Abstract:
The research aimed to find the effects of particle size on the compressive
strength and leachability for the solidification of Battery Waste Sludge (BWS) by
using cement and rice husk ash(RHA).Sixteen experiment samples under different
size fractions were assigned to be above 150 microns,75-150 microns, under
75 microns and particle of unseparated mixed sizes (all the sizes mentioned above).
The ratio of mixture cement : RHA : BWS was constant at 1:0.5:0.15, and the water
cement ratio was varied using the flow tests. The specimens were cured under different
periods at 7,14,21,28 days.
The Battery waste water sludge was collected and analyzed for lead
content,which was about 587 mg/g of dried sludge, while the leachability of lead was
about 148 mg/L.The particle size of RHA&BWS and the curing time affected
compressive strength and lead leachability.The compressive strength increased as the
particle size of RHA decreased (P<0.001) and the compressive strength increased as
the particle size of BWS decreased (P=0.037).The lead leachability decreased as the
particle size of RHA decreased (P=0.001)and the lead leachability decreased as the
particle size of BWS decreased (P<0.001). The compressive strength increased as the
curing time increased (P<0.001) and lead leaching decreased as the curing time
increased (P=0.002).
The optimum condition in the process of solidified sludge was a mixture of
particle sizes of RHA and BWS under 75 microns at 28- day curing time.
The optimum condition of solidified sludge has passed the standards required for
compressive strength and lead leachability.It can be accepted that the effect of
RHA&BWS on compressive strength and lead leachability is a combined effect of its
size and curing time.