Fig. 1

Overview of activated sludge (AS) viruses. A Geographic distribution of collected AS samples. The location sites of AS are presented as orange circles, with circle size representing the number of wastewater treatment plants (WWTPs). B UpSet plot showing the number of viral operational taxonomic units (vOTUs) and their sharedness between AS with different wastewater types at the species level. C Pie chart showing the number of vOTUs clustered in AS from different countries at the species level. D Accumulation curve of vOTUs (orange) and viral protein clusters (vPCs, gray). Dots represent the average number of vOTUs and PCs, and error bars represent the range. The numbers of vPCs are divided by five for better visualization. E Histogram showing the distribution of viral genome size (log₁₀ scale) and quality