Abstract:
The aim of this experimental research was to investigate the compressive
strength and the amount of lead leached from solidified battery waste sludge using
calcium carbide waste (CCW) which is a by-product of the acetylene gas process, and
rice husk ash (RHA) which is a by-product of brick burning. The purpose of this study
was to determine the optimum treatment conditions. CCW:RHA was tested at ratios of
0.3:0.7, 0.4:0.6, 0.5:0.5, 0.6:0.4 and 0.7:0.3 while sand:sludge:water to binders (w/b)
ratios were constant at 2.75:0.2:0.65. The solidified waste was cured for 28 days to
test its compressive strength and Leachate Extraction Method. The optimum ratio of
CCW and RHA was 0.4:0.6. At this ratio, the mixture had the highest compressive
strength and the amount of lead leached was acceptable. Then ratios of sludge to
CCW:RHA were set at 0.05, 0.10, 0.15, 0.25 and teated at intervals of 1, 7, 14, 21, 28
days for the compressive strength and lead leachability using Leachate Extraction
Method and Accumulated Test.
Results indicated that with different ratios of sludge and different curing times,
there were significant difference in compressive strength(p-value<0.05) and lead
leached(p-value<0.05). The highest compressive strength of solidified waste with ratio
of sludge of 0.25 was 23.58±1.438 kgf/cm2 at 28 days. The highest leaching lead of
solidified waste with ratio of sludge of 0.25 was 2.657±0.036 mg/L at 21 days. All
average amounts of leached lead met the requirements of the Ministry of Industry of
Thailand.
The optimum ratio of CCW : RHA : sand : w/b ratio : sludge was
0.4:0.6:2.75:0.65:0.25 which provided a compressive strength and the amount of lead
leached that met the criteria requirement of the Ministry of Industry of Thailand.
At this ratio,the predicted leaching lead equation in this study was
Leaching lead (mg/L) = -0.020 + (0.092 Compressive strength) (R2 = 0.886)