Recycling Human Waste into Energy

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Harnessing the Power of Poo

Custommade, May 26, 2015. Image credit: OpenClipartVectors

Repurposing Waste Worldwide

In an effort to protect our world for future generations, recycling has become more and more common on both a local and global level. In addition to paper and plastic, people are experimenting with new and diverse recycling processes. Less conventional recycling innovations have enabled all types of communities to reach their goals of becoming more sustainable.

We already know landfill waste—which was once thought to both take up space and emit harmful greenhouse gases—can be recycled in a variety of ways, from creating energy to building materials.

Brace yourselves for the next big thing in renewable energy: human waste.

Yes, in the name of extreme resourcefulness, recycling human waste is the ultimate, efficient way to use what naturally occurs. Though the topic may sound taboo, even Bill Gates is in on the big poo movement (and was recently seen drinking potable water converted out of human excrement). So how is human waste recycled and reused, and is it really worth the trouble?

Poo Energy: From Flush to Fuel

The practice of utilizing human excrement as an energy source dates back to the 16th century. Today, as countries and cities strive to meet new sustainable energy requirements, recycling human waste into energy is gaining popularity.

In most developed nations, organic waste is deposited in landfill sites, typically located just outside major cities. After it is treated, most landfill waste leaves behind a nasty sewage sludge that is difficult to dispose of. This byproduct emits dangerous greenhouse gases such as carbon dioxide and methane, which are harmful to the environment.

However, communities across the globe have adopted a process called Anaerobic Digestion (AD) to utilize this leftover waste. Anaerobic Digestion breaks down the sludge to produce valuable biogas and nutrient-rich digestate. 

Biogas is a mixture of gasses that can be produced from any raw material such as agricultural waste, plant material, manure, and municipal sewage. Specifically, biogas contains a mixture of carbon dioxide (CO2) and methane that results in bio-methane, a high British thermal unit (BTU) methane that is completely renewable and provides a low-carbon alternative fuel. Biogas can be used as fuel directly or fed through a unit with combined heat and power to generate electricity.

Although biogas is what we look for in regards to producing energy, digestate produced by the AD process is quite valuable. Because it is packed with fully fermented nutrients, digestate is an excellent organic fertilizer and is incredibly environmentally friendly.

Meet the Omni Processor

The Omni Processor is basically a revved up steam engine that safely burns waste at an extremely high temperature. The Omni Processor system burns at such a high temp that it meets all the U.S. emissions standards and doesn’t emit a foul odor.

Using a steam engine system, the Omni Processor can produce more than enough energy necessary to burn the next batch of waste, which makes the machine self powering. Even better, it produces extra energy.

Processing Poo Into Water and Power

While it’s easy to grimace over poo water and even poo power, excrement is a viable source of clean drinking water and energy. “The processor wouldn’t just keep human waste out of the drinking water; it would turn waste into a commodity with real value in the marketplace,” Gates says. “It’s the ultimate example of that old expression: One man’s trash is another man’s treasure.”

Poo-Fueled Energy

Although the Omni Processor is on a mission to turn human waste into a practical and sustainable resource for developing communities, there are quite a few countries that have been taking advantage of their community’s collective output for years.

Some countries, including Sweden and Germany, have been using anaerobic digestion for years. Local sewage plants sell their energy back to the national grid network in both countries. In fact, the process is so popular and profitable that some plants have started to produce purpose-grown crops in order to create more waste to feed the anaerobic digestion units. These crops usually include grasses and maize, which have a high methane yield. The practice of growing their own crops to burn enables sewage plants to control the full-cycle process of “growing” high methane, from crop to energy production.

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