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Dr. Iván ÑancucheoProfesor AsociadoUniversidad San Sebastián, Concepción
Nuevas tendencias para el tratamiento de drenajes ácidos de minas y soluciones industriales utilizando
reactores sulfidogénicos acidófilos”
In contrast, although sulfur is usually very abundant in natural
and man-made acidic environments, there have been
relatively few studies on sulfur-cycling in these.
Acidophilic iron-oxidisers +
Acidophilic iron-reducers +
Acidophilic sulfur-oxidisers +
Acidophilic sulfate-reducers ?
* Río Azufre; a small,
abandoned sulfur
mine; pH~ 2,3
What is the problem to obtain acidophilic SRB cultures?
• Sulfidogenesis at low pH is a proton-consuming reaction. The pH of
enrichment cultures increases (→ pH ~7) and selects for neutrophiles, not
acidophiles
initial pH: 2.0 2.9 3.5 4.0 4.5
• Lactate as carbon source
pHinternal 6.5
pHexternal 2.0CH3COOH
CH3COO- + H+
Fe-based medium Zn-based medium
sterile overlayer
overlay medium for direct isolation of
acidophilic SRB
underlay inoculated with acidophilic heterotroph AcidocellaPFBC
Selective recovery of transition metals based on the different solubilities
of their sulfide phases
pH 2 pH 4 pH 7
Fe2+ Fe2+ Fe2+ FeS
Zn2+ Zn2+ ZnS
Cu2+ CuS
• many transition metals can be highly effectively removed from mine waters
as reduced sulfide minerals
• the challenge was to make a “clean” products, i.e, free of other metal
sulfides and other minerals such as gibbsite (Al(OH)3)
Acidophilic sulfidogenic system operates as an
Upflow Biofilm Reactor (UBR)
Packed bed(immobilized SRB)
pH electrodeFeed in(pH 1.5-4)
Effluent out(pH 2-5)
meterpump
4 C3H8O3* + 7 SO4
2- + 14 H+ → 12 CO2 + 7 H2S + 16 H2O
H2S + Me2+ → MeS↓ + 2 H+
Acidophilic sulfidogenic reactor performance data :
Mynydd Parys AMD, Wales, UK
Analyte Concentration
(mg/L)
SO42- 2750
Fe2+ 280
Al3+ 90
Mg2+ 80
Zn2+ 70
Cu2+ 45
Ca2+ 42
Na+ 15
Mn2+ 10
NH4+ 1.8
(pH 2.1)
Objective: selective removal of copper (as CuS)
Acidophilic sulfidogenic reactor performance data:
Mynydd Parys AMD
Acidophilic sulfidogenic reactor performance data:
Cwm Rheidol AMD, Wales
Analyte Concentration
(mg/L)
SO42- 1162
Fe2+ 167
Al3+ 13
Mg2+ 48
Zn2+ 196
Cu2+ trace
Ca2+ 20
Na+ 12
Mn2+ trace
(pH 2.5)
Objective: selective removal of zinc (as ZnS)
• Fed characterized by extremely low pH (2.1) and zinc and iron as main transition metals (0.5 and 2 mM, respectively)
• The sulfidogenic system (2.3 L) was operated as a continuous flow mode unit for 99 days at 30°C
Simultaneous removal of Zn and Fe for treating acidic
mine water (Río Azufre; Arica y Parinacota Region)
Zn
GlycerolpH
Fe
Glycerol remaining
Flow rate
Acetate
Bacteria
Sulfate removal from extremely acidic wastewater* using the
acidophilic SRB bioreactor
Measurements correlate well with theoretic chemical stoichiometries
*pH 1.6 – 3
20 mM (~2 g/L) sulfate
no transition metals
0
10
20
30
40
50
60
70
80
0 20 40 60 80 100 120
Time (days)
Su
lfate
(m
M)
1.25
1.3
1.35
1.4
1.45
1.5
pH
feed pH
Sulfate in effluent
Sulfate added
4 C3H8O3* + 7 SO42- + 14 H+ → 12 CO2 + 7 H2S + 16 H2O
pH 1.45 – 1.3
~ 55 to 70 mM sulfate (~ 6.7 g/L)
no transition metals
Raffinate:
Packed bed(immobilized SRB)
pH electrodeFeed in(pH 1.6)
Effluent out(pH 3)
meterpump
H2S → S0
At. ferrooxidans
Net reaction: SO42- + glycerol → S0 + CO2
Where does the H2S go?
SO42- → H2S
As5 in acidic solutions ?
Dr. Ivan Nancucheo
Universidad San Sebastián,
Concepción
Phone: + 56 9 4910 1205
Muchas gracias
Sabrina Hedrich; BGR, Germany
Gordon Southam; University of Queensland
Guilherme Oliveira, ITV, Brasil
Walter Mac Cormack; Instituto Antártico Argentino
Alex Schwarz; Universidad de Concepción
Pedro Galleguillos; CICITEM