Processing sludge makes the water clean
“Sludge that is processed for energy and fertiliser is sludge that is not discharged into watercourses. Comprehensive processing at scale would reduce the organic load contributing to combined sewer overflows. / Sludge processed for energy, not dumped. Swimmers safe year-round.”
wrong Retired in version 2.0.0, 2 October 2026.
Where it appeared: Briefing paper, section 4; Home page: 'Clean rivers and beaches'.
Why it failed
Sludge is only the solids a works takes out of the flow, and it is removed from the works by design; dumping at sea ended in 1998. Storm overflows bypass treatment altogether. Storm overflows spill when rain overwhelms combined sewers. Digestion returns a liquor to the works (11.6 tonnes of BOD and 3.6 tonnes of ammoniacal nitrogen a day in 2025-26). Natural Resources Wales attributes bathing-water bacteria to sewage inputs, urban drainage, farming and wildlife, not to sludge.
Evidence
- Welsh Water, Annual Performance Report 2025-26, tables 8A, 8C, 8D
- NRW, Wales Bathing Water Report 2024
- Welsh Water, storm overflows
- Urban Waste Water Treatment Directive, Article 14: sludge disposal to surface waters phased out by 31 December 1998
- Senedd Research, Water quality in Wales (2023)
What the site says now
Clean water and waste-as-a-resource are presented as separate problems with separate fixes.