Q: What would be the best minimal cost, implementable sanitary sewer system for animal agriculture (cows, pigs, sheep, horses, poultry) that would achieve a significant reduction in the spread of agricultural pollutants, particularly animal fecal pollutants and runoff, onto food crops and into waterways, which significantly raise the microbial pollution of our oceans as measured near to shore?

Asked by Laurie Girand, MBA '87, San Juan Capistrano, Calif.

Ah, manure—it's a sticky situation, and in more ways than one. But it's also a passion of ours here at SAGE, and your question inspired the very first SAGE song and music video.

Whatcha Gonna Do (With All That Poo)

No matter what species of livestock we're talking about, the problems are more or less the same: bacteria that can make us sick, and nutrients that can harm the environment. Let's focus on cattle, if for no other reason than the fact that in today's burger-and-steak world, cattle literally outweigh the entire human race. And those cattle are overflowing, well, with what happens when a whole lot of corn spends time in a rumen—13 billion metric tons of feces each year, worldwide. What all that stinky stuff needs is time—time for natural or planted landscapes to absorb valuable nutrients, and time for the contaminating bacteria to die.

In most situations today, however, things aren't quite so simple. Our meat consumption has doubled in just the past 50 years, and our manure problems with it. The number of farms and ranches producing livestock has fallen over the same time period, and therein lies the problem—an inherently unbalanced meat machine we call a feedlot.

Feedlots have turned America's cattle, once patient hikers and stolid mountaineers, into overfed urbanites. In these city-sized fattening pens, the cattle simply stand, eat and poo. The animals gorge on rich corn and soy—rather than on the grasses and other forage their four-chambered stomachs evolved to handle—and in turn produce an average of 150 pounds of dung per day. During the typical 14-month life of a feedlot steer, it will produce about 60,000 pounds of waste. With a full-grown animal yielding around 600 pounds of beef, that's 100 pounds of feces per pound of patty.

Cow dung, of course, is no new thing. But not too long ago, most of it was prized as fertilizer, carefully collected and spread on fields to boost crops. Now, thanks to feedlots and industrial farming, the feces is in one place and the fields are in another, a disconnect that turns fertilizer to waste.

So what to do? The first line of defense is containment, and the second is putting the stuff to good use. The feedlot industry already struggles with sewer systems, and comes up as often as not with manure lagoons—which are every bit as awful as they sound. Overflow from these lakes of fluid feces (mixed with urine and water to make it pumpable, pipeable and sprayable) is a major source of environmental contamination.

Fortunately, there are solutions. The first is as old as the problem: get manure back onto fields, where it can do good. Because nobody is likely to start shipping manure cross country anytime soon, that means a return to integrated farming, where crops and livestock are raised in close proximity. Spreading manure in its solid form (during drier seasons) will keep most of it from seeping out into groundwater and aquatic habitats. Or if liquid manure is what you've got, specialized equipment can be used to inject it into the soil, helping to prevent runoff. Using much simpler technology, manure can also be diverted to an anaerobic digester where naturally occurring bacteria turn it into methane.

Unfortunately, even if all these measures are taken, it won't be enough—there's just too much poop. According to a USDA study released in 2000, 73 counties in America have more manure than they have fields to spread it on. And besides, manure is not the only problem livestock produce. The bottom line is this: We eat too much meat—and the rest of the world is rapidly catching up. As someone whose birthday dinner for 15 years was flank steak, I know how hard it will be to break that habit. But if America doesn't wake up and smell the bull, we'll be up manure creek without a paddle.