SECTION 13226 FILTER MEDIA

SECTION 13226
FILTER MEDIA


PART 1 - GENERAL

1.1     WORK INCLUDED

A.   Provide all labor, materials, equipment and services required to furnish and install filter media and support gravel shown on the Drawings and described herein.

1.2     RELATED WORK

A.   Section 13222 - Filter Underdrain System. B.   Section 13223 - Filter Disinfection.
C.   Section 13225 - Filter Washwater Troughs

1.3     REFERENCES

A.   AWWA Specification B100, latest edition.

1.4     SUBMITTALS

A.   Submit shop drawings to the Engineer for review.

1.5     QUALITY ASSURANCE

A.   Filter media and filter underdrains shall be furnished by a single supplier.

B.   Material shall be of a quality that meets or exceeds the requirement of AWWA Specification
B100 (latest edition).

C.   Samples of each gradation of support gravel and media representative of that to be furnished shall be submitted to a licensed and recognized laboratory for a complete analysis. Analyses shall be made within the six (6) months prior to the beginning of construction and five (5) copies submitted to the Engineer for approval prior to product shipment.


PART 2 -  PRODUCTS

2.1     SUPPORT GRAVEL

A.   The support gravel shall consist of a minimum of 12 inches of clean, durable and rounded particles with the gradations shown in the Gravel Schedule.

2.2     FILTER SAND

A.   The filter sand shall be composed of hard, durable, clean silicious particles free of mica. The average specific gravity, effective size, and uniformity coefficient shall be as indicated by the Filter Media Schedule.

2.3     FILTER ANTHRACITE

A.   The filter anthracite shall be graded, hard and durable anthracite coal particles. The anthracite shall have a minimum specific gravity uniformity coefficient, effective size and hardness shall be as indicated by the Filter Media Schedule. The anthracite shall be free of iron, sulphides, clay, shale, extraneous dirt and excessive dust.
2.4     FILTER MEDIA SCHEDULE

A.   The filter media and support gravel shall have physical characteristics as noted in the Filter Media Schedule. Each layer shall be placed in accordance with the manufacturer's recommendations to the depth indicated.

B.   The filter media shall be furnished by the filter equipment manufacturer and shall be shipped in bags for installation by the Contractor. The media shall be installed under the technical direction of the filter equipment manufacturer.

FILTER MEDIA SCHEDULE (Existing Filters No. 1 and No. 2) (New Filters No. 3 and No. 4)


Bed
Designation Effective
Size Uniformity
Coefficient Specific
Gravity Hardness
(MOH scale) Depth
(inches)  
Anthracite 0.90-1.05 mm 1.3 or less 1.60+ 2.7 or more 24  
Sand 0.45-0.55 mm 1.4 or less 2.60+ --- 12

PART 3 -  EXECUTION

3.1     INSTALLATION

A.   The filter media shall be installed in accordance with the supplier's detailed instructions. The supplier shall provide supervision of the installation to insure proper compliance with procedures by the contractors.

B.   After the filter sand is placed, the filter shall be backwashed and the top of the sand bed shall be lightly scraped to remove any fines and debris. The finished sand depth shall be as indicated by the Filter Media Schedule following the scraping procedure.

C.   After the filter anthracite is placed, the filter shall be backwashed and the top of the filter anthracite shall be lightly scraped to remove any fines and debris. The finished filter anthracite depth shall be as indicated by the Filter Media Schedule following the scraping procedure