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Ref No. [UMCES[CBL 11-020
5
4.3. Particle Size Distribution (PSD)
Water samples analyzed for particle size were drawn from challenge water and after each
filter tested at each time point. Analysis was conducted at the Occoquan Watershed Monitoring
Laboratory in Manassas, Virginia.
The EPA ASTM D4464 laser method was used to analyze these samples. While particles
were detected and sized in the challenge water samples, particles were too dilute in the post 20-,
10- 5- or 0.1 µm samples (below detection limits) to be characterized.
For all samples analyzed after the 20 µm, 10 µm, 5 µm and 0.1 µm filters there was no
detectable data due to low particle concentrations or counts. Thus, the data below list only the
challenge conditions for the skid/filtration system. The average particle size in the challenge
water ranged from 6.009 µm to 14.493 µm.
Trial # 1 –
Test Filter #1, 0.1 µm (no pre filters). 19 Jan 2011
Challenge Water
PSD (µm)
Time Point
Sample Time
Avg
StDev
LCS @ 1 µm – initial
1.003
T-0 Initial
11:17
6.124 0.033
T-1 Mid – no sample
N/A
N/A
T-2 Final
11:32
6.141 0.062
Trial # 2 –
Test Filter #5, 0.1 µm (no pre filters)
.
19 Jan 2011
Challenge Water
PSD (µm)
Time Point
Sample Time
Avg
StDev
T-0 Initial
12:15
6.204 0.018
T-1 Mid – no sample
N/A
N/A
T-2 Final
12:42
BDL
BDL
LCS @ 1 µm – final
1.003
Trial # 3 -
Pre filter 20 µm > Test Filter #1, 0.1 µm. 13 Jan 2011
Challenge Water
PSD (µm)
Time Point
Sample Time
Avg
StDev
LCS @ 1 µm – initial
1.005
T-0 Initial
10:30
12.893 1.060
T-1 Mid
11:05
14.493 0.884
T-2 Final
12:00
6.091 0.067
LCS @ 1 µm – final
1.002