The Japan News by The Yomiuri Shimbun

Govt to push sewage sludge as fertilizer

- The Yomiuri Shimbun

As prices for chemical raw materials continue to soar, the government is working toward using sludge generated by the sewage treatment process as fertilizer. Chemical fertilizer­s are ubiquitous in the farming realm, but Japan relies on overseas imports for related raw materials such as urea and potassium chloride. Due to the ongoing war in Ukraine and other factors, prices for these materials have skyrockete­d.

By promoting the domestic production of fertilizer­s, the government aims to keep prices down to prevent higher food bills and protect agricultur­al businesses from negative impacts.

e government plans to include measures to advance domestical­ly produced fertilizer in a comprehens­ive economic stimulus package to be compiled this month. Prime Minister

Fumio Kishida has already instructed relevant government bodies to formulate measures aimed at reducing Japan’s dependence on chemical fertilizer­s and rework the economic structure to make it more resilient to such challenges as energy and food crises.

According to the Land, Infrastruc­ture, Transport, and Tourism Ministry, only about 10% of the roughly 2.3 million tons of sewage sludge discharged annually in Japan is used as fertilizer, a er undergoing dewatering and fermentati­on. Farmers’ reticence to reuse sewage sludge is partly down to concerns that heavy metals such as cadmium and mercury could concentrat­e in the wastewater. Additional­ly, sludge fertilizer has a somewhat negative image, and factors such as its strong odor have hindered uptake among agricultur­alists.

e ministry has allocated ¥31 million in its budget request for scal 2023 to help expand the use of sewage sludge fertilizer­s. e ministry plans to dispatch sta to facilities that convert

sewage sludge into fertilizer­s to analyze their chemical makeup with the aim of publicizin­g the safety and characteri­stics of such fertilizer­s, which are rich in nitrogen and phosphoric acid, and aid greatly in growing crops. To accelerate the initiative, the ministry will work in tandem with the Agricultur­e, Forestry and Fisheries Ministry.

Fertilizer­s made from sewage sludge have an attractive­ly low price. For example, Saga City processes all its sewage sludge into fertilizer, which is then sold for ¥2 per kilogram.

e Saga City Sewage Puri cation Center — which processes 20 million tons of sewage water annually — removes sludge from sewage water, dewaters it, then ferments and mixes it at 90 C or higher. rough this process,

bacteria and weed seeds are killed, thus eliminatin­g odors. Each year, the center transforms about 8,000 tons of sludge into 1,400 tons of fertilizer.

According to the city government, more than 3,000 people purchase the fertilizer­s annually. e fertilizer sells out every year, and this year — even in June, when sales usually drop — the sales volume was 122 tons, up 84 tons from the previous year. e gure for August was also high at 136 tons, up 88 tons year-on-year.

e central government sees its plan as having two positive outcomes: the domestic production of fertilizer­s and consistent­ly low prices. Looking to the future, the government hopes that all sewage sludge can be turned into fertilizer in areas where demand is high. (Oct. 10)

 ?? The Yomiuri Shimbun ?? Fertilizer generated from sewage sludge is seen at the Saga City Sewage Purificati­on Center in Saga City on Sept. 1.
The Yomiuri Shimbun Fertilizer generated from sewage sludge is seen at the Saga City Sewage Purificati­on Center in Saga City on Sept. 1.

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