This paper describes a
study that was conducted to investigate the effect of sample preservation and holding time on the
results obtained for percentage removal of total organic carbon (TOC). To investigate the effect of sample preservation and storage, a series of source water and finished
water samples were collected from the Pittsburgh Water and Sewer Authority (PWSA) Drinking
Water Treatment Plant and were analyzed for TOC content. Multiple samples were collected on
day 0. Half of the samples were preserved to a pH level of 2 with either phosphoric or sulfuric
acid, while the other samples were not preserved. Acid preservation (pH 2) of 40 ml aliquots of
this source and finished water required 0.2 ml of either acid. Preserved and unpreserved samples
from this series were analyzed for TOC concentration on days 0, 7, 14, 21, and 28 following
initial sample collection. The percentage removal of TOC was calculated on each analysis day
by subtracting the measured finished water TOC value from the source water value, and then
dividing this difference by the original source water TOC concentration.
The source water for the PWSA Treatment Plant is the Allegheny River which typically has a
TOC content in the regulatory category of >2.0-4.0 mg/L, and an alkalinity of approximately 35
mg/L (as CaCO<sub>3</sub>). With this source water chemistry, PWSA is required by the Stage 1 D/DBP
Rule to remove 35.0% of the source water TOC in its conventional treatment process.
TOC analyses for this study were conducted in the PWSA Laboratory using a Sievers model 900
Portable TOC Analyzer. Includes 4 references, table, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 150 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 7 |
| Published : | 11/01/2007 |
