(Measures against radioactive substances in sewage facilities)

Radioactive substances released by the accident at Fukushima Daiichi Nuclear Plant of Tokyo Electric Power Company (TEPCO) were accumulated on land surface of residential areas, and particularly through the combined sewage systems (that collect both rainwater and soil water), such substances flowed into the sewage treatment plants when it rained. They were condensed in sludge in the process of treatment, and were detected in sewage sludge or in its incinerated ash. Thus, the use of sludge for construction material such as raw stock for cement or for agricultural products as compost had to be suspended.

Since it was not assumed under the current act that radioactive substances would spread out of the premises of the nuclear plant, the Nuclear Disaster Countermeasure Office headed by the prime minister made public “views on temporary treatment of byproducts of water and sewage treatment plants from which radioactive substances have been detected” on June 2011 and later in December of 2011, the Ministry of the Environment issued “the guidelines regarding wastes”. Then, on January 12012, “the special act to deal with environmental contamination due to radioactive substances emitted from the nuclear power plant accident caused by the Great East Japan Earthquake (the special act to deal with contamination of radioactive substances)” featuring two main measures against “decontamination” and against “polluted wastes” took full effect.

MLIT held a “study council regarding measures against radioactive substances in sewage facilities” jointly with the Japan Sewage Works Association (a public interest incorporated association) in June 2011,

discussed such matters as clarification of behavior of radioactive substance in sewage treatment plants and prediction of future developments, effects on the surrounding environment, effective information provision and control methods including measures for volume reduction of sludge, and issued an intermediate report summarizing the current findings on November 25, 2011.

Prefectures	Cumulative quantities (t)
Iwate	Approx. 590
Miyagi	Approx. 22,000
Akita	—
Yamagata	—
Fukushima	Approx. 30,000
Ibaraki	Approx. 3,000
Tochigi	Approx. 2,600
Gunma	Approx. 5,300
Saitama	Approx. 9,500
Chiba	Approx. 1,100
Tokyo	Approx. 3,300
Kanagawa	Approx. 19,000
Yamanashi	Approx. 240
Nagano	Approx. 1,000
Niigata	—
Shizuoka	—
Total	Approx. 97,000
Source: MLIT

Under the special act to deal with contamination of radioactive substances, wastes that contain over 8,000 becquerel of radioactive cesium and are so designated by the national government will be treated as designated wastes. Under the basic policy set forth, (1) out of the designated wastes, sludge generated in public sewage facilities and river-basin sewage facilities will be treated by the Ministry of the Environment in cooperation with MLIT, (2) treatment of designated wastes will be undertaken by prefectures and cities from which such wastes are emitted, and (3) in order to promote recycling wastes, as long as their safety is confirmed, utilization of recycled products (cement, recycled crushed stone, etc.) out of the wastes should be promoted to the extent possible. Proper treatment is expected to be implemented under this act.