Farmer Jonathan Trower scoops up a wodge of wet wipe-resembling material from a patch of stinging nettles. “It’s called rag,” he says. “It’s bits of cotton buds, tampons, things like that.” It litters a field on his Stanstead Bury Farm, which lies next to Thames Water’s Rye Meads Sewage Treatment Works. During heavy rainfall, the company can use its “safety valve” to discharge sewage diluted with water into a muddy ditch, which connects with the River Stort around 300 metres from the outfall. When the discharge dries up, some of the material is left behind on Mr Trower’s land, which he maintai…