This is on an entirely different scale, and not only that, the UK water companies are under investigation for their practice of dumping sewage during storm over

This is on an entirely different scale, and not only that, the UK water companies are under investigation for their practice of dumping sewage during storm overflow situations; it may be nefarious, it may simply be inadequate capacity. IMHO it's unlikely, unless they are being exceptionally brazen, that they're skipping the easiest and most easily observable step in sewage processing, filtering out solids.