| چکیده انگلیسی مقاله |
At the present time, there is not a main sewerage and sewage treatment plant in Tehran but some small sewage treatment plants were built in this city. The main objectives of this study were to investigate the stabilization condition and reuse of the disposal sludge in some of these treatment plants. This research completed on four sewage treatment plants consisting of Shoush, Ghytareyh, Ekbatan and Sahebghraneyh over ten months (October 1996 to July 1997). The general condition and operation of these plants were considered and also indexes of sludge stabilization and reuse including VS/TS ratio, pH, flotation, color, odor, coliform and fical coliform were determined. The average ratios of VS/TS in disposal sludge of sewage treatment plants; Shoush, Ghytareyh, Ecbatan and Sahebghraneyh were estimated and been 69.25%, 70%, 71% and 70.25% respectively. The average of pH values in disposal sludge of sewage treatment plants; Shoush , Ghytareyh , Ekbatan and Sahebghraneyh were determined and they were 6.48, 6.93, 6.68, 6.65 respectively. Also the average fical coliform density in disposal sludge of sewage treatment plants; Shoush, Ghytareyh, Ecbatan and Sahebghraneyh were estimated and they were 2.61´106 , 2.68´105, 7.5´105 , 1.2´107 per gram respectively. The results of this research showed that the disposal sludge from these plants were raw and destabilized. The microbial quality of the disposal sludge was evaluated and results showed that maximum was in class B of USEPA category. Therefor, at the best condition the disposal sludge may be used for the reconditioning the poor soil or forest areas, but never be used as a fertilizer for the agriculture. If these types of sludge are used as a fertilizer, so microbial quality of these must be improved up to class A of USEPA category with additional stabilization process. |