Wastewater
Evidence-led explainers on wastewater, with every figure sourced.
Why combined sewers discharge to rivers at all, why recorded spills rose so sharply, and what would actually fix it.
Wastewater treatment is mostly a controlled biological process: micro-organisms are fed the pollution and then removed.
Treated wastewater is already a major water source, mostly without anyone noticing. Planned potable reuse just makes it explicit.