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Given the scarcity of water resources and the rising costs of providing safe drinking water, identifying hazards and assessing relevant risks is critical for optimizing water supply systems. This study aimed to identify the hazards and provide an integrated risk assessment of the main water supply system components in Torbat-e-Jam using the World Health Organization’s Water Safety Plan. It also aimed to provide appropriate control measures to reduce the existing risks. Based on the results of risk analysis, access to healthy drinking water in the water supply system in the city of Torbat-e-Jam requires the following: determining wellhead protection area for all of the water resources, renovation, and replacement of worn-out and broken pipelines, maintaining a desirable distribution system pressure, supplying sufficient chlorine residual in the distribution system and storage tanks, increasing consumers’ awareness and regular review to investigate the reliability of control measures. Also, the research results suggest that the most important advantages of managing and assessing risks in water supply systems include a better understanding of the system and potentially damaging factors, provision of control measures to reduce direct and indirect losses caused by incidents, reduction of systems breakdown, and finally protection of water generated in all drinking water supply chain. [ABSTRACT FROM AUTHOR]

Drugs, especially antibiotics, as a group of emerging contaminants, pose a serious threat to the environment and aquatic ecosystems due to their adverse effects, cumulative properties, and developing drug resistancy. Therefore, this study aimed to evaluate the removal efficiency of tetracycline (TC) antibiotic from aqueous solutions using photocatalytic process in the presence of magnetic iron sulfide (Fe-S/CuS) nanoparticles on a laboratory scale. The magnetic nanocomposite was first characterized by transmission electron microscopy, X-ray diffractometer, vibration sampling magnetometer, Field-emission scanning electron microscopy, Fourier-transform infrared spectrometer, diffuse reflection spectroscopy, and energy-dispersive X-ray spectroscopy techniques. Factors, such as pH, reaction contact time, nanocomposite dose, and contaminant concentration on the removal efficiency were studied. All the experiments were performed at room temperature under UV-A light. The results of this study indicated that the highest removal efficiency of TC was obtained at optimum pH of 7. The results also showed that in the initial concentration of TC antibiotic (20 mg/L), the removal efficiency increased by increasing contact time and also by increasing the dose of the desired nanocomposite, the removal efficiency first increased and then decreased. Moreover, the synthesized nanocomposite had the ability to be reused with an 18% reduction in the removal efficiency in five consecutive cycles. Finally, the results of this study showed the acceptable efficiency of Fe-S/CuS nanocomposite in photocatalytic removal of TC antibiotic. [ABSTRACT FROM AUTHOR]