Retrospective Evaluation of Cured-in-Place Pipe - (NEPIS)(EPA ...
Retrospective Evaluation of Cured-in-Place Pipe - (NEPIS)(EPA ...
Retrospective Evaluation of Cured-in-Place Pipe - (NEPIS)(EPA ...
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5.3.4 Wastewater Analysis. Retrieved wastewater samples were tested by American Analytical<br />
Laboratories, Inc., on April 14, 2010, <strong>in</strong> accordance with <strong>EPA</strong> Test Methods. <strong>EPA</strong> Method 150.1 was<br />
used to determ<strong>in</strong>e the pH <strong>of</strong> the samples. <strong>EPA</strong> Method 8015 was used to determ<strong>in</strong>e the DRO and GRO<br />
concentrations to test for the presence <strong>of</strong> petroleum hydrocarbons. The results are listed <strong>in</strong> Table 5-12.<br />
The pH value measured (7.54) is <strong>in</strong>dicative <strong>of</strong> typical residential sewage. The wastewater analysis<br />
suggests that the wastewater stream has characteristics typical to residential areas, and no abnormal pH<br />
value or hydrocarbon concentrations were measured.<br />
Table 5-12. Results <strong>of</strong> Wastewater Analysis for Columbus 36-<strong>in</strong>. L<strong>in</strong>er<br />
Sample ID pH<br />
86<br />
DRO<br />
(mg/L)<br />
GRO<br />
(mg/L)<br />
Pearl 36 7.54 1.99 34.3<br />
5.3.5 Annular Gap. A feeler gauge was used to measure the annular space around the perimeter<br />
where the sample was removed. The l<strong>in</strong>er appeared to be very tight along the sides and bottom <strong>of</strong> the<br />
sample and a spac<strong>in</strong>g greater than 0.127 mm was measured at only three locations (see Figure 5-31) – all<br />
along the top side <strong>of</strong> the sample removal area (see note on crown annulus gap <strong>in</strong> Section 5.3.3). The end<br />
measurements shown <strong>in</strong> Figure 5-31 were taken at approximately 4 <strong>in</strong>. from each end <strong>of</strong> the cutout and<br />
the middle measurement was taken at its center. S<strong>in</strong>ce the l<strong>in</strong>er sample was removed from the host pipe,<br />
no laboratory annular space measurements were possible.<br />
Figure 5-31. Annular Space Measurements Around the Sample Removal Area<br />
(Columbus 36-<strong>in</strong>. L<strong>in</strong>er)<br />
5.3.6 L<strong>in</strong>er Thickness<br />
1.64mm 0.86mm<br />
0.87mm<br />
Gap determ<strong>in</strong>ed to be < .127 on sides and bottom. Feeler<br />
Gauge m<strong>in</strong>imum is .127<br />
5.3.6.1 Ultrasound Test<strong>in</strong>g. An ultrasonic meter (Olympus 37DL Plus) with a 2.25 MHz contact<br />
transducer was utilized <strong>in</strong> the field <strong>in</strong> an attempt to measure the thickness <strong>of</strong> the CIPP l<strong>in</strong>er (Figure 5-32).<br />
However, the ultrasound test<strong>in</strong>g for thickness did not produce any read<strong>in</strong>gs (apparently due to the<br />
thickness <strong>of</strong> this l<strong>in</strong>er). This issue is discussed further <strong>in</strong> Section 6.<br />
5.3.6.2 Field Measurements. Caliper measurements <strong>of</strong> the exhumed l<strong>in</strong>er thickness were recorded<br />
around the edges <strong>of</strong> the extracted sample <strong>in</strong> the field as shown <strong>in</strong> Figure 5-33. The l<strong>in</strong>er thickness<br />
measurements taken <strong>in</strong> the field are shown <strong>in</strong> Figure 5-34. The average thickness for the sample was<br />
calculated to be 14.2 mm and standard deviation was 1.5 mm. The orig<strong>in</strong>al design thickness was not<br />
known, but it was assumed to be 15 mm (i.e., the same as the l<strong>in</strong>er used for the adjacent l<strong>in</strong>e).