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'Sewer Assets': Japan's Use of Sewage Sludge as Fertilizer Leads to 'Rich-Tasting Foods'

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There's a new taste sensation cropping up nationwide, and it might not be what you expect: foods grown using sewage sludge and treated wastewater.

New technologies are springing up for increasing the production of tomatoes, as well as heightening the deliciousness of nori (edible seaweed). And the Japanese government, aiming to export waste treatment technology and its application to agriculture, is dubbing the previously incongruous combination of sewage and gastronomy "sewer bistro."

The Aichi Prefectural Toyo River Sanitation Center -- which is responsible for sewage treatment serving four cities in the eastern part of the prefecture, including Toyohashi -- has on its premises something that appears to be quite out of place: a 500 square meter agricultural greenhouse, filled with a crop of plump tomatoes.

At first, the operation appears to be that of regular hydroponic cultivation. In fact, however, carbon dioxide resulting from an electricity generation process involving gas that has originated from sewage sludge is being blown onto the tomato seedlings through greenhouse ducts -- with increased concentrations of carbon dioxide around the seedlings stimulating the process of photosynthesis.

In addition, the seedlings are introduced to treated sewage that includes elements such as phosphorous. The first experiment of its kind anywhere in the world, this process has resulted in crop yields that are around 30 percent higher than normal.

"They were very rich in flavor. They were delicious," commented Aichi Gov. Hideaki Omura after sampling the tomatoes.

Toyohashi University of Technology professor Hiroyuki Daimon, 48, who has been conducting substantiative experiments on the process since last year, indicated confidence in the project. "The complex technology increases the existential value of the wastewater treatment plants," he noted.

There are, additionally, numerous entrepreneurial examples already existing in this regard.