DIVISION 11 - EQUIPMENT
Section 113__ - Trickling Filter Media System

1.01 SCOPE OF WORK

A. Installation of trickling filter media support system, PVC structured sheet media modules and protective surface grating, as shown on drawings and as specified herein.

A. ASTM - American Society for Testing and Materials

B. AISC Code of Standard Practice

C. PCI - Prestressed Concrete Institute

A. Definitions:

1. Media Support System - Structural system designed and supplied by Trickling Filter Media System manufacturer to support Structured PVC Media Modules while maximizing ventilation and drainage. Support system to be pre-engineered PVC/glass-reinforced ABS piers supporting pultruded fiberglass grating, or alternatively reinforced concrete piers and pre-cast, pre-stressed concrete lintels.

2. Structured PVC Media Modules - Media modules are fabricated from PVC sheets and completely corrugated at an angle of 60 degrees from the horizontal to form a cross-corrugated pattern between adjacent sheets, creating a continuous and horizontal redistribution of air and wastewater. Modules will be either 1 ft. (0.305 m) or 2 ft. (0.610 m) high, 2 ft. (0.610 m) wide, and either 4 ft. (1.219 m) or 6 ft. (1.829 m) long.

3. Protective Surface Grating - Interlocking polypropylene panels, a minimum 1-1/4 in. (31.75 mm) height, to absorb hydraulic impact, provide operator access, provide a protective layer from foot traffic, and added UV protection to the top layer of Structured PVC Media Modules. Alternatively, fiberglass grating of similar height and similar opening size may be substituted.

B. Description of Trickling Filter Media System:

1. System shall provide for the following requirements:

a. Number of Towers: ____

b. Tower Diameter: ____ ft.

c. Depth of Media: ____ ft.

d. Volume of Media Required: ____ cu. ft. (including provisions for wastage)

2. System includes Media Support System, Structured PVC Media Modules and Protective Surface Grating.

C. Interface with Adjacent System(s):

1. Install Trickling Filter Media System within the Trickling Filter tower as recommended by Trickling Filter Media System manufacturer, or as directed on project drawings. System to be installed in coordination with Rotary Distributor System work.

D. Tolerances:

1. Media Support System shall be installed true level, plus or minus __ in. (13 mm) in height.

2. Structured PVC Media Modules shall be constructed to ensure that solvent bond points are within __ in. (13 mm) from the top and bottom of the modules on all sheets.

3. Structured PVC Media Modules tolerances for height, width and length shall be plus or minus __ in. (13 mm) for each dimension (tolerances may vary by sheet thickness).

4. A maximum of 2-in. (50 mm) is allowed during installation between the field-cut edges of the Structured PVC Media Modules and the tank perimeter wall and the center column.

5. The top of the Media Support System and the top of the support ledge (as specified in Section 3.02 H) should be at the same elevation and within a maximum tolerance of plus or minus 1/8 in. (3.18mm) in elevation.

E. Performance Requirements:

1. Media Support System:

a. Media Support System shall be designed and pre engineered to support the design load (40 lbs. / sq. ft. per ft. of media (195.3 kgs / m__ per 0.3 m)) of Structured PVC Media Modules. The Media Support System must allow for field adjustments to meet height tolerances, and be readily adjustable to allow for variations in floor slope to ensure vertical alignment of piers. Concrete piers must provide adequate re-bar reinforcement and the pre-cast, pre-stressed concrete lintels must be engineered to meet the load requirements and shall be installed with lintels at a maximum of 2-ft. (0.610 m) center-to-center spacing. Concrete masonry units such as cinder blocks, underdrain tiles or other such inadequate structural members will not be acceptable. Similarly, grouting to achieve leveling requirements will not be acceptable as structural load bearing material, except as necessary to secure concrete lintels to piers.

b. Media Support System shall be designed and engineered to maximize ventilation and drainage requirements, while ensuring sufficient contact with Structured PVC Media Modules such as to prevent media from wrapping around supports. Pre-engineered pier caps must allow for drainage and ventilation. Pre-engineered systems shall incorporate nominal 12-in. (350 mm) wide pultruded fiberglass grating of adequate strength to meet the design load, while not allowing excessive deflections. Concrete lintels must be at least 8-in. (200 mm) wide at the lintel/media interface. Concrete lintels of 10-in. (250 mm) wide must incorporate a 2-in. (50 mm) center drain channel.

2. Structured PVC Media Modules:

a. Each Structured PVC Media Module shall be fabricated from PVC sheets and formed in a pattern to provide "vertical flow" between the adjacent sheets. The media modules shall ensure adequate contact between liquid, air, and biomass by providing for a suitable flow cavity for the liquid path, including a mid-module splash slope for redistribution of the liquid. Random, cross-flow or horizontal media are not acceptable.

b. The flute height for each corrugation in the Structured PVC Media Module giving the vertical flute orientation shall be 2 in. (50.80 mm). There shall be a minimum of 24 sheets per 24-in. (0.610 m) wide module.

c. Each Structured PVC Media Module must provide a minimum surface area of 30 sq. ft. / cu. ft. (98 m_ / m3) with a minimum of 95% void-to-volume ratio.

d. Each module shall have a minimum bearing capacity of 400 lbs. / sq. ft. (1952.8 kgs. / m?). Modules in the top layer shall have a minimum bearing capacity of 1000 lbs. / sq. ft. (4882 kgs / m__). In addition, media modules shall be capable of withstanding a minimum loading of 40 lbs. / sq. ft. per foot (195.3 kgs / m? per 0.3 m) of media height above the module as placed in the filter. Media modules in the bottom layer shall have the designed load bearing capacity as estimated by the loading of 40 lbs. / sq. ft. per foot (195.3 kgs / m__ per 0.3 m) of media height or 1000 lbs. / sq. ft. (4882 kgs / m__), whichever is greater, when placed on media supports.

e. The maximum allowable deflection shall be 1.5 percent at a test temperature of 75°F (24°C).

f. The finished modules shall be suitable for normal wastewater temperatures between 50°F and 75°F (10°C and 24°C).

3. Protective Surface Grating:

a. Protective Surface Grating shall be a minimum 1-? in. (31.75 mm) in height for additional top layer UV protection. Additionally, no greater than a 2 in. by 2 in. (50.80 mm by 50.80 mm) opening will be allowed for protection from hydraulic impact. Protective grating must have a non-skid surface. Protective Surface Grating must not adversely impact or damage media. If fiberglass grating is selected, cut edges must be properly sealed to prevent damage to grating and/or operators.

 

A. Qualifications of Manufacturer:

1. Trickling Filter Media System manufacturer shall certify that they have a minimum of 10 installations of Structured PVC Media Modules in wastewater treatment applications, and at least 5 years continuous experience in manufacture and supply of Structured PVC Media Modules in wastewater treatment applications.

2. The Media Support System shall be a standard product of the Manufacturer specifically designed for wastewater applications, and the Trickling Filter Media System manufacturer shall certify that they have more than 5 existing Media Support System installations in use in wastewater treatment applications. Alternatively, an active member of Prestressed Concrete Institute (PCI) must produce any pre-cast, pre-stressed concrete lintels in accordance with the PCI Design Handbook and MNL-116, Manual for Quality Control.

3. The Structured PVC Media Modules shall be a standard product of the Manufacturer, and the Trickling Filter Media System manufacturer shall certify that they have the existing installations of the Structured PVC Media Modules as required in this Section 1.04A.

4. The Protective Surface Grating shall be a standard product of the Manufacturer specifically designed for wastewater applications, and the Trickling Filter Media System manufacturer shall certify that they have more than 5 existing installations of the Protective Surface Grating, unless fiberglass grating meeting the height and opening specifications is supplied.

5. Pre-qualification is required for bidding, except for acceptable manufacturers named herein.

B. Installation Requirements:

1. Install Trickling Filter Media System in accordance with Manufacturer's written instructions.

2. Trickling Filter Media System manufacturer provides services of qualified representative onsite to provide instructions on storage, handling, installation, cutting, etc in accordance with the requirements of Section 3.03 A.

C. Source Quality Control:

1. All Media Modules shall be formed and assembled in the Manufacturerís on-going principal manufacturing facility. Assembly in temporary facilities or field assembly is prohibited.

 

A. Shop drawings required for following:

1. Media Support System

2. Structured PVC Media Modules

3. Protective Surface Grating

B. Product Data required as follows:

1. Media Support System

a. Materials

b. Installation instructions

2. Structured PVC Media Modules

a. Materials

b. Installation instructions

3. Protective Surface Grating

a. Materials

b. Installation instructions

C. Samples

1. At least 10 days prior to bid, submit to Engineer samples of Media Support System, Structured PVC Media Modules (2 ft. width x 2 ft. height by minimum 4 ft. long (0.610 m x 0.610 m x 1.219 m)) and Protective Surface Grating 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 Trickling Filter Media System. 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. Operating instructions

c. Maintenance instructions

E. Certificates:

1. Provide certificate of compliance with Quality Assurance requirements of Section 1.04 A and C.

 

A. Delivery

1. Structured PVC Media Modules shall be shipped and delivered to job site on pallets for ease of handling and to prevent damage.

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. Structured PVC Media Modules shall not be stacked more than 8-ft. (2.4 m) high (one over the other). All modules shall be stored on the shipping pallets.

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 tower).

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 cannot be wrapped tightly around the media. There should be at least a 6-in. (150 mm) 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-in. (300 mm) 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. Covers can become loose over time due to wind or rain and must be re-secured. A check of the stored area should be done to make any minor repairs to the cover or to restack any modules that may have fallen.

7. Structured PVC Media Modules exposed to extended non-operational periods in the tower shall be adequately protected to prevent damage by temperature and weather conditions.

C. Handling

1. Structured PVC Media Modules shall remain on shipping pallets until ready to install.

2. Abusive handling of the material shall not be permitted.

3. Structured PVC Media Modules may get brittle at low temperatures or softer at high temperatures. Therefore, care should be used in the handling of modules.

 

A. Sequencing:

1. Install Media Support System.

2. Install Structured PVC Media Modules.

3. Install Protective Surface Grating.

B. Scheduling:

1. Schedule shall be consistent with project completion date and account for Trickling Filter Media System manufacturer's production and shipping terms.

 

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

1. AccuPier®Media Support System

2. AccuPac® CF-1900 Cross-Flow Structured PVC Media Modules

3. AccuGrid® BioGrating

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

A. Media Support System:

1. The Media Support System stanchion shall be constructed of rigid PVC.

2. The Media Support System base and cap shall be constructed of glass-reinforced ABS to allow the base and cap to be solvent bonded to the stanchion.

3. Pultruded fiberglass grating shall be used to span from pier to pier.

4. Alternatively, concrete piers and concrete lintels of adequate structural integrity may be substituted for manufacturer's pre-engineered system. If concrete piers and lintels are substituted, Trickling Filter Media System manufacturer is responsible for ensuring adequate structural integrity consistent with the requirements of Sections 1.03 E 1 a and 1.04 A 2.

B. Structured PVC Media Modules:

1. The material of construction shall be flame resistant, self-extinguishing, rigid corrugated PVC sheets that are conducive to biomass and UV protected. The media modules shall be resistant to rot, fungi, bacteria and inorganic/organic acids and alkalies as commonly found in municipal wastewater.

2. The PVC sheets shall be of uniform thickness and free from holes, air bubbles, foreign matter, undispersed raw material or other manufacturing defects that may adversely affect their performance.

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

C. Protective Surface Grating

1. The Protective Surface Grating (BioGrating), when installed per manufacturer's recommendations shall provide a continuous protective surface for the Structured PVC Media Modules, minimizing hydraulic impact on the media, providing additional UV protection, and allowing operator access to all areas of the tower. Such grating shall comprise of multiple square mesh of 2 in. x 2 in. (50 mm x 50 mm) openings, molded together to provide a strong, lightweight panel. Each panel of the grating will measure about 24 in. (610 mm) in width, 24 in. (610 mm) in length, 1-? in. (31 mm) in height, and shall weigh approx. 2 lbs. (0.9 kgs).

2. The material of construction shall be rigid polypropylene specifically UV stabilized for inhibiting UV degradation of the BioGrating under extended exposure to the sun. The material shall be inert and resistant to naturally occurring wastewater constituents.

3. BioGrating shall be installed in panels side-by-side and placed on top of the Structured PVC Media Modules as shown on the manufacturers' installation drawings. Each panel shall be snapped together with the adjacent panel with locks 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 BioGrating shall be designed to prevent damage to the media, and allow for ease of placement and removal. The BioGrating material design shall be such that hold down ties, clips or fasteners are not required.

5. Alternatively, fiberglass grating meeting the requirements of 1. Minimum height of 1-? in. (31 mm) and; 2. A multiple square mesh of a maximum of 2-in. x 2-in. (50 mm x 50 mm) openings may be used. Fasteners shall be used with fiberglass grating to lock panels together.

 

A. Media Support System:

1. The Media Support System shall be comprised of four elements: the base assembly, the stanchion, the cap and the pultruded fiberglass grating.

2. The base assembly shall be comprised of two interlocking pieces:

a. The base disk shall have indentations in the interior perimeter to allow ready alignment with the grid pattern marked on the tower floor. Additionally, the base disk shall have an indentation to indicate slope when lined up with the base flange.

b. The base flange shall have a broad base providing stability. The base shall further have pre-drilled locations to allow the base assembly to be fixed in location and slope using power-driven nails (nail gun) to the tower floor once alignment and leveling is complete.

c. The base flange shall have percent slope markings on the perimeter providing for a quick approximation of the slope of the tower floor.

3. The stanchion shall allow for field cutting to length to accommodate varying stanchion lengths to ensure the entire Media Support System is installed within elevation tolerances established in Section 1.03 D 1.

4. The cap shall be specifically designed to support the entire width of pultruded fiberglass grating, while allowing drainage and ventilation through the cap.

5. The base assembly, stanchion and cap shall be solvent bonded in the field after cutting to elevation and leveling complete to provide a strong, rigid pier.

6. Pultruded fiberglass grating shall be placed on top of the pier assembly.

7. Alternatively, concrete piers and concrete lintels of adequate structural integrity consistent with the requirements of Sections 1.03 E 1 a and 1.04 A 2 may be substituted upon the review and approval of the Engineer.

B. Structured PVC Media Modules:

1. All PVC sheets shall be thermoformed into corrugated sheets and have dedicated bond points to allow precise alignment of sheets during assembly and installation. Non-thermoformed sheets, which do not provide dedicated bond points for precise sheet alignment, are not acceptable.

2. The self-supporting Structured PVC Media Modules shall be made from the assembly of the corrugated sheets. These corrugated sheets shall be solvent bonded together at these dedicated bond points to give a cross-corrugated pattern, providing a finite number of contact points thereby forming strong and homogenous media modules. Adhesive glues shall not be allowed since they may weaken with time. Similarly, thermal welding of sheets is not acceptable since the bond strength is inadequate for the rugged structural requirements.

C. Protective Surface Grating:

1. The BioGrating shall be molded in individual units with integral locking connections.

2. Alternatively, fiberglass grating meeting the requirements of this Section 11___ may be substituted. Fiberglass grating must be clipped together using stainless steel clips to prevent separation when the tower is in operation.

 

A. Field measurements:

1. Field verify all dimensions affecting installation, particularly tower diameter. If any discrepancies are found between actual field measurements and the enclosed drawings, Contractor must notify Engineer and Trickling Filter Media System supplier immediately.

2. Layout all work prior to installation.

B. Protection:

1. Protect adjacent surfaces, piping and other items as may be required.

2. Protect Trickling Filter Media System material as outlined in Section 1.06 B.

 

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 Media Support System shall be installed in accordance with Manufacturer's recommendations. The tower base shall be cleaned of any debris prior to proceeding with installation of the Structured PVC Media Modules.

C. The Structured PVC Media Modules shall be installed in accordance with Manufacturer's recommendations. Media modules shall be conveyed to the top of the filter wall by mechanical conveyor or crane. Cranes shall be used or conveyors shall be constructed as necessary to transport the media to the working level inside the trickling filter, and the media modules shall be moved by hand for final placement.

D. The media module edges should be protected from damage due to workmen walking on them. To prevent such damage and to prevent toppling over of modules in case of cantilever support system, the Contractor shall use plywood or other suitable temporary planking.

E. The Structured PVC Media Modules shall be carefully cut or trimmed to fit the tower to within the tolerances specified in Section 1.03 D 4. The shaping, cutting and trimming of the media modules may be done in the trickling filter provided that precaution is taken by the Contractor to prevent any chips, broken pieces, or debris from falling into the media by using canvas tarpaulins or similar working materials to cover the media modules. All media modules shall be cleared of any such fallen material before a new layer of media is added. The top layer of media should also be completely protected from damage and such falling material due to any subsequent work prior to start up of the system.

F. The media modules shall be placed in the trickling filter to provide the closest possible fit with adjacent modules without damaging the modules. The module packing arrangement shall be as recommended by the media manufacturer and shown on the installation drawings. Media modules within each layer shall be installed such that the sheets of all modules are parallel to each other. Modules in respective layers shall be installed at right angles to the layer immediately below and above.

G. The media modules in the bottom layer shall be placed on the Media Support System as shown on the installation drawings. A support ledge (minimum of 4 in. (100 mm) wide) must be provided around the center column and the tank perimeter wall, and is the responsibility of the Contractor. Support ledge and Media Support System elevations must meet the tolerances specified in Section 1.03 D 5.

H. The Protective Surface Grating shall cover the entire media surface and shall be installed in accordance with Manufacturerís recommendations.

I. After completion of installation of the Trickling Filter Media System, the Contractor shall submit a written Certificate of Proper Installation (CPI).

 

A. Trickling Filter Media System manufacturer shall provide the services of a qualified field installation supervisor. Such supervision shall be provided for ___ working days (max.) (not to exceed 8 hrs per day), and ____ trips (max.) with a maximum stay of 30 days per trip.

 

A. The Trickling Filter Media System, including Media Support System, Structured PVC Media Modules and Protective Surface Grating, shall be guaranteed to be free from defects in material and workmanship for a period of 1 year from date of Substantial Completion by Owner, or 14 months from date of shipment, whichever is earlier.

 

A. The Trickling Filter Media System manufacturer shall provide one structural test (four modules per test) for each different thickness of Structured PVC Media Modules to be used in the project. The test shall simulate service conditions and conform to the following criteria:

1. The test sample shall consist of four full-size media modules stacked two modules high with two modules in each layer. The arrangement of the stack shall simulate the geometry as placed in the filter towers. The top modules shall be perpendicular to the bottom modules, and the PVC sheet planes shall be in a vertical position.

2. Modules intended for the base layer shall be tested on a simulation of the Media Support System. Modules intended for all other layers shall be tested on a flat base.

3. Test loads shall be the design load of the media as specified. The test load shall be at a temperature of 75°F (22.8°C) plus or minus 2°F (1.2°C).

4. A preload equal to 10% of the design load shall be applied to act as a seating load. This seating load shall be retained for a 1-hour period.

5. After 1 hour, the deflection shall be noted and considered zero and the load increased in 10% increments of the design load. Each loading increment shall be held for 5 minutes and the deflection recorded at the end of the 5-minute period. Incremental loading shall continue until failure.

6. Maximum allowable deflection at the test load shall be 1.5 percent. The term "deflection" shall mean the vertical deflection expressed as percent of the vertical distance between the top and bottom faces of the media stack under the pre-load conditions.

B. Testing shall be completed in Manufacturers' facilities, and shall result in a report certified by a Professional Engineer prior to installation of Structured PVC Media Modules.

C. Trickling Filter Media System manufacturer's with a minimum of 10 installations of Structured PVC Media Modules in wastewater treatment applications, and at least 10 years continuous experience in manufacture and supply of Structured PVC Media Modules in wastewater treatment applications without an incident of Structured PVC Media Modules failure may provide reports on similar gauge media from prior testing in lieu of testing of media produced specifically for this project.

 

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