Table 1 shows the present state of industrial waste generation and recycling ratios in Japan.
Thirty percent of discharged waste disappears by intermediate treatment and 40% are reused
owing io the technical developments in waste management and utilization. The intermediate
treatment methods are incineration, dehydration, and melting. Incineration, which realizes
volume reduction and sanitary resolution against putrescible substances, is becoming more
widely used. Sludges, which have high water contents, are reduced in volume by dehydration
as well as incineration. The melting method has been developed mainly for the treatment of
sewage sludge for utilization purposes. However, rubbish from construction works are
scarcely reduced by intermediate
treatment. Slag and dust are
reused positively, but sludge and
destruction rubbish generated in
large quantities have not yet been
well utilized. Thirty percent of
waste generated, except for reused
and reduced waste, are disposed of
at disposal sites.
Waste landfill sites in Japan are
classified into three categories:
Least Controlled Landfill Site for
non-hazardous wastes, Controlled
Landfill Site for municipal solid
waste (MSW) under the
incinerated and/or organic refuse
conditions and non-hazardous
wastes, and Strictly Controlled
Landfill Site for hazardous wastes.
The limited numbers of disposal
sites are expected to be filled up
with waste materials in the near
future and many local
governments are struggling to
secure new disposal sites, while the prefectural government has been engaging a large-scale reclamation nearby Tokyo and
Osaka Bays for disposal of waste and surplus materials. illegal dumping and improper
treatment of waste, especially sludge and destruction rubbishes from construction works are
recent serious social problems.
It is important to grasp the waste characteristics and the generating conditions. The former
includes whether the waste material is inorganic or organic, whether it contains toxic and
harmful substances or not. The latter means when, where, and how waste materials are
generated.