processes - primary and secondary treatment

• Effluent requirements - tertiary treatment

• Treatment intensification selected for constrained plant sites

• Created plant facility layouts to meet treatment needs

32

Treatment Intensification

• Treatment intensification considered over conventional treatment due to limited footprint

33

Process Overview

Chemically Enhanced Primary Treatment (CEPT)

Allows the treatment of higher flows by increasing surface overflow rate

Ballasted Activated Sludge (BioMag)

Addition of magnetite (inert iron particles) to enhance settling

Integrated fixed film activated sludge (IFAS)

Use of plastic media to increase activated sludge inventory

Chemically Enhanced Primary Treatment (CEPT)

PrimarySludge

PrimaryEffluent

Coagulant Polymer

CEPT can increase primary clarifier capacity by approximately three times.

Primary Clarifier

RawInfluent

Chemically Enhanced

Conventional Activated Sludge (CAS)

• Activated sludge relies on bacterial growth to remove organics and nitrogen.

• Bioreactors and secondary clarifiers a single process when rating secondary capacity.

AX AE

PE SE

WAS

RAS

Fast Settling (Low SVI)

Poor Settling (High SVI)

Process Intensification Options

AX AE

PE SE

WAS

RAS

AX AE

PE SE

WAS

RAS

Recovered

Magnetite

Make-Up

Magnetite

BioMag™ increases settling rates in the clarifier.

Integrated Fixed Film Activated Sludge (IFAS) Ballasted Activated Sludge (BioMag™ by Evoqua)

IFAS increases active bacteria in bioreactor without increasing the solids loading to the clarifiers

Plant Site Layouts

37

- Base Case

- Regional alternatives

Derby – Base Case

38

Derby Plus Ansonia - Regional Alternatives

39

With BioMag With IFAS

Derby Plus Seymour - Regional Alternatives

40

With BioMag With IFAS

Derby Plus Ansonia & Seymour - Regional Alternatives

41

With BioMag With IFAS

Ansonia – Base Case

42

Ansonia Plus Derby - Regional Alternatives

43

Ansonia Plus Seymour - Regional Alternatives

44

Ansonia Plus Derby & Seymour - Regional Alternatives

45

Seymour Base Case or Seymour Plus Beacon Falls Regional Alternatives

46

Alternatives Screen-Out

47

No. Alternative Description

3 Derby to Ansonia

4 Derby to Ansonia, Effluent Pumped to Housatonic River

5 Derby and Seymour to Ansonia

5b Derby and Seymour to Ansonia, Effluent Pumped to Housatonic River

6 Derby to Seymour and Ansonia

8 Ansonia to Derby

9 Seymour and Ansonia to Derby

10 Seymour to Ansonia, Part of Ansonia to Derby

Next Steps

48

Short List of Regional Alternatives

49

No. Alternative Description

3 Derby to Ansonia

4 Derby to Ansonia, Effluent Pumped to Housatonic River

5 Derby and Seymour to Ansonia

5b Derby and Seymour to Ansonia, Effluent Pumped to Housatonic River

8 Ansonia to Derby

9 Seymour and Ansonia to Derby

10 Seymour to Ansonia, Part of Ansonia to Derby

Task 3 Look Ahead

1. Develop and evaluate short list regional alternatives

2. Compare short list regional wastewater alternatives

a) Non-cost criteria

b) Cost criteria

3. Recommend one or two regional alternatives for final development

50

23 RA

7 RA

1 RA

Thank you!