Attachment_G_-_Underdrain_Specifications.pdf

Fire hose connection Hydrant Garden Hose connection

Filter 7, Right Bay

Fire hose connections (including a couple hydrants) are available around the perimeter of the filter building.

These are located on the provided map.

Filters 17 through 24 are partially inside the filter building. A couple garden hose connections are available inside. These are located on the provided map.

Type S® Underdrain

Type S® Universal Operation and Maintenance Manual for Flume Installation

Copyright

Type S® Universal – Flume Installation

©2018 Xylem Water Solutions Zelienople LLC. All rights reserved.

No part of this publication may be reproduced in any material form whether by photocopying or storing in any medium by electronic means without the prior written consent of the copyright owner.

Xylem

227 South Division Street

Zelienople, PA 16063 USA

Phone: (724) 452-6300

Fax: (724) 452-1377 www.FBLeopold.com http://www.fbleopold.com/

Table of Contents

1 Receiving and Storage

1.1 Loss or Damage in Transit

1.2 Storage

1.3 Field Assembly Figures

2 Assembly and Installation Instructions

2.1 Filter Preparation Instructions

2.1.1 General

2.1.2 Type of Filter – Flume

2.1.3 Checking Filter

2.1.4 Installation Materials and Equipment

2.1.5 Anchor Rod Installation

2.1.6 <ORIFICE PLATE INSTALL>

2.2 Underdrain Lateral Assembly

General

Recommended Handling Procedures

Assembly of Laterals

Protection of Underdrain and Media Retainer

2.3 Underdrain Installation

Protection of Underdrain Laterals

Level Tolerances

Grout Specifications

Setting the Underdrain Laterals – General

2.3.5 Flume Block Installation - Grout-Tite® Bridge

Grouting the Spaces between Laterals

Installation with I.M.S® 200 Media Retainer

Final Checks

Block Modifications

2.4 Field Assembly Figures

3 START-UP

3.1 START UP PROCEDURE

3.1.1 Introduction

Table of Contents

3.1.2 Recommended Startup Procedure

3.2 TESTING

3.2.1 Preparation for Testing

3.2.2 Hydraulic (Water) Testing

3.2.3 Air Testing

3.2.4 Concurrent Air and Water Testing

4 OPERATION

4.1 GENERAL

4.2 RECOMMENDED BACKWASHING PROCEDURE

5 MAINTENANCE

5.1 GENERAL

6 WARRANTY, SERVICE, PARTS

6.1 GENERAL WARRANTY

6.2 I.M.S® 200 MEDIA RETAINER WARRANTY

6.3 SERVICE

6.4 PARTS

7 PRODUCT DATA

7.1 Appendix 1

7.1.1 General

7.1.2 Materials

7.1.3 Proportions

7.1.4 Addendum for Sea Water

Strength

7.2 UNDERDRAIN CURVES

8 Project Drawings

Read This First This document contains instructions for proper handling, storage, installation, operation, and maintenance. Read all instructions in their entirety prior to installing and operation the underdrain system. Failure to follow proper instructions may void the manufacturer’s warranty.

SUBJECT CAUTION REF

Grout Selection and Preparation

Failure to use the recommended grout and prepare it properly may result in a reduced strength underdrain structure or failure of the underdrain system.

O&M para 2.3 Appendix I

Grout Installation Failure to place the fill grout within 24 hours after underdrain laterals are set in base grout may result in a reduced strength underdrain structure or failure of the underdrain system.

O&M para 2.3 Appendix I

Grout Penetration Failure to achieve full penetration of the fill grout to the base grout may result in a weakened underdrain structure or failure of the underdrain system.

O&M para 2.3 Appendix I

Anchor Rod Installation

Failure to install the anchor rods properly may result in a reduced strength underdrain structure or failure of the underdrain system.

O&M para 2.1, 2.3 project dwgs, epoxy mfg. Instructions

Anchor Rod Epoxy Installation

Failure to install the anchor rod epoxy properly may cause poor adhesion between the anchor rod and the concrete and may result in a reduced strength underdrain structure or failure of the underdrain system.

O&M para 2.1, 2.3, and project dwgs, epoxy instructions

Installation Tolerances

Failure to adhere to all tolerances; including but not limited to those related to wall sleeve and orifice locations, floor elevations, anchor rod size, locations and depths; may result in poor filter performance and/or failure of the underdrain system.

O&M para 2.1, 2.2,

2.3 project drawings

Floor Roughness Failure to install underdrain system on a filter floor with sufficient roughness may cause inadequate bonding between the base grout and floor and may result in a reduced strength underdrain structure or failure of the underdrain system.

O&M para 2.1, 2.2,

2.3 project drawings

Expansion Joints Failure to install the underdrain system in a manner that eliminates the effects of shifts at an expansion joint on the filter floor may result in equipment damage or failure of the underdrain system.

Project drawings and contract drawings

Filter Operation Failure to operate the filter system properly or within recommended limits may cause poor filter performance and/or excessive stresses on the system that may result in equipment damage or failure of the underdrain system.

O&M sections 3 and 4

Uncontrolled Air Failure to prevent uncontrolled air from entering the filter during backwash may cause excessive stresses on the system that may result in equipment damage or failure of the underdrain system.

O&M sections 3 and 4

Air Scour High Loop

Failure to incorporate a high loop in the air scour piping may allow backwash water to damage blower equipment or cause excessive surges during backwash that may result in equipment damage or failure of the underdrain system.

O&M sections 3 and 4, project drawings, and contract drawings

Air Scour Vent Valve

Failure to properly implement and utilize an air scour vent valve with a positive displacement type blower may cause excessive stresses during backwash and may result in equipment damage or failure of the underdrain system.

O&M sections 3 and 4, project drawings, and contract drawings

I.M.S® 200 Media Retainer

Failure to follow proper installation and operating procedures may cause poor filter performance and/or excessive stresses during backwash and may result in failure of the underdrain system.

O&M sections 2 and 5, and product application guide

Media Testing Xylem is not responsible for performing onsite media testing and will not be held responsible, financial or otherwise, for results that do not meet the contract specifications.

Receiving and Storage

1 Receiving and Storage CAUTION: Failure to follow proper receiving and storage procedures, instructions, recommendations and cautions may void the manufacturer’s warranty.

NOTE: Refer to Section 2, 2.3 for all field assembly figures.

1.1 Loss or Damage in Transit

It is the consignee’s responsibility to inspect the shipment immediately upon arrival and notify the carrier and Xylem if loss or damage has occurred. If loss or damage is evident at time of delivery, make a notation of the details on the carrier's delivery receipt before signing it.

If loss or damage is concealed and discovered after delivery, request the carrier in writing to make an inspection and issue a report. THIS MUST BE DONE WITHIN 15

DAYS!

Xylem is willing to assist in claim matters. Xylem cannot accept responsibility for material shipped FOB shipping point.

1.2 Storage

Please note as consignee, you are responsible for the protection of your underdrains, and related equipment i.e., anchor rods, O-rings, air header, etc. Delivery constitutes acceptance and transfer of title, so please note the following storage requirements.

• The Leopold, a xylem brand, Underdrain must be correctly stored to prevent warpage caused by uneven loading.

• Blocks are shipped palletized and covered with 5 mil polyethylene bags. Each pallet must be stored on a flat pad or firm ground and restrained to prevent overturning. Do not stack pallets on top of each other.

• Un-palletized block should be stacked on a flat level surface. Block must be stored with the apex of the primary lateral in an upright position as shown in Figure 1-1. Do not stack over 10 blocks high. They must not be stacked on the sides.

• Any loose block must be covered with 5 mil polyethylene to keep it clean and to protect sealant filled joints from the weather. If sealant is missing from the groove, it must be reinstalled before that block can be used.

• The maximum block temperature not to exceed 60°C (140°F). This may require removing from containers and/or storing under a canopy to prevent direct sunlight.

Receiving and Storage

• The blocks can be stored for approximately one (1) year prior to installation if all the above conditions are met for storage and a UV resistant cover is provided to prevent the 5 mil polyethylene bags from deteriorating. If the plastic bags are destroyed, they must be replaced or other suitable coverage provided.

1.3 Field Assembly Figures

Figure 1-1 STACKED UNDERDRAIN WITH I.M.S® 200 MEDIA RETAINER

Assembly and Installation Instructions

2 Assembly and Installation Instructions CAUTION: Failure to follow proper assembly and installation procedures, instructions, recommendations and cautions may void the manufacturer’s warranty.

NOTE: Refer to Section 2, 2.4 for all field assembly figures. Refer to Section 3 for all project drawings.

2.1 Filter Preparation Instructions

2.1.1 General

The installation of the Leopold, a xylem brand, Universal Type S® Underdrain System is simple and problem free provided these recommendations are followed. In all cases, it is recommended that an authorized Xylem Field Service Representative be present to instruct and train all personnel in the appropriate installation procedures. Please refer to the Plans and Specifications for this project. If "Certification" of the installation is required by Xylem, an authorized Xylem Field Service Representative must be present during the entire installation.

CAUTION: A Xylem Field Service Representative must be present for the complete installation of a minimum of the first filter.

NOTE: Forty-five (45) days’ notice is needed to schedule a Xylem Field Service Representative.

2.1.2 Type of Filter – Flume

A flume installation is one where a channel is built into the filter floor. The backwash water enters through it and is then directed up into the block. See Figure 2-1.

If an air header is required in the flume, install the header before setting the anchor rods. If an air header is required to be located above the underdrain, it can be installed when desired. Refer to the approved project drawings furnished by Xylem for dimensions and details for installation of the air header.

2.1.3 Checking Filter

CAUTION: Failure to adhere to all dimensions and tolerances may result in improper installation, poor filter performance and/or failure of the underdrain system.

The first procedure on any installation should be to check the dimensions of the filter and levelness of the floor. The first procedure on any installation should be to check the dimensions of the filter and levelness of the floor. Verify the location and dimensions of the flume and levelness across the flume.

NOTE: All dimensions should agree with dimensions as shown on the approved project drawings furnished by Xylem for the project. Figures in this document are for reference only, do not attempt to assemble and install equipment without referring to the approved project drawings.

If the measured filter width is smaller than the size shown on the approved project drawing, contact the Xylem Project Manager prior to adjusting the number and/or spacing of underdrain laterals.

If your flume arrangement does not conform to what is pictured, refer to the approved project drawings for any differences.

CAUTION: Do not deviate from the approved project drawings without written approval from the Xylem project manager.

If special plates (inlet diffusers, air shields, orifice plates, etc.) are required, make sure they are properly mounted per the approved project drawings.

If the floor is out of level, the high areas must be chipped to make the floor level to within 1" (25mm) between the highest and lowest areas. If the filter floor is dry, it should be dampened to ensure a good grout bond.

CAUTION: Grout will not bond properly to epoxy admixtures, painted areas, or smooth surfaces. Filter floor and wall (up to above the grout fillet) must be clean, with no paint or coatings, where it will be in contact with grout. The floor must have a rough surface equivalent to a minimum 1/8” (3mm) profile broom finish before placing floor grout.

2.1.4 Installation Materials and Equipment

The following materials and equipment are NOT SUPPLIED BY Xylem, but are recommended for the installation of the underdrain and related equipment.

• Mortar mixer (not a cement mixer)

• Transit (should be a laser)

• Portland cement (see Appendix I)

• Sand (see Appendix I)

• Sikaflex 1A or FDA and NSF approved equal

• Wood for wedging (may be scrap 2" x 4" to cut onsite)

• Epoxy for anchor rod installation (if not embedded during pouring of floor).

Suitable epoxy systems: EPCON C6 or Hilti RE500

• Two rubber mallets

• Two torpedo levels

• Two 4' levels

• Staple gun with 3/8" or 1/2" staples

• Two flat shovels

• Five 5-gallon buckets

• Two trowels

• Flashlight

• Traffic cone

• 5-7 laborers

• Sufficient number of chip boards or foam boards (to cover underdrain lateral during/after installation

2.1.5 Anchor Rod Installation

CAUTION: The anchor rod and epoxy installation are critical to obtaining proper strength of the underdrain structure. Failure to: 1) install the anchor rods properly; 2) adhere to all dimensions including but not limited to location, hole size, height, and depth embedment; and 3) follow the epoxy manufacturer’s instructions in their entirety may result in a reduced strength underdrain structure and/or failure of the underdrain system.

The locations, spacing and the height of the anchor rods shall be as shown on the approved project drawings. The height of the anchor rods shall be measured from the highest point of the filter floor and the top of all the anchor rods shall be on the same elevation within ±1/4" (6mm).

The size and depth of the holes shall be per the approved project drawings and the application of the epoxy material shall be in strict accordance with the epoxy manufacturer’s instructions. See Figure 2-2.

The anchor rod installation procedure shall be as follows:

1. Drill holes into the existing concrete floor in the location shown on the approved project drawings to a minimum depth of 5” (127mm). The drill bit size shall be in accordance with the epoxy manufacturer’s instructions.

2. Clean each hole thoroughly using a wire brush, vacuum, compressed air, and any other equipment necessary in accordance with the epoxy manufacturer’s instructions.

3. Thoroughly clean the anchor rod to ensure no foreign matter or substances are on the rod that might prevent the epoxy from bonding properly.

4. Loosely connect the horizontal and vertical components of the anchor rod assembly. This will allow for ease of alignment and allow the vertical components to rotate as necessary.

5. Apply the epoxy in the hole starting from the bottom and working upward until the proper amount of epoxy is deposited in accordance with the epoxy manufacturer’s instructions.

6. Install the anchor rod to a depth of 5” (127mm) into the hole using the proper motion in accordance with the epoxy manufacturer’s instructions.

7. Allow the epoxy to cure in accordance with the epoxy manufacturer’s instructions before proceeding.

8. After the epoxy has cured, a non-destructive vertical pull test shall be performed on 100% of the anchors (both legs). This pull test shall be conducted by the Xylem Field Service Representative and the procedure shall be as follows:

a. Using the test equipment supplied by Xylem, load each anchor to be tested with 3,600 lbs (16,014 N) tension in 900 lb increments (4,004 N).

b. After reaching 3,600 lbs (16,014 N), hold the load for 1 minute. All test results shall be documented and included in the service report.

c. Any anchor that fails to reach 3,600 lbs (16,014 N) or shows signs of slippage will be considered a failure.

d. In the event of a failed anchor, install a replacement anchor in accordance with all applicable instructions and retest.

NOTE: The required torque for 900 lbs (4,004 N) is 9 ft-lbs (46 N-m). The required torque for 3,600 lbs (16,014 N) is 34 ft-lbs (46 N-m). The torque is based on dry (un-lubricated) stainless steel threads.

CAUTION: Do not proceed with underdrain installation until the anchor rods have successfully passed the pull test.

9. After testing is complete, set the final elevation of the horizontal member of the anchor rod by rotating the bottom nut. The top of the horizontal member should be set in relation to the highest elevation of the filter floor. See project drawings for horizontal member dimension.

NOTE: Do not install horizontal crossbar until the preceding lateral has been set.

See Figure 2-4.

10. Lock the horizontal member in place by tightening the top nut against the top of the horizontal member.

NOTE: During the installation of the underdrain laterals, the anchor rod elevations and positions shall be verified and final adjustments may be required.

2.2 Underdrain Lateral Assembly

CAUTION: Do not proceed with assembly and installation of underdrain laterals until a Xylem Field Service Representative has provided instruction.

General Each lateral run should be assembled completely per Section 2.2.3. For outdoor installations when the ambient temperature is greater than 90ºF (32ºC) and in direct sunlight, the underdrain laterals should be assembled under a roof or tarp and stacked in or about the filter prior to installation. The assembled laterals should be covered with chip boards or foam boards and should be installed in the base grout per Section 2.3.4 within 72 hours of assembly.

Recommended Handling Procedures Based on the length of the lateral, it is necessary to provide the minimum support as shown in Figure 2-6 when handling and moving the assembled laterals.

Assembly of Laterals The laterals are assembled from the appropriate number of standard, flume and make-up blocks in accordance with the approved project drawings. The Xylem Field Service Representative shall instruct the contractor in proper assembly and installation of the underdrain. Instructions provided by the Xylem Field Service Representative shall be strictly adhered to.

The procedure shall be as follows:

1. The groove of the tongue and groove joint as shipped is filled with a synthetic rubber sealant, which is covered with protective tape. This tape must be removed and the sealant be inspected. If the groove is not fully filled with the sealant, an additional bead of 1/8" (3mm) diameter caulking must be added to the groove.

2. Place ring gasket in the exterior groove on spigot end of block making sure the O-ring splice is located at the bottom of the block. See Figure 2-7.

3. Assemble the filter blocks using the block assembly tool. The blocks should be examined for straightness of the internal walls before assembly. If the walls are bowed outward, use a 2 x 4 as shown in Figure 2-8 inserted into the block to straighten the walls just before assembly with the block assembly tool.

4. Insert the spigot end of one block into the bell end of another block but do not force them together.

5. Use the Assembly Tool (See Figure 2-9) to pull the blocks together. Initially, slowly pull the blocks together until the bell just makes contact with the O-ring. If the O-ring dislodges from the spigot, press it back into place with your fingers.

Then, proceed pulling the blocks together.

6. Make sure the adjustment screws on the tool are adjusted tight enough so that all snap lugs on the spigot are seated into the receptors in the bell. Check this adjustment periodically.

7. The tongue and groove joints must be inspected as follows:

NOTE: If the joint is not properly assembled it shall be taken apart and corrected. If the tongue and groove is excessively deformed, reject the part and start with a new piece. When it is certain that the inside joint is properly assembled, check to make sure the O-ring is in the groove.

a. Examine each joint after assembly of that joint. Check the entire length of the triangular joint, both sides of the tongue and groove to make sure the joint is properly engaged, with a flashlight and a mirror on each block.

b. Make certain that all of the interlock tabs on the inside perimeter of the bell end are properly seated. See Figure 2-10.

c. When a plate is welded on the end of the block, the tongue joint must be examined through the top deck holes.

CAUTION: Each joint must be inspected. Assembly with leak-free joints must be accomplished. Quality control of this procedure is the responsibility of the contractor and Xylem certification shall not relieve the contractor of this responsibility.

8. End Plates - Just before installing the end plate, look down the lateral and make sure it is clean. The end plate has to be caulked with a urethane sealant (Sikaflex 1A, NOT SUPPLIED BY Xylem) and press fit in place. Add the caulking in the corresponding grooves and around the top perimeter of the end plate that match with the triangular walls and outside edges. The objective is to seal the end of the last block in the lateral. See Figure 2-11. End plates must be held in place during lateral placement by stapling into the lateral walls. After the lateral is set in the base grout (see Section 2.3 Installation), blocks or wedges as shown in Figure 2-12 should be used to hold the end plates in place until end grout is placed.

NOTE: If this is not done properly, the end plate may pull off and leak.

Protection of Underdrain and Media Retainer CAUTION: Any damage to the I.M.S® 200 Media Retainer will require replacement by an authorized Xylem Field Service Representative. Do not attempt to operate the underdrains if there are damaged or dirty I.M.S® 200 Media Retainers.

Cut individual Pieces of Masonite or plywood board to fit between the guides on the block. Duct tape around the perimeter of the fitted Masonite, thus adhering the Masonite/plywood board to the underdrain.

2.3 Underdrain Installation

CAUTION: The underdrain laterals shall be installed in strict accordance with these instructions and the approved project drawings. Special attention shall be paid to the levelness and full penetration of cement grout at the joints between the laterals. Fill grout between laterals must be installed within 24 hours after the laterals are set on the base grout.

Protection of Underdrain Laterals After the entire process of grouting has been completed, and when the final fill grout has set up, the underdrain laterals shall be immediately and completely covered with chip boards or foam boards until water is available to flood the filter. The filter cell shall be flooded with at least 6” (150mm) of water over the top of the underdrain laterals. The boards or water are expected to protect the underdrain from debris and extreme temperature differentials, until the filter media is installed. If the filters are flooded with water, they will have to be periodically chlorinated to prevent biological growth.

It is recommended that the filter media be installed within approximately three (3) months to protect the underdrain. The media should be installed with water covering the I.M.S® 200 Media Retainer. If there is no water over the retainers and the media effective size is less than 0.75mm, then install a minimum of 2” (50mm) of support gravel in the range of 1.0mm to 2.0mm before installing the filter media being careful not to disturb the gravel. After the media has been installed, leave the filter drain valve open and cover the filter media with suitable covering that will last until the filters will be put into operation.

Level Tolerances Each underdrain lateral should be level to within ±1/8" (3mm). Between laterals, the level should be within ±1/8" (8mm) from gradeacross the filter bay. When the level is checked with a laser or transit, readings should be taken at the center of the various blocks.

It is helpful in installing the filter to strike a grade line around the filter wall as a guide.

This line should be measured using the Installation Grade Line found on the contract drawings and from the high spot in the floor.

Grout Specifications CAUTION: Failure to use the recommended grout and prepare it properly may result in a reduced strength underdrain structure and/or failure of the underdrain system.

See Appendix 1 for recommended grout specifications. If the grout specifications recommended herein are in conflict with those in the ENGINEER’S specifications, consult Xylem before proceeding.

The mixture of sand, cement and water in correct proportions shall be mixed in a small batch mortar mixer until there is a uniform distribution of materials and shall be discharged completely before the mixer is recharged. The cement grout shall then be used immediately with the same consistency.

The consistency of the base grout shall be heavy enough to support the weight of the lateral. If the grout is too wet, the lateral will float up and down or “bounce” and can’t be leveled correctly. The consistency of the fill grout could be thinner than that for the base grout. However, it is not recommended to use an extreme thin fill grout since shrinkage could present a problem.

Setting the Underdrain Laterals – General CAUTION: TEMPERATURE CONTROL – Temperature affects setting time and rate of increase for grout strength. For optimum performance maintain grout and concrete structure within the range of 64ºF (18ºC) to 77ºF (25ºC) prior to, during, and 48 hours after placement of the grout. At low temperatures (below 50ºF (10ºC)) grout setting time is extended and bleeding may occur. AT NO TIME MUST THE GROUT BE

EXPOSED TO TEMPERATURES LESS THAN 40ºF (5ºC) FOR THE FIRST 48

HOURS AFTER PLACEMENT. At high temperatures (greater than 86ºF (30ºC)) grout setting time is reduced affecting placement. It is recommended that grout at high temperatures be sheltered from the heat, or be conducted early in the morning. Setting times can be increased using a retarding admixture.

1. Lay base grout on the filter floor to the depth shown on approved contract drawings and 12” (300mm) wide.

2. Set the underdrain laterals in the base grout, one next to the other with the spaces as shown on the approved project drawings.

NOTE: When moving the underdrain laterals, LIFT IT – DO NOT SLIDE IT. If you must slide it, tip it up on a corner and slide it on the surface as shown in Figure 2-13.

3. Apply sufficient pressure to bed and level the lateral. DO NOT USE A HAMMER

FOR ALIGNMENT AS THIS WILL DAMAGE THE BLOCK.

4. Level the lateral by placing a 2 ft. 2 x 4 along the top of the I.M.S® 200 Media Retainer and tap it with a rubber mallet.

5. Dig out the excess grout to level the lateral if it is excessively high; however, digging out too much grout can cause voids.

6. Stop laying laterals when there are only three (3) rows remaining in the filter.

This provides more work room and eliminates the necessity of standing on a row just finished.

7. Cover the installed laterals and allow the base grout to set up (typically overnight) prior to finishing the lateral installation.

8. Install the last three (3) rows after the other laterals have set up.

9. Cover the laterals until the next day when the base grout has set up and the joints are prepared for fill grout.

CAUTION: It is important to note that if the underdrain laterals are exposed to a temperature difference of 25 degrees or greater they should be covered with foam boards immediately after the base grouting has been completed. The boards will protect the laterals from sunlight and will also keep heat inside the laterals at night when the air temperature drops. Foam board no less than 1” (25mm) thick can be used as a cover only, not as a working surface. If the Masonite boards that are used for the underdrain cover (See section 2.2.4.2 and .3) are a minimum of 1/8” to 1/4" (3 to 6mm) thick, they can be used as a work surface during the grouting process. For heavy equipment the laterals must be covered with 1/2” (13mm) thick plywood. Equipment such as yard buckets or wheelbarrows can then be used on this working surface.

Boards should also be placed under ladders, scaffolds, etc., on the top of the work surface to prevent damage to the top deck of the laterals.

2.3.5 Flume Block Installation - Grout-Tite® Bridge

At this point the anchor rods should be installed and the laterals assembled. If not, refer back to Section 2.1.6 and Section 2.2.3 respectively.

1. Install the PVC flume sealing plates on the sides of the flume by first using the slots and anchors provided to level the plate. Reference the approved arrangement drawings to determine the height to install the retainer plate. See Figure 2-3.

2. Drill intermediate holes through the plate and into concrete at the same time once the plate has been leveled. Anchors should be no more than 18” (457mm) apart.

3. Attach PVC flume sealing angles to both ends of the flume with anchors setting the top of the angles to the match the bottom of the underdrain ribs at the location of the bridge. Refer to approved arrangement drawings for dimensions.

See Figure 2-3.

4. When laying the base grout per Step 1 of Section 2.3.4, also place a bed of grout onto the flume sealing angle for the underdrain to rest in. This will create a seal preventing fill grout from running into the flume.

5. Install the first lateral with no bridge initially installed.

Note: The first and last laterals in the filter do not get bridges in the outer sides of the underdrain block alongside the wall.

6. Insert a Grout-Tite® Bridge into the slots provided in the underdrain ribs of the lateral just installed. Ensure the bridge is centered about the flume opening.

7. Install an anchor rod crossbar at this time ensuring the proper height is set.

Refer to Section 2.1.6 item 9.

8. Lower the next underdrain lateral between the anchors and align the cut ribs with the bridge in the previously installed lateral.

9. Apply even pressure to bed the lateral into the base grout.

10. Adjust the center spacing ensuring the previous lateral was not moved. The

Grout-Tite® Bridge is designed specifically for the spacing of the project without any additional moving or adjusting of the bridge with allowance for slight variations.

11. Repeat steps 5-9 until the last lateral is ready to be placed.

12. Cut off the ribs sections below the slots of the last lateral to allow the underdrain to be dropped into place on top of the last Grout-Tite® Bridge. See Figure 2-5

13. Place additional stiff grout on top of the bridge between the last two laterals to ensure a complete seal to keep out the flowable fill grout.

Place additional stiff grout on top of the bridge between the outer laterals and the walls over the flume to ensure a complete seal. This is done to prevent flowable fill grout from entering the flume.

Grouting the Spaces between Laterals

CAUTION: Failure to prevent grout from getting into the primary lateral of the flume block may result in poor filter performance and/or failure of the underdrain system. Proper installation of the Grout-Tite® bridges seals off the flume from the fill grout.

The fill grout at the joints between laterals provides structural strength to the underdrain for all loading conditions. The grout at the joints between laterals and the base grout can then form a solid monolithic structure to hold the laterals in place.

Within 24 hours after the laterals have been properly bedded in base grout, the spaces between the laterals should be filled with flowable grout as soon as the base grout has set. Make sure that each lateral is completely sealed and impervious to any run-in before starting the grouting.

CAUTION: Failure to achieve full penetration or to place fill grout within 24 hours of setting the base grout may result in a reduced strength underdrain structure and possible failure of the underdrain system.

When the laterals are covered with boards, remove the cover only for those laterals that are to be grouted. The laterals shall then be covered again soon after the completion of the grout process.

Two recommended procedures to help in the grouting process are: a traffic cone used as a funnel or a 20-gauge steel splash board. See Figures 2-14 and 2-15.

1. Pour grout against the splash board and trowel into place.

2. Allow the grout to flow freely all the way down to completely meet with the base grout. Neither air spaces nor voids are allowed between the fill grout and the base grout, nor shall air pockets be allowed in the fill grout.

3. Tamp and work the fill grout down and penetrate all the voids using asteel bar or similar device.

4. Ensure that all the spaces around the anchor rods are properly grouted.

5. Extend grout to within 1/4” (6mm) of the laterals as shown in Figure 2-14 and clean up any spillage.

6. Ensure all orifices and recesses are open and clean of grout and debris.

7. Cover all underdrain laterals with the chip or foam boards immediately after fill grouting procedure is complete. The laterals must remain covered with boards until water or filter media is available to cover the filter underdrain as was described in Section 2.3.1.

8. Place grout fillet along the ends of the lateral and the filter wall, extending onto the top surface of the underdrain as shown in Figure 2-16. The grout fillet should be placed at the same time as the spaces between the laterals are grouted to insure a good bond. The fillets along the end of the lateral at the wall may cover the installed I.M.S® 200 Media Retainer up to the first screw.

Installation with I.M.S® 200 Media Retainer It is essential that the I.M.S® 200 Media Retainer be kept clean during grouting procedures. The exposed Media Retainers are then immediately covered with a 30 lb.

roofing paper (or stronger to resist tearing).

1. Begin with a full-width sheet the length of the laterals.

2. Cut another piece off the width of one lateral, as shown on Figure 2-1.

3. Apply grout as shown in Figure 2-14 and Figure 2-15 over the joint opening on the roofing paper.

4. Slide the widest sheet to the next joint

5. Lift the narrow sheet to the next lateral.

6. Continue this method throughout entire filter.

Normally, the paper will last for 10-15 laterals. Once the paper is torn excessively, discard it and begin with a new sheet as above. The intent is to prevent any grout from coming in contact with the top surface of the I.M.S® 200 Media Retainer and plugging it. It is the contractor’s responsibility to keep the I.M.S® 200 Media Retainer clean during installation.

CAUTION: Any damage to the I.M.S® 200 Media Retainer will require replacement by an authorized Xylem Field Service Representative. Do not attempt to operate the underdrains if there are damaged or dirty I.M.S® 200 Media Retainers.

7. Cover all underdrain laterals with the chip or foam boards immediately after fill grouting procedure is complete. The laterals must remain covered with boards until water or filter media is available to cover the filter underdrain as was described in Section 2.3.1.

Final Checks After the underdrain has been completely set and grouted it should be checked carefully as follows:

1. Standard Underdrain: Ensure that all orifices in the top surface of each block are open and free of foreign materials and the block is not broken or damaged.

2. Underdrain with I.M.S® 200 Media Retainer: Ensure that hte entire I.M.S® 200 Media Retainer is clean and free of any grout or debris, and not broke or damaged.

3. Prior to placement of the gravel and media, the filter should be tested in accordance with procedures found in the specifications. If there are no specified test procedures, the filter should be tested in accordance with procedures found in Section 3.2 of this manual. Typically, no gravel will be provided on installation with I.M.S® 200 Media Retainer. (Check the approved Xylem project drawings for exceptions to special conditions).

4. The filter is now ready for the placement of gravel and/or media. If any delay is encountered between the completion of installation, the testing or placement of the gravel and media, the underdrain should be covered with approximately 3 feet (1m) of clean and disinfected water or with chip or foam boards to protect it from possible damage.

Block Modifications

DO NOT MODIFY BLOCKS WITHOUT APPROVAL.

CAUTION: Modification of blocks without approval in writing from the Xylem Project Manager may void the manufacturer’s warranty.

2.4 Field Assembly Figures

Figure 2-1 GENERAL FLUME ARRANGEMENT Figure 2-2 ANCHOR L-ROD INSTALLATION Figure 2-3 FLUME SEALING PLATE MOUNTING Figure 2-4 GROUT-TITE® BRIDGE INSTALLATION Figure 2-5 UNDERDRAIN RIB CUT Figure 2-6 UNDERDRAIN LATERAL HANDLING REQUIREMENTS Figure 2-7 O-RING GASKETS Figure 2-8 OUTWARDLY BOWED WALLS Figure 2-9 ASSEMBLY TOOL Figure 2-10 BELL AND SPIGOT ASSEMBLY Figure 2-11 END PLATE SEAL Figure 2-12 END PLATE AND WEDGE Figure 2-13 SLIDING UNDERDRAIN Figure 2-14 CONE Figure 2-15 SPLASH BOARD Figure 2-16 GROUT FILLET Figure 2-1 I.M.S® 200 MEDIA RETAINER PROTECTION

Figure 2-1 GENERAL FLUME ARRANGEMENT

Figure 2-2 ANCHOR L-ROD INSTALLATION

Figure 2-3 FLUME SEALING PLATE MOUNTING

Figure 2-4 GROUT-TITE® BRIDGE INSTALLATION

Figure 2-5 UNDERDRAIN RIB CUT

Figure 2-6 UNDERDRAIN LATERAL HANDLING REQUIREMENTS

Figure 2-7 O-RING GASKETS

Figure 2-8 OUTWARDLY BOWED WALLS

Figure 2-9 ASSEMBLY TOOL

Figure 2-10 BELL AND SPIGOT ASSEMBLY

Figure 2-11 END PLATE SEAL

Figure 2-12 END PLATE AND WEDGE

Figure 2-13 SLIDING UNDERDRAIN

Figure 2-14 CONE

Figure 2-15 SPLASH BOARD

Figure 2-16 GROUT FILLET

Figure 2-1 I.M.S® 200 MEDIA RETAINER PROTECTION

START-UP

3 START-UP

CAUTION: Failure to follow proper start-up and testing procedures, instructions, recommendations and cautions may void the manufacturer’s warranty.

3.1 START UP PROCEDURE

3.1.1 Introduction

The Leopold, a xylem brand, Underdrain Systems have been designed and manufactured to give many years of service when properly installed. It is necessary, however, to take special precautions during start-up.

When an underdrain installation is backwashed for the first time, the piping and underdrain laterals are susceptible to surges of hydrodynamic forces. These forces rise whenever the velocity or direction of flow is changed, such as at entrances and end of laterals and at tees, elbows, etc. The magnitude of the hydrodynamic force is directly related to volumetric flow rate and velocity.

Another force results from the development of internal pressures as the primary underdrain lateral fills with water. During this time, most of the fluid runs freely down that lateral. The flow rate and velocity are abnormally high as the water reaches the end of the lateral, where the velocity energy is converted to pressure. This excessive pressure may cause damage.

A similar pressure problem may be encountered if air is trapped in the piping system.

Unrelieved air will be compressed, leading to constricted flow passages, hydrodynamic forces and internal pressure. If the air is relieved in an uncontrolled manner, the resultant water velocity gradient could cause water hammer resulting in upset gravel and possibly structural damage.

CAUTION: The backwash rate must be limited to a rate that will not generate a differential pressure (net internal pressure) across the underdrain greater than 750 psf (5.2 psi [0.359 bar]). This is typically about 40 gpm/sf (98 m/hr). Also, filter systems using gravel for supporting the filter media must limit the maximum backwash rate to 25 gpm/sf (61 m/hr) to prevent gravel disruption unless a special gravel design has been provided.

3.1.2 Recommended Startup Procedure

The following steps are recommended:

1. Check for post-installation damage to the underdrain and I.M.S® 200 Media

Retainer. If damaged, contact the Xylem Project Manager.

2. Assure that all orifice holes and all depressions around the orifices in the top deck are open. Ensure that the I.M.S® 200 Media Retainer is free of grout, dirt, and debris.

3. The contractor shall review the piping system and insure that air release valves have been installed at all relative high points and are operational. Vacuum check valves must be installed on any air release valves on piping subject to negative pressures. The entire wash water piping system must be free of air before backwashing. This may require a water pressurization system to SLOWLY fill the system with an external water supply.

CAUTION: If the system drains between backwashes, it must be refilled and repressurized each time. If this occurs, the system must be checked for proper operation.

CAUTION: Do not use the agitator system to fill the system. This may result in media loss and/or damage to agitator bearings.

CAUTION: Never start the backwash pump against an open system, i.e.

with valves open between the pump and the filter. If the system uses a head tank, never introduce water quickly from the head tank.

4. Set the valves or flow controllers to about 10% of design backwash rate (1-2 gpm/sf [2.5-5 m/hr]) and start the flow slowly. Allow adequate time for trapped air to escape.

5. Carefully and thoroughly inspect the system, and correct any problems. Look for any sign of distress or movement in the system, repair leaks, etc.

6. Adjust the valves in a series of steps, (each time increasing flow by 1-2 gpm/sf [2.5-5 m/hr]) until the design rate is reached. This stepwise procedure must be followed to insure complete removal of trapped air. It may be necessary to alter the operation of some valves in order to do this. Check the system at each step.

Do not increase backwash flow to a higher setting until all visual/audible air expulsion has stopped.

7. At the end of the backwash, reduce the flow by 1-2 gpm/sf (2.5-5 m/hr) increments until it stops. Check the system at each step.

NOTE: The previous guidelines emphasize two principles: 1) make changes in flow slowly and 2) eliminate all air from the system. Adherence to these guidelines can help protect the underdrain and insure reliable performance.

3.2 TESTING

Prior to placement of the support gravel and filter media it is necessary to test the underdrain for proper installation. All installations must be tested with water as described below. Systems that include air as part of the backwash cycle must also be tested with air.

CAUTION: Before the gravel or filter media is installed, the filter control system shall be fully tested in automatic on empty filters and approved for automatic operation to insure that all equipment and devices perform and sequence as designed.

3.2.1 Preparation for Testing

In order to test the underdrain, it is necessary that the backwash (and air scour) flow systems be checked out and operational.

1. All open/close filter valves shall have been recently exercised and are fully operational.

2. All flow control loops shall be tested, calibrated and functional.

3. Backwash pumps shall have been run and tested.

4. All air release and vacuum check valves must be verified as operational and functional.

5. The blower and its relief and venting systems shall be operational.

6. An adequate supply of clean, disinfected backwash water shall be available for testing.

7. Testing personnel should be adequately trained to operate the system without causing hydraulic surges (water hammer), which can damage the integrity of the filter.

3.2.2 Hydraulic (Water) Testing

1. After the grout has cured for at least three (3) days, the surface of the underdrain should be inspected for clogged orifices. Debris must be removed and discarded. If I.M.S® 200 Media Retainer pores are clogged, the I.M.S® 200 Media Retainer will need to be replaced. Contact the Xylem Project Manager for assistance.

2. Using clean disinfected water, the filter should be filled through the backwash piping at a slow rate of approximately 2 gpm/sf (5 m/hr).

3. Continue filling with backwash water until the water level is about 6" (150mm) above the underdrain.

4. Stop filling and drain the filter until the water level just falls below top of underdrain, i.e. the water can't be seen.

5. Inspect underdrain surface and remove any debris that may have been flushed up to the surface.

6. Start filling again. Over a period of 1-2 minutes, increase the water rate to 15-20 GPM/SF (37-49 m/hr) or the specified maximum backwash rate. As the water is rising, look for localized turbulence or boils. The pattern should be reasonably uniform over the entire filter surface. If in doubt, repeat procedure.

7. If the pattern is uneven or there is localized turbulence or boils, lower water level and inspect the underdrain for plugged orifices, clogged I.M.S® 200 Media Retainer, bad joints, or displaced end plates. Repair as necessary and retest.

8. After all hydraulic testing has been successfully completed and if the filter employs air scour, proceed to air testing.

3.2.3 Air Testing

After successfully completing the hydraulic testing, it is necessary to test the underdrain for a proper air pattern. Prior to starting the air, insure that the blower and all valves and flow measuring devices are operational.

1. Fill the empty filter through the backwash system to a water level 4-6" (100-

150mm) above the top of the bare underdrain.

CAUTION: The blower system shall have a rate control valve. Systems that employ a positive displacement type blower system shall have an automatic vent (bypass) to atmosphere valve.

2. Positive displacement blowers will use a vent valve, while centrifugal blowers may use an in-line throttling valve. Start a positive displacement blower with the vent (bypass) valve open. Start a centrifugal blower with the throttling valve closed. Start the blower and open the air isolation (inlet) valve on the filter.

NOTE: Adjust the rate control valve slowly to obtain the design air flow rate. Adjust rate of flow from no flow to design flow over a period of approximately 60 seconds.

Never start the blower so that its full capacity is delivered to the filter immediately.

Refer also to the backwash and air scour sequence found later in this manual.

3. Check the air pattern in the filter. It should be reasonably uniform over the entire surface.

4. If dead spots or rows are noticed, try adjusting the air rate (up to down) to obtain a better pattern.

5. If certain areas show excessive air shut down the blower, drain the filter and examine the underdrain for punctures, bad joints, or loose end plates.

NOTE: If structural damage to the plastic or misaligned internal joints is found, it will be necessary to do a fusion weld repair. Contact the Xylem Project Manager for assistance.

3.2.4 Concurrent Air and Water Testing

After successfully completing the hydraulic testing and the air scour test, it is necessary to test the underdrain for a proper air/water pattern. All the conditions required for the hydraulic and air testing apply to the concurrent air and water testing.

1. In most cases, start with a water level 4”-6" (100-150mm) above the top of the bare underdrain.

2. Positive displacement blowers will use a vent valve, while centrifugal blowers may use an in-line throttling valve. Start a positive displacement blower with the vent (bypass) valve open. Start a centrifugal blower with the throttling valve closed. Start the blower and open the air isolation (inlet) valve on the filter.

NOTE: Adjust the rate control valve slowly to obtain the design air flow rate. Adjust rate of flow from no flow to design flow over a period of approximately 60 seconds.

Never start the blower so that its full capacity is delivered to the filter immediately.

Refer also to the concurrent air/water sequence found later in this manual.

3. After a reasonably uniform air pattern is established at the specified concurrent air rate over the entire filter surface, slowly introduce the backwash water to the specified concurrent rate.

4. Check the air/water pattern in the filter. It should be reasonably uniform over the entire surface.

5. If dead spots or rows are noticed, try adjusting the air and water rates slightly (up or down) to obtain a better pattern.

6. If certain areas show excessive air shut down the blower, drain the filter and examine the underdrain for punctures, bad joints, or loose end plates.

NOTE: If structural damage to the plastic or misaligned internal joints is found, it will be necessary to do a fusion weld repair. Contact the Xylem Project Manager for assistance.

OPERATION

4 OPERATION

CAUTION: Failure to follow proper operating procedures, instructions, recommendations and cautions may void the manufacturer’s warranty.

4.1 GENERAL

Since the Leopold, a xylem brand, Underdrain and associated filter system will be operated as only one part of a fully integrated water or wastewater treatment plant and because the filter control system may be existing or provided by others, it is the responsibility of the CONTRACTOR or ENGINEER to ensure that the control system is designed to operate as recommended. Once placed into operation, it is the responsibility of the OWNER to ensure the system is operated as recommended.

CAUTION: While the following items may be addressed in detail in other sections of this manual, disregarding them may result in poor filter performance, equipment damage or failure of the underdrain system.

1. Never backwash the filters with dirty water.

2. Never backwash the system without adequate flow measurement and flow control devices operational.

3. Never subject the underdrain to hydraulic surges (water hammer) caused by turning pumps on with the valves open or by quickly opening the backwash valves.

4. Never increase the water backwash rate to a high value before purging air from the underdrain and media.

5. Never fill any dry filter, at any time, from the top.

6. Never subject the filter, during filtration, to frequent major changes in flow rate.

7. Perform periodic disinfection of the filter to reduce biological or algal growth.

8. Provide and maintain accurate flow monitoring and control equipment for the water and air backwash systems.

9. Always operate the plant in accordance with the recommended procedures.

4.2 RECOMMENDED BACKWASHING PROCEDURE

CAUTION: All rate control valves shall open and close smoothly with a minimum 60 second cycle time.

CAUTION: Failure to properly…