Yeah it's mind boggling how in the 21st century, a "developed" country is still dumping solids from sewers.

Like, if they're letting plastic sheets through, it's almost certain that the other harmful parts of sewage, namely bacteria and over saturation of nutrients, are definitely not being adequately removed. You think London, which had countless bacterial epidemics throughout history due to untreated sewage in water ways, would be a little more careful.