convert them back into resources. It also provides that the rates of concrete blocks, wood products used in construction, and asphalt and concrete blocks recycled into resources will be increased to 95% by 2010.

To enable the recycling and making into resources of mixed construction waste, it is necessary to make them into products with stable properties and qualities. Technologies to sort such mixed construction waste involve sorting it by means of a sieve composed of a combination of rotary gears, removing oils attached on their surfaces with water, washing gravels and sand with water, which is crushed into recycled washed sand. The remaining silt and clay is dehydrated and dried and the material is then burned into recycled artificial aggregate.

## e) Recycling food waste

Food waste is the residues derived from animals or plants leftover during the processes of production, distribution, and consumption. Specifically they are processing residues produced in the food production process, unsold and disposed food products, food leftover after consumption, and cooking garbage. The food waste produced by the food production industry is relatively easy to recycle because it is easier to acquire the quantity of waste required for recycling and because the composition of a food waste is uniform. Such waste is made into compost or fertilizers or oils or fats are extracted from them. As a result, 78% of the food waste produced in the food production industry is recycled. Food waste produced during distribution and at restaurants is also made into compost or fertilizers or oils or fats are extracted from them. As a result, 24% of them are recycled.

Composting technology involves putting food waste into a rotary-kiln fermentation tank and rotating it for two or three days while

supplying air to accelerate fermentation. The fermentation tank heats to nearly $ 60^{\circ} $ C because sugars and cellulose (fibers) in the food waste is oxidative-decomposed by microorganisms. Pathogenic bacteria and eggs of parasitic worms are killed so that sanitary compost is produced.

Technology for producing eco-feeds from food waste involves collecting separated food residues suitable for making livestock feed and putting them into a heating and drying process, a fermentation process (drying, liquefying, etc.), a dehydration process by means of deep-frying and depressurizing (a tempura process), or a liquefaction process for making feed, in order to produce livestock feed. (Fig. 2-37)

Recently technology to make kitchen garbage or wood waste (residues in the agricultural process) into resources, such as fuels, by carbonizing, liquefying, and distilling has been put into practical use. (Fig. 2-38)

Fig. 2-38 Food and wood waste recycling project

Source: Kansai Saishigen Network Co., Ltd

Fig. 2-37 Composting facilities

Source: JFE Environmental Solutions Corporation

## f) Recycling paper

In recent years used paper has been used in the paper-manufacturing industry at record-breaking rates. The quantity of used paper used in 2005 was about 18.59 million tons. The major area of use for used paper is board papers such as cardboards. In that area the ratio of used paper as materials has reached 90%. On the other hand, in the area of paper in paper manufacturing, the ratio of used paper as a material is less than 40%. For newspaper or sanitary paper products, the ratio has already reached more than 50%. While