The Biowar Sh*tbomb

Figure Legend: 2007 Census of Agriculture data from the United States Department of Agriculture (USDA) shows the geographic concentration of hog and pig production in the US. Source: USDA Census of Agriculture; 2007 Census Ag Atlas Maps 

Each of those dots in the above figure are CAFOs or IFAPs. That is, Confined Animal Feeding Operations, or Industrial Food Animal Production facilities. Really, it just depends on who you're talking to. Each dot on the map represents 20,000 hogs and pigs--in other words, the equivalent of a fairly big town. And each animal is producing an average of 74 pounds (33.5 kilos) of waste per day. [links to .pdf I averaged the waste production of five different classes of hogs and pigs to get the number quoted] That's about 1.48 million pounds or 671 metric tonnes of shit and piss per day. When hogs are raised in this kind of concentration, they are being raised under contract: a contract that spells out everything about the way an individual animal is brought to market weight or whatever the end goal is. Feeding, confinement, environment, drug use, delivery weight,all is spelled out in detail--frequently the feed specified is a feed produced in the vertically integrated corporation contracting for the final "product." The only thing the farmer owns or controls? Yup, 671 metric tonnes of waste per day.
This is not a minor issue. This waste is a greenhouse gas producer, it's difficult to dispose of (spreading it on fields is the preferred technique, but the volumes are a problem--the land cannot absorb the amount of nutrients), and it's often contaminated with low levels of pharmaceuticals used in raising animals in confined quarters. These are shit-bombs that go off at thousands of sites every single day--and that's just in America. Add in Canada and China and this becomes a nightmarish situation. It is estimated that, in America, livestock produce more than 100 times the waste that the amount of human sludge treated by municipal waste-water treatment every year.[Gerba, C. P., & Smith, J. E. (2004).  Sources of pathogenic microorganisms and their fate during land application of wastes. Journal of Environmental Quality, 34(1), 42-48.]