What Happens to Slaughterhouse Waste?

Fair warning: This post is not for the faint of stomach. In fact, if you're about to bite into a sandwich right now, put it down, save it for later, and brace yourself.

Ever wonder what happens to all the bones, organs, hooves, and other inedible bits leftover from the slaughterhouse? How about euthanized pets, roadkill, animal afterbirth, spoiled meat, and the domestic creatures that perish of natural causes? As much as folks don't want to think about these unsavory topics, it's all got to go somewhere. That somewhere is the rendering plant.

The slaughterhouse industry has gotten a lot of attention lately, from the atrocities of the big plants to the plight of the small processor, but for years, the "silent industry" of rendering plants had gone largely unnoticed in the public consciousness.  Rendering plants handle all of these wastes and carcasses in a relatively efficient manner with minimal environmental impact, producing usable products like fertilizers, tallow, gelatin, and animal feed.

But times are changing. It turns out feeding cows the remains of their brethren isn't such a good idea, and after the recent Mad Cow scare, regulation on rendering plants skyrocketed. The government demanded rigorous testing for Mad Cow and immediately halted the practice of feeding rendered animals to cattle. Starting in 2009, the FDA required that all brains and spinal cords, the tissue that carries the prions that cause Mad Cow Disease, be removed from cows older than 30 months before rendering. These were obviously good moves on the government's part, but there were unintended consequences. As has happened in so many other places in the food chain, the rendering industry has consolidated under the pressure, leaving us with bigger and fewer plants and all the problems that that entails. It is becoming harder and harder for rendering plants to meet demand, meaning there is an ever-growing need for an alternative solution.

As we are slowly understanding that, "Hey wow, feeding vegetarian animals rendered carcasses is not the brightest policy," we are still left to figure out what, exactly, we should do with all this "deadstock." The short answer is that there is no good answer. Burial used to be very popular, and still is, but there is increasing evidence of groundwater contamination. Incineration effectively destroys disease, but it releases poisons and greenhouse gases into the air. An article on the topic from The Atlantic concludes that anaerobic digestors are the most hopeful option. They produce a biogas that can be used as a source of energy, and indeed this has already been effectively implemented in China. But these digestors don't deactivate prions or break down fatty acids well, are water-intensive, and they can lead to dangerous heat-resistant bacteria. Furthermore, they are rare and just aren't practically available right now.

When I first heard about this problem, the first solution that sprang to my mind was that great biological recycler: compost. Indeed, the process would work splendidly in theory. Studies have found that composting can effectively deactivate prions if carefully monitored, and the end product is the best soil amendment there is, rich in nutrients and organic matter. But this solution, shockingly, was only recently made legal in many states, and it remains illegal in many others. Furthermore, it's not just pure animal that gets rendered these days. Antibiotics, hormones, euthanasia drugs, medicines, flea collars, metal tags, packaging, and more all get thrown into the pile, all of which would render the resulting compost unfit for the vast majority of applications. The industrial food system strikes again, rendering what would have been an elegant solution almost useless.

Of course individual organic and sustainable farmers, butchers, and certain small processors can still use the composting method just fine, but that doesn't address the vast majority of America's deadstock. We raise far too many animals in far too great a concentration, and we are increasingly discerning about which parts of an animal we're willing to eat. We essentially have no solution for dealing with this ever-growing mountain of animal waste. More and more we're being faced with exactly what it means to be living with a system that is unsustainable. Like so many facets of our industrialized food system, rendering as we know it literally cannot continue.

Photo credit: Red Junasun via Flickr