CHAPTER9
Seawater Desalination Plants: Heavy Coastal Industry
Thomas Hopner
9.1
Introduction
The global capacity of desalination plants, which is now in the range of 16 million m~ day-I,
is growing annually by a capacity of about 2 million m 3 day-I (Wangnick 1994). This
means an annual increase in about five of the large-type plants which are mainly situated at coasts. Desalination plants provide a basic need to population, industry and
agriculture. This seems sometimes to evoke the impression that desalination plants are
in all means environmentally compatible. Even in fundamental texts, environmental
aspects are often missing (e.g. Al-Gobaisi 1994, 1995; Awerbuch 1994). Papers on environmental impacts are in a minority and most of them come from the USA (Kipps 1991;
Herbranson and Suemoto 1993; Del Bene et al. 1994,) and papers showing a correspondingtitle are rare (e.g. Al-Azzaz et al. 1989;El Din et al. 1994, Mannaa 1994, Mickley 1995).
Anyone who looks for the keyword "desalination" in the otherwise very comprehensive
Coastal Zone Management Handbook (Clark 1996) will be surprised to find merely a
very little comment on desalination brine among other (suspected) impacts on seagrass
meadows. This is an excellent indicator of the fact that desalination plants are usually
left out of consideration. On one hand, the nature of desalination plants does not justify this; on the other, there is no reason that desalination plants must fear coastal management and environmental impact assessments (EIAs) more than power stations or
other coastal industrial works.
Because of the water scarcity of the Middle East countries and the rapid development of industry, cities and agriculture along the coast, a rapid increase in water consumption is expected (Awerbuch 1994). Even if strategies of water re-use become more
effective, the additional demand cannot be fulfilled by conventional and regenerative
water supply (Magid 1995). Replacement of conventional sources and provision of additional demand can be expected only from seawater desalination (Al-Sofi 1993). So a
steep increase in the number of coastal desalination plants is expected. No wonder that
the "desalination market breaks all records" (Wangnick 1994). In the case of the Arabian Gulf, this exploding development is located around an enclosed sea. This merits
special attention. In addition, it is concentrated along the most sensitive coastal zones.
Regarding fuel and power consumption, use of additives, area consumption and
othereffects, desalination plants are heavy industry with waste production and chemical emissions into the air and the water. Price and Robinson (1993) list desalination
plants on a level with other emittents and among "major environmental pressures of
the Gulf". The marine environment may be affected in the first instance by the brine
discharged, by the additives or their conversion products and by the corrosion products. The emission load and the environmental impact are highly site specific, depend-
Seawater Desalination Plants: Heavy Coastal Industry
Thomas Hopner
9.1
Introduction
The global capacity of desalination plants, which is now in the range of 16 million m~ day-I,
is growing annually by a capacity of about 2 million m 3 day-I (Wangnick 1994). This
means an annual increase in about five of the large-type plants which are mainly situated at coasts. Desalination plants provide a basic need to population, industry and
agriculture. This seems sometimes to evoke the impression that desalination plants are
in all means environmentally compatible. Even in fundamental texts, environmental
aspects are often missing (e.g. Al-Gobaisi 1994, 1995; Awerbuch 1994). Papers on environmental impacts are in a minority and most of them come from the USA (Kipps 1991;
Herbranson and Suemoto 1993; Del Bene et al. 1994,) and papers showing a correspondingtitle are rare (e.g. Al-Azzaz et al. 1989;El Din et al. 1994, Mannaa 1994, Mickley 1995).
Anyone who looks for the keyword "desalination" in the otherwise very comprehensive
Coastal Zone Management Handbook (Clark 1996) will be surprised to find merely a
very little comment on desalination brine among other (suspected) impacts on seagrass
meadows. This is an excellent indicator of the fact that desalination plants are usually
left out of consideration. On one hand, the nature of desalination plants does not justify this; on the other, there is no reason that desalination plants must fear coastal management and environmental impact assessments (EIAs) more than power stations or
other coastal industrial works.
Because of the water scarcity of the Middle East countries and the rapid development of industry, cities and agriculture along the coast, a rapid increase in water consumption is expected (Awerbuch 1994). Even if strategies of water re-use become more
effective, the additional demand cannot be fulfilled by conventional and regenerative
water supply (Magid 1995). Replacement of conventional sources and provision of additional demand can be expected only from seawater desalination (Al-Sofi 1993). So a
steep increase in the number of coastal desalination plants is expected. No wonder that
the "desalination market breaks all records" (Wangnick 1994). In the case of the Arabian Gulf, this exploding development is located around an enclosed sea. This merits
special attention. In addition, it is concentrated along the most sensitive coastal zones.
Regarding fuel and power consumption, use of additives, area consumption and
othereffects, desalination plants are heavy industry with waste production and chemical emissions into the air and the water. Price and Robinson (1993) list desalination
plants on a level with other emittents and among "major environmental pressures of
the Gulf". The marine environment may be affected in the first instance by the brine
discharged, by the additives or their conversion products and by the corrosion products. The emission load and the environmental impact are highly site specific, depend-