USING NATURAL ORGANIC MATTER AS A REMEDIATION MATERIAL IN ENVIRONMENTAL APPLICATIONS
Natural organic matter (NOM) is being characterised and
investigated for use as a remediation material in various applications.
Two readily available environmental materials are
being tested: Material A: 68% by weight of the material is
organic including 19% humic acid, 28% fulvic acid and 21%
humin. 32% of the material is inorganic, containing 23% iron.
Material B: 57% by weight of the material is inorganic, 3% is
humic acid, 27% is fulvic acid and 13% is humin. The humin
fraction of these two materials may contain humic acid that
has been immobilised by clays or other minerals. The materials
have been tested in three applications; i) As a permeable
reactive barrier A permeable reactive barrier is a passive, in
situ method that is used to remediate contaminated groundwater.
As groundwater flows through it, the barrier extracts
contaminants, significantly reducing their concentration. Both
materials are capable of extracting metals and organic pollutants
from groundwater ii) Extraction of iodine from urine 131I
may be given to patients with thyroid problems for diagnosis
or treatment. About 30% of the activity (2-3 GBq) is excreted
in urine during the first day after administration. In some
parts of Europe, the radioactive urine is collected in tanks at
the hospital. The objective of this investigation is to determine
whether the radioiodine can be extracted from urine and
concentrated in a smaller volume of solid. iii) Extraction of
iron and other contaminants from industrial effluents During
the production of kaolinite or China Clay, brown discoloration
caused by Fe3+-containing impurities is removed by the
addition of acid and a reducing agent, forming soluble Fe2+.
The latter is then removed from the effluent by precipitation
with NaOH and flocculants. This study investigates the use of
solid NOM to bind iron and co-contaminants directly, avoiding
the need for alkali addition and precipitation of large
quantities of slurry.