Newsletter and Technical Publications
of Alternative Technologies for Freshwater Augumentation
America and The Caribbean>
PART C - CASE STUDIES
5.5 Recycling of Industrial Effluent in Jamaica
Recycling of industrial effluent is now being practiced by several
industries to reduce the demands on freshwater resources and to reduce
pollution of the environment. The recycling of industrial effluent was
spearheaded by the bauxite/alumina companies operating in Jamaica, and
they are the largest recyclers at the present time. The bauxite/alumina
industry produces a waste product known locally as "red mud,"
which consists of over 70% water, enriched with caustic soda and organics.
The waste is thickened to 28% solids and sprayed on a sloping drying bed
in a layer 8 to 10 cm thick. The liquid fraction is collected at the toe
of the drying bed and is channeled via pipelines to a sealed holding pond.
Pumps move the effluent from the holding pond back to the plant via a
pipeline where it is recycled through the process. The system consists of:
- Deep mud thickeners (conical vessels).
- High pressure pumps and pipelines to the drying beds.
- Drying beds, sealed to prevent infiltration of the effluent to the
- An effluent holding pond, also sealed to prevent infiltration of the
effluent to the groundwater.
- Recycling pumps and pipelines to the plant.
This technology is described in Part B, Chapter 3, "Wastewater
Treatment Technologies and Reuse."
Extent of Use
This technology is used at four bauxite/alumina plants in Jamaica.
Efforts are under way to encourage other industries to follow suit and
recycle process and waste waters.
Operation and Maintenance
Problems encountered in the operation and maintenance of the system
include mechanical breakdowns of the pumps; ruptures of the pipelines,
necessitating a total shutdown of the system; and heavy rains that
overload the system, resulting in spillage to the environment. The
bauxite/alumina companies, all being multinational corporations, have few
problems in replacing parts or equipment, and generally maintain a large
equipment inventory. Each bauxite company has a preventive maintenance
program, which also reduces downtime.
The skills needed to operate the system are varied. Overall direction is
provided by the senior production engineer. However, skill levels range
from laborers, who turn valves on and off, to chemical engineers, who
manage the system.
Level of Involvement
The private sector and the government are involved in the implementation
of this technology and in certain facets of the operation. The
bauxite/alumina companies provide the capital and the engineering designs,
and construct the systems. The government, through several specialized
agencies, reviews the engineering designs and grant the permits for
construction to proceed. Part of the permitting process involves the
conduct of an environmental impact assessment. After the permit is
granted, construction of the systems is monitored by the government to
ensure that design specifications are adhered to. The relationship between
the public and private sectors is cooperative and complementary.
Initial capital costs vary and are dependent on the volume of work to be
done in preparing the site, resettling persons living on or near the site,
and making the necessary changes in the plant infrastructure. The minimum
investment to date in any one system has been $50 million. Operation and
maintenance costs are not available as this information is confidential
and proprietary to the bauxite companies.
Effectiveness of the Technology
The system, as designed and operated, is very effective in reducing
contamination of groundwater resources. Because it is completely sealed,
it does not allow infiltration of liquid effluents, and recycling this
fraction reduces the risk of contamination of groundwater resources from
effluent disposal. The use of this system has reduced groundwater
contamination in one area by 44% since 1985, as reported by the Water
Resources Authority. Despite some disadvantages, due predominantly to the
large land areas consumed by the drying beds and holding ponds, the
application of this technology, in all cases, has proved to be
The technology is suitable for application in areas where large tracts
of non-agricultural land--i.e., in excess of 200 ha--are available. In
addition, the land should not be steeply sloped, and a supply of
nondispersive clay should be available in close proximity to provide
impermeable material for sealing the bottom and sides of the drying beds
and holding ponds. The technology can be, and is being, adapted for other
- Use of this technology reduces the rate of freshwater withdrawal from
aquifers; savings of 4 to 5 Mm3/year of freshwater have been
- Recycling of process water reduces the volume of caustic soda
solution needed, as the caustic soda is recycled with the effluent.
- The use of energy, to pump freshwater from depths greater than 100 m,
is reduced, thereby saving on the import bill (foreign exchange) for
- Contamination of groundwater is reduced by removing and recycling the
liquid fraction of the waste stream that is a risk to groundwater
quality; likewise, the retention of a high percentage of the caustic
soda in the thickened mud (solid fraction) and in the recycled process
water makes this contaminant less available for migration to the
- The bauxite/alumina companies are better able to meet the ISO 9000
and ISO 14000 certifications and thereby gain a competitive advantage in
- The decreased input costs reduce operational costs, resulting in
higher profit margins for the companies and more tax revenue for the
government, increasing both the level of investment in the country and
- Better environmental management by the corporate sector results in
fewer governmental regulations; other multinational corporations are
likely to see such conditions as favorable and invest in Jamaica.
- The incidence of water pollution is reduced, increasing the
availability of freshwater for domestic and irrigation uses and reducing
the cost of water to citizens; this increases the standard of living and
- There is an increased risk of pollution of surface water resources,
due to the large size of the holding ponds and the possibility of
- Technical problems within the plants may be experienced, reducing the
level of production and affecting the volume of recycled effluent;
hence, storage volumes can increase to the point where overflows occur,
affecting the environment.
- The quality of effluent may vary significantly, affecting the degree
of treatment provided by this technology and thus, potentially, the
level of production at the plants.
- The technology is capital-intensive, not labor-intensive, and
provides few spin-offs for nearby communities where unemployment may be
- As a result of the land-intensive nature of this technology, its
implementation may result in the relocation of residents, disrupting
their lives and causing great inconvenience; for farmers and other small
businesspeople, a new location may be less suitable and/or create the
need to seek other employment.
- Agricultural land may be lost in some cases, decreasing food
Further Development of the Technology
This technology can be more effective if overflows and spills from the
system are managed better. Design parameters, especially relating to the
effects of rainfall/runoff and the rate at which the plants can accept
recycled effluent to prevent negative environmental impacts, need to be
Basil P. Fernandez, Hydrogeologist and Managing
Director, Water Resources Authority, Hope Gardens, Post Office Box 91,
Kingston 7, Jamaica. Tel. (809)927-1878. Fax (809)977-0179.
Fernandez, Basil 1991. Caustic Contamination of Karstic Limestone
Aquifers in Two Areas of Jamaica. In :Proceedings of the Third Conference
on Hydrology, Ecology, Monitoring, and Management of Groundwater in Karst
Terranes. National Ground Water Association. Dublin, Ohio, U.S.A.