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Second Helpings: Recycling Cairo's Food Waste

Scientific American
Second Helpings: Recycling Cairo's Food Waste
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Getting the Green Light: Zabaleen have innovative approaches to waste, including solar panels that are …

Forget about candy bars and potato chips--if current trends continue, the term "junk food" might have an entirely new meaning. In January, a report by the Institution of Mechanical Engineers found that of the four billion tons of food produced globally, approximately half becomes waste. This figure can be attributed to several factors, including stringent sell-by dates and the demand for cosmetically perfect produce. Instead of alleviating hunger, this food often ends up in landfills and produces methane, a potent greenhouse gas that contributes to global warming.

Food doesn't just become waste, waste also becomes food. The burning of trash produces dioxins; the toxic chemical compounds are environmental pollutants that can potentially be harmful to humans. In recent years, dioxin levels have led to food scares for everything from citrus to products containing eggs. In 2008, sales of buffalo mozzarella dropped by 40 percent and its import was banned in some countries following concerns regarding dioxin contamination. Campania, the region known for the production of the cheese, is also known for problems with illegal trash burning and dumping and the traces of dioxin found were believed to be linked to the trash.

One community in Cairo is doing its part to stop the junk-food cycle. For over seventy years, the Zabaleen have acted as Cairo's informal waste management providers. Every day, they collect 60 percent of Cairo's waste. The 8,000 tons of garbage are brought back to Moqattam, the area of Cairo where the Zabaleen reside. There, trash is sorted and managed and nearly 80 percent of all waste collected is recycled; that is four times the rate of formal solid waste management companies.

Organizations including the United Nations have recognized their contribution within the international community. But for the Zabaleen, it's not always easy being green. Despite campaigns and magazines that attempt to glamorize eco-friendly efforts, the Zabaleen have faced obstacles and stigma surrounding their work.

In 2003, three multinational companies were awarded solid waste management contracts in Egypt. The shift was met with criticism since many Zabaleen had to pay the companies in order to continue collecting garbage. The new system was also seen as less efficient; the multinational firms only recycled 20 percent of waste, with the remainder being burned or deposited in landfills.

The threat of the H1N1 virus in 2009 posed another challenge to the Zabaleen's waste collection system. In response to the global threat of swine flu, the Egyptian government culled all the country's pigs. In a decision the World Health Organization described as "a real mistake," practically overnight, approximately 400,000 pigs were gone.

The implications for the Zabaleen were twofold. For the predominantly Coptic Christian community, the pigs were an affordable source of protein. They were also an integral part of their complex recycling system, eating Cairo's organic waste. The measure also had repercussions for the city--with no pigs to feed, the Zabaleen no longer had any use for food waste. Rotting food began to accumulate on the streets, turning the pigless city into a pigsty and the government acknowledged the flaws in its decision.

The Zabaleen continue to collect and recycle garbage, investing in technology, tools, and information that can turn one man's trash into another man's treasure. Bottle tops are taken to an aluminum smelter while plastic bottles are sanitized and shredded before being sold to companies that reprocess the materials into polyester. Beyond being profitable micro-enterprises, these recycling techniques decrease the amount of trash that ends up in landfills and oceans.

The Zabaleen are using new methods to address Cairo's organic waste; some invested in goats to pick up the pieces following the culling of the pigs. While goats are happy to pig out on plants and paper, not all scraps suit their palate. Solar Cities has been installing biodigesters that work off food waste.

Instead of rotting in landfills, in controlled and closed settings like biodigesters, organic waste can be harnessed and converted into biogas, a clean and renewable energy. This can then, in turn, be used cook food--a way of using old food to make new food.

For biodigesters to generate biogas, bacteria breaks down organic matter including food scraps, plant material and livestock manure through anaerobic digestion. The digestion has three main stages. During the first phase, hydrolysis, biodegradable material decomposes into smaller molecules including sugars. Next, these molecules are converted into acids. In acetogenesis, acetogenic bacteria convert sugars into short-chain acids, mainly acetic acid, CO2 and H2. Finally, anaerobic bacteria use hydrogen and acetate to carry out methanogenesis. The acids are converted into methane, creating a biogas made up of around 60 percent methane and 40 percent carbon dioxide.

When the process is complete, the majority of what is produced is a slurry that also makes an excellent fertilizer. The remainder at the top is biogas, which can be used with any type of propane or natural gas stove. A hose runs from the biodigester to the stove, it just needs to be turned on and now you're cooking with biogas.

Along with the Zabaleen, other residents in Cairo and throughout Egypt are beginning to use biogas. In his book, Garbology: Our Dirty Love Affair with Trash, Edward Humes talks some serious trash regarding the legacy of garbage, "Each of our bodies may occupy only one cemetery plot when we're done with this world, but a single person's 102-ton trash legacy will require the equivalent of 1,100 graves. Much of that refuse will outlast any grave marker, pharaoh's pyramid or modern skyscraper: One of the few relics of our civilization guaranteed to be recognizable twenty thousand years from now is the potato chip bag."

Recycling waste and making biogas requires starting the day with a hearty meal. Ful medames is a filling fava bean dish that is part of a traditional Egyptian breakfast. Ful means "fava" while medames comes from a Coptic word for "buried." The name reflects the tradition of cooking the dish by burying a covered pot under hot coals.

These days, we can put a modern twist on cooking an ancient traditional dish. To begin, some meth is cooked up that would make Walter White any renewable energy advocate proud.

Served along with tea, eggs and bread, bioful medames provides fuel for the tummy and biofuel for the day.

BioFul Medames

2 Cups Dried Fava Beans, soaked overnight

1 Large Tomato, diced

1 Teaspoon Cumin Powder

1 Tablespoon Lemon Juice

1 Pinch Red Chili Powder

2 Tablespoons Olive Oil

Salt to taste

After soaking the fava beans over night, drain and rinse them. Add to a pot with enough fresh water so there is enough water to cover them by about 2 inches.

On top of your stove (biogas if you have it), bring favas to a boil then reduce to a simmer.

Add the tomato, garlic, cumin, and chili powder. Cook the beans for about 4 hours or until soft, adding water as necessary.

Mash the beans as much or as little as you'd like, mix in salt and lemon juice. Drizzle with olive oil.

Share with friends, family, biodigesters--don't let any go to waste!

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