Abstract:
Water percolating through the decomposing waste matters in a dumpsite picks organic
and inorganic compounds and becomes leachate. Since leachate infiltrates into the soil
profile and accumulates in groundwater aquifers, it causes heavy contamination in
groundwater flows. This contaminated groundwater plume should be treated. Permeable
Reactive Barrier (PBR) is an in-situ method to treat contaminated groundwater. This can
also be effectively applied to treat landfill-leachate-contaminated groundwater. In this
study PRBs were modelled by five laboratory-scale columns. First column was filled
with a mixture of Dewatered Alum Sludge (DAS), Washed Quarry Dust (WQD), Saw
Dust (SD), Fire Wood Charcoal (FWC) and Silica Sand (SS). Second column was filled
with the above materials in equal layers. The third, fourth and fifth columns were filled
with Granular Activated Carbon (GAC), Zero-Valent Iron (ZVI) and Red Laterite Soil
(RLS) respectively. RLS represents the typical soil. The latter three columns were used
as controls. The columns were flushed with tap water for several days to remove all
readily flushable contaminants of the media. Thereafter the columns were loaded with
10 % diluted landfill-leachate collected by a dumpsite. The treatment of efficiencies of
parameters such as COD, BOD5, Nitrogenous compounds and Total Dissolved Solids
(TDS) by the reactive media in each column was estimated by characterizing influent
and effluent samples. Removal of organic matters in control experiments was higher
than those of the experimental columns. BOD5 removal was almost 80% in all control
columns Removal efficiency of mixture is almost equal to controls. Least removal
shown by the column with layers but more than 50%. The highest removal efficiency for
NH3-N occurred in the experimental columns with mixed reactive materials. Therefore
the tested low-cost and waste matter can be considered as potential reactive media for
PRBs to treat landfill leachate contaminated groundwater.
