This slide presentation outlines a study to: define the term "Consecutive Systems" (CS) -
water system purchasing water from another system,
earlier regulation non-specific, and
specific under Stage 2 DBP Rule; DBP control strategies for CS -
characterize DBPs in CS and WS based on historical
surveys and sampling survey, develop a hold study protocol for CS,
understand impact of storage facility operation,
evaluate booster disinfection; and, answer the following questions:
how does a WS and CS set water quality goals at the
point of purchase; what is the best management practice for water age
in CS; and,
what are the feasible options for WSs to assist CSs
for complying with DBP Rule? The project approach included:
historical survey;
sampling survey;
development of hold study approach;
bench-scale evaluation of disinfection strategies;
evaluation of storage facilities; and, AwwaRF Reports. Summary of the
utility survey included:
large portion of the contacted utilities participated on this
survey;
utility survey provided valuable information on disinfection
practices for both WSs and CSs;
WS with source water of higher TOC or bromide (DBP
precursors) practiced non-Cl<sub>2</sub>/Cl<sub>2</sub> system; and,
equal number of WS either practiced Cl<sub>2</sub>/Cl<sub>2</sub> and/or
Cl<sub>2</sub>/NH<sub>2</sub>Cl, whereas larger portion of CSs practiced Cl<sub>2M</sub>/NH<sub>2</sub>Cl.
Summary of DBPs precursors included:
for both WSs and CSs meeting the 80% MCLs (64 µg/L) of
TTHMs will require finished water TOC ¿¿¿¿¿¿¿ 3.0 mg/L;
for both WSs and CSs meeting the 80% MCLs (48 µg/L) of
HAA5 will require finished water TOC ¿¿¿¿¿¿¿ 4.0 mg/L. Summary at distributions included:
for both WSs and CSs dominant DBP in distribution is
TTHMs;
the dominance of TTHMs is greater for Cl<sub>2</sub>/NH<sub>2</sub>Cl system
to Cl<sub>2</sub>/Cl<sub>2</sub> system;
TTHMs and HAA5 growth (i.e., of finished to distributed
water) is similar for Cl<sub>2</sub>/Cl<sub>2</sub> system but reduces for
Cl<sub>2</sub>/NH<sub>2</sub>Cl system;
HAA5 slightly decreases in distribution system; and,
no significant relationship were found on this survey for
DBPs with water age. Includes tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 650 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 27 |
| Published : | 06/01/2006 |
