Mercury Speciation of MSWI Flue Gas on Pilot
and Industrial Scales
J . WANG, Z. XIAO, and o. LINDQVIST
An on-line system has been applied to measure mercury (Hg) speciation from a pilot combustion
simulator and from an industrial scale Municipal Solid Waste Incineration (MSWi) plant in Goteborg,
southwest Sweden. Under simulated waste incineration conditions, 60-80% Hg was found in its
oxidized form Hg(Ii). At the MSWI plant, equipped with a modern flue gas cleaning system, Hg
at concentrations about 10-15 pg m . .1 was emitted to the atmosphere, of which 15-20% was Hg(II).
1
I ntrod uction
Mercury is a highly toxic non-essential element with no known biological
function (Carty and Malone 1979). From the 1950S to the early 1970S, Hg
poisoning events were mostly reported as an acute local problem. Since then, our
understanding of the emission, transport and deposition of mercury in the
environment has improved, especially in the last 10 years. The importance of
mercury cycling in the atmospheric pool has been established, and Hg pollution
has been described today as a regional and a chronic problem. The notion of
mercury as a global pollutant has been recognized worldwide, and an elevated Hg
concentration in freshwater fish is a current problem in many countries
(Lindqvist et al. 1991; Lindqvist 1994).
Waste incineration and coal combustion are two major artificial sources of
mercury emission into the atmosphere. Flue gases contain mercury in different
physical and chemical forms, dependent on the concentrations of trace gases
such as S02 and HCI, and on combustion conditions. The speciation and
association of Hg to different ligands regulate the toxicity, transport pathways
and residence time in different compartments of the ecosystem. The need to
develop and apply a suitable method to measure industrial emission from
different types of combustion processes has been emphasized since the first
international Hg conference in 1990, and speciation information is still badly
needed in modelling work describing Hg cycling in the environment and its final
fate (Rodhe 1996).
Liquid solutions and solid absorbents have been used for selective collection of
different Hg species from flue gases (Bergstrom 1986; Metzger and Braun 1987;
Bloom et al. 1993; Larjava 1993). Recently, an on-line method for measuring both
elemental and total mercury in flue gas has been developed in our laboratory,
and applied to study Hg speciation in flue gas {Lindqvist and Schager 1990; Wang
Environmental Science
Mercury Contaminated Sites (ed. by R. Ebinghaus et al.)
cD Springer· Verlag Berlin Heidelberg 1999
and Industrial Scales
J . WANG, Z. XIAO, and o. LINDQVIST
An on-line system has been applied to measure mercury (Hg) speciation from a pilot combustion
simulator and from an industrial scale Municipal Solid Waste Incineration (MSWi) plant in Goteborg,
southwest Sweden. Under simulated waste incineration conditions, 60-80% Hg was found in its
oxidized form Hg(Ii). At the MSWI plant, equipped with a modern flue gas cleaning system, Hg
at concentrations about 10-15 pg m . .1 was emitted to the atmosphere, of which 15-20% was Hg(II).
1
I ntrod uction
Mercury is a highly toxic non-essential element with no known biological
function (Carty and Malone 1979). From the 1950S to the early 1970S, Hg
poisoning events were mostly reported as an acute local problem. Since then, our
understanding of the emission, transport and deposition of mercury in the
environment has improved, especially in the last 10 years. The importance of
mercury cycling in the atmospheric pool has been established, and Hg pollution
has been described today as a regional and a chronic problem. The notion of
mercury as a global pollutant has been recognized worldwide, and an elevated Hg
concentration in freshwater fish is a current problem in many countries
(Lindqvist et al. 1991; Lindqvist 1994).
Waste incineration and coal combustion are two major artificial sources of
mercury emission into the atmosphere. Flue gases contain mercury in different
physical and chemical forms, dependent on the concentrations of trace gases
such as S02 and HCI, and on combustion conditions. The speciation and
association of Hg to different ligands regulate the toxicity, transport pathways
and residence time in different compartments of the ecosystem. The need to
develop and apply a suitable method to measure industrial emission from
different types of combustion processes has been emphasized since the first
international Hg conference in 1990, and speciation information is still badly
needed in modelling work describing Hg cycling in the environment and its final
fate (Rodhe 1996).
Liquid solutions and solid absorbents have been used for selective collection of
different Hg species from flue gases (Bergstrom 1986; Metzger and Braun 1987;
Bloom et al. 1993; Larjava 1993). Recently, an on-line method for measuring both
elemental and total mercury in flue gas has been developed in our laboratory,
and applied to study Hg speciation in flue gas {Lindqvist and Schager 1990; Wang
Environmental Science
Mercury Contaminated Sites (ed. by R. Ebinghaus et al.)
cD Springer· Verlag Berlin Heidelberg 1999