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Danish City to Power Water Treatment Plant Using Sewage

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Every city produces sewage, but now, Aarhus, Denmark is hoping to prove that their waste doesn't have to be, well, wasted. As New Scientist reports, the Danish metropolis will become the first city to power its water system using energy harnessed from sewage and wastewater.

After undergoing a $3.2 million renovation, Aarhus’s Marselisborg Wastewater Treatment Plant is now capable of creating heat and electricity out of biogas. The waste is served up as a meal to bacteria kept in 100-degree "digesters," or large tanks. Byproduct gases like methane are then burned, generating more than 150 percent of the electricity required to power the plant. Any surplus electricity is either used to supply fresh water to the city of 200,000, or is sold back to the grid.

The concept of using human waste as an energy resource isn’t a new one: Last year a study from the United Nations University’s Institute for Water, Environment, and Health reported that biogas produced by all the world’s human poop could provide energy to up to 138 million homes. Aarhus is the first city to integrate this innovative idea into their water system, and now cities like Chicago, San Francisco, and Copenhagen are interested in following suit.

For Aarhus’s success to be recreated elsewhere, water plants need to be big enough to produce large amounts of biogas and the wastewater they use has to be the right makeup (too much water dilutes the energy content). Cities also need to have the funding to make the necessary infrastructure upgrades. Aarhus Water’s investment in their plant was pricey, but savings in maintenance and electricity sold to the grid are expected to make it up in five years.

[h/t New Scientist]

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All National Parks Are Offering Free Admission on April 21
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Looking for something to do this weekend that's both outdoorsy and free? To kick off National Park Week, you can visit any one of the National Park Service's more than 400 parks on April 21, 2018 for free.

While the majority of the NPS's parks are free year-round, they'll be waiving admission fees to the more than 100 parks that normally require an entrance fee. Which means that you can pay a visit to the Grand Canyon, Death Valley, Yosemite, or Yellowstone National Parks without reaching for your wallet. The timing couldn't be better, as many of the country's most popular parks will be increasing their entrance fees beginning in June.

The National Park Service, which celebrated its 100th birthday in 2016, maintains 417 designated NPS areas that span more than 84 million acres across every state, plus Washington, D.C., American Samoa, Guam, Puerto Rico, and the Virgin Islands.

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environment
How the Planet Has Changed Since the First Earth Day in 1970
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The first Earth Day in 1970 was celebrated with protests, nature walks, concerts, and other activities meant to spark interest and engagement in the planet's well-being. Since then, April 22 has been a day to reflect on our impact on the environment, on broad and individual scales. So just how much has the Earth changed since the first Earth Day 48 years ago? According to this video from the American Museum of Natural History, it's changed a lot, and not for the better.

The world's population has doubled since 1970, from 3.7 billion then to over 7 billion today. While there are more people consuming resources, more resources are also being consumed per person. On average, we're each burning 37 percent more fossil fuel than we were in 1970, eating 60 percent more meat, and taking 495 percent more plane trips. All that consumption adds up to 1.2 trillion tons of CO2 emitted in the past five decades, which contributed to ocean waters warming 1°F and sea levels rising more than 5 inches.

Those numbers look pretty grim, but it isn't all bad news: Humans have also made significant strides toward protecting the environment in that same period, including passing the Endangered Species Act, designating protected marine areas, and signing international agreements to reduce greenhouse gas emissions across the globe.

People are also more aware of what can be done on a personal level to reduce their carbon footprint. For tips on how to be greener this Earth Day, check out our list of eco-friendly habits.

[h/t American Museum of Natural History]

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