Perchlorate is a health concern because
it disrupts the thyroid gland's use of
iodine in the generation of metabolic
hormones and could ultimately hinder
normal physical growth and development.
Because perchlorate contamination of drinking
water has only recently come to the forefront,
no technology has been established as
the optimal treatment process for perchlorate
removal.
This research evaluated the use of activated
carbon filtration to reduce perchlorate
concentrations using conventional contact
times and without generating a concentrated
perchlorate waste stream. Abiotic granular
activated carbon filtration experiments
demonstrated that perchlorate was removed
by ion exchange rather than chemical reduction.
Biological reduction of perchlorate in
the low-microgram-per-litre concentrations
was achieved using biologically active carbon
(BAC) filtration. Batch experiments verified
the biological reduction and demonstrated
that microorganisms in the BAC filter converted
perchlorate to chlorate.
Study results indicate that BAC filtration
has the potential to be very cost-effective and
efficient for removing perchlorate. Before
BAC filtration can be applied to full-scale
perchlorate remediation, however, the
process must be optimized with respect to
operating conditions and water quality characteristics.
The findings described here
should help raise the general awareness of
promising biologically based technologies,
which are already in extensive use in Europe
and are making inroads in the United
States. Includes 39 references, figures.