ers (starting from April 2001) and home personal computers (starting from October 2003) are obliged to recycle such computers by The Law for Promotion of Effective Utilization of Resources. The target rates set for the promotion of recycling are 50% or over for the desk top computers (machine itself), 20% or over for notebook (laptop) personal computers, 55% or over for cathode-ray tube displays and 55% or over for liquid crystal displays (Figure 2-30 and 2-31).

The recycling rate of manufacturers in Year 2008 were, 77.3% for desk top computers (machine itself), 54.1% for notebook (laptop) personal computers, 75.4% for cathode-ray tube displays and 70.8% for liquid crystal displays, all categories exceeded the legal targets.

Personal computers are collected in other ways than shown above, such as direct collection by the wastes disposer from the user or through the leasing/rental company, sales shop or sales company, or by the collection/disposal of municipal entities.

### J. Small-size secondary battery (nickel-cadmium battery, nickel-hydride battery, lithium battery, sealed lead acid battery)

For small-size secondary batteries, scarce resources such as $ \left[\mathrm{Ni}\right] $ nickel, $ \left[\mathrm{Cd}\right] $ cadmium, $ \left[\mathrm{Co}\right] $ cobalt and

(Pb) lead are used, recycling of small-sized secondary batteries has more effect than primary batteries, because the recycling of the latter is limited to only the metal casing.

The manufacturers of small-sized secondary batteries are obliged to recycle such batteries by The Law for Promotion of Effective Utilization of Resources. The target rates set for the promotion of recycling: are 60% or over for nickel-cadmium batteries, 55% or over for nickel-hydride batteries, 30% or over for lithium batteries and 50% or over for sealed lead acid batteries.

The recycling situation of small-sized secondary batteries (including the ones used for cellular phones and PHS – Personal Handy-phone System) in Year 2008 was, 886 tons recycled with a 73.3% recycling rate for nickel-cadmium batteries, 202 tons recycled with a 76.6% recycling rate for nickel-hydride batteries, 297 tons recycled with a 63.3% recycling rate for lithium batteries and 1,729 tons recycled with a 50.0% recycling rate for sealed lead acid batteries, all categories achieved the legal targets.

### K. Sewage sludge

With the spread of sewage coverage, polluted sludge

## 2 Municipal wastes

## (1) Municipal wastes (garbage)

### A. Changes of the generated amount of garbage

The total amount of garbage generated and the daily amount of garbage generated per person dropped slightly after 1979, the year of the second oil crisis, but from around 1985 there has been a sharp increase which leveled off in 1990; from 2001 until the present there has been a decreasing trend. (Figure 2-33)

(sewage sludge) generated from sewage works increases year by year. (Figure 2-32). In Year 2007, about 78.40 million tons of sewage sludge was generated (a decrease of about 260,000 tons from the previous year achieved by converting into concentrated sludge), and this accounted for almost 20% of the generated total industrial wastes, the amount of sewage sludge brought into final disposal sites was 400,000 tons (a decrease of 40,000 tons from the previous year), approaches for decreasing weight have been promoted by various means such as intermediate processing including dehydration and incineration and reclamation. The effective usage rate of sewage sludge in Year 2007 was 77% when converted into specific dry weight.

While sewage sludge is mostly recycled for construction materials such as cement raw materials, its utilization form has expanded in a variety of ways, e.g., it has been used for green farming focusing on the nature of sewage sludge with its wealth of organic substances. As well as using it as a fertilizer in the form of compost for green farming, the effort to collect phosphorus contained in sewage sludge to use as a raw material for fertilizers has been advanced. Regarding efforts to use sewage sludge for energy, digestion gases such as methane gas which is generated in the process of anaerobic digestion are used for digestion gas power generation, sewage sludge is used as a solid fuel and waste heat generated from burned sewage sludge is used for various purposes.

1.72 million tons of sewage sludge, converted by specific dry weight, was reclaimed as cement material (870,000 tons), building material (510,000 tons) such as bricks or blocks, green farming (330,000 tons) such as fertilizer and solid fuel (10,000 tons).

Figure 2-32 Changes to sewage sludge by year

### B. Changes of the garbage processing methods

When considering the changes of garbage processing methods, the ratio of direct recycling and recycling after intermediate processing in fiscal 2008 was 19.0%. The amount of garbage directly sent for final disposal has been steadily decreasing, with a ratio 1.8% in fiscal 2008. (Figure 2-34).