DIVISION 11 - EQUIPMENT
Section ___ - Tube Settler System

1.01 SCOPE OF WORK

A. Installation of tube settler modules, protective surface grating, baffles, effluent trough(s), weirs, and support system as shown on drawings and as specified herein.

A. ASTM – American Society for Testing and Materials

B. NSF International – Standard 61

C. AISC Code of Standard Practice

D. AWS D 1.1 Structural Welding Code

A. Definitions:

1. Tube Settler Module – Tube settlers are comprised of multiple tubular channels sloped at an angle of about 60°, which allow enhanced settling characteristics and accumulation of solids within a settling basin. Modules will be 2 ft. (0.610 meters) height, 1 ft. (0.305 meters) or 2 ft. (0.610 meters) widths, up to 10 ft. (3.66 meters) lengths as required by the tank geometry and support structure.

2. Protective Surface Grating – Interlocking panels, a minimum 1-1/4 in. height, to absorb hydraulic impact (during washdowns), provide operator access, provide a protective layer from foot traffic, and added UV protection to tube settler area.

3. Support System – Structural system designed to support tube settlers, baffles, and troughs as required. Support system to be provided as per engineer’s plans or tube settler system manufacturer design.

4. Baffle System – System to direct water through tube settler area. Provided as per engineer’s plans or tube settler system manufacturer design. To be designed in conjunction with support system

5. Trough/Weir System – Effluent launders to remove clarified water from sedimentation basin. Provided as per engineer’s plans or tube settler system manufacturer design.

B. Description of System:

1. System includes tube settler modules, protective surface grating, baffles, weirs, and support structures.

C. Interface with Adjacent System(s):

1. Install tube settler system within clarifier as recommended by tube settler manufacturer, or as directed on project drawings.

D. Tolerances:

1. Top of adjacent tube modules shall be installed true level, plus or minus 1/2 inch in full length.

2. A maximum 1/4 inch space is allowed between installed modules.

E. Performance Requirements:

1. Each tube shall have a cross sectional perimeter of approximately 10.0 inches (0.254 meters) to give a low Reynolds number and of an approximate triangular shape that allows rapid accumulation, concentration, and drainage of solids.

2. Cross corrugation of tubes with mixing points within individual modules is not allowed. This causes mixing currents, which adversely affect the settlement of solids as well as re-suspend the settled solids within the system.

3. Reversal of tube direction between adjacent modules is not allowed. Such reversal causes mixing currents at the surface of the module as described above.

4. Protective surface grating shall not impact performance of tube settlers or cause physical damage to tube settler material.

A. Qualifications of Manufacturer:

1. Tube settler module manufacturer shall have minimum 5 years continuous experience in manufacture and supply of tube settlers. Pre-qualification is required for bidding, except for acceptable manufacturers named herein.

B. Installation Requirements:

1. Install tube settler system in accordance with manufacturer’s written instructions.

2. Tube settler system manufacturer provides services of qualified representative onsite to provide instructions on installation, cutting, etc.

C. Source Quality Control:

1. Certification of tube modules as complying with ANSI/NSF-Standard 61 for use in potable water.

2. Individual modules will bear the seal as being NSF Certified.

3. All equipment to use potable grade material suitable for use in drinking water plants.

A. Shop drawings required for following:

1. Tube Settler Modules

2. Protective Grating Surface

3. Support Structure

4. Baffle(s)

5. Trough(s)/Weirs

B. Product Data required as follows:

1. Tube Settler Modules

a. Materials

b. Installation instructions

2. Protective Grating Surface

a. Materials

b. Installation instructions

3. Support Structure

a. Materials

b. Installation instructions

4. Baffle(s)

a. Materials

b. Installation instructions

5. Trough(s)/Weirs

a. Materials

b. Installation instructions

C. Samples

1. At least 10 days prior to bid, submit to Engineer 1 ft. width x full height by minimum 2 ft. long sample of tube module for any manufacturers to be considered for pre-qualification to bid. (Include with submittal sample 3 copies of complete product specifications, and written instructions for field cutting and installing tube modules). Sample to be retained by Owner. Manufacturers named as acceptable herein are not required to submit samples.

D. Operating and Maintenance (O&M) Instructions:

1. O & M Instructions shall include:

a. Storage and installation procedures

b. Cleaning procedures

E. Certificates:

1. Provide certificate that tube settler modules are Tested and Certified by NSF to ANSI/NSF Standard 61 Drinking Water System Components.

A. Delivery

1. Tube modules shall be shipped and delivered to job site on pallets.

B. Storage

1. All material and equipment shall be shipped, stored, handled, and installed in such a manner as to not degrade quality or serviceability.

2. The tube settling modules shall not be stacked more than four high (8 ft.) (one over the other).

3. All modules shall be stacked such that the PVC sheet planes are in a vertical position (similar to the manner of their placement inside the tank).

4. A light colored cover shall cover all modules required to be stored in the open beyond two months. Ideally these covers should be double sided such as a white on black. The white side, facing out, is used to reflect light away. Clear covers are prohibited. Black is not recommended. Black will absorb heat and if the cover comes in direct contact with the media, this heat can be quickly transferred to the media.

5. Covers can not be wrapped tightly around the media. There should be at least a 6" air gap between the cover and top of media. The ends of the cover should be securely anchored on all sides with at least a 12" air gap at the bottom. These covers should provide shading while allowing air to pass through to prevent heat from building up.

6. Modules should be checked at least once a week. It is very possible that the covers can become loose over time due to wind or rain. A check of the stored area should be done to make any minor repairs to the cover or to restack any modules that could have fallen.

C. Handling

1. Tube modules shall remain on shipping pallets until ready to install.

2. Any abusive handling of the modules shall not be permitted. Workmen shall be careful in placing the tube modules and avoid any damage to the corners and tube edges.

3. Personnel shall not stand or walk directly on top of the modules, except as outlined in Section 2.02A.5.

4. Media modules may get brittle at low temperatures or soft at high temperatures. Therefore, care should be used in the handling of modules.

A. Sequencing:

1. Install module supports.

2. Install baffle(s), weir(s), and trough(s) as necessary.

3. Install tube modules as recommended by manufacturer.

4. Install protective surface grating

B. Scheduling:

1. Schedule shall be consistent with project completion date and account for tube settler system manufacturer’s production and shipping terms.

A. Brentwood Industries, Inc. of Reading, Pennsylvania.

B. Approved equal. (Pre-qualification required per Section 1.05 C).

A. Tube Modules

1. The material of construction shall be flame resistant, self-extinguishing, rigid PVC.

2. Material shall be inert and resistant to naturally occurring constituents in water and to the normal dosage of water treatment chemicals required in the treatment process.

3. Tube settler modules must be Tested and Certified by NSF to ANSI/NSF Standard 61 Drinking Water System Components. Evidence of certification must be included with submittal package and indelibly marked on the sheets of the modules.

4. The PVC sheet shall be prime, rigid PVC conforming to commercial standard ASTM D1784:12454B with the following properties.

5. The modules shall be self supporting and of structural integrity adequate to support foot traffic, Such foot traffic may occur only on the surface of a 4’ X 4’ x 3/8" thick plywood sheet placed on the modules to prevent any damage to the tube edges.

6. Structural integrity of the modules shall be maintained under a loading of 15 pounds per sq. ft. (psf) (73.23 kgs/m_) which includes the module dead weight plus a uniformly distributedresidual solids load of 10 psf (48.82 kgs/m_) while bearing a movable live load of 250 lbs (550 kgs) concentrated over a one sq. ft. (0.0929 sq. meter) area

B. Protective Surface Grating

1. The protective surface grating when installed as per manufacturer’s recommendations shall provide a protective surface (such as operator access or for minimizing the hydraulic impact on the media during washdowns, etc.) on top of the tube settler media. Such grating shall comprise of multiple square mesh of 2 in. x 2 in. (app. 50 mm x 50 mm) openings, molded together to provide a strong and light weight panel. Each panel of the grating will measure about 24 inches (610 mm) in width, 24 inches (610 mm) in length and about 1 _ inches (app. 31 mm) in height. In addition, each panel shall have a net weight of about 3 lbs. (app. 1.4 kgs). The grating panels will contact with the media to provide an economical as well as an effective grating when the grating panels are placed on top of the tube settler media. Any grating heavier than the specified weight, or which can cause damage to the tube settlers shall not be acceptable.

2. The material of construction shall be rigid [polypropylene/fiberglass] that will be specifically UV stabilized for inhibiting UV degradation of the grating under extended exposure to the sun. The material shall be inert and resistant to naturally occurring constituents in water and wastewater.

3. Grating shall be installed in panels side-by-side and placed on top of the tube settler media as shown on the plans and drawings for the project. Each panel shall be snapped together with the adjacent panel with locks provided at the edges of each panel. The grating panels shall be placed on top of the media such that the grating is in contact with the media.

4. The grating system shall be designed to prevent damage to the tube settler media, and allow for ease of placement and removal. System material design shall be such that hold down ties or fasteners are not required.

C. Support System:

1. The support system shall be constructed of [stainless steel / painted carbon steel] as designed and provided by the maker of the tube settlers.

2. The support structure shall be designed to support 200 lbs. per lineal foot, or a concentrated load of 250 lbs. placed anywhere on the structure. The maximum deflection of the structure under full live load shall be l/240 of the span.

D. Baffles:

1. Shall be constructed of [plastic / steel] with a structural steel frame.

2. The structural steel frame shall be fabricated of [stainless steel / painted carbon steel]. The panels shall be attached by means of [plastic / steel] fasteners to provide an adequate secure attachment.

E. Troughs and Weirs:

1. Shall be constructed of [fiberglass reinforced plastic / stainless steel].

2. Weirs shall be adjustable, V-notch type.

F. Welding materials:

1. In accord with AWS specifications.

2. Compatible with materials being welded.

A. Tube Modules:

1. All PVC sheets shall be thermoformed and have a continuous, dedicated glue guide to allow precise alignment of sheets during assembly and installation. Non-thermoformed sheets, which do not provide dedicated guides for precise tube alignment, are not acceptable.

2. Fabricated modules shall be comprised of tube-like channels sloped at an angle of about 60° placed in same direction to prevent mixing points and unstable flow patterns. Modules consisting of tubes in alternating directions are not acceptable.

3. The settling tube length (consistent with efficient solids separation) shall not be less than 27 inches

4. Rectangular or square shape tubes or "cross-flow" tube settlers shall not be acceptable.

5. Join PVC sheets and channels by solvent bonding to provide a rigid structure, resistant to separation of sheets.

B. Structural steel for tube module supports:

1. Fabricate all structural steel components as shown on the drawings and to comply with AISC Code of Standard Practice.

2. Accurately cut and mill ends of members to provide neat appearance and to provide full contact of surfaces prior to welding and joining.

3. Camber horizontal members to accommodate dead load deflection.

4. Fabricate items with joints neatly fitted and secured.

5. Grind exposed welds smooth and flush with adjacent surfaces.

6. Where mechanically fastened, make exposed joints flush butt type hair line joints.

7. Where mechanical fastening in field, provide slotted holes.

8. Supply components necessary for complete anchorage and fastening of metal fabrications.

9. Fit and shop assemble as appropriate for delivery to site.

 

A. Field measurements:

1. Field verify all dimensions affecting installation.

2. Layout all work prior to installation.

B. Protection:

1. Protect adjacent surfaces, piping and other items.

2. Protect tube settler material as outlined in Section 1.06B.

A. Approval for installation or incorporation in this project will be made only after submittal of shop drawings, or other data as specified herein.

B. The tube settler modules shall be installed in accordance with manufacturer’s recommendations.

A. Tube settler system manufacturer shall provide the services of a qualified field installation supervisor. Installation supervision shall be provided for ___ working days (not to exceed 8 hours per day). This time period will be for ____ trips with ____ days per trip.

A. Tube settler system shall be guaranteed to be free from defects in material for a period of 1 year from date of Substantial Completion by Owner, or 14 months from date of shipment, whichever is earlier.

A. Spare tube modules - Furnish ______ full size (minimum __ ft. lengths) spare tube modules to Owner.

B. Wastage tube modules - Furnish ______ full size (minimum __ ft. lengths) modules to contractor as wastage during installation. Any remaining modules (after installation) shall be given to Owner.

C. Wastage/Spare Protective Surface Grating – Furnish _____ full size panels to contractor as wastage during installation. If fiberglass grating is being provided, a fiberglass patch and repair kit must be provided as necessary to repair cut fiberglass ends.

 

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