In the context of the COVID-19 pandemic, wastewater-based epidemiology (WBE) emerged as a useful tool to account for the prevalence of SARS-CoV-2 infections on a population scale. In this study, we analyzed wastewater samples from three large (>300,000 people served) and four small (<25,000 people served) communities throughout southern Germany from August to December 2021, capturing the fourth infection wave in Germany dominated by the Delta variant (B.1.617.2). As dilution can skew the SARS-CoV-2 biomarker concentrations in wastewater, normalization to wastewater parameters can improve the relationship between SARS-CoV-2 biomarker data and clinical prevalence data. In this study, we investigated the suitability and performance of various normalization parameters. Influent flow data showed strong relationships to precipitation data; accordingly, flow-normalization reacted distinctly to precipitation events. Normalization by surrogate viruses CrAssphage and pepper mild mottle virus showed varying performance for different sampling sites. The best normalization performance was achieved with a mixed fecal indicator calculated from both surrogate viruses. Analyzing the temporal and spatial variation of normalization parameters proved to be useful to explain normalization performance. Overall, our findings indicate that the performance of surrogate viruses, flow, and hydro-chemical data is site-specific. We recommend testing the suitability of normalization parameters individually for specific sewage systems.

The Nile River serves as a central source of water for around 487 million people. Agriculture in the riparian states largely depends on the Nile's water supply due to irrigation. In this study, the potential for irrigated agriculture in Sudan is evaluated to estimate the future increase in water pressure in the region. In geographic information system (GIS) software a model for land suitability analysis (LSA) is developed. Datasets of parameters such as precipitation, temperature, slope, landcover, and selected soil properties represent the prevailing conditions. The resulting maps of the LSA show suitable and not suitable areas for irrigated agriculture. To determine the yearly water demand for irrigated agriculture the suitable areas are offset by the irrigation water demand for mixed cultivation of Faba beans, sorghum, and sugarcane calculated with the Food and Agriculture Organization of the United States (FAO) software AquaCrop. It shows that there is great potential for irrigated agriculture, especially in the southeast, where large irrigation schemes already exist. In northern Sudan, not suitable areas accumulate. The calculated irrigation water demand is 33.5 BCM/year, which is 19.5 BCM/year additionally compared to 2017. The estimated irrigation amount shows the importance of collaboration between the countries in the Nile basin to increase the water resources available for irrigation to avoid conflict over resources. The uncontrolled extension of irrigated agriculture in Sudan will increase the pressure on the already scarce water resources in Egypt.

In the context of the COVID-19 pandemic, wastewater-based epidemiology (WBE) emerged as a useful tool to account for the prevalence of SARS-CoV-2 infections on a population scale. In this study we analyzed wastewater samples from three large (> 300,000 people served) and four small (< 25,000 people served) communities throughout southern Germany from August to December 2021, capturing the fourth infection wave in Germany dominated by the Delta variant (B.1.617.2). As dilution can skew the SARS-CoV-2 biomarker concentrations in wastewater, normalization to wastewater parameters can improve the relationship between SARS-CoV-2 biomarker data and clinical prevalence data. In this study, we investigated the suitability and performance of various normalization parameters. Influent flow data showed strong relationships to precipitation data; accordingly, flow-normalization reacted distinctly to precipitation events. Normalization by surrogate viruses CrAssphage and Pepper Mild Mottle Virus showed varying performance for different sampling sites. The best normalization performance was achieved with a mixed fecal indicator calculated from both surrogate viruses. Analyzing the temporal and spatial variation of normalization parameters proved to be useful to explain normalization performance. Overall, our findings indicate that the performance of surrogate viruses, flow and hydro-chemical data is site-specific. We recommend to test the suitability of normalization parameters individually for specific sewage systems.