Tokorozawa Kunugiyama Incinerator forestation and regulatory torrent, late 1990s to around 2002

Tokorozawa Kunugiyama Incinerator forestation and regulatory torrent, late 1990s to around 2002

In the forests of the valley, the chimneys of small incinerators lined the mountains and black smoke billowed in the air. The press later took this as a symbol of dioxin pollution, but actual measurements showed that Tokorozawa was not the only place where dioxin pollution was particularly bad. Nevertheless, the unrest among residents spread nationwide and flared up into opposition to the construction of a final disposal facility. Tokorozawa City, in the midst of the whirlwind, finally decided to subsidize and eliminate all incinerators in the city.

From a technological standpoint, exhaust gas purification was an unavoidable issue even for the small furnaces of the time. Wet scrubbers use water and catalysts to remove sulfur and other components, while particulate matter is collected by cyclones, electrostatic precipitators, and fabric-type bag filters. The combination of these methods was the dividing line between how to control "smoke" at the site.

The turning point in the system was the switch in the terminology of the permit standard from "five tons per day" to "two hundred kilometers per hour. Thereafter, small furnaces with a catalog capacity of 190 kilograms per hour became the mainstream in the permit-free zone, and they were supplied one after another by various companies. Low-priced simple furnaces disappeared and were replaced by models equipped with secondary combustion burners and exhaust gas purifiers. One of the reasons for this is that the Law Concerning Special Measures against Dioxins requires that furnaces with a capacity of 50 kilograms per hour or more become subject to notification. The market was lined with ultra-compact models that could burn less than 50 kilograms per hour, but they were not powerful enough for full-scale processing of demolition mixtures.

The reality of operation and processing is harsh. Furnace materials deteriorate each time the machine is stopped for ash removal because continuous feeding is not possible, and waste plastics with high calorific value cause incomplete combustion and clinker if the air supply does not keep pace with the furnace. As a countermeasure, dry distillation furnaces and gasification/combustion furnaces are introduced, in which combustible gas is separated by heating and then burned in a secondary stage. However, the structure becomes more complex, and the burden of pretreatment, operation and management, and construction costs jump.

Profitability was also shaky. It is not easy to maintain stable operation at all times with exhaust gas purification and secondary combustion equipment in place, and if the unit cost of treatment falls, profits will dwindle. The difference between the apparent capacity and the actual incineration capacity also put pressure on management.

Thus, the small furnaces that had sprung up in Tokorozawa's Kunugiyama were simultaneously subjected to two waves of technological and institutional change. The logic of the equipment, namely exhaust gas purification, and the logic of the system, namely permit units and notification thresholds. At the intersection, the smoke gradually thinned out, and at the same time, the economics of small-scale in-house disposal faded, and urban waste began to look for a new place to go.