SECTION 11347 GRIT DEWATERING AND DISPOSAL EQUIPMENT

This spec was part of the Des Plaines, IL River WRF project tat bid Feb 26, 2015.

SECTION 11347

GRIT DEWATERING AND DISPOSAL EQUIPMENT


PART 1 GENERAL

1.1 SECTION INCLUDES:

A. Grit Dewatering Equipment:
1. Grit Classifier: M-2-3-1.
2. Grit Separation Cyclone.

B. Control Panels:
1. 25-LCP-2-1.

1.2 SYSTEM DESCRIPTION

A. The grit washing system shall operate intermittently as the grit slurry is pumped from the vortex grit chamber to the separation cyclone by the grit pumps. The classifier system shall wash, dewater and remove organics from the grit, and convey it into a grit disposal container.

B. The grit washing system control panel (25-LCP-2-1) shall control the grit classifier operation as well as the existing grit control pumps and the existing degritter, as shown on P&ID 09-I-3.

1.3 REFERENCES

A. ASTM:
1. ASTM A283 - Low and Intermediate Tensile Strength Carbon Steel Plates.
2. ASTM A48 - Gray Iron Castings.

B. AGMA:
1. AGMA Section 218.01 - Rating the Pitting Resistance and Bending Strength of Spur and Helical and Involved Gear Teeth.
2. AGMA Section 440.04 - Single and Double - Reduction Cylindrical - Worm and Helical - Worm Speed Reducers.

C. AFBMA:
1. AFBMA Std: 9 - Load Ratings and Fatigue Life for Ball Bearings.
2. AFBMA Std: 11 - Load Ratings and Fatigue Life for Roller Bearings.

1.4 DESIGN REQUIREMENTS

A. Grit Classifier and Cyclone:
1. Design grit slurry flow, gpm: 250.
2. Cyclone inlet pressure,
a. Design, psig: 6
b. Maximum, psig: 10.
3. Classifier maximum underflow, gpm: 24.

4. Performance: Minimum 95% of 150 mesh grit with specific gravity of 2.65 in underflow.

1.5 SUBMITTALS

A. Shop Drawings: Submit under provisions of Division 1, including the following:
1. Complete assembly and installation drawings.
2. Descriptive information on material and equipment furnished, including design conditions and performance data.
3. Electric motor data and gear reducer data.
4. Electrical control information, including schematics, panel drawings, and component specifications.

B. Submit operation and maintenance manuals under provisions of Division 1.

C. Submit certificates of proper installation and operator training under provisions of Division 1.

1.6 DELIVERY, STORAGE AND HANDLING

A. Deliver, store and handle the equipment under the provisions of Division 1.


PART 2 PRODUCTS

2.1 ACCEPTABLE MANUFACTURERS

A. Weir Specialty Pumps (WEMCO); Salt Lake City, UT.

B. Or Equal.

2.2 GENERAL

A. All equipment shall be the end product of one equipment system manufacturer. The manufacturer shall be responsible for the complete system.

2.3 METAL FABRICATION

A. Metal parts as described herein conforming to Section 05500.

B. Structural Steel: ASTM A 283.

C. Plates and Structural Members for Submerged Service: Minimum thickness 1/4-inch 316 stainless steel unless otherwise indicated.

D. Anchor bolts, fasteners, nuts and washers: 316 stainless steel.

2.4 EQUIPMENT

A. Cyclone: Furnish factory assembled grit separation cyclone conforming to the detailed requirements herein:
1. Materials of construction:

a. Cyclone vortex finder: Abrasion Resistant alloy approximate hardness 500 Brinell.
b. Feed chamber: Cast iron, with replaceable liner.
c. Cylindrical and conical section: Steel and/or aluminum, with individually replaceable liners, one piece per section.
2. Location: Free-standing on upper level, as shown on the Drawings.
3. Inlet connection: 4-inch flanged.
4. Overflow connection: 6-inch flanged.
5. Vortex finder size: 4-inch maximum.
6. Inlet pressure gauge:
a. 1-inch NPT minimum gauge connection tapped into cyclone inlet.
b. Furnish a diaphragm protected, pressure gauge with 0-15 psig scale, Ashcroft 1279 or equal.
7. Provide a feedbox inlet with a 6-inch diameter outlet, for use with the classifier feedbox. Inlet shall be constructed of 316 SST, and have a removable cover.

B. Classifier: Furnish factory assembled grit classifier consisting of a settling tank and screw type conveyor, and conforming to the detailed requirements herein.
1. Settling tank:
a. Materials of construction: 316 stainless steel.
b. Type: Flared.
c. Minimum weir length: 24 inches.
d. The classifier shall be constructed so that maintenance can be performed without draining the grit-settling tank.
e. Provide a 316 stainless steel, side-mounted feedbox to receive flow from the grit separation cyclone. The feedbox shall be designed to prevent splashing when the grit system is in operation, be self-draining, and prevent grit buildup within the box.
2. Screw conveyor:
a. Spiral construction: Single ribbon spiral constructed of preformed steel, welded to shaft, with replaceable wear shoes bolted to the flight sections.
b. Diameter: 12-inches.
c. Maximum speed: 12 rpm.
d. Length: 90-inches, minimum.
e. Shaft design: 3,000 psi maximum stress, fatigue life of 20 years at 98% reliability.
f. Screw guard: Fiberglass construction, provide over full length of screw and allow visual observation.
g. Provide V1010 solenoid valve, per the requirements of specification section 15100, with 3/8” NPT valve cock for the grit wash.
h. The screw conveyor shall be constructed so sufficient clearance is provided between the screw and settling tank to allow the formation of a grit bed to prevent tank wear.
3. Grit chute: Provide an adjustable, three-sided, 45-degree grit chute, constructed of 316 stainless steel.
4. Lower bearing:
a. Lower bearing shall consist of a sealed bronze, oil-lubricated, sleeve- type bearing. The bearing shall be housed in a watertight enclosure suitable for completely submerged operation in grit service.

5. Motor: Furnish motor compatible with the driven equipment herein. Motors shall be furnished as specified in Section 11338, and shall conform to the detailed requirements herein.
a. Motor nameplate horsepower: 1/2 HP.
b. Type drive: Constant speed.
c. Nominal (synchronous) motor rpm: 1800 rpm.
d. Motor mounting: Horizontal.
e. Enclosure: Explosion Proof, Class 1 Division 1, Group D.
f. Power: 460 volt, 3 phase, 60 Hz.
g. The motor shall have NEMA B starting torque and low starting current. The motor shall not be overloaded beyond the nameplate rating under any normal conditions encountered.
h. Motor shall be provided with Klixon type motor temperature switches in each phase winding.
6. Mechanical Drive: Furnish factory assembled drive mechanism:
a. Primary Reduction:
1) Type: V-belt.
2) Service factor: 1.25 or greater.
3) Number of belts: One.
4) Belt size: 3V or greater.
5) Driver sheave: 2.8 P.D.
6) Provide OSHA approved guard and adjustable motor mount with jack screws.
b. Final Reduction:
1) Type: Cycloidal.
2) Service factor: 5 or greater
3) Lubrication: Grease.
4) Gear case: Cast iron ASTM A 48, Class 40 B housing, enclosing all gears, and sealed.

2.5 FINISHING

A. Shop and Field Painting:
1. Contractor shall verify compatibility of shop prime and field paint.
2. Finish all non-stainless steel, plastic and reinforced fiberglass surfaces to conform to Section 09900 and the following:
a. External surfaces: System No. 5.
b. Interior surfaces: System No. 2.

2.6 INSTRUMENTATION AND CONTROL

A. Furnish controls and control panel compatible with the grit dewatering and disposal system herein. Control panels and controls shall be furnished in accordance with Division 13 and Division 16, Contract Drawing 09-I-3, and shall conform to the requirements herein.

B. Provide local-mounted control stations/switches for each Grit Classifier:
1. Enclosure/Switch: NEMA 7X/rated for Class 1 Division 1 environment.
2. Switches:

a. Provide an access door interlock switch mounted to the classifier’s spiral guard. Switch shall be Square D 9007-CR53B2 Explosion Proof with rocker arm for sensing guard removed, Or Equal.
b. Provide a torque limit switch mounted to the classifier’s screw drive system.

C. Grit Control Panel 25- LCP-2-1 minimum requirements:
1. Enclosure: NEMA 4X stainless steel.
a. Provide Hoffman enclosure, or equal.
b. Surface mount switches and lights on exterior of panel door.
c. Built in accordance with specification section 13325.
d. Components in accordance with specification section 13326
e. All motor starters shall be NEMA rated.
2. Power supply: 480 volt, 3 phase, 60 Hz.
3. Provide single panel disconnect with panel protection.
4. Provide starter in panel with overload auxiliary “Fail” contact for each motor.
5. Provide transformer for all controls and lights.
6. Provide a motor current monitoring device for each motor.
7. Provide starter and power for operation of Flush Water Solenoid.
8. Control power ON-OFF switch.
9. Provide an Allen Bradley MicroLogix 1400 series PLC controller with Ethernet port for interface to plants central SCADA system. Provide programming for control of entire system locally from touchscreen or remotely from plant’s central SCADA control system.
10. Provide an Allen-Bradley, PanelView Plus, 6 inch or larger color touch screen. All indicators, buttons, switches described below shall be implemented via touch screen.
11. Indicator Lights:
a. “Panel Power” - white.
b. “Control Power” – white.
c. “Degritter Run” - green.
d. "Degritter in Auto” – white.
e. “Degritter Fail” - red.
f. “Grit Pump 1 Run” - green.
g. "Grit Pump 1 in Auto” – white.
h. “Grit Pump 1 Fail” - red.
i. “Grit Pump 2 Run” - green.
j. "Grit Pump 2 in Auto” – white.
k. “Grit Pump 2 Fail” - red.
l. “Grit Classifier On” - green.
m. “Grit Classifier in Auto” – white.
n. “Grit Classifier Fail” - red.
12. Fault reset buttons:
a. Grit Pump 1
b. Grit Pump 2
c. Degritter
d. Grit Classifer.
13. SPDT dry contacts for indication of:
a. Grit Washer Run.
b. Spray Run.
c. Grit Pump Run.

d. Common Fail.
e. Power Available.
f. System in Auto.
14. Input signals:
a. Hand-Off-Auto switches for each motor.
b. Local EMERGENCY STOP switch for Grit Classifier.
c. Motor high temp switches for Grit Classifier motor.
d. Grit Classifier access door interlock switch.
e. Grit Classifier torque switch.
15. Output signals:
a. Flush Water Solenoid.

D. Functional Description:
1. The controls shall provide for automatic timed operation as well as manual operation of the Grit Classifier, Grit Pump 1, Grit Pump 2, and Degritter.
2. The field mounted E-Stop Switches for the Grit Classifier shall be wired directly to the control circuit for the associated Motor Starter Coil and as an input to the PLC.
3. The PLC shall monitor the field mounted Hand-Off-Auto Switches for the Grit Classifier, Grit Pump 1, Grit Pump 2, and Degritter.
4. Motor overtemp conditions condition shall be monitored for the Grit Classifier. Overtemp condition shall cause the motor to stop and require manual reset and illuminate a fault light.
5. Access door open switch shall be wired directly to the control circuit for the classifier Motor Starter Coil and as an input to the PLC.
6. Degritter Automatic mode shall operate as follows:
a. The Degritter shall be operated from clock time with duration timers.
b. The clock timer shall allow at least 3 entries each for start and stop in a 24 hour period.
c. The duration timer shall allow for at least 3 separate durations and shall be set up for hours and minutes of operation.
d. The Degritter shall use the plant SCADA Ethernet network interface to receive influent plant flow. An adjustable flow set point shall be provided. If the set point is exceeded, the Degritter shall run continuously until the plant influent flow falls below the set point. The Degritter shall then return to the programmed timer operation.
7. Classifier Automatic mode shall operate as follows:
a. The Classifier and selected Grit Pump shall be operated from clock time with duration timers.
b. The clock timer shall allow at least 3 entries each for start and stop in a 24 hour period.
c. The duration timer shall allow for at least 3 separate durations and shall be set up for hours and minutes of operation.
d. The Classifier shall begin operation after an on-delay timer counts out. The Classifier shall continue to run as long as the selected grit pump is running. The Classifier shall stop operation when an off-delay timer counts out after the grit pump stops.
e. The flush water solenoid shall open immediately when the Automatic cycle starts and will remain open as long as the classifier is rotating. The solenoid shall close when an off-delay timer counts out after the Classifier stops.

f. The classifier and selected Grit Pump shall use the plant SCADA Ethernet network interface to receive plant influent flow. An adjustable flow set point shall be provided. If the setpoint is exceeded, the Classifier and selected Grit Pump shall run continuously until the plant flow falls below the set point. The Classifier and selected Grit Pump shall then return to the programmed timer operation.
8. Manual restarting of the system shall not be required in the event of a power outage.


PART 3 PART EXECUTION

3.1 INSTALLATION

A. Install in accordance with the Drawings, shop drawings and manufacturer's instructions.

B. Level bases and grout with non-shrinking grout.

C. Eliminate any strain from piping.

3.2 MANUFACTURER'S SERVICES

A. Provide manufacturer's services under provisions of Division 1.

B. Minimum Service Requirements:
1. Installation: As required for proper installation.
2. Start-up and Field Testing: One day on site.
3. Operating Training: One day on site.

C. Service to Repair Defective Work: Provide during one-year warranty period under the provisions of the General Conditions.


END OF SECTION