Author/Authors :
Rahmani، K نويسنده School of Public Health, Tehran University of Medical Sciences, Tehran, Iran , , Mahvi، A H نويسنده School of Public Health and Center for Environmental Researches, Tehran University of Medical Sciences, Tehran, Iran , , Vaezi، F نويسنده School of Public Health, Tehran University of Medical Sciences, Tehran, Iran , , Mesdaghinia، A R نويسنده School of Public Health, Tehran University of Medical Sciences, Tehran, Iran , , Nabizade، R نويسنده School of Public Health, Tehran University of Medical Sciences, Tehran, Iran , , Nazmara، Sh. نويسنده ,
Abstract :
Biological removal of lead was observed in this study during treatment of synthetic
solutions of this heavy metal by a sample of waste activated sludge (WAS) having MLSS
concentration of 10000 mg/L. The objective was determining the capability of WAS in removal of
lead in three different conditions of treatment: without any aeration and feeding, by simultaneous
aeration and feeding and by aeration without feeding. Besides, the effect of initial metal concentration
and contact time in these treatment stages were determined.Results showed that the efficiency of
lead removal was reduced by increasing the initial metal concentration, but the changes of contact
time had resulted in different responses depending to the test condition. Moreover, it was found
that the effects of aeration and feeding in increasing the efficiency of treatment were more pronounced
for the stage of treating lower concentrations of lead. The maximum removal of lead in the first step
(without aeration and feeding) was 55.2 % in contact time of 75 minutes, in the second step (without
feeding and by 12 hours aeration) 63.3% and third step it was 94.2 % in contact time of 48 hours .The
initial lead concentration in these experiments was 5 mg/L.
