Environment Agency regulatory position on when you cannot comply with best available techniques associated emission limits (BAT-AELs) for certain substances discharged to sewer at chemical waste treatment installations.
Source
https://www.gov.uk/government/publications/compliance-with-bat-aels-for-indirect-emissions-to-water-at-chemical-waste-treatment-installations-rps-371Canonical document at the regulator. Always cite this URL — not the Vantage detail page — in compliance evidence.