september 21, 2018...september 21, 2018 town of groton 45 fort hill road groton, ct 06340 attn: mr....

September 21, 2018

Town of Groton

45 Fort Hill Road

Groton, CT 06340

Attn: Mr. Harold Clark

Ref: In-Service Inspection

Tank No.Sludge

Dear Sir:

Please the enclosed report on the STI - SP001

In-Service Inspection of the Sludge Tank

at the Town of Groton facility in Groton, CT 06340.

We trust the enclosed to be complete and satisfactory;

however, should there be any questions or if additional

information is required, please do not hesitate to contact us.

Very truly yours,

________________________

Bertram Jay Phillips

PCA Job No.35446

STI SP001 IN-SERVICE INSPECTION

PCA JOB NO.: 35446

September 13, 2018Date of Inspection -

Town of Groton

Water Pollution Control Facility

Sludge Tank

Groton, CT 06340

Prepared by:

PCA ENGINEERINGNEW ENGLAND LLC7 West End WayNorwell, Ma 02061Tel (781) 261-9688 Fax (781) 261-9679

Section I: Summary of Findings & Suitability for Service

Section II: Inspection Information & Tank Overview

Section III: Checklist

Section IV: Shell Drawing & Ultrasonic Thickness Data

Section V: Photographs

TABLE OF CONTENTS

PCA ENGINEERING NE LLC

SUMMARY OF FINDINGS

SECTION I:

SUMMARY OF RESULTS

Tank Description: The sludge tank is a 16, 000 gallon vertically oriented storage tank reported to be installed in 1972. It was originally designed as a Decant tank but was converted. It is constructed of welded carbon steel and is currently storing Sludge. The tank is installed within a building using steel legs on a concrete floor.

Containment:

There is no immediate containment for this tank. The contents would be directed to a tunnel system with drains and sumps that would return the product to the Raw Influent Well.

Shell & Roof & Bottom Plates:

There are several pinholes in the shell plates as a result of internal corrosion. There are two horizontal brackets installed on the shell interior that have trapped product creating a condition for corrosion.

With exception to the isolated areas of corrosion, the ultrasonic thickness

measurements were within 5% of the original nominal thickness of the plates. The shell original thickness is 0.281” and the minimum thickness obtained

measured 0.148” at the area of corrosion. The original thickness for the roof plates is 0.187” and the minimum reading obtained measured 0.200”. The original thickness for the bottom plates is 0.250” and the minimum reading obtained measured 0.237”. Original thicknesses are assumed.

The tank steel supports and concrete footings are in good condition.

Accessories: Inspection of the appurtenances found no unusual conditions. General Findings: An isolated band of corrosion was located on the shell approximately 15” to 21” from the top of the tank corresponding to internal brackets attached to the shell. Recommendations: Repair areas of corrosion on the shell using the following three (3) lap weld patch plates: .

1. 12” x 18” x ¼” 2. 12” x 12” x ¼” 3. 12” x 48” x ¼”

Remove the brackets attached to the shell interior.


&

INSPECTION INFORMATION

SECTION II

TANK OVERVIEW

Inspection Company:

Address :

Date of Inspection: 9/13/2018 Tank No.:

Previous Inspection: 35446

Inspector:

API-653 Certification No. 24662

INSPECTIONS PERFORMED:

X General Inspection of Tank using STI SP001 Annual Inspection Checklist

X Ultrasonic Thickness Measurements of Shell Plates

Other:

Comments:

Bert PhillipsDrew Lawrence

PCA Job No.:

Reviewed By:

INSPECTION INFORMATION

7 West End Way

PCA Engineering NE LLC

Norwell, MA 02061

Sludge


TEST PROCEDURES Ultrasonic Thickness and Pit Depth Measurements: An Olympus model 45M ultrasonic thickness gauge with a 0o - 5 MHz dual crystal transducer was used to obtain ultrasonic thickness measurements on the plates. The 45M has A-Scan and B-Scan Verification capabilities.

Measurements were obtained in a grid pattern at representative access

locations on the shell & end plates. Multi-Echo modes were utilized to minimize the effects of coated surfaces.

Areas to be measured were cleaned using a wire brush and then an UltraGel couplant applied to afford an acoustical connection between the probe and steel.

Pit depths were measured using a Thorpe Pit Gauge.

The results of the above tests are listed in Thickness Data Tables and the enclosed PCA Drawings.


Name Name Name

Number and Street Number and Street Number and Street

00000

City, State, Zip Code City, State, Zip Code City, State, Zip Code

TANK ID

SPECIFICATION:

DESIGN: UL SWRI Horizontal Rectangular

API Other

Manufacturer: Last Repair/Reconstruction Date:

Dimensions (ft): Diameter 16.00 Height 10.00 Width Length Cone 1.00 Capacity: 15541

Construction: Bare Steel Cathodically Protected (Check one A. Galvanic or B. Impressed Current) Date Installed:

Coated Steel Concrete Plastic/Fiberglass 16,000

Double Bottom Double Wall Lined Date Installed:

Containment: Earthen Dike Steel Dike Concrete Synthetic Liner Other Common Holding Area

Manifolded to another containment? Yes No

Dimensions (ft): Diameter Height Width Length Capacity: gallons

CDRM: Type:

Release Prevention Barrier Type:

gallons Last Change of Service Date:

Groton, CT 06340 170 Gary Court

Sludge

Unknown

Vertical

Date Installed:

1/1/1972

Date Installed:

Contents: Sludge Construction Date:Unknown

0

Rated capacity is gallons

STI SP001 AST RECORD

Town of Groton Town of Groton

INSTALLER INFORMATIONOWNER INFORMATION FACILITY INFORMATION

Water Pollution Control Facility45 Fort Hill Road


CHECKLIST

SECTION III

General Inspection Information:

Retain Until Date: (36 months from inspection date)

Inspector Name:

Tank Inspected (ID #):

For equipment not included in this standard, follow the manufacturer recommended inspection/testing schedules and procedures.

The periodic AST Inspection is intended for monitoring the external AST condition and its containment structure. This visual inspection does not require

a certified inspector. It shall be performed by an owner's inspector who is familiar with the site and can identify changes and developing problems.

Remove promptly upon discovery standing water or liquid in the primary tank, secondary containment area, interstice or spill container. Before discharge to the

environment, inspect the liquids for regulated products or other contaminants and dispose of it properly.

In order to comply with EPA SPCC (Spill Prevention, Control and Countermeasure) rules, a facility must regularly test liquid level sensing devices to ensure proper

operation (40 CFR 112.8(8)(v)).

(*) designates an item in a non-conformance status. This indicates that action is required to address a problem.

Non-conforming items important to tank or containment integrity require evaluation by an engineer experienced in AST design, a certified inspector, or a tank

manufacturer who will determine the corrective action. Note the non-conformance and corresponding corrective action in the comment section.

Retain the completed checklists for 36 months.

Complete this checklist on an annual basis supplemental to the owner monthly-performed inspection lists.

Note: If a change has occurred to the tank system or containment that may effect the SPCC plan, the condition should be evaluated against

then current plan requirement by a Professional Engineer knowledgeable in SPCC development and implementation.

Task

1.1 Containment Check for: Yes No* N/A

structure • Holes or cracks in

containment wall or

floor

• Washout

• Liner Degradation

• Corrosion

• Leakage

• Paint Failure

• Tank Settling

2.1 Foundation Settlement or

foundation washout?

Yes* No

2.2 Concrete pad Cracking or spalling? Yes* No N/A

or ring wall?

Not Applicable

Drew Lawrence

Inspection Guidance:

Item

Inspection Date:

No containment area

STI SP001 ANNUAL INSPECTION CHECKLIST

2.0 Tank Foundation and Supports

1.0 Tank Containment

Prior Inspection Date:

9/13/2021

Sludge

Comments

9/13/2018

Status

AST Inspection Standard September 2011

TaskItem CommentsStatus2.3 Supports Check for corrosion Yes No* N/A

paint failure, etc.

2.4 Water drainage Water drains away

from tank?

Yes No* N/A

2.5 Tank grounding Strap secured and in

good condition?

Yes No* N/A

3.1 Confirm the system is

functional, includes the

wire connections for

galvanic systems

Yes No* N/A

3.2 a. inspect the

operational

components (power

switch, meters, and

alarms).

Yes No* N/A

b. Record hour meter,

ammeter and

voltmeter readings

Yes No* N/A

4.1 Coating Check for coating

failure

Yes* No

4.2 Check for:

• Dents

• Buckling

• Bulging

• Corrosion

• Cracking

Yes* No

4.3 Roof slope Check for low points

and standing water

Yes* No N/A

5.1 Vents Verify that

components are

moving freely and vent

passages are not

obstructed for:

• Emergency vent

covers

• Pressure/vacuum

vent poppets

• Other moving vent

components

Yes* No

Steel

condition

Galvanic

cathodic

protection

system

4.0 Tank Shell, Heads, Roof

Coating system is in god condition

5.0 Tank Equipment

Vent is in good condition, penetrates roof

No dents located

Tank is inside a building

Impressed

current

system

3.0 Cathodic Protection

Tank supports are in good condition

Tank is inside a building


TaskItem CommentsStatus5.2 Valves Check the condition of

all valves for leaks,

corrosion and

damage.

Yes* No

5.2.1 Cycle the valve open

and closed and check

for proper operation

Yes No* N/A

5.5.2 Check for proper

operation. (Note that

there may be small , 1/4

inch drain plugs in the

bottom of the valve that

are not visible by

looking from above

only)

Yes No* N/A

5.2.3 Check that the valve is

in proper orientation.

(Note that fuel must be

discharged back to the

tank via a separate pipe

or tubing.)

Yes No* N/A

5.2.4 Check that the valve to

check operation.

(Electric solenoids

can be verified by

listening to the plunger

opening and closing. If

no audible confirmation,

the valve should be

inspected for the

presence and operation

of the

plunger.)

Yes No* N/A

5.2.5 a. Manually cycle the

valve to ensure

components are moving

freely and that the valve

handle or lever has

clearance to allow valve

to close

completely.

Yes No* N/A

b. Valves must not be

wired in open position.

Yes No* N/A

Anti-siphon,

check and

gate valves

Pressure

regulator

valve

No leaks or corrosion around tank valves

Expansion

relief valve

Solenoid

valves

Fire and

shear valves


TaskItem CommentsStatusc. Make sure fusible

element is in place and

correctly

positioned.

Yes No* N/A

d. Be sure test ports

are sealed with plug

after testing

is complete and no

temporary test fixture

or component remains

connected to valve.

Yes No* N/A

5.3 Check condition of

equipment, including:

• The window is

clean and clear in

sight leak gauges.

• The wire

connections of

electronic gauges

for tightness and

corrosion

• Activate the test

button, if

applicable.

Yes No* N/A

5.4 a. If corrosion damage,

or water has

compromised the ability

of the unit to perform

spill

containment functions,

replace the unit.

Yes* No N/A

b. Inspect the

connections to the AST

for tightness, as well as

the bolts,

nuts, washers for

condition and replace

if necessary.

Yes* No N/A

c. Drain valves must

be operable and

closed

Yes* No N/A

5.5 a. Check that the

strainer is clean and in

good condition.

Yes No* N/A

Spill

containment

boxes on fill

pipe

Interstitial

leak detection

equipment

Strainer


TaskItem CommentsStatusb. Access strainer

basket and check cap

and gasket seal as well

as bolts.

Yes No* N/A

5.6 a. Check that the filter is

in good condition and is

within the

manufacturer's expected

service life. Replace if

necessary.

Yes No* N/A

b. Check for leaks and

decreased fuel flow

Yes No* N/A

5.7 Follow manufacturer's

instructions. Check for

corrosion and

blockage of air

passages.

Yes* No N/A

5.8 Test according to

manufacturer's

instructions and

authority having

jurisdiction (AHJ). Verify

leak detectors are suited

and properly installed

for aboveground use.

Yes No* N/A

5.9 a. Has the equipment

been tested to ensure

proper operation?

Yes No* N/A

b. Does equipment

operate as required?

Yes No* N/A

c. Follow

manufacturer's

instructions.

Yes No* N/A

5.10 a. Follow

manufacturer's

instructions and

regulatory

requirements for

inspection and

functionality

verification.

Yes No* N/AOverfill

equipment

Leak detector

for

submersible

pump

systems

Liquid level

equipment

Filter

Flame

arrestors


TaskItem CommentsStatusb. Confirm device is

suited for above

ground use by the

manufacture

Yes No* N/A

6.0 Insulated Tanks

6.1 Check condition of

insulation for:

•Missing sections

•Areas of moisture

•Mold

•Damage

Yes* No N/A

6.2 Check for damage that

will allow water intrusion

Yes* No N/A

7.0 Miscellaneous

7.1 Are they in good

condition?

Yes No* N/A

7.2 Ensure that all labels

and tags are intact and

readable.

Yes No* N/A

Additional Comments:

Insulation

cover or

jacket

Labels and

tags

Electrical

wiring and boxes

Insulation


&

DRAWINGS

ULTRASONIC THICKNESS DATA

SECTION IV:

16.00

Tank Dimensions in (ft)

-01

NTS

1.00

10.00

Groton, CT 06340

NORWELL, MA 02061 Tel (781) 261-9688 SludgeTank No.

PCA ENGINEERING NE LLC OVERVIEW

9/13/18

35446

7 WEST END WAY Town of Groton

6" Nozzle

DRAWN BY:

BPDESIGN BY: APPROVED BY:

DATE: SCALE: DATE:

DRAWING NUMBER:

DRAWING TITLE:

Roof Plates

Access Hatch

Manway

3" PLG

4" Vent

6" Fill

8" Nozzle

6" Nozzle

12" X 18" Patch Plate

(recommended)

12" X 12" Patch Plate (recommended)

12" X 48" Patch Plate

(recommended)

Bottom Plates

Average

Maximum Repairs Are Required

Minimum

Original Tank Dimensions in (ft)

ULTRASONIC THICKNESS MEASUREMENTS

-01

1 '

Town of Groton Groton, CT 06340

SludgeTank No.

9/13/18 35446


NORWELL, MA 02061 Tel (781) 261-9688

7 WEST END WAY

0.148

0.281 0.187 0.250

0.247

0.258

0.2370.200

Shell Plates Roof Plates

0.218

0.2470.279

0.279

10 '

1 2 3 4 56 7 8

Roof Plates

Bottom Plates

DRAWN BY:

BPDESIGN BY: APPROVED BY:

DATE: SCALE:

N.T.S.DATE:

DRAWING NUMBER:

DRAWING TITLE:

9

10

11

Pinholes

1. 3. 5. 7. 9.

2. 4. 6. 8. 10.

11.

0.261 0.258

ULTRASONINC THICKNESS MEASUREMENTS (in)

0.221

AREA No. AREA No. AREA No. AREA No.

0.260

0.201 0.198 0.242 0.244

AREA No.

0.210 0.249

0.256

0.174 0.148 0.259 0.261

0.260 0.261

0.260 0.261 0.259 0.258

0.241 0.259

0.248

0.261

0.235

0.260

0.260 0.260 0.278 0.247

0.276

0.246 0.247 0.229 0.235

0.255 0.240

0.261 0.259 0.260 0.247

0.240 0.247

0.240

0.237

0.243 0.244 0.260 0.261

0.2450.219 0.261

0.200 0.246 0.244 0.275

0.249 0.259

0.261

0.243

0.209

0.151 0.251 0.258 0.259

0.208

0.261 0.247 0.250 0.247

0.259 0.248

0.261 0.279 0.247 0.259

0.259 0.247

0.247

0.213

0.235

0.261 0.259 0.234 0.247

0.216

0.255 0.240 0.255 0.276

0.275 0.260

0.243 0.256 0.261 0.261

0.251 0.260

0.213

0.258

0.255

0.258

0.241

0.242

0.242

0.242

0.254

0.242

0.237

270O

0.249

180O

0.249

90O

0.249

0O

0.2648" Suction

0.162

0.250

0.280

0.197

0.162

0.249

0.280

0.197

0.279

0.196

BOTTOM APPURTENANCES

0O

0.182

0.249

0.280

0.195

6" Nozzle

6" Nozzle

Old Decant Nozzle

SHELL APPURTENANCES

8" Nozzle

90O

180O

270O

0.168

0.148

0.126

0.1230.121

0.169

0.127

0.122

0.168

0.126

0.122

20" Manway w/ 6" Nozzle

3" Product Level Gauge

4" Vent

0.249

90O

ROOF APPURTENANCES 0O

180O

270O

0.152

0.124

ULTRASONINC THICKNESS MEASUREMENTS (in)

0o

90o

180o

270o

PHOTOGRAPHS

SECTION V:

Top of tank-appurtenances

PHOTO NO. 1

Sludge Tank

PHOTO NO. 2


Bottom of tank

PHOTO NO. 4

Shell apputenances

PHOTO NO. 3


Areas of corrosion and leaking located on shell

PHOTO NO. 6

Interior corrosion area on shell-pinholes

PHOTO NO. 5


PHOTO NO. 7

Recommended lap patch plate repairs


Notwithstanding anything contained in this report, nothing herein shall be construed as a representation,

warranty or guarantee, either expressed or implied, regarding the future structural integrity or future life

expectency of any of the items tested. This report and any analysis provided is in all rerspects subject to and

shall be interpreted within the limitations and parameters of the test procedures performed. In the event

testing is performed using a sampling procedure, this report and any analysis shall be limited to those areas

actually tested and the type of tesrt conducted, and the customer is cautioned not to extrapolate the results

of the test samples.

september 21, 2018...september 21, 2018 town of groton 45 fort hill road groton, ct 06340 attn: mr....

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