As factory farms take over more and more of the nation’s livestock production, a major environmental threat has emerged: Pollution from the waste produced by the immense crush of animals.
The Environmental Protection Agency estimates that America’s livestock create three times as much excreta as the human population. By the agency’s reckoning, a dairy farm with 2,500 cows – which is large, but not exceptional – can generate as much waste as the people in a city the size of Miami.