Compliance with new Safe Drinking Water Act (SDWA) regulations has resulted in a change in finished water
quality for many systems throughout the United States. Most often the finished water
quality change has been due to compliance with disinfection byproduct regulations (Stage
1 D/DBP Rule). Changes in finished water quality has been concurrent with an increase in lead
occurrence in some distribution systems, and issues with colored
water (iron), or problems with new building plumbing systems. The
increase in corrosion is not immediately known because changes in water quality do not
illicit an immediate corrosion byproduct response and routine monitoring parameters do
not indicate a problem exists. In addition, since many systems have been on reduced
monitoring under the Lead and Copper Rule, specific analysis for compliance parameters
of lead and copper are not routinely done, with as much as six years allowed between
sampling for Pb or Cu for those on reduced monitoring. Many factors can increase corrosion rates, making it difficult to determine the exact
cause. In addition using corrosion inhibitors is only effective if the type and dose is
properly selected. Problems with lead in recent years have been attributed to change in
treatment processes in order to lower disinfection byproducts. Lower organics, higher
chlorides, higher sulfates, higher pH's, chloramines and "free ammonia", and lower
alkalinity may all be playing a role.
Finding a solution to drinking water corrosion problems requires a careful review of
finished water characteristics, distribution system materials, types and locations of
complaints, and a review of water quality changes throughout the entire distribution
system including: residual disinfectant levels, inhibitor phosphate concentrations, pH,
alkalinity, and nitrate/nitrite (in chloramine systems). Includes 5 references, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 260 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 10 |
| Published : | 11/01/2007 |
