Scientific American: Poop to Plastic?

When making a list of the most promising new sustainability innovations, sewage probably wouldn’t be the first topic that springs to mind. Let’s face it – beyond being the butt of jokes, what other good can come out of human waste? Well, one company thinks they’ve figured out how to use sewage to reduce humanity’s environmental impact and oil dependence.

Wastewater treatment plants could be a gold mine in the quest to replace the petroleum used every year to make plastic for packaging. energyNOW! correspondent Lee Patrick Sullivan got a whiff of how sewer sludge is being turned into sustainable plastic. Watch the full video.

You’ve probably never given a lot of thought to what happens to wastewater, but it’s a major environmental issue. Municipal water treatment plants nationwide process more than 150 million gallons of wastewater every day. When the treated water is released into a river or ocean, it leaves behind more than four million tons of sludge, mostly burned or trucked away to landfills. That’s a lot of waste, and it’s expensive, costing as much as $200 million annually.

That’s where Micromidas comes in. They’ve figured out how to convert sludge into a usable product. “Literally, we are brewing plastic,” said John Bissel, Micromidas CEO. “It’s very similar to brewing beer or anything else.” It’s been known for a while that a chemical in wastewater can be used to make plastic, but the challenge has always been extracting and converting it at a competitive price compared to the source of most of America’s plastic – oil.

The breakthrough lies in Micromidas’ proprietary process. The company takes sludge, renders it down to a liquid resembling chicken broth, and applies a cocktail of designer bacteria microbes. The chemical reactions that follow change the liquid’s composition into a thicker product, which is then run through an extruding machine, producing plastic.

If the idea catches on, it could mean big business. Nearly five percent of the oil consumed in America, about 300 million barrels a year, goes into making plastic products like shopping bags and water bottles. Combined with reducing costs for wastewater treatment and the impact of sludge being transported and buried at landfills, plastic from sewage makes sense. “Taking wastewater sludge and turning it into a bioplastic is pretty nice,” said Michael Donahue, Sacramento Water Treatment Plant. “It’s a pretty good idea.”

Even so, there’s still one hurdle to clear – the stigma of plastic from poop. But don’t worry; their product will never become water bottles. “Realistically, we’re looking for tertiary packaging applications,” said Bissel. Tertiary refers to third-level packaging, like the layer of plastic surrounding a DVD player, the rings surrounding packs of bottles, or the wrap that secures products on pallets at big box stores around the country.

Other bioplastics are already on the market, but they’re derived from plants and are generally more expensive than oil-based plastic. These products require land, fertilizer, and water. By comparison, Bissel says all his technology requires is a laboratory and ingredients unlikely to run out any time soon.

Micromidas’ product will hit markets next year, so we’ll soon find out if sustainable plastic stinks, or if it can come out smelling like roses.

Micromidas website

Related story:

Micromidas to test sludge-to-plastic tech: http://news.cnet.com/8301-11128_3-20006130-54.html

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