Perspectives are different frameworks from which to explore the knowledge around sustainable sanitation and water management. Perspectives are like filters: they compile and structure the information that relate to a given focus theme, region or context. This allows you to quickly navigate to the content of your particular interest while promoting the holistic understanding of sustainable sanitation and water management.
Scum is the general name given to the floating layer of dirt or froth on the surface of a liquid. It is also used to describe the layer of solids formed by wastewater constituents that float to the surface of a tank or reactor (e.g., oil and grease).