Environmental Engineering Reference
In-Depth Information
of wastewater pollutants by modifying the various process steps utilized by indus-
tries, thus not only simplifying treatment needs but also saving raw materials,
making the industrial operation more economic. The experience thus far in DCs
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indicates three things:
1. The NEnPAs/industry ministries have not established sufficient regulatory
mechanics to enforce use of CP; hence, use of CP to date has been limited
because of the required upfront investment in reorienting the industrial pro-
cessing methods, and the time required (3 years or more) before these costs
can be recovered, together with the pressures prevailing in most DCs for
realizing immediate financial gains, and the continuing lack of regulatory
enforcement for controlling pollution discharge requirements.
2. The best success in use of CP in the DCs has been in industries that are
branches of international companies that can afford the upfront investments
and, moreover, have the goal of increasing overall long-term profits.
3. The best approach is for the DC to gain support from the country's indus-
trial/trade associations to encourage industries to use CP
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.
Industrial Estates
Usually, the most practical approach for controlling industrial pollution in DCs
is the use of industrial estates where polluting industries are required to locate, as
illustrated by the Industrial Estates Authority of Thailand. These estates offer eco-
nomic advantages in furnishing a central treatment plant for managing pollutants
treatable by the central plant, and with the estate administering the permit system
including performance monitoring and enforcement. The administrative costs of
proper control of pollutants with these estates are vastly simpler and inexpensive
compared to the situation when the industries are in separate locations.
Marine Disposal
As noted in the section on “Urban Sewerage and Excreta Management,” when
disposal to unconfined offshore ocean waters is feasible, the costs for treat-
ment/disposal can be greatly reduced because of open ocean's virtually unlimited
supply of oxygen for stabilizing BOD, and because the ocean waters can receive
many types of inorganic compounds without damage which cannot be accepted by
confined receiving waters. Selenium, for example, is a serious toxic substance for
receiving waters used for irrigation but of no special significance when discharged
to the open seas.
Figure 4.15 illustrates this capability of the open seas for accepting many
types of inorganic compounds. One example of this advantage of open ocean dis-
posal is the World Bank's project for metropolitan sewerage planning at Abidjan
(Ivory Coast), where such disposal is vastly less costly and much more practical
than a previous proposal, which attempted to require in-house treatment by the
many industries in the metropolitan region
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. Another is the recommendation
