Present illegal dumping site in Teshima of trigger for recycling society #2
2015/06/18Our last article reported current treatment at the illegal dumping site in Teshima Island. This time, we would like to report the treatment process of the wastes such as shredder residues, polluted sludge, slag and polluted soil transported from Teshima at the intermediate treatment facility in Naoshima Island called the Information Center for Energy and Environmental Education.
The background to treatment of wastes at the facility in Naoshima is as follows.
In August 1999, Kagawa prefecture offered proposals for Naoshima intermediate treatment plan.
In March 2000, Naoshima town announced to accept the proposal.
On 6 June 2000, Teshima residents reconciled with Kagawa prefecture regarding the environmental pollution dispute.
Then, the governor of Kagawa Prefecture at the time apologized to the Teshima residents for having permitted to accept the wastes. (In fact, the former governor had permitted to bring in industrial wastes to the island with ignoring the islanders’ intention and taking traders’ side.)
According to Mr. Kenji Goto, General Manager at Kagawa Naoshima JA office and Teshima KS office of Kubota Environmental Service Co., Ltd., the concepts of Teshima Waste Treatment Project are as follows;
1. To recycle and utilize all the materials including slag and fly ash produced by the intermediate treatment as resources.
2. To disclose information thoroughly.
3. To concern environment and safety.
More than 60,000 tons of wastes transported from Teshima are processed a year with Kubota’s technologies and facilities combined at the Information Center for Energy and Environmental Education, which operates at full capacity with 300-330 of average number of working days a year. The treatment of wastes from Teshima has to be completed by the end of business year 2016.
The facility is fully recycling oriented, where the by-products such as fly ash and slag produced in the melting process as well as wastewater from plants and rainwater are recycled thoroughly.
The wastes transported from Toshima are melted in a rotating surface melting furnace after being crashed and sorted by various kinds of pre-treatment equipment such as crashers and magnetic separators. Combustible materials attached on the surface of ferrous materials and rocks are incinerated in a rotary kiln furnace separately.
Kubota’s rotating surface melting furnace is central to the intermediate treatment facility. This melting furnace has a unique melting method of revolving the furnace itself in the form of a mortar to melt wastes evenly. Dioxins are completely decomposed by treatments at a high temperature of about 1,300℃. The treatment capacity is 100 tons per day
The furnace takes around 170 liters of oil to treat a ton of wastes from Toshima, which consumes less oil than ash melting due to its contained combustible materials. After flowing down from the center of the furnace, the melted wastes turned into granulated slag by rapid quench.
In the process of intermediate treatment of the wastes from Toshima, by-products including 60% of slag, 4% of fly ash, 3% of copper containing material and 1 % of aluminum containing material are produced and fully recycled.
Slag is crashed by slag crashers and valuable metals such as aluminum and copper are recovered by separators. After being checked its safety and quality, all the crashed slag is used for aggregates for concrete in construction works in Kagawa Prefecture.
Molten fly ash, which contains salt by 70%, zinc by 10%, lead by 5%, copper by 0.5%, is dechlorinated to recover valuable metals at Mitsubishi Material’s Naoshima Smelter and Refinary.
Melted metals obtained by incineration and melting contain copper by 30% and silver by 0.03%, which are sold to Mitsubishi Material Corp. by bidding. The copper content rate of 30% is surprisingly high considering current general composition of melted metals. Having been treated quite roughly without recovering valuable materials thoroughly before being shredded, the shredded dusts illegally dumped at Toshima might have higher copper content. At the same time, higher salts content in ash fly could be caused by disposal of harness as a shredded dust.
It costs JPY 3-3.5 billion a year to treat wastewater, to excavate at Teshima, to transport by sea and to operate the intermediate treatment facility. As mentioned before, it is realized how much it costs to treat wastes appropriately. The brochure of Teshima Waste Treatment Project made by Kagawa prefecture says as follows;
“The Seto Inland Sea – with over hundred large and small islands with intricate shorelines, is a place of magnificent scenic beauty. Illegal dumping cases of industrial wastes happened tragically at Teshima island on this beautiful Seto Inland sea and this symbolizes Japan’s typical “economy-first, others-second, society”. This case, eventually, induced the society to focus on “wastes problem” and led our country to create an environment-friendly “Recycling-Oriented Society”. The problem of Teshim let new effort for “Recycling-Oriented Society”, in which emitted wastes are recycled and utilized as resources, as well as controlling the amount of waste. Non-recycling wastes are to be treated properly with the goal of becoming environment-friendly. Environmental remediation at Teshima and wastes treatment and its recycling project (without any final landfilling of by-products such as fly ash and slag) at Naoshima, have already started to achieve our “Recycling-Oriented Society”.
After the illegal dumping case at Teshima, numerous laws relating to environment and recycling have been developed and a recycling-oriented society has been formed in Japan. But, could Japan have formed a recycling-oriented society in a real sense?
The export of miscellaneous scraps to China from Japan increased drastically after 2000. Something like debris was exported to China in bulk as if they were escaped from strengthened Japan’s environmental and recycling regulations. Trades using a loophole of the Japan’s Waste Disposal and Public Cleaning law have continued, which permits scraps containing even hazardous materials to be exported if those scraps are evaluated as valuable. Would it be an overstatement to say that Japan is partly to blame for the Chinese environmental problems caused by improper recycling?
To sustain a recycling-oriented society in the true sense, it is necessary that generators, intermediate processors and resources-recycling business operators work together. From the perspective of economic rationality, it’s true that most of the waste treatments in Japan cost more. Then, allowing wastes to be exported abroad would be fraudulent. Lessons from Teshima case would be wasted completely.
People involved in recycling should ask themselves their attitudes toward recycling seeing the reality of Teshima. The future of Fukushima appears to be the same as the past Teshima. Decadences of the island, the town and the hometown for some people were caused by prioritizing economic issues. Something can be learnt from the current situation of Teshima to consider the future of Fukushima.
[Edited By O.Sasaki]