IWC 12-41 

Design and Start-up of a Full-scale 

Biological Selenium Removal System for 

Flue Gas Desulfurization (FGD) 

Wastewater from a Power Generating 

Station 

Antonio Lau1

, Michael Pudvay1, John Bradberry2, Ray 

D’Alesandro2

, Steve Frank2, Anthony Garaventa2, Shelley 

Wojciechowski2

, Enos Stover3, Ross Stover3, Chris 

Campana3

, Robert Bernstein4, Harry McNamee4

1 – Infilco Degremont, Inc., 8007 Discovery Drive, Richmond, VA 23229 

2 – GenOn, 1750 Power Plant Road, New Florence, PA 15944 

3 – Stover & Associates, Inc., PO Box 2056, Stillwater, OK 74076 

4 - URS Corporation, 510 Carnegie Center, Princeton, NJ 08540

Keywords: Flue Gas Desulfurization, Wastewater, Heavy Metals, Denitrification, 

Selenium, Reduction 

 
IWC 12-41 

Table of Contents 

Abstract 3 

 

1. Introduction 4 

FGD Wastewater Treatment 4 

The iBIO® Biological Wastewater Treatment Process 5 

2. Microbial Reactions for Denitrification and Selenium Removal 8 

3. Process Design Considerations 8 

 3.1 Selenium Removal Target Concentration 8 

 3.2 Integration into Existing WWT Facilities 9 

 3.3 Carbon Source Selection 9 

 3.4 Treatment System Robustness Considerations 10 

 3.5 Final Process Flow Diagram 10 

4. Full-scale Start-up Considerations 12 

 4.1 FGD Wastewater Characteristics 12 

4.2 Biological Seed Acclimation 12 

 

5. Full-Scale Results 13 

 5.1 Oxidation Reduction Potential Monitoring 13 

 5.2 Denitrification Performance 16 

 5.3 Selenium Removal Performance 17 

6. Conclusions 18 

7. References 18 

8. Acknowledgements 19 

Figures 

Figure 1.1 Schematic Diagram of a FGD Scrubber System 4 

Figure 1.2 Schematic Diagram of the iBIO® Biological Treatment System 5 

Figure 1.3 Denitrification and Selenium Removal Major Components 7 

Figure 3.1 Process Flow Diagram of the Installed Selenium Treatment System 11 

Figure 4.1 Biological Seed Acclimation Unit 13 

Figure 5.1 Oxidation Reduction Potential (ORP) Chart 14 

Figure 5.2 Oxidation Reduction Potential (ORP) in Reactors 15 

Figure 5.3 Nitrate/Nitrite Removal from FGD Wastewater (Laboratory Data) 16 

Figure 5.4 Selenium Removal from FGD Wastewater 17 

Tables 

Table 1.1 Major Process Equipment List - iBIO® Treatment System 6 

Table 4.1 FGD Wastewater Characteristics – Design Basis 12 

Table 5.1 Total Selenium Concentration through Wastewater Treatment 18 

Table 5.2 Total Selenium Removal Across Wastewater Treatment Units 18 
IWC 12-41 

Abstract 

This paper describes the design, start-up and commissioning of a full-scale 

biological treatment system that was installed at a coal-fired power generating 

station to remove selenium and nitrates from a Flue Gas Desulfurization (FGD) 

blowdown stream. The new patented iBIO® wastewater treatment (WWT) system, 

which was first pilot-tested at power generating stations, is based on a suspendedgrowth continuously stirred-tank anaerobic reactor that has been seeded with a 

source of commonly available anaerobic microorganisms which were subsequently 

acclimated to remove selenium from the FGD wastewater. This new innovative 

WWT system was integrated into the existing FGD wastewater treatment units at 

the power generating station to provide the additional selenium removal capability 

from the wastewater. 

This demonstrated biological selenium removal treatment system provides a robust 

and cost-effective alternate technology to coal-fired utilities that use FGD wet 

scrubbers to control their sulfur oxide (SOx) emissions with the additional need to 

consistently meet the more stringent lower-level selenium effluent limits. 

 
IWC 12-41 

Flue Gas

FGD Scrubber

Gypsum

Blowdown Effluent

Phys‐Chem

         (Existing)

Figure 1.1 Schematic Diagram of a FGD Scrubber System 

Wastewater Treatment Systems 

Anaerobic

Biological  

(Expansion)

Aerobic

Biological  &

Sand Filtration

     (Existing)

     Limestone

1. Introduction 

Air emissions from coal-fired power 

plants require the installation of 

various types of air pollution control 

system technologies. One such 

technology is the use of wet scrubbers 

for the removal of sulfur dioxide (SO2) 

from stack emissions. The wet 

scrubbing of flue gases with lime or 

limestone slurries is a proven and 

commercially established process to 

decrease SO2 emissions. However, 

inherent with this treatment system is 

the blowdown of a slurry stream that 

contains elevated concentrations of 

suspended and dissolved solids, 

chlorides, sulfates, heavy metals 

(chromium, mercury, selenium, etc.), 

and nitrates. FGD systems available 

in the marketplace have different 

combinations of characteristics (such 

as coal type, scrubber type, additive 

use, operational strategies, etc.) that 

result in extremely varied wastewater 

characteristics. 

This paper discusses the design and 

start-up of a full-scale biological 

wastewater treatment plant expansion 

implemented at a power generating 

station to remove nitrates and residual 

oxyanions (specifically, selenites and 

selenates) present in the wastewater 

after undergoing an initial physicalchemical treatment process for the 

removal of total suspended solids 

(TSS) and heavy metals from the FGD 

blowdown stream. 

Figure 1.1 shows a schematic diagram 

of the FGD scrubber system and the 

new biological wastewater treatment 

plant expansion for the blowdown 

stream. The new biological treatment 

system was retrofitted into the 

existing wastewater treatment 

processes. 

Vent Gases

 

 

 

 
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Figure 1.2 Schematic Diagram of the Complete Biological Treatment 

System for Selenium Removal 

The new biological wastewater 

treatment system is a patented 

anaerobic activated sludge suspendedgrowth system developed to remove 

nitrates and heavy metals 

(specifically, oxidized ions such as 

selenates, selenites, chromates, 

vanadates, etc.). 

The biological treatment system uses 

anaerobic microorganisms commonly 

available from industrial and municipal 

wastewater treatment plants and 

requires a carbon source to conduct 

their microbial activities. 

This treatment system was designed 

to handle contaminant fluctuations 

from the FGD physical-chemical 

wastewater treatment system. Pilotscale demonstrations of this process 

were previously described by Stover 

et. al. (Reference 1, IWC 07-49) and 

Teng et. al. (Reference 2). Figure 1.2 

and Table 1.1 show a schematic 

diagram and equipment list, 

respectively, of the complete 

biological treatment process which 

includes the “anoxic/anaerobic” 

section as well as the “aerobic” 

polishing treatment system. 

ble 1.1 Process Equipment List 

 
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Table 1.1 Major Process Equipment List for the Complete Biological 

Treatment System 

Figure 1.3 shows the major components for the denitrification and selenium 

removal steps which consist of an Anoxic Reactor, Anaerobic Reactor, Anaerobic 

Clarifier and a Gravity Sand Filter.

1 Anoxic Reactor for Denitrification

2 Anaerobic Reactor for Heavy Metals Reduction

3 Anaerobic Clarifier

4 Anaerobic Sludge Recycle Pump

5 Anaerobic Sludge Waste Pump

6 Sludge Holding Tank

7 Sludge Dewatering Pump

8 Continuous Backwash Sand Filter

9 Aerobic Reactor

10 Aerobic Reactor Aeration Blower

11 Aerobic Clarifier

12 Aerobic Clarifier Sludge Recycle Pump

13 Aerobic Clarifier Sludge Waste Pump

14 Continuous Backwash Sand Filter
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Carbon Source

Figure 1.3 Denitrification and Selenium Removal Major Components

To AEROBIC

Biological

Polishing

Treatment

System

Nutrients

Sludge

Handling

System

Anoxic Reactor  

“Denitrification”

Anaerobic Reactor

“Selenium”

  Anaerobic Clarifier

Gravity Sand Filter

FGD 

Wastewater 

after 

PhysicalChemical

Treatment

Coagulant

Flocculant

Sludge Recycle

Sludge Waste
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2. Microbial Reactions for 

Nitrate and Selenium Removal 

by the Biological Treatment 

Process 

Soluble selenium in FGD wastewaters 

is primarily present in the form of 

selenates (SeO4

2-) and selenites 

(SeO3

2-). Selenites, to some extent, 

can be removed through chemical 

precipitation, leaving selenates as the 

primary selenium species remaining in 

the wastewater. Biological processes 

have proven to be a viable and robust 

option for removal of selenates from 

wastewaters (References 1,2,4). A 

number of microorganisms are able to 

utilize the oxygen in selenate for 

energy and growth in a manner 

similar to the way denitrifying 

microorganisms utilize the oxygen 

from nitrates (NO3

-

). The selenium 

removal bacteria are commonly known 

as the “sulfur reducing bacteria” (SBR) 

and they only operate in a reducing 

environment. The selenium removal 

process can be represented as follows: 

SeO4

2- (selenates) + Carbon Source + 

Microorganisms ------> Se0 (solid) + 

CO2 + H2O + Biomass 

Similarly, the denitrification reaction 

carried out by heterotrophic bacteria 

known as “denitrifiers” operate in an 

anoxic environment and can be 

represented as follows: 

NO3

1- (nitrates) + Carbon Source + 

Microorganisms ---- N2 (gas) + H2O

+ Alkalinity + Biomass 

While the biological reduction of 

nitrates results in gaseous nitrogen 

formation, the biological reduction of 

selenates and selenites results in the 

formation of elemental selenium (Se0

), 

which is insoluble and can be removed 

along with the biological solids. 

Microorganisms gain more energy 

from using the oxygen in nitrate than 

they do from using the oxygen in 

selenate, and as such, nitrates must 

first be reduced to near zero levels 

before selenate reduction will take 

place. Both types of microorganisms 

(SRB and denitrifiers) were found to 

be capable of reducing the oxidized 

selenium compounds to elemental 

selenium. The process configuration 

used in this new biological system 

optimizes these microbiological 

reactions by providing two separate 

reactors to allow the environmental 

conditions to be better established in 

each stage. First, the biological 

reduction of nitrates is conducted in 

the Anoxic Reactor, which is followed 

by a second Anaerobic Reactor for the 

biological reduction of selenates and 

selenites where more reducing (i.e., 

more negative Oxidation Reduction 

Potential (ORP)) conditions are 

created for the SRB microorganisms. 
IWC 12-41 

3. Process Design 

Considerations 

3.1 Selenium Removal Target 

Concentration 

The power generating station had a 

target to reduce the concentration of 

Total Selenium from 1.3 mg/L in the 

untreated FGD blowdown stream down 

to <0.21 mg/L in the effluent of the 

wastewater treatment system. 

3.2 Integration into Existing 

Wastewater Treatment Facilities

The power generating station had an 

existing physical-chemical treatment 

system which included the typical 

precipitation of metals at an elevated 

pH followed by an aerobic biological 

treatment system which consisted of 

sequencing batch reactors, mainly for 

organics reduction. As a final 

polishing step, the Total Suspended 

Solids (TSS) of the wastewater is 

reduced by flowing through 

multimedia pressure filters. 

In this project, it was possible to 

insert the new anaerobic biological 

treatment process after the existing 

physical-chemical treatment system to 

be followed by the existing aerobic 

treatment process to remove the 

residual organic carbon and ammonia 

nitrogen to the required permit limits. 

As part of the process design for the 

new biological treatment system, a 

six-month laboratory study was 

conducted to simulate and validate the 

selenium removal performance using 

actual FGD wastewater from the 

power generating station. 

3.3 Carbon Source Selection 

FGD wastewaters do not have 

sufficient amount of organic carbon to 

support the microbiological reactions 

to denitrify and reduce selenium. 

Therefore, an external source of 

organic carbon is required to be added 

to the anaerobic treatment system. 

Molasses is known to support 

biological selenium reduction, but it 

can be difficult to handle due to its 

high viscosity, and can vary in 

composition, even from a single 

provider. It is suspected that the 

sugar fraction of molasses is primarily 

responsible for supporting selenium 

reduction, and as such, sugar 

(sucrose) was used in our initial pilot 

studies. 

A commercially-available liquid carbon 

source (carbohydrate-based product) 

was also evaluated in the laboratory 

and was selected for this project. This 

liquid carbon product is nonflammable, and according to the 

manufacturer, has both a consistent 

compositional make-up and a long 

shelf-life. The material flows readily 

at temperatures as low as 16°F, with 

a viscosity of about 100 cp at this 

temperature, and therefore is easier 

to handle than molasses. The 

material is approximately 50% by 

weight carbohydrate, with a COD 

concentration of 670,000 mg/L, which 

is higher in concentration than sugar 

solutions, which have a typical 

maximum concentration of 25 to 35 

percent by weight. 
IWC 12-41 

Discussion on the selection of the 

appropriate carbon source for this 

process was provided by Lau, et. al. 

(Reference 3, IWC 11-33, and 

Reference 5) which describes a pilot 

study conducted to confirm the 

applicability of the liquid carbon 

source. 

3.4 Treatment System Robustness 

Considerations 

Consideration was taken in the design 

of the biological treatment system to 

provide a design that was both robust 

and operationally flexible, while still 

being able to meet the stated effluent 

requirements. Some critical items that 

were incorporated are the following: 

(1) Equalization Tank to provide 

sufficient wastewater holding time to 

allow for minor mechanical 

repairs/changes, (2) instrumentation 

redundancies for critical parameters, 

such as the ORP and pH sensors, (3) 

bypassing loops for the anaerobic 

reactors and anaerobic clarifier. 

3.5 Final Process Flow Diagram 

The final Process Flow Diagram shown 

in Figure 3.1 provides the major 

components of the new biological 

treatment system installed at the 

power generating station for selenium 

removal. The design flow rate of this 

treatment system is 410 gpm (0.6 

MGD). The major process 

components include: 

 Chemical addition systems for 

the carbon source, 

macronutrients (urea, 

phosphoric acid), 

micronutrients, coagulant (ferric 

chloride) and flocculant 

(polymer). 

 Anoxic and Anaerobic Reactors 

for denitrification and selenium 

reduction. 

 Anaerobic Clarifier for the 

separation of the anaerobic 

biomass from the treated 

wastewater followed by a 

gravity sand filter for additional 

polishing of the suspended 

solids. 

 The reactors and the clarifier 

vessels are equipped with a 

foam control system which 

recirculates the contents of the 

vessel and sprays it on top of 

the tank. 

 The vent gases are collected 

and sent to a biofilter for 

biological conversion of sulfides 

into sulfates. 

 A “Sludge Storage Tank” was 

included to maintain an on-site 

inventory of acclimated 

bacteria. 
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Figure 3.1 Process Flow Diagram of the Installed Selenium 

Treatment System 
IWC 12-41 

4. Full-Scale Start-Up 

Considerations 

4.1 FGD Wastewater 

Characteristics 

The FGD wastewater characteristics 

used for process design is shown in 

Table 4.1 

Table 4.1 FGD Wastewater 

Characteristics Design Basis 

4.2 Biological Seed Acclimation 

The biological treatment system 

utilizes anaerobic microorganisms that 

have been acclimated to the existing 

FGD wastewater. This treatment 

process does not require the purchase 

of expensive proprietary 

microorganisms supplied by some 

vendors for the specific removal of 

selenium compounds. This treatment 

process, in contrast, uses typical 

anaerobic microorganisms easily 

available and found in industrial or 

municipal wastewater treatment 

sludges, usually obtained for a minor 

cost to the client. 

For this project, the source of the 

anaerobic bacteria was from anaerobic 

sludges of a WWT facility treating food 

manufacturing wastewaters. The 

bacteria were acclimated to the actual 

FGD wastewater in a separate 

“Biological Seed Acclimation Unit” 

which consisted of a 6,000 gallons 

anaerobic reactor followed by an 

anaerobic clarifier (see Figure 4.1). 

The major factor in the acclimation 

process was the controlled increase of 

the chloride concentration in the 

mixed liquor from ~500 mg/L up to 

~20,000 mg/L while maintaining the 

proper Oxidation Reduction Potential 

(ORP) in the reactor. The bacterial 

acclimation process was initiated ~3 

Parameter Concentration 

(mg/L) 

Ammonia (NH3-N) 8

Nitrate (NO3-N) 10

Total Kjeldahl 

Nitrogen (TKN) 62

Sulfate (SO4) 3,789

Chemical Oxygen 

Demand (COD) 897

C-BOD5 53

Total Suspended 

Solids (TSS) 91

Total Selenium 1.3

Chloride (Cl-) 20,000

Total Dissolved 

Solids (TDS) 28,907

pH 6.6
IWC 12-41 

months prior to the full-scale start-up date.

 

Figure 4.1 Biological Seed Acclimation Unit 

5. Full-Scale Results 

5.1 Control of the Oxidation 

Reduction Potential (ORP) in the 

Reactors 

One of the critical parameters in the 

operation of the selenium removal 

reactors is the Oxidation Reduction 

Potential (ORP) of the mixed liquor. 

The ORP is an analytical parameter 

reported in milliVolts (mV) which is 

obtained when the ORP sensor is 

placed in contact with the liquid being 

measured. The ORP value defines 

whether the reactor is in an oxidizing

environment or a reducing

environment. An oxidizing reactor 

environment (or an oxygenated 

environment) is indicated by a positive 

ORP value (ORP>0 mV); the higher 

the positive ORP value, the stronger is 

the oxidizing environment. In 

contrast, a reducing reactor 

environment (or an oxygen depleted 

environment), is indicated by a 

negative ORP value (ORP<0 mV); the 

more negative the ORP value, the 

stronger is its reducing environment. 

The Selenium Removal Anaerobic 

Reactors require a “reducing 
IWC 12-41 

environment” for the bacteria to 

accomplish their tasks. This ORP 

scale is graphically shown below in 

Figure 5.1. 

Figure 5.1 Oxidation Reduction Potential (ORP) Chart 

 Positive ORP Values => Oxidizing Environment 

(ORP > 0 milliVolts) 

 

 Negative ORP Values => Reducing Environment 

 (ORP < 0 milliVolts) 

 -150 mV (minimum level for selenium removal) 

 -200 to -300 mV (Target Operation) 

 -300 to -350 mV (Conservative Operation) 

The purpose of monitoring ORP in the 

Selenium Anaerobic Reactors is to 

ensure that the oxidized species of 

selenium (i.e., selenates and 

selenites), are reduced to elemental 

selenium. Selenates and selenites are 

soluble compounds and they are not 

sufficiently removed in the existing 

physical-chemical treatment system to 

meet the required lower selenium 

effluent limit. Therefore, the 

wastewater is treated in the new 

Selenium Removal Anaerobic Reactors 

under a reducing environment where 

the selenate and selenite compounds 

are converted by the bacteria into 

their insoluble elemental selenium

form. The elemental selenium 

precipitates out of solution and stays 

with the biomass as a particulate 

material and it leaves the treatment 

system via the Anaerobic Clarifier 

waste biomass. As a requirement 

prior to precipitation of the oxidized 

selenium compounds, the nitrates 

present in the wastewater must be 

reduced to nitrogen gas. 

During the start-up period, the 

strategy was to operate the Anaerobic 

Reactors at a controlled ORP value of 

at least -300 mV. This was a 

conservative ORP value with sufficient 

flexibility to allow the removal of 

selenium to meet the target effluent 

selenium concentration if the 

maximum system design value of 1.3 

mg/L Total Selenium is reached in the 

untreated FGD wastewater. Once the 

WWT Operator develops sufficient 

expertise with this biological 

treatment system, an optimization 

process will be implemented to adjust 
IWC 12-41 

the ORP value that will result in a more cost-effective operation. 

To achieve a negative ORP value, the 

addition of the correct proportions of a 

carbon source, macronutrients (urea, 

phosphoric acid) and micronutrients is 

necessary. These chemicals are 

added to the Anaerobic Reactor to 

serve a two-fold purpose: (1) they 

are first needed for proper biological 

growth, and (2) they are needed to 

support the biological reaction 

mechanisms necessary to reduce 

nitrates, selenites, and selenates in 

the Anaerobic Reactors. Sulfate 

reduction to hydrogen sulfide occurs 

simultaneously when the oxidized 

selenium species are converted to 

elemental selenium. Thus, vent gases 

containing sulfides are collected and 

sent to a biofilter for oxidation to 

sulfates. 

Figure 4.3 below shows the ORP level 

achieved in both Anaerobic Reactors 

during the full-scale start-up period. 

The data shows that the ORP was 

maintained between -300 mV to -400 

mV, as originally planned. 

Figure 5.2 Oxidation Reduction Potential (ORP) in Selenium 

Anaerobic Reactors 

‐600

‐500

‐400

‐300

‐200

‐100

0

2/1/2012 3/1/2012 4/1/2012 5/1/2012 6/1/2012

Oxidation Reduction Potential (mV)

Sampling Date

Oxidation Reduction Potential in Selenium

Reactors

Anoxic Reactor

Anaerobic Reactor
IWC 12-41 

Figure 5.3 Nitrate/Nitrite Removal from FGD Wastewater 

(Laboratory Data) 

5.2 Denitrification Performance 

Currently, the FGD wastewater at this 

power generating station has a very 

low concentration of nitrates and 

nitrites in the wastewater (<10 mg/L). 

Daily analytical monitoring showed 

that the nitrate values were <1 mg/L 

in the effluent stream of the new 

biological treatment system indicating 

complete denitrification. The full-scale 

data confirmed the laboratory finding 

that was obtained when the same 

wastewater was tested over a sixmonth period. The laboratory data 

showed that the treatment system 

successfully removed the 

(nitrate/nitrite) concentration from 

~22 mg/L (average) down to <0.2 

mg/L as shown in Figure 5.3 below.

5.3 Selenium Removal 

Performance 

The reduction of total selenium 

throughout the wastewater treatment 

process is shown in Figure 5.4 and 

Tables 5.1 and 5.2 below. The 

influent selenium concentration from 

the FGD blowdown ranged from 0.1 to 

0.7 mg/L and the final effluent from 

the complete WWT system had a total 

selenium concentration range of 0.02 

to 0.22 mg/L. The new Selenium 

Treatment System, when operating at 

steady-state conditions, does produce 

an effluent wastewater that meets the 

targeted total selenium concentration 

of <0.21 mg/L. 
IWC 12-41 

Total selenium removal across the 

major wastewater treatment 

processes is shown in Table 5.2. The 

physical-chemical treatment process 

consisting of pH elevation and 

coagulant/polymer addition was able 

to remove 51% of the total selenium. 

This result is expected because 

historical data from this power 

generating station indicates that the 

selenium species in the influent 

wastewater is ~90% in the selenite 

form. During the start-up period, the 

selenium removal across the 

Anaerobic Treatment System was 

36% and across the complete WWT 

system was 69%. These results were 

obtained during the start-up period 

while the system is not yet stabilized 

at the optimized operating and 

performance conditions. Higher 

removals of selenium are expected as 

the system gets optimized. 

Figure 5.4 Selenium Removal from FGD Wastewater 

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

2/6/2012 3/6/2012 4/6/2012 5/6/2012 6/6/2012

Total Selenium (mg/L)

Sampling Date

Total Selenium Concentration

Surge Tank

Phys‐Chem Effluent

Final Effluent
IWC 12-41 

Table 5.1 Total Selenium Concentration through Wastewater Treatment 

Sampling Point Total Selenium Concentration Range 

(mg/L) 

FGD Blowdown - Influent to WWT 0.12 - 0.68 

After Physical-Chemical Treatment 0.06 - 0.28 

After Anaerobic Biological Treatment 0.02 – 0.23 

Table 5.2 Total Selenium Removal Across Wastewater Treatment Units 

Process Average Total Selenium Removal (%)

Physical-Chemical Treatment 51 

Anaerobic Biological Treatment 36 

Across All WWT Units 69 

6. Conclusions 

As coal-fired power generating 

stations face stricter effluent 

regulations, there is a need for 

advanced wastewater treatment 

technologies to meet the lower, 

stricter limits. The selenium removal 

anaerobic biological wastewater 

treatment system installed at this 

power generating station has 

demonstrated that it can meet the 

targeted selenium concentration of 

<0.21 mg/L in the effluent stream. In 

fact, total selenium concentrations of 

<0.1 mg/L were obtained on many 

operating days. 

In summary, the application of a 

suspended-growth activated sludge 

treatment system which includes 

anoxic, anaerobic and aerobic reactor 

stages proved to be successful for the 

removal of selenium compounds from 

FGD blowdown wastewaters from a 

power generating station. 

7. References 

1. Stover, E.L., Pudvay, M.L., 

Kelly, R.F., Lau, A.O., Togna, 

A.P., “Biological Treatment of 

Flue Gas Desulfurization 

Wastewater,” IWC 07-49, 

68th International Water 

Conference, Orlando, FL 

(2007). 

2. Teng, J., Kelly, R., Lau, T., 

Mehta, S., Berry, M. “iBIO®

Biological Treatment System 

for Flue Gas Desulfurization 

Wastewater,” Air Quality 
IWC 12-41 

Conference, Baltimore, MD 

(2008). 

3. Lau, A.O., Labban, R., Mehta, 

S., Togna, A.P., “Evaluation 

of Carbon Sources for the 

Anaerobic Treatment of Flue 

Gas Desulfurization (FGD) 

Wastewaters for Heavy 

Metals Removal,” IWC 11-33, 

72nd International Water 

Conference, Orlando, FL 

(2011). 

4. Sandy, T., C. DiSante, 

“Review of Available 

Technologies for the Removal 

of Selenium from Water”, 

Final Report prepared for the 

North American Metals 

Council, CH2M Hill (June 

2010). 

5. Onnis-Hayden, A., Du, Y., Yu, 

S., Ledwell, S., Togna, P., 

Gu, A.Z., “Characterization Of 

Alternative Carbon Sources 

For Denitrification,” 

proceedings of the 84th

Annual Water Environment 

Federation Meeting and 

Exhibition, Los Angeles, CA 

(2011). 

8. Acknowledgements 

We would like to acknowledge the 

following individuals for their 

analytical and operations support 

during this project: John Williamson, 

Laboratory Manager, and Denise 

Horner, Sr. Chemist, both from 

Degremont North America Research & 

Development Laboratory; Brittany 

Looke, Chemist, and Cody McLachlan, 

Lead Operator, from the Stover 

Group.