Appendix E: Bag Filter

UFC 3-280-04

17 DEC 2003

APPENDIX E

BAG FILTER

E-1

WASTE STREAM CHARACTERISTICS

Maximum Flow: 7 L/s (110 gpm).

Maximum operating Temperature: 60 degrees C (140 degrees F).

Design Influent Suspended Solids: 1 mg/L (1 ppm).

Design Effluent Particle Size: 10 microns.

Filter change out frequency: twice weekly (maximum).

Influent pH: 8.0.

The waste stream to be treated also contains residual soluble alum from

upstream treatment process and aluminum nitrate(s) and barium chloride(s), which is to

be treated by a downstream membrane process. Trace amounts of amyl alcohol are

also present in the waste stream (s = soluble).

E-2

SELECTION OF FILTER MATERIALS OF CONSTRUCTION. The chemicals

in the waste stream are compared to the General Chemical Resistance Chart, Table D-

1 (cartridge filter example) and manufacturer data like that presented for Vendor A in

Table E-1. The chemical resistance chart is compared to polypropylene filter material

and based on the comparison polypropylene is compatible with the chemicals in the

waste stream.

Table E-1. Vendor A Filter Fabric Properties

Specific

Tensile

Abrasion

Weak

Strong

Weak

Strong

Fabric

Gravity

Strength

& Flex

Acids

Alkali

Solvents

Temperature

Degrees F

Cotton

1.55

44109

Fair

Poor

Excellent

Good

200240

Polyester

1.38

64124

Very

Good

Poor

Good

275325

Good

Glass

2.56

200215

Poor

Excellent

Good

Fair

Poor

Excellent

500600

Nylon

1.14

58128

Excellent

Fair

Poor

Excellent

Good

275300

Nomex

1.14

58128

Very

Fair

Poor

Excellent

Good

400450

Good

Polypropylene

0.91

5085

Very

Excellent

Fair

200220

Good

Saran

1.69

1544

Good

Excellent

Poor

160185

Teflon

2.30

47

Poor

Excellent

Very

450500

Good

A review of Table D-1 shows that polypropylene is also compatible with the

maximum operating temperature and its resistance to alkalis indicates that the pH of 8

will not impact filter performance. Therefore, filter materials of construction can be poly-

propylene. The Vendor A and B bag filter bulletins (not attached) show that the bag filter

and bag filter core are all constructed of polypropylene. The Vendor bulletins also indi-

cate these filters are available in a 10-micron rating.

E-1