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Worldwide, humans produce vast quantities of biosolids. In a single day, New York City alone makes 1200 tons, or about 50 truckloads. And the amount of biosolids is growing as populations expand around the planet.

The old solution was to dump them into the sea or a landfill. But more treatment plants and stricter regulations are prompting people to find clever ways to recycle the dried sludge. About 50 to 70 percent of it is now used, mostly to boost soil quality or fertilize crops. But the rest remains unused or stockpiled. In the United States, it’s estimated that nearly a third of the 7 to 8 million tons of biosolids produced each year still end up in landfills. As organic particles in the waste decompose, greenhouse gases such as carbon dioxide escape and can contribute to global warming.

And then there are bricks.

The world makes trillions of them each year. The soil it takes to make them is enough to fill 1,000 holes, each as big as a soccer field and nearly as deep as The Empire State Building is tall. And it takes a lot of energy, too.

Other researchers have tried mixing bricks with biosolids and other waste products. Dr. Mohajerani had experimented already with cigarette butts. So turning waste into a building material didn’t seem so far-fetched.

Over the course of half a decade, he and a team of researchers collected biosolids from two wastewater treatment plants in Melbourne and mixed them with soil to make hybrid bricks of varying proportions. They fired them for 10 hours, at nearly 2,000 degrees Fahrenheit, and cooled them, then compared them in tests to normal bricks.