The Philadelphia Water Department (PWD) relies upon conventional treatment with ferric chloride coagulation and chlorine disinfection to
produce safe, clean drinking water. Recent regulations such as the Long-Term 2 Enhanced Surface
Water Treatment Rule and the Stage 2 Disinfectants/Disinfection Byproduct Rule are prompting
utilities to further limit the production of disinfection byproducts, namely TTHM and HAA5. This may
be achieved through a change in disinfection practice or through an overall reduction in the amount of
total organic carbon in the water. Previous pilot studies have investigated the effects advanced oxidation
and moving the point of chlorination have on DBP formation. The primary focus of this segment of pilot
plant investigations was the use of MIEX, a magnetized ion exchange resin, to reduce total organic
carbon of treated water and, in turn, reduce DBP production.
The secondary objectives were to assess the impact of MIEX pretreatment on coagulant/treatment
chemical demand and on filter production. Tertiary considerations included the effects of MIEX on
metals residuals, treatment residuals (sludge) production and chloride to sulfate ratio of the finished
water.
A six-month pilot study was conducted in warm water (May to November 2006) when the potential for
DBP production was highest. Water that had been conventionally treated was compared to water
pretreated with MIEX. Performance was evaluated using three coagulants: ferric chloride;
polyaluminum chloride; and, aluminum sulfate. Data presented in this paper reflects only the ferric
chloride experiments. Capital and operational costs and ease of integration of the existing full-scale
plant are still being evaluated and compared to previously studied alternatives for DBP control. Includes 2 references, tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 260 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 12 |
| Published : | 11/01/2007 |
