Pigs Aid Wastewater Research In 'Big Poop Project'

Tons upon tons of pig waste are at the center of a research project in California aimed at making wastewater treatment technology more compact and affordable.

Scientist with the J. Craig Venter Institute in La Jolla are working with hogs in this new and ambitious effort.

“The project starts with pig waste — tons of it — produced by 21 swine kept in chain-link pens at the Escondido campus. The pigs pack on a few pounds a day, and produce several pounds of waste daily that is collected in the name of research. Water polluted with the waste is cleaned and purified, primarily with technology that has been around for decades,” The San Diego Union-Tribune reported.

“The focus of the ‘big poop project’ is to make that technology— the BioElectrochemical Sanitation Technology, or BEST — more compact and affordable in poor and rural parts of the world, said Venter scientist Orianna Bretschger,” the report said.

The researchers are using pig waste as a substitute for human waste during this phase of their research since it is less dangerous and gets produced more quickly.

They want to “shrink the BEST technology to the size of a container trailer, and get the cost down to roughly $500 per trailer, which could serve a community of about 2,500,” the report said.

Bretschger weighed in, per the Union-Tribune: “The pigs put on 250 pounds in four months and are constantly growing, eating and pooping.”

Bretschger’s technology uses microbial fuel cells (MFCs), according to the institute. “Her team has been working to understand the microbial mechanisms and natural microbial communities that are associated with MFC wastewater treatment; and apply these findings to practical applications. These efforts have already led to the successful treatment of municipal wastewater and sewage sludge at the 100-gallon per-day scale, enough to support a small household,” the institute said.

Here’s how the technology works, per the report:

The waste is dried out, then shoveled and placed in a drain, while a slurry of corn and grain feed is hosed into the drain. The waste drains into an underground sump that holds 1,000 gallons of the smelly mixture. The wastewater is then siphoned from the sump into a feeder bin that refines the waste, before it streams out to the heart of the system where microbial fuel cells remove the bacteria. The power created in the chemical process of removing the bacteria is enough to fire up a light bulb — one per fuel cell. Additional treatment systems, similar to those used in swimming pools, make the water safe enough to drink.

The researchers are motivated by an awareness that sanitation services are still hard to come by in many parts of the world. “There are 2.5 billion people who still do not use an improved sanitation facility and a little over 1 billion practising open defecation,” according to the United Nations.

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