Section 09900 PAINTS AND COATINGS. Stainless steel tanks shall be
fabricated of Type 304 stainless steel conforming to ASTM A 167 with
structural support conforming to ASTM A 276. Exterior painting or coating
shall be provided in accordance with Paragraph PAINTING.
2.2.12.3
Site Glasses
A [_____] mm inch diameter observation port shall be provided in the tank
wall. The observation port shall be located [at the surface of the filter
media] [at the media interface] [_____].
2.3
MEDIA
Filter materials shall conform to the requirements of AWWA B100. Sieve
analysis shall be performed in accordance with ASTM C 136 and AWWA B100.
Specific gravity shall be determined in accordance with ASTM C 127 for
support media and ASTM C 128 for [silica sand] [anthracite coal]
[high-density media].
2.3.1
High-Density Sand
The high-density sand shall be [garnet] [ilmenite] [_____] with a specific
gravity of [3.6] [4.0] [4.2] [_____], uniformity coefficient less than or
equal to [_____], and an effective size between [_____] and [_____].
Ninety-five percent shall be larger than or equal to [_____].
2.3.2
Silica Sand
The silica sand shall have an effective size between [_____] and [_____],
uniformity coefficient less than or equal to [_____], and a specific
gravity of [2.55] [2.60] [2.65] [_____].
Ninety-five percent shall be
larger than or equal to [_____].
2.3.3
Anthracite Coal
The anthracite coal shall have a specific gravity of [1.45] [1.50] [1.55]
[1.73] [_____], uniformity coefficient of [_____], and an effective size
between [_____] and [_____]. Ninety-five percent shall be larger than or
equal to [_____]. The anthracite media shall be clean and free from thin
or scaly pieces, and shall have a calcium carbonate and magnesium carbonate
hardness of [_____].
2.3.4
Support Media
The support gravel shall consist of hard, rounded stones with an average
specific gravity of not less than [_____]. Not more than [_____] percent
by weight shall have a specific gravity of [_____] or less. The gravel
shall contain not more than [_____] percent by weight of thin, flat, or
elongated pieces (pieces in which the largest dimension exceeds three times
the smallest dimension), and shall be free from shale, mica, clay, sand,
loam, and organic impurities of any kind.
2.4
CONTINUOUS BACKWASH FILTRATION SYSTEM
2.4.1
Equipment Capacity
Each unit shall be a moving bed, continuous backwash [upflow] [downflow]
granular media filter, having a capacity to filter [_____] L/minute gpm of
water at the operating conditions identified in Paragraph Design Criteria.
SECTION 11393
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