“Bistro Sewage” programs are being promoted in many parts of the Japanese nation that use fertilisers made from sludge, a byproduct of sewage treatment, to grow vegetables.
The project, in its fifth year, is now under way in 16 prefectures. The land ministry and other organisations decided in April to dub such vegetables as junkan sodachi (cyclically nurtured).
At the nation’s largest sewage technology fair, held at the Tokyo Big Sight exhibition center in August, Gesuido Koho Platform, an industry and government academic organisation working to raise public awareness about sewage, handed visitors to its booth junkan sodachi cucumbers, corn and other vegetables raised in Nagano and Aomori prefectures.
“Many visitors from local governments showed a willingness to promote the project,” a GKP official said.
The sludge, treated water and carbon dioxide produced in the process of sewage treatment at sewage disposal plants, are full of three main macronutrients: nitrogen, phosphorus and potassium. The project converts sludge into fertiliser, utilises treated water for rice production and laver culture and uses heat and carbon dioxide for greenhouse cultivation of vegetables.
“Resources from sewage make nutrient-rich fertiliser and water and we have received reports that they help increase yields and produce sweeter fruit,” said an official at the Ministry of Land, Infrastructure, Transport and Tourism.
Fertiliser from sewage treatment causes no health problems as the levels of harmful substances, including arsenic, mercury and lead, are only one-sixth to one-30th the maximum permissible amounts set by the fertiliser regulation law, according to the ministry.
One obstacle for the project is the public image of sewage. Farmers have voiced concerns that consumers may shun vegetables produced with the use of fertiliser from sewage treatment.
Source: japantimes.com.jp
