چكيده لاتين :
In the present investigation, for the first time in Iran, dewatered sludge waste from air
heater washing wastewater treatment ofa thermal power plant was subjected to investigation of the
cement base stabilization and solidification experiments in order to reduce the mobility ofheavy and
othe r hazardous metals as well as increasing the compressive strength ofthe solidified product for
possible reuse of the waste . The solidification was done with two cement based mix designs with
different waste/cement ratio is different samples. The results of leaching test on the solidified
samples revea led that regarding the sand-cement mixture even with 25% waste /cement ratio, the
leach ing of heavy metals has completely been controlled up to 95%. In cement stabilization process
the leaching ofY,Ni, Zn and Cr could be decreased from 314.1, 209.1,24.8 and 5.5 mg/Lrespectively
in the raw waste to 6,32.1,3.6 and 3.6 mg/L in a mixture with 20% waste/cement ratio. During
stabilization with cement-sand, the TCLP leachate contents of mentioned metals have been decreased
to 4.2, 16.2,2.5 and 2.2 mg/L with waste/cement ratio of20%. X-ray diffraction studies showed that
portlandite, calcite, lime, larnite and quartz have been shaped during the stabilization process. The
compressive strength test results revealed that in both mixture samples, decreasing the compressive
strength with increasing the amount ofwaste content in the mixture occurs. In sand-cement solidified
samples with waste/cement ratio 25% and in cement solidified samples with waste/cement ratio 20%,
a 40% decrease occurs in the compressive strength in comparison with the waste free mixtures.
