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Minamata Online Season
Mercury Flow in the Wastes Stream of China
Qingru WU
Tsinghua University
Oct 15, 2020
Air Hg emission trend and cross-media effect
2
Atm
osp
her
ic H
g e
mis
sion
s (
t)
Atmospheric Hg emissions have
shown a downward trend in China.
Improved air Hg emission control led to
the increase of Hg burden in the waste.
ULE: Ultra-low emission
Wu et al., ES&T, 2016; Liu et al., ES&T, 2019 Wen et al., JHM, 2020
ULENon-ULE
75%
87%
0
200
400
600
800
P50 =
0.16 mg/kg
0
100
200
300
400
P50 =
0.33 mg/kg
Hg content of wastes (fly ash)
Non-ULE ULE
PC
Boiler
SCRDust
collector WFGD
ULE retrofit
Fly ash Emission removal
How much of Hg in solid wastes is re-emitted?
3Wu et al., ES&T,2015
Hg would be reemitted to air or
released to water/soil during the
disposal of those waste/byproduct
from air pollution control devices.
Research scope of this study
4
To examine the Hg sources and fate in China
To examine the flow of mercury within and among 8 sectors (31 subsectors)
Fuel
consumption
Coal-fired power plants
Incineration and interment
Municipal solid wastes incinerationCoal-fired industrial boilers
Residential coal combustion Biomass combustion
Other coal combustion Interment
Natural gas combustion
Production activities using Hg
Mercuric chloride catalyst productionOil refining
Vinyl chloride monomer (VCM)
productionOil combustion
Building
materials
production
Iron and steel smelting Thermometer production
Sphygmomanometer productionCement production
Fluorescent lamp production
Nonferrous
metal smelting
Copper smelting Battery production
Lead smelting Dental amalgam production
Zinc smelting
Use of Hg-added products
Use of thermometer
Industrial gold smelting Use of sphygmomanometer
Artisanal and small-scale gold mining Use of fluorescent lamp
Aluminum smelting Use of battery
Hg recovery Hg production from recyclable resources Primary Hg ore mining Primary Hg ore mining
Conceptual framework of mercury flow analysis
5Hui et al., ES&T, 2017
Hg input (Tier 1) and distribution (Tier 2)
6
Hg input Activity level Hg input factor
Raw materialSample
number
Raw coal 494
Zinc concentrate 381
Lead concentrate 198
Copper concentrate 207
Gold concentrate 26
Limestone 167
Iron concentrate 73
Mercury is inputted embedded in raw
materials or as pure Hg.
National concentrates sampling sites Number of samples
CoalAir
AmmoniaPC Boiler
SCR
ESP/FF
FGD
Stack
Limestone
Bottom Ash Fly Ash Gypsum
Exhausted Flue GasEconomizer
APH
Waste
water
RηSCR+ESP
ηFGD
𝒅𝒇𝒃𝒐𝒕𝒕𝒐𝒎 𝒂𝒔𝒉 = 1 − 𝑅 𝒅𝒇𝒇𝒍𝒚 𝒂𝒔𝒉 = 𝑅 × 1 − 𝜂𝑆𝐶𝑅+𝐸𝑆𝑃𝒅𝒇𝒘𝒂𝒔𝒕𝒆 𝒘𝒂𝒕𝒆𝒓 = 𝑅 × 1 − 𝜂𝑆𝐶𝑅+𝐸𝑆𝑃 × 𝜂𝐹𝐺𝐷 × 𝑎
𝒅𝒇𝒈𝒚𝒑𝒔𝒖𝒎 = 𝑅 × 1 − 𝜂𝑆𝐶𝑅+𝐸𝑆𝑃 × 𝜂𝐹𝐺𝐷 × (1 − 𝑎)
𝒅𝒇𝒇𝒍𝒖𝒆 𝒈𝒂𝒔 = 𝑅 × 1 − 𝜂𝑆𝐶𝑅+𝐸𝑆𝑃 × (1 − 𝜂𝐹𝐺𝐷)
R released rate of PC boiler;𝜼𝑺𝑪𝑹+𝑬𝑺𝑷mercury removal efficiency of SCR and
ESP;𝜼𝑭𝑮𝑫 mercury removal efficiency
of FGD; a the proportion of mercury to
waster waste water
Hg distribution factor are determined by the Hg
removal efficiency of air pollution control devices,
which are obtained from field measurements.
Tier 3: Wastes & byproducts
• How wastes were disposed?
• How was Hg re-distributed during different types of waste
disposal processes?
7
Wastes disposal
8
Over half industrial wastes are re-used or land-filled
Wastes
Municipal wastes
Industrial wastes
Hazardous wastes National List of Hazardous Wastes
Metallurgical industry
Energy industry
Petrochemical industry
Mining industry
Light industry
Other industry
3%3%3%
13%
18%
28%
32%
3%
3%
3%
28%
Land Cement clinker Fly ash bricks
Commodity concrete Building roads
Mineral substances Used in agriculture
3%3%3%
13%
18%
28%
32%
3%
3%
3%
28%
Land Cement clinker Fly ash bricks
Commodity concrete Building roads
Mineral substances Used in agriculture
Disposal of industry wastes
Wastes disposal
9
Wastes
Municipal wastes
Industrial wastes
Hazardous wastes National List of Hazardous Wastes
Metallurgical industry
Energy industry
Petrochemical industry
Mining industry
Light industry
Other industry
0
500
1000
1500
2000
2500
3000
3500
4000
2010 2011 2012 2013 2014
贮存量
处理量
综合利用量
产生量
Stock
Disposal
Reuse
Production
Unit: 10kt
Disposal of hazardous wastes
Wastes disposal
10
Wastes
Municipal wastes
Industrial wastes
Hazardous wastes National List of Hazardous Wastes
Metallurgical industry
Energy industry
Petrochemical industry
Mining industry
Light industry
Other industry
0%
20%
40%
60%
80%
100%
2006 2007 2008 2009 2010 2011 2012
81.8 81.9 82.9 80.2 79.4 76.9 72.6
3.7 2.7 1.7 1.6 1.5 3.3 2.7
14.5 15.4 15.4 18.2 19.2 19.9 24.7
填埋 堆肥 焚烧Landfill LandfillCompost Incineration
1) Poor landfill site: Significant environmental
pollution
2) Controlled landfill site: Problems on seepage,
leachate treatment, daily cover
3) Advanced landfill site: Standard landfill site,
accounting for more than 20%.
Hg re-distribution during waste disposal (Tier 3)
11
Final fates of Hg consist of six categories:
Hg emissions to air, releases to water, and releases to land
Hg emissions/releases in this study do not consider Hg transportation
across different environmental media through biogeochemical cycling.
Hg exports
The term “export” indicates Hg exported abroad by embedding in Hg-
containing products
Hg stabilization
The term “stabilization” means that Hg is properly treated in an
environmental sound manner.
Hg stocks
The term “stock” implies that Hg is stored in wastes and byproducts
due to the delay of sales or disposal (more than 1 year). Wastes and
products containing Hg are generally sealed-stored. Thus, they are
regarded to have few environmental impacts during the storage period.
However, once these wastes and products are reused, the embedded Hg
will re-enter production activities and cause potential environmental
impacts.
, 1, ,l q l l h q l h
h
r RE RM
The notation r-REl,q indicates Hg re-distribution from
waste/byproduct l to fate q;
RMl stands for Hg embedded in byproduct l;
α is the utilization rate of waste/byproduct l;
βh is the application proportion of treatment process h;
θq×1,l,h is a column vector, whose element θq1,l,h represents the
distribution factor from waste/byproduct l to fate q during
the treatment process h.
Hg re-distribution factors are calculated by
identifying the utilization/disposal method of
wastes/byproducts and Hg distribution during
different utilization/disposal process.
Re-distribution of Hg in fly ash disposal processes for example
12
Hg re-distribution during utilization of fly ash
1)Producing cement clinker 5% stabilized; 95% emitted to air
2)Producing fly ash bricks 7%-40% emitted to air; the rest stabilized
3)Producing commodity concrete 100% stabilized
4)Building roads 100% stabilized
5)Producing mineral substances 5% released to water;
the rest released to land as wastewater treatment residues
6) Used in agriculture 100% released to land
Hg re-distribution factors for fly ash utilization/disposal
Fate Air Water Land Stabilization
Hg re-distribution factor, % 30.0 0.1 38.0 31.9
Hg flows in China
13
Nonferrous metals
Smelting (NMS)
Incineration and
interment
Primary Hg ore
mining
Use of Hg-added
products
Land 651
Stock 795
Stabilization
420
Water 84
Fuel
consumption
Production activities
using Hg
428
265
1019
11 38
83
71
105
8 8
181
92
4137486
222
41
723 53
Hg input 2643
95
790
408
47
26
116
257760
645
35
Unit: t
1
Recovery companyHg
3To Biomass
66*
20
To NMS
Primary
Hg 20
Building materials
production
2
Biomass 3
Export 129**12814
374
Air 633
226
176
170
28
21
10
4
12
19
Hg as impurity
1714Hg ore
926 Hg input: overall situation of motive
Hg in China’s anthropogenic activities. clean energy or scrap metals substitution;
use of recycled Hg; reducing the production
and use of Hg-added products.
Emission and Release: Direct
environmental impact:,51.8%end-of-pipe Hg control;
increasing controlled landfills and
strengthening solid waste recycling
Safely disposed: 15.8%
Stock: Potential environmental impact,
depending on the disposal/utilization
methods
Atmospheric Hg emissions
14
0.32%1.58%4.42%
16.11%
19.91%
21.96%
35.7% Fuel consumption
Building materials production
Nonferrous metal smelting
Secondary emissions
Incineration and interment
Production activities using Hg
Primary Hg mining
0.32%4.42%
1.58%
Hg re-emissions from waste reuse
15
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12)
0
5
10
15
20
25
30
Atm
osp
her
ic H
g e
mis
sions
(t)
Emissions sources
(1) Recovery of zinc oxidize in zinc smelters
(2) Wastes disposal in cement plants
(3) Disposal of waste Hg-added products
(4) Disposal of smelting slags in zinc smelters
(5) Production of recycled Hg
(6) Fly ash used for bricks production
(7) Acid slags roasting in zinc smelters
(8) Flue gas desulfurization gypsum used for wallboard production
(9) Acid slags roasting in lead smelters
(10) Smelting slags disposal in copper smelters
(11) Acid slags roasting in copper smelters
(12) Disposal of smelting slags in lead smelters
About 102 t of Hg is emitted due to the use of
wastes/byproducts. Recovery of zinc oxide in
zinc smelters and wastes disposal in cement
plants contribute to 26% and 25% of total
secondary atmospheric Hg emissions.
If solid wastes containing Hg are treated
through high temperature, we should
either remove Hg from solid wastes before
the treatment or strengthen Hg reduction
of APCDs for treatment procedures. This
is especially important for solid wastes
disposal in zinc smelting and cement
plants.
Hg release to water and land
16
Nonferrous metal smelting
Use of Hg-added products
Fuel consumption
Production activities using Hg
Primary Hg mining
1.20%4.82%
13.25%
31.33%
49.40%
Nonferrous metal smelting
Use of Hg-added products
Fuel consumption
Production activities using Hg
Primary Hg mining
1.20%4.82%
13.25%
31.33%
49.40%
0.15%1.08%5.41%
12.83%
13.6%
14.68%17.93%
34.31%
Nonferrous metal smelting
Production activities using Hg
Primary Hg mining
Building materials production
Fuel consumption
Use of Hg-added products
Incineration and interment
Hg recovery
0.15%5.41%1.08%
0.15%1.08%5.41%
12.83%
13.6%
14.68%17.93%
34.31%
Nonferrous metal smelting
Production activities using Hg
Primary Hg mining
Building materials production
Fuel consumption
Use of Hg-added products
Incineration and interment
Hg recovery
0.15%5.41%1.08%
0.15%1.08%5.41%
12.83%
13.6%
14.68%17.93%
34.31%
Nonferrous metal smelting
Production activities using Hg
Primary Hg mining
Building materials production
Fuel consumption
Use of Hg-added products
Incineration and interment
Hg recovery
0.15%5.41%1.08%
34.31%
Water Land
Hg stocks in wastes/products
17
Subsectors Hg stocks (t) Waste/product types
Hg recovery 374
Hg-containing catalysts, waste activated
carbon
Zinc smelting 310
Waste acid sludge, waste water treatment
sludge, calomel
Lead smelting 40
Waste acid sludge, waste water treatment
sludge
Fluorescent lamp
production 40Fluorescent lamp
Copper smelting 18
Waste acid sludge, arsenic slag, waste water
treatment sludge
Dental amalgam
production 7 Dental amalgam
LGSP 7
Waste acid sludge, waste water treatment
sludge, arsenic slag
Wastes stored in the Hg
recovery companies and
zinc smelters can be used
as Hg recovery materials.
Utilization/disposal of these
wastes in a environmental
sound manner will reduce
potential emissions/releases
Challenges for Hg waste management
Around 651 t Hg released to land, which proposes environmental risks. Around 795 t Hg
stored in the wastes, which proposes big challenge for waste treatment/disposal.
Information gaps: No information system on the production, transfer, recycle, and
disposal of Hg-containing waste.
The system of waste sorting, collection and recycling is still in its infancy.
Current comprehensive utilization of solid wastes can reduce Hg releases to land, but
lead to Hg re-emissions to air.
Limit values for mercury containing waste are not set. Technical guidelines on mercury
waste management in environmentally sound manners not set.
18
References
• Hui M L, Wu Q R, Wang S X, Liang S, Zhang L, Wang F Y, Lenzen M, Wang Y F, Xu L X, Lin Z T, Yang H, Lin Y, Larssen T, Xu M, Hao J M. Mercury flows in China and global drivers. Environ Sci Technol, 2017, 51: 222-231.
• Wu Q R, Wang S X, Li G L, Liang S, Lin C-J, Wang Y F, Cai S Y, Liu K Y, Hao J M. Temporal trend and spatial distribution of speciated atmospheric mercury emissions in China during 1978–2014. Environ Sci Technol, 2016, 50(24): 13428-13435.
• Wu Q R, Wang S X, Hui M L, Wang F Y, Zhang L, Duan L, Luo Y. New insight into atmospheric mercury emissions from zinc smelters using mass flow analysis. Environ Sci Technol, 2015, 49(6): 3532-3539.
• Liu K Y, Wu Q R, Wang L, Wang S X, Liu T H, Ding D, Tang Y, Li G L, Tian H Z, Duan L, Wang X, Fu X W, Feng X B, Hao J M. Measure-specific effectiveness of air pollution control on China's atmospheric mercury concentration and deposition during 2013-2017. Environ Sci Technol, 2019, 53(15): 8938-8946.
• Wen M, Wu Q, Li G, Wang S, Li Z, Tang Y, Xu L, Liu T. Impact of ultra-low emission technology retrofit on the mercury emissions and cross-media transfer in coal-fired power plants. J Hazard Mater, 2020, 396: 1-8.
19