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Scientists Are Transforming Garbage And Sewage Into Electricity

In Sweden and California, scientists are testing new ways to turn the waste me make into relatively clean energy.

by Rebekah Marcarelli
Nov 13 2013, 4:22pm

Landfills are overcrowded, and Europe and the US contribute to 32 percent of global greenhouse gas emissions. Together, these two problems could destroy the world, but scientists in America and Sweden are hoping to stop these trends by turning garbage and sewage into electricity.

This ideas might sound crazy (it is crazy), but Sweden has been burning trash to create electricity since the 1980s. According to Hans Wradhe, the head of the Swedish Environmental Protection Agency’s Waste and Chemical Section, Swedish politicians have always supported the idea. “I think the Swedish politicians saw two great advantages: a way to stop landfilling of waste, and a way to get cheap energy to district heating plants,” Hans said via email.

Because of these practices, Sweden cut carbon emissions by nine percent between 1990 and 2006, exceeding goals set by the Kyoto Protocol according to the Guardian. However, Sweden has burnt so much trash in recent years, they’re running out of garbage to burn and have started importing trash from other countries, such as Norway. A report by Sweden’s Waste Refinery reported that Sweden imported 174,600 tons of trash in 2012. Researchers have predicted waste importation will increase to 1.5 million tons by 2015 and to 2.5 million by 2020.

The idea of burning garbage for energy — without causing a great deal of air pollution — sounds like a dream come true, but even Hans admitted the process needs improvement: “Incineration of waste is not very complicated, but there is a need for advanced cleaning devices for the emissions from the plants, in order to reduce emissions of dioxins and other harmful substances.” (Dioxins are a group of chemicals that have a number of health issues associated with them including immune system damage, reproductive and developmental problems, and even cancer.)

Other scientists believe Sweden’s practices encourage wastefulness. “From an environmental point of view, it’s a huge problem,” Lars Haltbrekken, the chairman of the Friends of the Earth environmental group, told the New York Times. “There is pressure to produce more and more waste, as long as there is this overcapacity.”

Despite the controversy surrounding Sweden’s energy solutions, researchers at the University of California, Santa Cruz are following Sweden’s lead and looking to waste to solve America’s carbon emission problems. With a team of researchers, associate professor of chemistry Yat Li has created a system that combines sunlight and wastewater to create hydrogen gas. (Wastewater is any water that's quality has been compromised, such as sewage.) Yat's system combines a microbial fuel cell with a photoelectrochemical cell, a type of solar cell, to harness electricity from the bacteria that feeds on wastewater's organic compounds, such as feces in sewage. The electricity harvested from the feasting bacteria is then used to help the solar cells in a water-splitting process that creates hydrogen and oxygen.

“While producing hydrogen by splitting water is an environmentally clean method, clean water is also an important human resource,” Yat said. “It would be ideal if we [could] use wastewater to produce hydrogen fuel. This motivated us to explore a sustainable strategy to simultaneously address wastewater treatment and recovery of energy in wastewater for hydrogen generation.”

The team noticed that as the device worked, the water that was black from rancid waste gradually became clearer. The amount of organic compounds declined as quickly as 67 percent in 48 hours. The bacteria could keep fueling the process of creating hydrogen gas as long as there was crap to eat, and there is certainly no shortage of shit in this country.

“The device will eventually be tested on site at the wastewater treatment plant,” Yat said. “We pictured that one day the microbial cell component will be integrated with the pipelines of wastewater reclamation plant for the continuous wastewater feeding, the photoelectrochemical part will be setup at the open space to harvest sunlight, and the hybrid device will produce hydrogen in a cost-effective and sustainable way.”

The device is not going to be ready for commercial use in the near future, but for now it will be tested in a nearby California treatment plant.

"Fortunately, the Golden State is blessed with abundant sunlight that can be used for the field test," Yat said in a statement on UCSC's website.

Burning garbage and collecting energy from feces-eating bacteria are not the cleanest forms of energy, but they could help reduce waste and the carbon emissions that cause global warming. The real solution is to cut down waste and emissions altogether, but since that's unlikely to happen, we might as well put our crap to good use.

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