Background: Sewage SLUDGE (Biosolids) is a byproduct of WASTEwater treatment that accumulates in large quantities. Effective stabilization and disinfection of sewage SLUDGE prior to land application are necessary to not only protect human health, but also to induce the public its benefits and safety. Currently, many WASTEwater treatment plants in Iran dispose great amounts of untreated sewage SLUDGE to the environment. Objectives: The purpose of this work was to upgrade WASTEwater treatment plants by lime stabilization of WASTE SLUDGE. Materials and Methods: Lime stabilization of WASTE SLUDGE from Shoosh WASTEwater treatment plant was performed in a 10-L reactor.Microbial quality of lime-stabilized SLUDGE was checked for 6 weeks in the reactor. During this stage, pH, FC (fecal coliforms) and viable helminthes ova density were determined and compared with SLUDGE stabilized criteria suggested by USEPA.Results: Average number of fecal coliforms and viable helminthes ova in WASTE SLUDGE were 1.65 × 1012 MPN/g of dry solids (DS) and 353 ova/4 g of dry solids, respectively. Conclusions: The results of this study showed that sewage SLUDGE stabilization with hydrated lime reduced fecal coliforms more than 99.99% and also stabilized SLUDGE covered standards of class B of USEPA criteria.

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.

Biological treatment of industrial WASTE water with ACTIVATED SLUDGE is Knon as one of the most effective methodes in removing toxic material such as formaldehyde. In this research it is attempted to set in motion and preserved the biological formaldehyde treatment system with ACTIVATED SLUDGE and the existing microorganisems will use the formaldehy as their food to grow.That is why an aerobic reactor with the volume of 8 liter known as Bioreactor is used. The primary biologic environment is provided by the returned SLUDGE in Zargandeh WASTE Water treatment plant and the system is started in the form of Batch.The input optimum formaldehyde as well as desired retention time to obtain the most efficient way for COD elimination and output formaldehyde are provided the highest percentage of COD volume with input formaldehyde concentration 70.ppm would be when retention time is 24 hours. Input formaldehyde concentration increase or residence time decrease will result in reduction of COD and pH elimination percentage.

The ACTIVATED SLUDGE process simply involves bringing together WASTEwater and a mixed culture of microorganisms under aerobic conditions. The system usually includes a secondary treatment given to the settled sewage, and requires an environment in which active microorganisms are maintained in intimate contact with WASTEwater in the presence of sufficient oxygen. In this study, the treatment of industrial effluents, by using laboratory ACTIVATED SLUDGE unit was investigated. The reduction of the pollution laws was determined, using the biochemical oxygen demand (BOD) and the chemical oxygen demand (COD) methods. The results indicated that the pollution laws were reduced by up to 98% in the ACTIVATED SLUDGE unit.