Application of Gamma irradiation in treatment of Waste Activated Sludge to Obtain Class a Biosolids

Abstract

<b>Problem statement:</b> The main objective of the current study was investigation of the&#13; possible application of Gamma irradiation for treatment of the activated sludge generated&#13; wastewater treatment stations, to achieve the standard requirements in term of pathogens content.&#13; <b>Approach:</b> Activated sludge samples were collected from Riyadh wastewater plant and analyzed&#13; quantitatively for the presence of important bacterial parameters including fecal coliforms and <i>Salmonella</i>&#13; spp. The collected samples were treated with various doses of Gamma irradiation and bacterial count was&#13; determined. <b>Results:</b> The results indicated that all tested sludge samples were positive for the presence of&#13; fecal coliforms and <i>Salmonella</i> spp, with different counts in different stages of wastewater treatment. The&#13; raw sludge showed to have the highest coliforms and <i>Salmonella</i> spp counts of 1.1×10⁸ and 2×10³ MPN&#13; g^-1 dry sludge, respectively. Furthermore, coliforms and Salmonella spp were detected in final resulted&#13; sludge with count of 2.5×10⁷ and 6×10² MPN g^-1 dry sludge, respectively. It was found that treatment of&#13; samples with gamma irradiation was able to reduce the fecal coliforms and <i>Salmonella</i> spp effectively&#13; and the reduction efficiency was increased by increasing the irradiation dose. Fecal coliforms and&#13; Salmonella counts were reduced to less than 100 MPN g-1 dry sludge by exposing to 1.5 and 0.25 kGy&#13; respectively. Furthermore, Gamma radiation dose of 2.0 kGy was able to remove both fecal coliforms&#13; and <i>Salomnella</i> spp completely. In addition, D₁₀ values were determined and was found to be 0.25 and&#13; 0.24 kGy for fecal coliforms and <i>Salmonella</i> spp., respectively. <b>Conclusion/Recommendations:</b> The&#13; results indicating that the resulted activated sludge generated from Riyadh wastewater plant are rich with&#13; important pathogens and therefore further treatment procedures are necessary to achieve the required&#13; standards, before any land application. Application of Gamma irradiation in treatment of the activated&#13; sludge showed to be a promising safe technology for this purpose

Fractional Calculus Theoretical Evolution for Radiation Quantities

“…Fractional calculus launches as a very useful tool could be used to express the dissipation which is associated with, almost, all physical processes in nature (Ajlouni, 2011), by having new operators, new criteria and new set of subordination theorems could be obtained with some earlier results and standard methods (Thongwan et al, 2011;AL-Ghonaiem et al, 2010;Cansee et al, 2010). The new complexified dynamics guides to a new dynamics which may differ totally from the classical mechanics cardinally and may bring new appealing consequences.…”