198
everywhere and diversely influences the operation of the Earth system.
Much experience is available regarding the
acidification of small masses of fresh water, primarily lakes from Europe from the second half of
the twentieth century. This change may block the
operation of fresh water ecosystems to a degree
that natural biocoenoses could be destroyed. Selfpurification capacity of dead waters decreases
drastically. Similar processes occurred in many
Scandinavian lakes in the 1960s and 1970s due to
the deposition of sulphur dioxide arriving from
German and British industrial districts.
Acid pollutants damage human health as well
both directly and indirectly. They cause respiratory problems when breathed for a long time
(depending on the concentration of the pollution
as well).
Decrease of pH in three media (air, water, soil)
could induce or intensify corrosion effects in the
environment. Especially air pollution has damaging effects on the elements of the built environment and with damaging national monuments
great financial and cultural losses may arise.
Atmospheric chemical processes contribute to
the development of smog (Sect. 4.1.2.3). Los
Angeles smog occurs even in lands distant from
habited areas reducing the distance of sight and
damaging vegetation. London smog causes environmental damage most frequently in the vicinity
of the cities and industrial areas of China.
Further increase in the intensity of acidification in the environment could be hindered and
even its reduction is possible. The most important
tasks are summarised as follows.
The majority of the sulphur content of coal is
removed during the cleaning procedure already
in or near the mines. (Cleaning means the removal
of sand, clay and other valueless material—raw
sulphur and sulphur containing minerals among
them.) Unfortunately the waste obtained in this
was has a high sulphur content posing further
environmental issues but these are mostly local
effects. Washing out pyrite alone reduces the sulphur content of coal by 8–33%. Removal of
organic sulphur, however, requires chemical
treatment. Sulphur removal with the method
adopted by the Environmental Protection Agency
of the USA can be realised with 52% efficiency
and less than half costs compared to the traditional washing methods.
Several technologies are known to reduce SO 2
and NO x emission from firing fossil fuel. Only the
oldest one is mentioned here, limestone injection
procedure, the chemical basis of which is that
CaCO 3 reacts with sulphur dioxide and nitrogen
oxide forming sulphate (gypsum) with two water
molecules and calcium nitrate. With this method
sulphur dioxide and nitrogen oxide emissions can
be reduced by 60–80% and 50% respectively.
The application of this procedure is economically feasible. Even the obtained gypsum can be
used for commercial purposes.
Desulphurization after firing (performed generally in the chimney) is also based on a similar
chemical reaction. CaCO 3 or CaO is sprayed into
the gas mixture released during firing and thus
sulphur dioxide is absorbed chemically. The
obtained mass has a high water content, it has to
be stored and treated after dehydration. Despite
this after care, this is the most widespread method
as it requires relatively small investment which,
however, still amount to 15–20% of the construction costs of the power plant. Efficiency of the
technology is very good, around 90–95% of sulphur dioxide can be absorbed with the so-called
wet procedure.
Primarily nitrogen oxides are the sources of
acid formation in exhaust gas of vehicles. NO x
emission of petrol-fuelled vehicles can be
reduced effectively applying catalytic converters
that absorb other pollutants as well.
The simplest and most economical way of
preventing and reducing acidification is saving
energy. The most effective solution could be in
the long term to apply renewable energy resources
in increasing ratio.
Efforts can be made to remediate damage
caused already by acidification in the environment. Although these are symptomatic treatments, they could be necessary of acidification is
too strong. Adding lime to the soil and surface
water (primarily lakes) is a proven method.
Material containing CaCO 3 (lime slurry, limestone grist, loess, etc.) has been used for increasing soil pH for a long time while their application
4 Changes on Earth as a Result of Interaction Between the Society and Nature
everywhere and diversely influences the operation of the Earth system.
Much experience is available regarding the
acidification of small masses of fresh water, primarily lakes from Europe from the second half of
the twentieth century. This change may block the
operation of fresh water ecosystems to a degree
that natural biocoenoses could be destroyed. Selfpurification capacity of dead waters decreases
drastically. Similar processes occurred in many
Scandinavian lakes in the 1960s and 1970s due to
the deposition of sulphur dioxide arriving from
German and British industrial districts.
Acid pollutants damage human health as well
both directly and indirectly. They cause respiratory problems when breathed for a long time
(depending on the concentration of the pollution
as well).
Decrease of pH in three media (air, water, soil)
could induce or intensify corrosion effects in the
environment. Especially air pollution has damaging effects on the elements of the built environment and with damaging national monuments
great financial and cultural losses may arise.
Atmospheric chemical processes contribute to
the development of smog (Sect. 4.1.2.3). Los
Angeles smog occurs even in lands distant from
habited areas reducing the distance of sight and
damaging vegetation. London smog causes environmental damage most frequently in the vicinity
of the cities and industrial areas of China.
Further increase in the intensity of acidification in the environment could be hindered and
even its reduction is possible. The most important
tasks are summarised as follows.
The majority of the sulphur content of coal is
removed during the cleaning procedure already
in or near the mines. (Cleaning means the removal
of sand, clay and other valueless material—raw
sulphur and sulphur containing minerals among
them.) Unfortunately the waste obtained in this
was has a high sulphur content posing further
environmental issues but these are mostly local
effects. Washing out pyrite alone reduces the sulphur content of coal by 8–33%. Removal of
organic sulphur, however, requires chemical
treatment. Sulphur removal with the method
adopted by the Environmental Protection Agency
of the USA can be realised with 52% efficiency
and less than half costs compared to the traditional washing methods.
Several technologies are known to reduce SO 2
and NO x emission from firing fossil fuel. Only the
oldest one is mentioned here, limestone injection
procedure, the chemical basis of which is that
CaCO 3 reacts with sulphur dioxide and nitrogen
oxide forming sulphate (gypsum) with two water
molecules and calcium nitrate. With this method
sulphur dioxide and nitrogen oxide emissions can
be reduced by 60–80% and 50% respectively.
The application of this procedure is economically feasible. Even the obtained gypsum can be
used for commercial purposes.
Desulphurization after firing (performed generally in the chimney) is also based on a similar
chemical reaction. CaCO 3 or CaO is sprayed into
the gas mixture released during firing and thus
sulphur dioxide is absorbed chemically. The
obtained mass has a high water content, it has to
be stored and treated after dehydration. Despite
this after care, this is the most widespread method
as it requires relatively small investment which,
however, still amount to 15–20% of the construction costs of the power plant. Efficiency of the
technology is very good, around 90–95% of sulphur dioxide can be absorbed with the so-called
wet procedure.
Primarily nitrogen oxides are the sources of
acid formation in exhaust gas of vehicles. NO x
emission of petrol-fuelled vehicles can be
reduced effectively applying catalytic converters
that absorb other pollutants as well.
The simplest and most economical way of
preventing and reducing acidification is saving
energy. The most effective solution could be in
the long term to apply renewable energy resources
in increasing ratio.
Efforts can be made to remediate damage
caused already by acidification in the environment. Although these are symptomatic treatments, they could be necessary of acidification is
too strong. Adding lime to the soil and surface
water (primarily lakes) is a proven method.
Material containing CaCO 3 (lime slurry, limestone grist, loess, etc.) has been used for increasing soil pH for a long time while their application
4 Changes on Earth as a Result of Interaction Between the Society and Nature