Finished water hardness is not regulated,
but many utilities target residual hardness
levels at 50-100 mg/L as calcium carbonate
in order to minimize such adverse effects as
scale formation, deposition in hot water
pipes, and inhibition of the cleansing action
of soap and detergents. Operational data
from a Florida utility that had implemented
a full-scale magnetic ion exchange (MIEX®)
process upstream of its lime-softening
facilities demonstrated improved calcium
removal after implementation of this treatment.
However, the effects of natural organic
matter (NOM) in the lime-softening process
were not well understood. To bridge this
information gap, the authors undertook a
systematic study of anion exchange removal
of NOM and lime-softening.
Analysis of simulated natural waters with
varying concentrations of dissolved organic
carbon (DOC) provided evidence that NOM
interferes with lime-softening by inhibiting
calcium carbonate nucleation and crystal
growth. In this research, when model water
and real waters were pretreated with anion
exchange resin, DOC concentrations were
reduced and the result was improved calcium
removal by lime-softening. Includes 19 references, table, figures.
| Edition : | Vol. 101 - No. 6 |
| File Size : | 1
file
, 690 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 10 |
| Published : | 06/01/2009 |
