First the Egyptians culled their pig herd. That hurt pig farmers - they lost their pig-related income, receiving very little compensation. That was only the beginning; they lost an important source of revenue, so they've been getting poorer over time.
Next normal people started to suffer, because garbage that had been pig food became food for vermin and bacteria. Of course, when that report came out, the city wasn't even saturated with garbage; the city was starting to fill up with garbage and it was beginning to be a problem.Garbage was still being produced faster than it was disappearing, so it was clear the problem would only get worse.
Now the New York Times reports that Egyptians have a fullblown garbage crisis. Having gotten rid of their waste processors (pigs!) and not having replaced them, they are now up to their ears in edible garbage. There's rotting food everywhere.
In 1870, almost 140 years ago (a time when America's waste handling was as primitive as in Cairo), Joseph Harris wrote:
NY Times), there'll be more uneaten garbage. That leftover garbage will become food for vermin, unless humans pay to haul it off.
Of course, the category of food that pigs will eat, that other farm animals won't eat, includes things like feces and garbage - the kind of things we don't want to have around, because it spreads disease. Here's the Cambridge World History of Food on the phenomenon:
The Garbage Pig
The garbage pig was essentially "presented" with its food intake, either at a fixed site or within a circumscribed area. In eastern Asia, where centuries-old deforestation and high population densities did not favor mast feeding, pig raising was long ago oriented toward consuming wastes. Important in China and Korea, at one time, was the privy pig, kept to process human excrement into flesh for human consumption. Four young pigs could derive sustenance from the waste of a family of four humans, which provided the animals with approximately 2 kilograms of human excreta and 220 grams of garbage each day (Miller 1990). In Asia, food provided by humans rather than by foraging promoted sedentary habits that, in turn, led to the evolution of several breeds with a swayback and a dishlike face. But even the miniaturized types of Asian pigs have big appetites and large litters.
The garbage pig could also be found in ancient civilizations outside of eastern Asia. Robert L. Miller (l990) has brilliantly reconstructed the scavenging role of the pig in dynastic Egypt. But, thus far, similar evidence is lacking for ancient Greece and Rome. In Europe, the garbage pig goes back to the Middle Ages but seems not to have been common until the fifteenth century, when the so-called Celtic pig, with white skin and pendant ears, emerged. Families fattened their pigs primarily on food scraps, and when winter neared, the animals were butchered. Their meat was cured and their fat rendered to make lard for cooking and especially for food preservation. Thus, the human diet was diversified during the cold months.
This form of pig keeping expanded as forest clearing advanced and the scale of food processing increased. Grist and oil mills generated large quantities of waste materials that could be consumed by pigs, as could the garbage from institutions like hospitals and convents. Before proper sewage disposal was implemented, many cities had swine populations to serve as ambulatory sanitation services. In medieval Paris, so many pigs were locally available for slaughter that pork was the cheapest meat. The monks of Saint Anthony – the patron saint of swineherds – were given special rights to keep pigs within the city walls. In New York City, pigs wandered the alleyways well into the nineteenth century. Naples was the last large European city to use pigs for sanitation. Neapolitan families each had a pig tethered near their dwellings to consume garbage and excrement.
One consequence of pigs being such unfussy eaters is that it will pretty much always pay to keep a certain number of pigs by feeding them edible waste. The reason is that the alternative is paying to haul away what could be pig feed. That's true whether the food is whey, DDGS or Grade A Cairo garbage.
Which brings me to an important point: in James McWilliams's recent book, he argues that environmentalists should stop eating meat. His point is that all livestock raising (even grassfed beef), results in environmental problems.
I disagree: obviously pigs can (as in Egypt pre-cull) do a useful job and produce meat at the same time. Without pigs, you actually have to spend more money (and burn more fossil fuels) to deal with the waste. According to this line of thinking, environmentalists like McWilliams should exhort consumers to eat garbage-fed pigs. Not free-range pigs, not cornfed pigs - but just 100% garbage fed pigs.