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This paper describes the application of the storm water management model (SWMM) for predicting the sewage quality in the sanitary sewer system of the study area resulting from the leaking of stormwater surface runoff to the system during rainfall events at different return periods. The concentrations of major pollutants were assessed in the sanitary sewer system at different rainfall intensities. Then, a solution to mitigate the problem was proposed using low impact development (LID) technology. The results of sensitivity analysis indicated that maximum build-up possible was the most sensitive parameter for model calibration. The model was calibrated using actual rainfall events, and statistical validation coefficients of R (0.81–0.82) and NMSE (0.0173–0.022) proved that the model is valid. The sewage quality assessment results showed that pollutants concentration increased to its maximum level at 20 min and gradually decreased to a slightly constant minimum value after 2 h. The proposed solution of LID reduced the pollutants concentrations by 82–88, 75–77, 52–55, and 7–10% for all pollutants at return periods of 2, 5, 10, and 25 years, respectively. To conclude, SWMM simulation successfully predicted the concentration of the pollutants, and leaking of stormwater surface runoff has changed the sewage quality.

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Friction stir processing (FSP) has been increasingly used to improve the surface characteristics of Al alloys. Investigation on FSP of heat-treated A380 Al alloy was performed to examine the impact of tool rotation speed on the surface characteristics. Heat treatment was accomplished using solution heat treatment followed by age hardening. The microstructure of the unprocessed and processed regions was characterized by utilizing an optical microscope, XRD, SEM and EDS. Surface properties were determined using hardness and pin-on-disk wear tests. The results showed that the heat treatment transformed the morphology of the silicon in the alloy matrix from fibrous to globular. FSP refined the microstructure in the stir zone due to the stirring effect. Hardness increased with an increment in the tool rotation speed due to increased densification of the stirring area. The wear test displayed the significant impact of the tool rotation speed on the wear rate as the wear rate decreased when the tool rotation speed tended to the highest value. The results also displayed that abrasive and delamination are the main mechanisms of surface deterioration.