Environmental Engineering Reference
In-Depth Information
Bacteriological Testing
After the main is placed back into service (some regulatory
agencies may require satisfactory bacteriological test results
before the main is placed back into service), samples should be
taken from the repaired main as described in Chapter 3 and
tested for total coliform bacteria. In most cases, samples should
be taken from both upstream and downstream of the repair. If a
positive total coliform test is obtained, corrective action should be
taken. Actions may include additional flushing or chlorination of
the repaired section. ANSI/AWWA Standard C651 requires con-
tinued sampling daily until two consecutive negative results are
obtained.
Documentation
Accurate records should be kept for future reference. The
date, location, type of break, materials used for the repair, per-
sonnel involved in the repair, procedures used, and test results
should be recorded. These records are useful if problems develop
or to determine a pattern of pipeline breaks in a specific area.
References
ANSI/AWWA C651. AWWA Standard for Disinfecting Water
Mains . American Water Works Association: Denver, Colo.
Good Practices for Preventing Microbiological Contamination of
Water Mains . 2001. American Water Works Association:
Denver, Colo.
Standard Methods for the Examination of Water and Wastewater .
(current edition). APHA, AWWA, WEF: Washington, D.C.
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