Permeable Reactive Barrier
for Remediation of
Acid Mine Drainage
By: Pimluck Kijjanapanich
Contents
I Introduction
O Objectives
S Scope of Study
L Literature Review
マスタ タイトルの書式設定
M Methodology
マスタ タイトルの書式設定
and Discussion
R1 Results
C Conclusions
R2 Recommendations
Acid Mine Drainage
•the result of oxidation by air and water of metal
sulfides contained within mined rock as well as
mine wastes.
•high acidity and high amounts of dissolved heavy
metals such as Fe, Zn, Ni, Cu and Pb.
•extremely toxic to most organisms in both
terrestrial and aquatic ecosystems.
The oxidation of pyrite
2
2
4
FeS2S   7 2 O2  H 2O  Fe  2SO  2H

Fe 2  1 4 O2  H   Fe 3  1 2 H 2 O
Fe3  3H 2O  FeOH 3S   3H 
3
2
2
4
FeS2S   14Fe  8H 2O  15Fe  2SO  16H

The methods for treating AMD
• The pH modification method - by using lime (CaO), limestone
(CaCO3), sodium hydroxide (NaOH) or sodium carbonate
(Na2CO3)
• Ion exchange
• Adsorption treatment
• Electrochemical treatment
• Membrane process
Disadvantages of the conventional active treatment of AMD (Brown et al., 2002)
• Relatively high operation and equipment maintenance cost
• The sludge is chemically complex, unstable, low density and gelatinous resulting
large volumes, making difficult and causes long-term problematic disposal
An interested approach to AMD treatment has been developed that imitate sulfate
reduction phenomena occurred in the nature that carry out by sulfate reducing
bacteria (SRB) and developed to use for AMD treatment.
Biological Sulfate Reduction
the use of anaerobic sulfate reducing bacteria
(SRB), which can reduce sulfate to sulfide by
oxidizing an organic carbon source.
2CH 2 O  SO42  2 H   H 2 S  CO2  H 2 O
H2S  M
2
 MS S   2H

Permeable Reactive Barrier
an emplacement of reactive materials in the subsurface
designed to intercept a contaminant plume, provide a flow
path through the reactive media and transform the
contaminant(s) into environmentally acceptable forms to
attain remediation concentration goals down-gradient of
the barrier (Powell and Puls, 1997).
The two basic designs of PRBs
Funnel-and-gate
PRB
Continuous
PRB
Advantages of Permeable Reactive Barrier
(Powell and Puls, 1997; Puls et al., 1999)
•No need for expensive above-ground facilities for storage, treatment
or transport, other than monitoring wells.
•After the installation the above-ground can be reused.
•There are no energy input and limited operational and maintenance
costs.
•The in situ contaminant remediation is more effective than the
simple migration control achieved by the impermeable barriers.
•Contaminants are not brought to the surface so that there is no
potential cross media contamination.
•There no disposal requirements or disposal costs for treated wastes.
•Avoid the mixing of contaminated and uncontaminated water that
occurs with pumping.
To develop an appropriate PRB system for treating
Acid mine drainage (AMD)
The specific objectives are:
•To select the appropriate organic material used as electron
donors for treating AMD using PRB.
• To investigate the reaction rate through batch and
continuous studies for evaluation of residence time in PRB
• To investigate the effect of pH and alkalinity on PRB
performance.
• To investigate the performance of PRB in removing of
heavy metal.
• Five types of organic material were used including;
1) rice husk
4) septage
2) coconut husk chip
5) composted pig manure
3) bamboo chip
• Sludge from Sanguan Wongse Industry wastewater treatment
was used as sulfate reducing bacteria (SRB) source.
• Batch experiment is conducted in order to select reactive
materials and the appropriate residence time for treating AMD.
•Column experiment is conducted in order to investigate the effect
of pH and alkalinity on PRB performance and heavy metal removal
efficiency.
• The experiments is conducted in laboratory PRB model under
anaerobic condition at ambient temperature.
• AMD from lignite coal mine will be used as a raw water.
Literature Review
• Reactivity
• Stability
• Availability and cost
• Hydraulic performance
• Environmental compatibility
• Safety
Waybrant et al., 1995 the
combination of more than
one organic source is more
successful than the use of
solely one material.
Gibert et al., 2004 The lower the content of
lignin in the organic substrates, the higher
its degradability and capacity for
developing bacterial activity and sheep
manure was the most successful electron
donor (sulfate removal level of > 99%)
• A group of anaerobic bacteria that can reduce
sulfate to form sulfide.
• The genus Desulfovibrio is one of the most
mentioned species in studies of SRB in natural
water and wastewater.
• Gram negative, curved rods and usually having a
single polar flagellum.
• Anaerobic environment
(Eh around -200 mV)
• pH 5-8
• The presence of electron donor
and appropriate sulfur species
• A physical support
According to the study of Costa et al. (2007), no
SRB activity was observed at pH 2. On the other hand, at
pH 5 and 7 SRB growth was observed and this different pH
(5 and 7) was not significantly to affect SRB growth.
Literature Review
Selection of organic carbon sources
Phase I: Batch Test
Phase II: Column Test
• Experiment set-up
• Investigate appropriate
organic carbon sources and
optimum residence time.
• PRB column design
• Select the two of the best organic carbon.
• Investigate the effect of pH and alkalinity
and heavy metal removal efficiency.
Laboratory Analysis
Data analysis and Discussion
Conclusion and Recommendation
To investigate appropriate organic carbon
sources and optimum residence time.
Rice husk
Coconut husk chip
Five organic materials
Composted pig manure
Bamboo chip
Municipal compost (septage)
valves
gas releasing pipe
Reaction Bottle
30 cm
AMD pH 6-7 1000 mL (66% by volume)
SRB source 100 mL (7% by volume)
1.5 L
Organic Material 300 mL (20% by volume)
7 cm
The criteria for making mixture
The 3 types of single material were selected:
• the two of the single materials that have maximum
sulfate reducing rate (composted pig manure, rice husk).
P
R
•the single material that has long lasting (coconut husk).
C
=> Mixed Material
RC
PR
PC
Type of Organic Material
PRC
Rice
husk
Mixture
Coconut
pig
husk chip manure
Rice husk & Coconut husk (RC) 50:50
+
+
-
Pig manure & Rice husk (PR) 50:50
+
-
+
Pig manure & Coconut husk (PC) 50:50
-
+
+
Pig manure, Rice husk & Coconut husk (PRC) 33:33:33
+
+
+
Remark:
+
-
Have this type of organic material in the formula
No have this type of organic material in the formula
=> Batch
Parameters
Alkalinity
Methods
Titration Method
Oxidation-reduction potential
(Eh)
ORP meter
pH
pH meter
Sulfate
Turbidimetric Method
Volatile solid per total solid
(VS/TS)
Dried at 105 and 550 oC
=> Sampling
Two of the reaction bottles were finished for analyzing
at each sampling time.
To investigate the effect of pH and alkalinity
and heavy metal removal efficiency.
Estimation of the Reduction rate and Residence time
Log phase

ln SO42
S 
ln  t  ln  10 
S0 
100 

HRT 
 
k
k

t

 ln SO42

0
Slope = -k
 kt
30 mL/hr (0.155 cm/hr)
gas releasing pipe
Name
A1
L1
A2
L2
Lime adding
-
+
-
+
Formula
1
1
2
2
screen
 0.4 cm
NaOH
=> Continuous
Parameters
Alkalinity
Methods
Titration Method
Dissolved Organic Carbon
(DOC)
High-Temperature Combustion
Method
Heavy Metal
(Fe, Cu, Zn and Mn)
Inductively Coupled Plasma
(ICP)
Oxidation-reduction potential
(Eh)
ORP meter
pH
pH meter
Sulfate
Turbidimetric Method
(Huttagosol and Kijjanapanich, 2008).
Parameters
pH
Acidity, mg/L CaCO3
Total hardness, mg/L CaCO3
Calcium, mg/L
Magnesium, mg/L
Sulfate, mg/L
Iron, mg/L
Manganese, mg/L
Copper, mg/L
Lead, mg/L
Zinc, mg/L
Value
4.20
91
740
260
54
623
0.58
15.1
0.074
0.005
1.80
Standard*
not excess 0.5
not excess 1.0
not excess 0.01
not excess 5.0
Standard**
5.0-9.0
not excess 1.0
not excess 0.1
not excess 0.05
not excess 1.0
* Groundwater Quality Standards of Thailand
** Surface Water Quality Standards of Thailand
Volatile solid per Total solid (VS/TS)
Type of organic materials
rice husk
Volatile solid/Total solid in 22 days
(VS/TS)
Reduced from 0.788 to 0.763
coconut husk chip
Maintained at 0.957
bamboo chip
Maintained at 0.984
municipal compost (septage)
Reduced from 0.455 to 0.412
composted pig manure
Reduced from 0.625 to 0.594
=> pH
Alkalinity =>
=> Oxidation Reduction
Potential (Eh)
Sulfate Removal =>
=> Color change in effluent
Bamboo chip media
Coconut husk media
Septage media
Rice husk media
Composted pig manure media
Change of color in effluent of
each organic material in 8 days
=> Color change in media
composted pig manure media
in 16 days
bamboo chip media
in 16 days
=> Alkalinity
Oxidation Reduction
Potential (Eh) =>
=> Sulfate Reduction
99
95
Sulfate Removal =>
84
96
Estimation of the Reduction rate and Residence time
Log phase

ln SO42

t
 St 
ln   ln  10 
S0 
100 

HRT 
 
k
k
Using % Sulfate removal = 90%
From the calculation, HRT = 8.22-11.23 days
Safety factor = 1.5, HRT = 12.33-16.84 days
Reactor size = 15 L

 ln SO42

0
 kt
Name
PRN
PRL
PRCN
PRCL
Lime adding
-
+
-
+
=> Alkalinity
Oxidation Reduction
Potential (Eh) =>
=> Sulfate Reduction
Sulfate Removal =>
=> Heavy metal Removal
Fe
Cu
Zn
Mn
Hydroxide Precipitation
=> Dissolved Organic Carbon (DOC)
• Composted pig manure and rice husk had maximum sulfate
reducing rate and coconut husk had long lasting
• The suitable hydraulic retention time (HRT) was 16 days.
• The percentage of sulfate removal was up to 98%, which the
residue sulfate concentration was 14.5 mg/L in PRL media.
• Effluent pH can be maintain in neutral range (6-8) and effluent
alkalinity from composted pig manure was the highest.
• The concentrations of iron reduced from 23.34 mg/L to around
2 mg/L and copper & zinc concentrations could reach below
groundwater quality standards of Thailand.
• The percentages of iron, copper, zinc, and manganese removal
were 93 %, 99 %, 88%, and 96 % respectively in PRL reactor.
• The column reactors, which added lime into the media, had
more efficiency than the reactor that no lime in the media.
• Other type of organic materials should be tested.
• The appropriate ratio of each type of organic material should be
defined.
• The lower pH of AMD should be tested on PRB system.
• Other type of heavy metal and other concentrations of iron,
copper, zinc, and manganese should be tested on PRB system.
• Plug flow system reactor should be developed to solve the
completely mixed problem.
•AMD from different type of mine should be investigated on PRB
system.
• Performance of pilot should be further investigated.