Welsh Water digests only a fraction of its sludge
“Welsh Water currently recovers energy from only a fraction of the sludge produced across its 838 treatment works.”
wrong Retired in version 2.0.0, 2 October 2026.
Where it appeared: Briefing paper, executive summary; Home page: 'sludge processed for energy, not dumped' and the asks.
Why it failed
98.2% of Welsh Water's sludge went through advanced anaerobic digestion in 2025-26 (98.5% in 2024-25; that is the company's reported result, not its target, which was 97.3%), 0.6% through conventional digestion and 1.0% was limed. That is a company-wide share by weight: it runs four advanced digestion plants (Cardiff, Afan, Cog Moors, Five Fords) with capacity above the sludge it produces, and carries sludge to them from its other works by tanker and pipeline. Only about 37% is made at the works that have a digester on site.
Evidence
- Welsh Water, Annual Performance Report 2025-26, tables 8A, 8C, 8D
- Welsh Water, APR 2024-25 tables (8D)
- Welsh Water, bioresources market information 2024-25
What the site says now
Shown as sourced figures: sludge.aadSharePct and related, on the home page and /figures.