Environmental Engineering Reference
In-Depth Information
TABLE 8.8
Examples of Sea Disposal of Various Kinds of Waste
Volume of Waste Disposal (million m
3
)
Municipal
Waste
Industrial
Waste
Soils from
Construction Site
Dredged
Materials
Site
Area (ha)
Total
Off-Amagasaki
113.0
2
3.9
5.8
4.1
16.0
Off-Izumi-Otsu
203.0
4
9.4
12.7
4.8
31.0
Off-Kobe
88.0
5
7.3
3.0
15.0
Osaka Port
95.0
5
6.3
2.8
14.0
Total
499.0
16
26.9
24.3
8.9
76.0
land disposal of waste, controlled and regulated discharge of municipal and industrial
wastes into the sea remains as the option of last resort. When such a need arises, waste
disposal sites in the sea must be constructed to meet safety and health protection require-
ments. Isolation of the waste from contact and dispersion into the sea is a prime require-
ment. In some countries, artiicial islands have been constructed for the principal purpose
of emplacing secure disposal facilities. These island-based disposal sites must conform to
all the regulations that attend land-based disposal sites, with the strict requirement for
monitoring and control to ensure no escape of leachate into the sea.
In some other cases, actual disposal sites have been constructed in the sea using seawalls
as containment walls to prevent escape of waste and leachates into the surrounding sea.
Typical examples are seen in Tokyo Bay and Osaka Bay. Table 8.8 give a short summary
of the waste disposal sites and materials disposed in four sites in Osaka Bay, constructed
under the auspices of the Phoenix Project. The objectives of the project not only focused
on the proper and safe disposal-discharge of the wastes in Osaka Bay, but also on pres-
ervation of the coastal marine ecosystem, and development of the regional area through
environmentally acceptable reclamation of shoreline.
8.8 Coastal Erosion
Coastal erosion is a problem that has confronted coastal communities for a long time. Some
will argue that this is a natural phenomenon and that the “problem” arises when the human
population occupies the coastal regions and imposes various requirements on the coast, such
as building structures, infrastructures, wharfs, etc. Alteration of the coastline is a natural
phenomenon, and erosion is a major factor in the alteration process. This alteration process
becomes a problem because of the requirements and expectations imposed by the human pop-
ulation. Erosion arises not only from the aggressive action of waves and currents, but also from
diminished sediment recharge from streams and rivers feeding into the sea. Flood control
dams and other river restoration projects can curtail the low of suspended particulates and
sediments. Without this sediment recharge and with erosive forces acting on the coastal plains,
erosion becomes a considerable issue. To counter the erosive forces and to prevent beach ero-
sion, armoring of the beach with revetments and seawalls is a procedure that has been adopted
by many coastal regions. Figure 8.20 shows an erosive beach on the coast of Japan facing the
Paciic Ocean. A huge number of concrete blocks have been installed to protect the coastline
and to gather sand. Figure 8.21 shows soil dumping as a countermeasure for erosion. The
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