The Environmental Protection Agency will propose Cryptosporidium CT
Tables for the Long Term 2 Enhanced Surface Water Treatment Rule
(LT2ESWTR). Preliminary indications show that the required CT values will be
higher than originally thought for Cryptosporidium inactivation. Several
water utilities would be impacted by higher CT-values with respect to
ozone operations and bromate control strategies. The Southern Nevada
Water Authority (SNWA) is currently implementing 900 MGD of
ozonation between two treatment facilities. The design of these facilities
was based on initial Cryptosporidium inactivation research to achieve a
2.0-log inactivation. Substantial pilot plant testing has already been
performed with respect to ozone operations and bromate mitigation
strategies. Previous testing indicated that a combination of 0.1 mg/L
ammonia and 0.5 mg/L chlorine could be used to maintain bromate levels
below the 10 ppb Maximum Contaminant Level (MCL) while achieving a
2.0-log Cryptosporidium inactivation. This combination was evaluated
with three other previously determined optimal strategies at seven
different CT values. The results were compiled into operational matrices
showing the impact on ozone dose, ozone residual quenching dose, and
bromate control strategies. Overall, the results showed substantial
increases in bromate formation, along with significant revisions to the
current bromate control strategies. Includes 3 references, table, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 460 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 7 |
| Published : | 06/15/2003 |
