ELECTRONIC SUPPLEMENTARY MATERIAL
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Appendix A
Table A.1. Particle size distribution of the two sediments
Sand (> 63 μm)
(% by mass)
Silt (63 ~ 2 μm)
(% by mass)
Clay (< 2 μm)
(% by mass)
Sediment I (Sandy Silt)
42.37 ± 0.42
49.57 ± 0.23
8.06 ± 0.19
Sediment II (Clayey Silt)
17.99 ± 0.13
55.94 ± 0.10
26.07 ± 0.33
Table A.2. Physicochemical properties of sandy silt sediment and clayey silt sediment
NO3SO42concentration
concentration
-1
(mg NO3 -N kg dw) (mg kg-1 dw)
Moisture
content (%)
ORP
(mV)
pH
AVS
concentration
(mg kg-1 dwa)
Sandy Silt
Sediment
52.16
± 0.87
-236.9
± 4.5
7.85
± 0.04
5556
± 1142
NDb
519
± 51
1.26 (± 0.10)
×10-6
Clayey Silt
Sediment
47.99
± 0.95
-175.2
± 3.9
7.99
± 0.03
573
± 73
ND
362
± 31
4.16 (± 0.38)
×10-7
a. dw refers to dry weight.
b. Non-detectable.
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Hydraulic
conductivity
(cm s-1)
Appendix B
No gas cavity
No gas cavity
Gas cavities
No gas cavity
No gas cavity
b)
a)
Fig. B.1. Sandy silt sediment column (a) without NO3- injection as control and (b)
with NO3- injection after 5 weeks of incubation
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Gas cavities
Gas cavities
No gas cavity
No gas cavity
No gas cavity
a)
b)
Fig. B.2. Clayey silt sediment column (a) without NO3- injection as control and (b)
with NO3- injection after 5 weeks of incubation
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Appendix C
Calculation of injected amount of NO3- in each treatment column
The treatment columns with a total volume of 1.92 l were packed with either 1.91 kg
wet sandy silt sediment or 2.20 kg wet clayey silt sediment to fill up the bottom 35 cm
of the column (the porosity of each sediment was 0.45). So, the volume of the wet
sediments (i.e., sandy silt or clayey silt sediments) in each column was 1.344 l. The
concentration of Ca(NO3)2 solution, which was prepared for injection, was 119 g
NO3--N l-1. The volume of Ca(NO3)2 solution injected in each treatment column was
28.23 ml.
The total amount of NO3- injected in each treatment column was:
119 mg NO3--N ml-1 × 28.23 ml = 3359 mg NO3--N
The dosage of NO3- in each treatment column was:
3359 mg NO3--N ÷ 1.344 l wet sediment = 2500 mg NO3--N l-1 wet sediment
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Appendix D
Calculation of the proportion of the calculated value of the oxidized AVS to the
measured value of the oxidized AVS in the treatment columns after 5 weeks of
incubation
The treatment columns packed with sandy silt sediment are used as an example to
show the calculation approach. The calculation approach and equations used for
clayey silt sediment are the same as for the sandy silt sediment.
Step 1: Amount of AVS oxidized after 5 weeks of incubation (measured value of
oxidized AVS)
The AVS concentration of the sandy silt sediment was 5556 mg kg-1 dry weight. A
total amount of 1.91 kg wet sandy silt sediment (47.84 % dry weight) was packed in
each sandy silt sediment column.
Therefore, the initial amount of AVS in each sandy silt sediment column was:
5556 mg kg-1 dry weight × (1.91 kg wet sandy silt sediment × 47.84 %) = 5077 mg
NO3--N
The amount of residual AVS in sandy silt sediment column after 5 weeks of
incubation was 2634 mg.
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Therefore, the amount of AVS oxidized after 5 weeks of incubation was:
5077 mg - 2634 mg = 2443 mg
Step 2: Amount of SO42- generated after 5 weeks of incubation
The SO42- concentration of sandy silt sediment was 519 mg kg-1 dry weight. A total
amount of 1.91 kg wet sandy silt sediment (47.84 % dry weight) was packed in each
sandy silt sediment column.
Therefore, the initial amount of SO42- in each sandy silt sediment column was:
519 mg kg-1 dry weight × (1.91 kg wet sandy silt sediment × 47.84 %) = 474 mg
The amount of residual SO42- in sandy silt sediment column after 5 weeks of
incubation was 7602 mg.
Therefore, the amount of SO42- generated after 5 weeks of incubation was:
7602 mg - 474 mg = 7168 mg
Step 3: Amount of AVS oxidized after 5 weeks of incubation (calculated value of
oxidized AVS)
Based on the stoichiometry of the following equation, the calculated value of the
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oxidized AVS (referred to S2- in the following equation) was obtained using the
amount of SO42- generated after 5 weeks of incubation.
8NO3 +5S2- +8H   4N 2 +5SO 42 +4H 2O
Therefore, the calculated value of the oxidized AVS (the molar mass of S2- was 32
g/mol and molar mass of SO42- was 96 g mol-1) was:
7168 mg ÷ 96 g mol-1 × 32 g mol-1 = 2389 mg
Step 4: Proportion of calculated value of oxidized AVS to the measured value of the
oxidized AVS after 5 weeks of incubation
According to the above calculation, the calculated value of the AVS oxidized,
obtained according to the change of SO42- during the incubation period, was 2389 mg;
while the measured value of the AVS oxidized after 5 weeks of incubation was 2443
mg.
Therefore, the ratio of the calculated value of the oxidized AVS and the measured
value of the oxidized AVS in the treatment columns after 5 weeks of incubation was:
2389 mg ÷ 2443 mg × 100 % = 97.8 %
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Appendix E
Calculation of the proportion of NO3- consumption by AVS oxidation (through
autotrophic denitrification) to the total NO3- consumption after 5 weeks of
incubation
The treatment columns packed with sandy silt sediment are used as an example to
show the calculation approach. The calculation approach and equation used for the
clayey silt sediment are the same as for the sandy silt sediment.
Step 1: Amount of AVS oxidized after 5 weeks of incubation (measured value of
oxidized AVS)
The AVS concentration of the sandy silt sediment was 5556 mg kg-1 dry weight. A
total of 1.91 kg wet sandy silt sediment (47.84 % dry weight) was packed in each
sandy silt sediment column.
Therefore, the initial amount of AVS in each sandy silt sediment column was:
5556 mg kg-1 dry weight × (1.91 kg wet sandy silt sediment × 47.84 %) = 5077 mg
NO3--N
The amount of residual AVS in the sandy silt sediment column after 5 weeks of
incubation was 2634 mg.
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Therefore, the amount of AVS oxidized after 5 weeks of incubation was:
5077 mg - 2634 mg = 2443 mg
Step 2: Amount of NO3- consumed by AVS oxidation after 5 weeks of incubation
Based on the stoichiometry of the following equation, the amount of NO3- consumed
by AVS (referred to S2- in the following equation) oxidation was calculated by the
amount of AVS oxidized after 5 weeks of incubation (the molar mass of S2- was 32 g
mol-1 and molar mass of NO3--N was 14 g mol-1)
8NO3 +5S2- +8H   4N 2 +5SO 42 +4H 2O
Therefore, the amount of NO3- consumed by AVS oxidation after 5 weeks of
incubation was:
2443 mg ÷ 32 g mol-1 × (8/5) × 14 g mol-1 = 1710 mg NO3--N
Step 3: Amount of NO3- reduced after 5 weeks of incubation
The total amount of NO3- injected in each treatment column was 3359 mg NO3--N
(the detailed calculation is given in Appendix C). The amount of residual NO3- after 5
weeks of incubation was 1523 mg NO3--N.
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Therefore, the amount of NO3- consumed after 5 weeks of incubation was:
3359 mg NO3--N - 1523 mg NO3--N = 1836 mg NO3--N
Step 4: Proportion of NO3- consumption by AVS oxidation to the total NO3consumption after 5 weeks of incubation
The amount of NO3- consumed by AVS oxidation after 5 weeks of incubation was
1710 mg NO3--N; while the total amount of NO3- consumed after 5 weeks of
incubation was 1836 mg NO3--N.
Therefore, the proportion of NO3- consumption by AVS oxidation to the total amount
of NO3- reduced after 5 weeks of incubation was:
1710 mg NO3--N ÷1837 mg NO3--N × 100 % = 93.1 %
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