disposal, the government aimed to both stabilize waste in a sanitary manner and reduce the volume of waste.

## (3) The post-high economic growth period

As its economy grew, Japan faced problems such as increases in the amounts of waste generated by business activities and the amount of water pollution caused by illegally dumped waste oil. During the so-called Pollution Diet session in 1970, the Public Cleansing Law was revised and renamed the Waste Management and Public Cleansing Law (Waste Management Law). This law defined the differences between municipal solid waste and industrial waste and, while holding municipal governments responsible for the disposal of municipal solid

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# The history of composting

Since ancient times, Japanese farmers had been using waste as fertilizer, either incorporating kitchen garbage into the soil through plowing, for example, or distributing incineration ash over the fields. Even in the post-war era, urban waste was still used as fertilizer in rural farming villages until the Showa 30s (1955-1964) because only small amounts of plastic and metal were included in the waste in those days.

However, as more rapid changes occurred, such as the outgrowth of cities, the widespread use of chemical fertilizers, and the aging and exhaustion of farming villages, urban waste management reached a major turning point.

In Japan, a mountainous country with little spare land for landfill use and a climate often characterized by high temperature and high humidity, incineration became more common in the Showa 40s (1965-1974) for the sake of sanitation and to reduce the volume of waste. There was also a move by municipal governments towards the machine composting of kitchen garbage (a process also known as fast composting) so that the compost produced could again be used by rural farmers, as before. Many such composting facilities were built and operated by municipal governments in the Showa 40s to 50s (1965-1984).

However, composting projects involving urban waste, especially household waste, encountered several problems, as described below. As a result, no users could be found for the compost produced and it had to be eventually disposed of in landfills, forcing municipal governments to withdraw from those projects.

(i) Foreign substances

As living standards rapidly improved in the Showa 30s to 40s (1955-1974), consumers started to buy a wider variety of goods. This resulted in the inclusion of greater amounts of foreign substances in waste, such as glass from glass bottles, metals from cans, and plastics from containers and other sundry items. Since the idea of sorting wastes was not common in those days, compost made from waste inevitably contained foreign substances. Farmers noticed that a field fertilized with compost made from such waste glittered in the sunlight. As a result, farmers began to avoid using compost made from waste.

(ii) Odors

Since Japan has a hot, humid climate, kitchen garbage easily goes rotten. For this reason, composting requires that appropriate measures be taken to minimize odors. Since insufficient measures to control odors were taken at composting facilities during this era, local people often regarded these facilities as an annoyance.

(iii) Farmers' labor

The Showa 30s to 40s (1955-1974) was a period in which young workers moved from rural to urban areas, leaving behind an aging population of farmers. Although the farmers knew that organic fertilizer was needed for sustainable agriculture, they found it increasingly difficult to apply organic fertilizer because of the heavy workload required. Older farmers preferred to use chemical fertilizer because it was then easier to distribute only those substances actually needed.

There has been little promotion of composting since then, except by certain municipalities in rural farming regions, but composting again began attracting attention in recent years as a means of biomass use. In 2000, the Food Waste Recycling Law was instituted and recycling targets were set. In 2007, this law was amended, mainly to define exceptions in those cases where “a recycling loop” is created by all parties concerned. Supported by these frameworks, new efforts towards composting have now been launched in many regions. While solving the problems described in (i) and (ii), above, these projects are also attempting to address the problem described in (iii) by establishing a face-to-face relationship with farmers in order to encourage collaboration.