20W18 SOW_V2_Overflow Pump and Electrical.pdf

Page 1 of 13 Statement of Work

PROJECT OK 20-W18

CHEYENNE AND ARAPAHO TRIBES WATER TREATMENT PLANT

RESIDUAL LAGOONS RENOVATION

OVERFLOW PUMP AND ELECTRICAL INSTALLATION

SCOPE OF WORK

PART 1 INTRODUCTION

1.01 SUMMARY OF WORK TO BE PERFORMED

A. Reduce water levels in residual lagoons and pump basin without interrupting operations of the Concho Water Treatment Plant (WTP).

B. Install approximately 220’ of buried electrical conduit and wire and approximately 24’ of above ground electrical conduit and wire to supply power to submersible pump in pump basin.

C. Supply two (2) submersible effluent pumps and install one of those pumps in the pump basin with floats and alarm system.

1.02 LOCATION & CONTACT INFORMATION

A. Location:

Concho Water Treatment Plant

200 White Rabbit Road, Concho, OK 73022

B. Project Contacts:

Project Engineer

Drew Kay

Office: 580-331-3492

Cell: 214-498-4354

Drew.Kay@ihs.gov

Contract Specialist

Jeff Earnest

Office: 405-951-3740

Cell: 405-203-1369 jeffrey.earnest@ihs.gov

1.03 NEED FOR PROJECT

A. Two concrete-lined residual lagoons to collect filter backwash water from the Concho

WTP are failing due to deteriorated components making the lagoons inoperable.

B. The existing pump basin and entire electrical system supplying the pump basin is inoperable and not discharging into the sanitary sewer collection system as designed.

Due to this critical failure, water levels in the lagoons have overtaken the freeboard of the concrete-lined lagoon structure and overflows at the southwest corner.

mailto:Drew.Kay@ihs.gov mailto:jeffrey.earnest@ihs.gov

OK 20-W18 Concho Residual Lagoons Overflow Pump and Electrical Installation

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PART 2 EXISTING SYSTEM

A. The Concho WTP and water system serves 8 Indian-owned homes and 24 non-residential units, including the Lucky Star Casino, Smoke Shop, Post Office, Tribal

Administration, Head Start, etc. Water is provided by two ground water wells located in two separate block pump houses. The location of the WTP and the wells are shown below in Figure 1.

Figure 1. Location of Wells and WTP

B. The water treatment plant has two concrete-lined residual lagoons which are utilized to collect filter backwash water. These lagoons were constructed with the original plant in the late 1960’s. The lagoons are approximately 30 feet x 90 feet, with a depth of approximately 3 feet at the deepest point. Current aerial views of the WTP and lagoons are shown in Figures 2 & 3.

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Figure 2. Aerial view of WTP and Residual Lagoons

Figure 3. Proposed Facilities Map

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2.02 RESIDUAL LAGOONS DEFICIENCIES

A. Currently, the depth of sludge in each lagoon is approximately 1-3 inches. The lagoons were last cleaned approximately 4-5 years ago. The WTP backwashes into the lagoons approximately every other day. The lagoons were originally designed to maintain freeboard through evaporation, however, they are not large enough to depend on evaporation alone. The lagoons are designed to overflow into a pump basin which discharges into the sanitary sewer collection system.

B. An evaluation of the lagoons was conducted on May 30, 2019. At that time, it was found that the existing pump basin and entire electrical system supplying the pump basin was inoperable and not discharging into the sanitary sewer collection system as designed. Due to this critical failure, water levels in the residual lagoons have overtaken the freeboard of the concrete-lined lagoon structure and are found overflowing at the southwest corner.

Figure 4. SW Corner of Lagoons Figure 5. SW Corner of Lagoons taken from the north taken from the south

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Figure 6. Pump Basin Showing Overflow Exceedance

Figure 7. Pump Basin Top View

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Figure 8. Existing LP Panel (3-phase, 120V) Figure 9. Location of the existing panel in SW

Corner of building

Figure 10. Location of the existing LP Panel

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PART 3 WORK TO BE COMPLETED

3.01 GENERAL

A. Contractor shall schedule with project engineer prior to beginning work.

1. Minimum lead time of 1 week is required.

B. Any damage to the water treatment plant, nearby fencing, pumps, and structures, during the course of the project shall be repaired at contractor’s expense.

C. All work is subject to applicable standards and regulations, including but not limited to;

1. OSHA 1910 Subpart I – Personal Protective Equipment,

2. OSHA 1910 Subpart J – Permit-required Confined Spaces,

3. NFPA 70 – National Electrical Code (NEC)

D. Items that require approval from project engineer shall be submitted for approval before beginning work.

1. Submittals can be sent via email, fax, or hard copy.

2. Project engineer shall approve, deny, or request further information from contractor within 1-week of submittal receipt.

3. Submittals include;

a. Submersible Pump and Controls,

b. Sewage Check Valve,

c. Electrical Conduit,

d. Electrical Wire,

e. Junction Boxes,

f. Single Pole Breaker.

E. All work is subject to inspection by project officer or their representative. Furnished and installed equipment is to be tested prior to project completion.

F. Provide warranty of one year for all work performed and equipment installed.

3.02 REDUCE WATER LEVELS IN RESIDUAL LAGOONS AND PUMP BASIN

A. Contractor shall drain residual lagoons to a level that will stop overflow in the southwest corner to allow for electrical conduit trenching and installation.

B. Contractor shall drain pump basin to a level that will allow for pump installation.

C. Contractor shall ensure that the Concho Water Treatment Plant (WTP) is able to continue backwash into the residual lagoons during construction.

1. Contractor will maintain drained water levels throughout construction.

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3.03 INSTALL ELECTRICAL LINE

A. Contractor shall install approximately 242’ of electrical conduit and appurtenances.

1. Contractor shall trench and install approximately 200’ of 1” electrically-rated PVC conduit from the center of the pump basin on the south end of the residual lagoons to the west side of the WTP in accordance with the attached proposed facilities map

(See Figure 3).

2. The Contractor is to install the first junction box immediately south of the pump.

Wiring will be allowed to be non-submersible rated between this junction box and the plant as long as the Contractor seals the junction box wiring with foam between this junction box and the pump.

3. All underground conduit bends are to be electrical sweeps (minimum 18”).

4. Trench depth shall be no less than 18” and no less than 24” under the road, as per

Table 300.5 of the NEC.

5. Contractor shall install two (2) NEMA type 3R junction boxes at the locations specified in the attached proposed facilities map (See Figure 3).

6. The first and second junction boxes are to be installed 18” above the ground with a

5/8” x 1 5/8” metal uni-strut installed a minimum of 12” into the ground.

7. Contractor shall install approximately 20’ of 1” electrically-rated, electrically-rated

PVC conduit beneath the existing driveway using a boring method.

8. Contractor shall continue installation of 1” electrically-rated PVC conduit from the ground to a height of 10 feet on the outside west wall of the WTP.

9. A conduit outlet body with gasket is to be installed at the 90 degree angle going into the plant.

10. Contractor shall continue installation of approximately 12’ of 1” electrically-rated

PVC conduit into the WTP and connect to existing 1” conduit entering the existing electrical breaker box.

11. Contractor shall seal entry of conduit into the WTP to be weather resistant.

B. Contractor shall install approximately 242’ of electrical wire and appurtenances.

1. Contractor shall install one (1) single pole breaker into existing electrical breaker box.

2. Contractor shall install approximately 242’ of electrical line from new single pole breaker in the existing electrical breaker box through the newly installed conduit to the pump basin of the lagoons.

3. Contractor shall reconfigure existing electrical breaker box to comply with NEC

408.4 (b) “Source of Supply” and NEC 110.16 (a) “Arc-flash Hazard Warning” regulations, including the labelling of the existing circuit breakers.

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4. To keep the voltage drop to within the NEC 210.19(A)(1), FPN #4’s recommended

3%, a minimum #8 copper AWG wire size shall be used.

3.04 INSTALL SUBMERSIBLE PUMP

A. Contractor shall supply two (2) submersible effluent pumps that meet the following minimum specifications:

1. 1/2 Hp motor

2. 115 Volts

3. Single Phase

4. Capable of pumping approximately 60 gpm at 13’ of head

5. 2" FNPT discharge

6. Handles a minimum of 2” solids

7. Installed on raised platform, maximum height 6”

8. Thermally protected motor

9. Designed for continuous duty

Manufacturer/Model: Zoeller N267 - 1/2 HP Cast Iron Sewage Pump (2") (Non-

Automatic) or equivalent.

B. Contractor shall supply and install one (1) 2”x2” sewage check-valve on the vertical line leaving the pump.

C. Contractor shall install one (1) submersible effluent pump and appurtenances into the pump basin on the south end of the residual lagoons.

D. Contractor shall provide one (1) submersible effluent pump to the operator.

E. Contractor shall supply and install float switch and alarm system to operate between

1’ and 5’ or as instructed during installation.

Manufacturer/Model: Little Giant 303HWXT – Tank Alert float switch and alarm or equivalent.

3.05 FINAL INSPECTION

A. Contractor shall schedule with project engineer and water system operator to perform final inspection in the installed facilities and appurtenances.

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