Water safety planning for healthcare facilities for extreme events.

Disasters such as the Ahr Valley flood in 2021 make us aware of the importance of functioning healthcare facilities. Their functionality depends on the availability of drinking water. Water safety planning is a long-established method to increase the safety of water utilities. Our work supports the implementation of water safety planning in healthcare facilities during normal operations and emergency situations concerning the water supply. The authors conducted a stakeholder mapping exercise and problem awareness analysis. Based on these results, it was identified what is needed to overcome barriers to water safety planning (WSP). Building on existing procedures, the WSP concept, and latest scientific findings, an event-specific risk assessment method for healthcare facilities was developed and applied in a case study. Based on an analysis of water demand, water-related processes, and infrastructure, potentially necessary components for establishing an emergency supply were identified. For these, based on technical and legal requirements, planning principles were developed, and prototypes of components for emergency water supply were built. They were tested in pilot trials, particularly regarding hygienic safety. For the management of crises in hospitals, a survey was carried out on the command structures used in practice. Finally, recommendations were drawn based on the German Hospital Incident Command System.

A comparison of efficiencies of microbiological pollution removal in six sewage treatment plants with different treatment systems.

Six sewage treatment plants (STP) were investigated over a 12-month period in order to measure the microbiological load of untreated municipal wastewater and to evaluate the removal efficiencies of different treatment systems. The STP investigated can be classified into three categories: bigger plants with tertiary treatment, smaller plants with enhanced secondary treatment, and very small compact facilities. The plants studied had a considerable quantitative impact on the hydrology of the catchment area; consequently, it was anticipated that the microbiological load of the effluent would also be significant. Eighty samples were taken from the influent and effluent of the STP, regardless of weather conditions, and several bacterial and two parasitological parameters were analysed. The average microbiological reduction of each STP was dependent on its capacity and treatment procedures and varied between 1.9 and 3.5log10. Small compact facilities had a significantly lower removal efficiency (2.0+/-1log10) and discharged treated wastewater with a poorer microbiological quality compared to larger plants with tertiary treatment or with enhanced secondary treatment (2.8log10). Final sand filtration and extensive intermediate settling considerably improved the overall microbiological removal efficiency. During the study period, the microbiological water quality of the receiving water course was not significantly impaired by the discharge of any of the investigated plants; however, the compact facilities showed critical treatment deficiencies. In particular, the reduction of Giardia cysts was insufficient (<1.5log10) compared to that of the bigger plants (>3.0log10). In order to quantify the overall impact of microbiological loads on the receiving watercourse in this catchment area, it is also necessary to assess the pollution from combined sewer overflow basins and diffuse pollution. This will be considered in subsequent studies.