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UNIVERSITY OF HAWAI'I LIBRARY
EVALUATION OF PARAMETERS INFUENCING OXYGEN TRANSFER EFFICIENCY IN A MEMBRANE BIOREACTOR
A THESIS SUBMITTED TO THE GRADUATE DIVISION OF THE UNIVERSITY OF HA WAI'I IN PARTIAL FULFILLMENT OF THE
REQUIREMENTS FOR THE DEGREE OF.
MASTER OF SCIENCE
IN
CIVIL & ENVIRONMENTAL ENGINEERING
DECEMBER 2006
By JingHu
Thesis Committee:
Roger W. Babcock, Chairperson Albert S. Kim
Chittaranjan Ray
We certify that we have read this thesis and that, in our opinion, it is satisfactory in scope
and quality as a thesis for the degree of Masters of Science in Civil & Environmental
Engineering.
THESIS COMMIITEE
ii
ABSTRACT
Design of fine-bubble aeration systems for membrane bioreactors (MBRs) is
challenging due to high mixed liquor suspended solids (MLSS) concentrations that cause
changes in alpha value, which is the ratio of mass transfer rate under process conditions
to that under clean water conditions.
This study describes the results of pilot-scale fine-pore aeration testing to determine
a-values and influencing factors for MBRs. Clean water and process water aeration tests
were performed at the Honouliuli WWTP during the period of December 2005 and
October 2006. Three different 9-inch diameter fine-pore diffusers were tested.
Comprehensive analyses of the sludge properties were conducted.
Through this study, correlations were found to exist between a-value and oxygen
uptake rate (OUR), particle size distribution (PSD), MLSS and viscosity of activated
sludge, thereby providing better understanding and design guidance for MBR aeration
systems.
iii
TABLE OF CONTENTS
ABSTRACT .................................................................................................................... iii
LIST OF TABLES .......................................................................................................... vi
LIST OF FIGURES ...................................................................................................... viii
LIST OF ABBREVIATIONS & SYMBOLS .................................................................. x
CHAPTER I: INTRODUCTION .................................................................................... I
1.1. Background ......................................................................................................... 1
1.2. Characteristics of Activated Sludge in MBRs .................................................... 3
CHAPTER 2: LITERA TORE REVIEW ......................................................................... 6
2.1. Methods for OTE/OTR measurement ................................................................. 6
2.2. Correlation ofOTE or a-value with Influencing Factors in Aeration ................. 9
CHAPTER 3: SCOPE AND OBJECTIVES OF WORK .............................................. 17
CHAPTER 4: FUNDAMENTALS OF OXYGEN TRANSFER TESTS ..................... 18
4.1. Fundamentals of the non-steady state method .................................................. 18
4.2. Fundamentals of the off-gas method ................................................................. 21
4.2.1. Theory of analysis ..................................................................................... 21
4.2.2. Correction to standard conditions ............................................................ 24
CHAPTER 5: MATERIALS AND METHODS ........................................................... 25
5.1. Pilot aeration column ........................................................................................ 25
5.2. Diffusers ............................................................................................................ 25
5.3. Apparatus .......................................................................................................... 25
5.4. MBR pilot description ....................................................................................... 27
5.5. Methods ............................................................................................................. 30
iv
5.6. Chemicals .......................................................................................................... 33
CHAPTER 6: DISCRIPTION OF FIELD STUDIES .................................................... 35
6.1. Clean water aeration column testing ................................................................. 35
6.2. Process water aeration column testing .............................................................. 37
CHAPTER 7: RESULTS AND DISCUSSION ............................................................. 42
7.1. Clean water aeration test ................................................................................... 42
7.2. Process water aeration test ................................................................................ 43
7.2.1. Evaluation of Diffuser Type on a-value .................................................... 43
7.2.2. Evaluation of Air Flow on a-value ............................................................ 44
7.2.3. Evaluation of MLSS and ML VSS concentration on a-value ..................... 45
7.2.4. Evaluation of Viscosity on a-value ............................................................ 48
7.2.5. Evaluation of OUR on a-value .................................................................. 50
7.2.6. Evaluation ofPSD on a-value ................................................................... 53
7.2.7. Evaluation ofSMP, EPS, TDS and SCOD on a-value .............................. 56
7.2.8. Evaluation ofMLSS. MLVSS, Viscosity, OUR and PSD on OTE ............. 58
CHAPTER 8: CONCLUSIONS, LIMITATIONS AND RECOMMENDATIONS .... 60
8.1. Conclusions from the study ............................................................................... 60
8.2. Limitations of the study .................................................................................... 61
8.3. Recommendations for future research .............................................................. 62
APPENDIX I: RAW DATA TABLES .......................................................................... 63
APPENDIX II: DATA SUMMARIES .......................................................................... 74
APPENDIX III: PHOTOGRAPHS ................................................................................ 90
REFERENCES ............................................................................................................... 96
v
LIST OF TABLES
T~le P~e
I. Comparisons of the Methods for OTE Measurement ...................................... 7
2. Factors Affecting Oxygen Transfer in Aeration Systems .............................. 10
3. Review of the Effect ofMLSS on Oxygen Transfer for MBRs .................... 13
4. Enviroquip 5MBR Pilot System Summary .................................................... 27
5. Chemicals Used in the Experiments .............................................................. 34
6. Comparison of a-value of 3 Diffusers ............................................................ 43
7. Clean Water Test (I) Raw Data ..................................................................... 63
8. In Situ OUR Test (1) Raw Data ..................................................................... 66
9. In Situ OUR Test (2) Raw Data ..................................................................... 67
10. In Situ OUR Test (3) Raw Data .................................................................... 68
II. In Situ OUR Test (4) Raw Data ..................................................................... 69
12. In Situ OUR Test (5) Raw Data ..................................................................... 70
13. In Situ OUR Test (6) Raw Data .................................................................... 71
14. In Situ OUR Test (7) Raw Data ..................................................................... 72
15. In Situ OUR Test (8) Raw Data ..................................................................... 73
16. Clean Water Test Results Summary ............................................................. 74
17. Off-gas Analysis (1) Data Summary ............................................................. 75
18. Off-gas Analysis (2) Data Summary ............................................................. 76
19. Off-gas Analysis (3) Data Summary ............................................................. 78
20. Off-gas Analysis (4) Data Summary ............................................................. 80
vi
21. Off-gas Analysis (5) Data Summary ............................................................. 82
22. Off-gas Analysis (6) Data Summary ............................................................. 84
23. Off-gas Analysis (7) Data Summary ............................................................. 86
24. Off-gas Analysis (8) Data Summary ............................................................. 87
25. Sludge Properties at Various MLSS Concentrations .................................... 89
vii
LIST OF FIGURES
Figure ~
1. Effect of SCOD Values on OTEzo ..................................................................... 10
2. Alpha-value as a function ofML VSS .............................................................. 11
3. Alpha-MLSS relationships for fine-bubble systems ........................................ 14
4. Specific oxygen transfer efficiency as a function ofMLSS ............................ IS
5. Alpha-Viscosity relationships for fine-bubble systems ................................... 16
6. Schematic of the Analyzer Structure ................................................................ 26
7. Anatomy of the Membrane Cartridge .............................................................. 28
8. Cutaway Illustration of Membrane Unit .......................................................... 28
9. Process Flow Diagram of the Enviroquip MBR .............................................. 29
10. Aeration Column Setup for Clean Water Testing ............................................ 36
11. Aeration Column Setup for Process Water Testing ......................................... 38
12. Average mass transfer coefficient for three fine pore diffusers ....................... 42
13. Average SOTE for three fine pore diffusers .................................................... 43
14. Alpha-value of the membrane diffuser at varied AFR ..................................... 45
15. Alpha-value of the ceramic diffuser at varied AFR ......................................... 44
16. Comparison of the a-value under different process conditions via MLSS ........................................................................... 46
17. Comparison of the a-value under different process conditions via MLVSS ........................................................................ 46
18. Correlation ofMLSS and a-value .................................................................... 47
19. Correlation of ML VSS and a-value ................................................................. 48
20. Correlation ofMLSS and viscosity .................................................................. 48
viii
21. Comparison of the a-value under different dit· .. .ty 49 process con IOns Via VlSCOSI ...................................................................... .
22. Correlation of viscosity and a-value ................................................................ 49
23. Correlation of OUR and MLSS ....................................................................... 50
24. Comparison of the a-value under different process conditions via OUR .............................................................. 51
25. Correlation of OUR and a-value ...................................................................... 51
26. Particle size distributions at various MLSS conc .............................................. 53
27. Correlation of particle size and MLSS ............................................................. 54
28. Comparison of the a-value under different process conditions via particle size ................................................... 55
29. Correlation of particle size and a-value ........................................................... 55
30. Relationship between SCOD and MLSS ......................................................... 56
31. Relationship between TDS and MLSS ............................................................ 57
32. Relationship between total SMP and MLSS .................................................... 57
33. Relationship between total EPS and MLSS ..................................................... 57
34. Correlation ofMLSS or MLVSS and VOTE ................................................... 58
35. Correlation of viscosity and VOTE ................................................................. 58
36. Correlation of OUR and VOTE ....................................................................... 59
37. Correlation of particle size and VOTE ............................................................. 59
ix
LIST OF ABBREVIATIONS & SYMBOLS
The following abbreviations and symbols are used in this paper:
ABS Acrylonitrile-Butadiene-Styrene
AECOR Aemtion Engineering Resources Corp.
AFR Air flow mte
ASCE American Society of Civil Engineers
ASP Activated sludge process
BOD Biological oxygen demand, mgIL
CASP Conventional activated sludge process
CST Capillary suction time
CER Cation exchange resin
DO Dissolved oxygen, mgIL
EMBR External membrane bioreactor
EPDM Ethylene Propylene Diene Monomer
EPS Extracellular polymeric substances, mgIL
HOPE High density polyethylene
HRT Hydmulic retention time, hr
MBR Membrane bioreactor
MCRT Mean cell residence time, hr
MOD Million gallons per day
MLSS Mixed liquor suspended solids, mgIL
"
MLVSS
OTE
OTR
OUR
PSD
PTFE
SCFM
SCOD
SMP
5MBR
SOTE
TDS
TSS
VOTE
VSS
a
C
Co
C' w
Mixed liquor volatile suspended solids, mgIL
Oxygen transfer efficiency in percent
Oxygen transfer rate, mg/L
Oxygen uptake rate, mg I L . hr
Particle size distribution
Polytetrafluoroethylene
Standard cubic foot per minute
Soluble chemical oxygen demand, mgIL
Soluble microbial products, mgIL
Submerged membrane bioreactor
Standard oxygen transfer efficiency in percent
Total dissolved solids, mg/L
Total suspended solids, mg/L
Volumetric oxygen transfer efficiency in percent
Volatile suspended solids, mg/L
Diffuser specific area, m 2 •
DO concentration, mg/L
DO concentration at time zero, mg/L
Equilibrium DO concentration at tested conditions, mg/L
Equilibrium DO concentration at 20'C, 1 atm and zero salinity. mg/L
Equilibrium DO concentration at the test temperature T, 1 atm and zero salinity. mg/L
xi
C· ST
D
MRog/i
ND
t
T
P,
v
Vo
Wo.
Tabular value of DO saturation concentration at 20°C, I atm and 100% relative humidity, mg/L
Tabular value of DO saturation concentration at the test temperature T, 1 atm and 100% relative humidity, mg/L
Particle diameter, J.Ull
Mass rate ofinerts, kg/s
Volumetric mass transfer coefficient, S-I
Volumetric mass transfer coefficient at 20·C, S-I
Molecular weights of oxygen
Molecular weights of inerts
Mole ratio of oxygen to inerts in the inlet stream
Mole ratio of oxygen to inerts in the off-gas stream
Total diffuser number
Time, s
Temperature, ·C
Barometric pressure during the test, psi
Standard atmospheric pressure 14.7 psi at 100% relative humidity
Total volumetric gas flow rates of inlet gas, m3 /s
Total volumetric gas flow rates of outlet gas, m3 /s
Liquid volume of water in the test tank, m3
Gas hold-up volume, m3
Mass flow of oxygen in air stream, kg/ s
Mole fractions of oxygen in the inlet gas
xii
Yco,(R)
z
a
aSOTE
TJr,40
p
T
n
Mole fractions of oxygen in the exit gas
Mole fractions of CO2 in the reference gas(R)
Mole fractions of CO2 in the off-gas (og)
Mole fractions of water vapor in the reference gas (R)
Mole fractions of water vapor in the off-gas (og)
Diffuser submergence, m
The ratio of the value of KLa measured in process water to the KLa measured in clean water
Oxygen transfer efficiency corrected for all process conditions such as DO, salinity, temperature and barometric pressure, except for a factor
Correction factor for salinity
Shear strain rate imposed on the sample, S-I
Shear stress, mPa
Yield stress, mPa
Absolute viscosity, mPa· s or cP
Absolute viscosity at a shear rate of 40 S·I, mPa· s
Empirical temperature correction factor
Absolute viscosity, mPa· s or cP
Density of oxygen at temperature and pressure of gas flow, kg/ m3
Temperature correction factor
Barometric pressure correction factor
xiii
1.1 Background
CHAPTERl INTRODUCTION
Statewide in Hawaii, approximately 16% (23 MOD) of municipal wastewater is
currently recycled. With the potential for compact, decentralized water reclamation
installations combined with very high quality permeate water, membrane bioreactors
(MBRs) promise to be an effective method for enhancing water recycling if they can be
shown to be reliable and cost effective (Babcock et al., 2003).
MBR systems can sustain higher biomass concentrations by replacing the secondary
clarifier with membrane filtration and allowing smaller aeration basins to be used. In an
MBR, the membranes create a physical barrier of solids and therefore the process is not
subject to gravity settling solids limitations. However, they are limited instead by fluid
dynamics of high solids mixed liquor, and by the effect of high solids on oxygen transfer.
Oxygen transfer is a major factor influencing the efficient and economic operation of
all aerobic bioprocesses, including MBRs. The overall volumetric mass transfer
coefficient, K La, is a parameter to characterize the rate of oxygen transfer in aeration
processes; where K L represents the mass transfer coefficient based on the liquid film
resistance and a, the interfacial area.
The value of alpha (11) is another parameter commonly used to describe the oxygen
transfer in biological aerated systems, which is the ratio of mass transfer rate under
process conditions (mixed liquor) to that under clean water conditions. This correction
factor quantifies the influence of mixed-liquor constituents on aeration capacity. It is an
important operating and design variable for aeration systems in activated sludge process
(ASP).
MBR systems utilize aeration in two forms. First, they utilize coarse-bubble (cross
flow) aeration for membrane scour to control permeability and fouling. Second, they use
fine-pore aeration for mass transfer of oxygen to meet biological requirements as well as
for mixing in the aeration tank. According to the report prepared for the Water
Environment Research Foundation (WERF, 2004), energy costs associated with aeration
in submerged MBR (SMBR) systems represent more than 90 percent of the total energy
cost. Therefore, potential oxygen limitations appear to be a serious cost issue for 5MBR
systems, and acquiring accurate oxygen transfer information on these systems is of great
necessity. Substantial savings in overall energy costs of WWTPs with MBRs can be
realized by using this information to improve the energy efficiency of the aeration
system. In addition, if designers understand the oxygen transfer in mixed liquor of an
aeration tank and factors that affect it, they can provide more optimized designs to treat
the wastewater to the required effluent quality.
The aeration, the oxygen transfer and the biomass characteristics interrelate with and
impact on each other. When studying aeration operations in MBRs, we need to consider
both the effects of biomass characteristics on aeration efficiency, represented by the
oxygen transfer parameters (Le., KLa and a-value), and the effects of aeration (intensity
and type of diffusers) on biomass characteristics (Germain and Stephenson, 2005).
Fine-pore aeration system design requires the determination of an appropriate a
value. However, this design in MBRs is challenging at high MLSS due to changes in a
values. Currently there is a lack of good data on a-values at the high MLSS found in
2
MBRs. If the wrong value of alpha is used, the aeration system can be either over
designed or under-designed. Previous studies have obtained correlations of a-values at
high solids with MLSS and with viscosity. However, the existing data have considerable
variability in the solids range of interest in current MBR designs (Babcock, 2006).
This context highlights the need for further research on accurate detennination of
oxygen transfer efficiencies and a-values in MBR process, as well as exploration of
relationships between a-values and more parameters describing mixed liquor properties
besides MLSS and viscosity. Better correlations may be obtained with these parameters.
1.2 Characteristics of Activated Sludge in MBRs
Activated sludge is a complex and variable heterogeneous suspension containing both
feed water components and metabolites produced during the biological reactions as well
as the biomass itself (Chang et al., 2002). It is a mixture of particles, microorganisms,
colloids, organic polymers and cations, which all have different shapes, sizes and
densities.
MBRs and conventional activated sludge process (CASP) have many similarities,
particularly in tenns of microbial metabolism and kinetics. However, substituting
membrane separation for gravity sedimentation allows much higher MLSS
concentrations (8,000 to 20,000 mgIL) in MBRs with resulting high metabolic rates.
Mainly due to the high MLSS, the sludge characteristic differs from conventional
activated sludge.
The activated sludge suspension is a non-Newtonian liquid with pseudoplastic
properties (Dick and Ewing, 1967). For Newtonian fluids, shear stress is proportional to
shear rate, with the proportionality constant being the viscosity, while the viscosity of
3
non-Newtonian fluids changes as the shear rate is varied. A pseudoplastic liquid is a non
Newtonian fluid whose viscosity decreases as the applied shear rate increases. This type
of behavior is also called shear-thinning.
High biomass concentrations give rise to non-Newtonian behavior with high apparent
viscosities. This can largely be attributed to the fact that cross-linked filamentous
organisms and flocs are present in the sludge. These high apparent viscosities affect the
energy required for pumping and oxygen supply of the microorganisms. They may
impede oxygen transfer and the degree of mixing by influencing bubble coalescence
(Germain and Stephenson, 2005; WERF, 2004).
High biomass also forms a high production of soluble microbial products (SMP) and
extracellular polymeric substances (EPS) in the bioreactor, which are both important
components in describing biomass kinetics. EPS are a complex mixture of proteins,
carbohydrates, acid polysaccharides, DNA, lipids, and humic substances that surround
cells and form the matrix of microbial flocs and films (Liao et al., 2004). They are an
essential part of activated sludge. The importance of EPS in controlling membrane
fouling has been studied extensively while there is little information on the role of EPS in
affecting oxygen transfer. SMP are the pool of organic compounds that are released into
solution from substrate metabolism (usually with biomass growth) and biomass decay
(Barker and Stuckey, 1999). Like EPS, SMP are primarily composed of proteins, humic
compounds and polysaccharides. In order to be able to reach the active sites of the
bacterial cell membrane, the oxygen contained in the air bubbles needs to penetrate the
liquid film surrounding the floes (SMP) and then diffuse through the floc matrix (EPS)
4
(Gennain and Stephenson, 2005). Therefore both compounds are likely to affect the
oxygen transfer.
Particle size is another parameter characterizing the biomass. Compared to
conventional activated sludge, the average diameter of a particle in a MBR is
considerably smaller, because bacteria are not selected for their ability to aggregate to
large, settleable floes. Moreover, the high shear forces introduced, particularly by
pumping during cross-flow filtration, can break up floes. In conventional activated
sludge, floes may reach several 100 J.lm in size (Wisniewski et aI., 1999). Hydrodynamic
stress in MBRs reduces floc size to approximately 30--60 J.lm in immersed systems
(Zhang et aI., 1997; Song et aI. 2003) and 3.5 J.lm in sidestream MBRs (Cicek et aI.,
1999).
Oxygen uptake rate (OUR) is a measure of the rate of oxygen utilization of
microorganisms in a body of liquid. It is a good indicator of metabolic activity of the
biological system and has been traditionally used in aerobic processes to estimate on-line
the biomass activity (Oca et aI., 2004). In MBRs, higher MLSS concentrations and
accordingly higher possible sludge age affects the bacterial numbers and the composition
of the microbial community, and thus changes OUR (Drews et aI., 2005; Li et aI. 2006).
OUR is a potential oxygen transfer parameter and could be used to control the aeration
rate or the sludge recycling rate in wastewater treatment.
Other biomass characteristics in MBRs may also have an impact on oxygen transfer
and accordingly a-values, such as the soluble COD fraction (SCOD) and the total
dissolved salt content (TDS). It's necessary to comprehensively investigate the influences
of these parameters on the diffusion of oxygen in MBR process.
5
CHAPTER 2 LITERATURE REVIEW
2.1 Methods/or OTE or OTR measurement
A variety of techniques exist for estimating oxygen transfer efficiency (OTE) or
oxygen transfer rate (OTR) of an aeration system, which can be generally divided into
four categories (Stenstrom, 1997; Stenstrom, 2005):
• Adsorption or re-aeration method
It adopts the same procedures as in clean water testing and converts the results to
field rates with conversion factors. This method determines KLa and the
equilibrium dissolved oxygen concentration C: for process water by first
removing DO from then re-oxygenating the water to near the saturation level.
• In-situ oxygen uptake rate (OUR) method
It's process water testing using methods to account for the biological consumption
of oxygen during the transfer test. It determines KLa for a mixed aeration tank
under process conditions by measuring the in-situ OUR under steady-state
conditions. The in-situ OUR is measured by monitoring the DO concentration
after stopping aeration.
• Material balance methods
They attempt to determine difference in inputs and outputs of oxygen consuming
material.
• Off-gas method
This method estimates the oxygen transfer capability by a gas phase mass balance
over the aerated volume. It requires the capture of a representative sample of the
6
gas, which exits the aeration basin surface, and analysis of this gas for its
composition.
The advantages and disadvantages of the above four methods presented in literature
studies (Capela et ai., 2004; Cornel P. et aI., 2003; and Krause S. et aI., 2003) are
summarized in Table 1.
Table 1. Comparisons of the Methods for OTE Measurement
Method Advantage Main Drawback
It is very difficult to accurately estimate the a-factor. Constant process conditions should be
Adsorption - maintained during the test duration. A minimum, incremental DO cone. of 2 mgIL should occur for implementing this method. It is difficult to accurately estimate oxygen consumption rate, especially in oxygen limiting conditions occurring in overloaded
OUR It's simple to perfonn. treatment plants. It requires that the aeration and mixing functions be dissociated to maintain the mixed liquor in suspension when aeration is stopped. It requires long-tenn knowledge of process operating conditions such as sludge wasting
Material rate. Balance - It's susceptible to error from sludge settling
in the aeration basin or stripping of volatile oxygen consuming compounds.
It is perfonned at real in-process It requires an accurate measurement of the conditions without requiring airflow rate and an estimate of the DO process modification or chemical saturation cone. in process water. addition to complete the test.
Off-gas The DO concentration or OUR does not interfere with the test procedure. It offers the advantage of differentiation in location and time.
7
Adopting the improved off-gas technique - mole fraction approach, the mass
transfer efficiency can be determined without measuring flow rates of gas entering and
exiting the fluid. This improvement overcomes the main drawback of traditional off-gas
method. By knowing the molar percents of the reacting or changing gas constituents
(oxygen, carbon dioxide, and water vapor), OTE can be calculated based on the gas phase
mass balance. In the meanwhile, there is no need to estimate the DO saturation
concentration in process water. Only equilibrium DO concentrations in clean water at
20°C and test temperature( C:20 and C:T ) need to be determined. Conclusively, the off
gas method is preferable to the other three methods for determining OTE in mixed liquor,
since it can be applied on a continuous mode at any particular location in the aeration
tank and under a wide range of process conditions.
Capela et aI. (2004) systematically compared the four measurement techniques under
process conditions in conventional WWTPs: the off-gas, hydrogen peroxide (HzOz), re
aeration, and in situ OUR methods. The HzOz method is based on the same principle as
the re-aeration method. It determines OTE by monitoring the DO concentration over the
time after adding HzOz. With the comparisons of pilot-scale and full-scale results of
oxygen-transfer coefficients obtained by different methods, the off-gas technique was
recommended for the analysis of diffused systems when applicable.
Krause et aI. (2003) conducted a comparison of the adsorption method with the off
gas method in full scale MBRs. Nevertheless with both methods comparable OTRs were
obtained, the varying results achieved by application of off-gas analysis revealed the big
advantage ofthls method, being able to record exactly the time-variation of the OTR. It's
8
also pointed out that the off-gas method only can be applied at DO concentration below
50% of the saturation concentration and at low air flow rates.
Currently off-gas method is widely accepted and has been the preferred method for
measuring OTE in operating aeration basins, because of its combination of reliability and
convenience. (Groves et al. 1992; lranpour et aI., 2000; Jranpour et aI., 2002; Mueller et
aI., 2000; and Stenstrom, 1989). The modern off-gas test was developed by Redmon et aI.
(1983) in conjunction with the U.S. EPA-sponsored ASCE Oxygen Transfer Standard
Committee. The technique measures actual OTE at process conditions assuming that inert
gases (nitrogen, argon) are conserved and can be used as a tracer. The fundamentals of
this method are described in detail in Chapter 4.
Brochrup (1983) and Babcock et aI. (1999) evaluated the precision and accuracy of
off-gas analysis. Brochrup estimated a coefficient of variation of 6% or less. Babcock et
aI. estimated an error of less than 10% for fine pore aeration systems and pointed out
these errors can be easily avoided by diligent maintenance of test equipment and by
maintaining good quality control practices. Therefore, if conducted carefully, with
maintained equipment, off -gas testing is a very accurate method for determining OTE
under process conditions.
2.2 Co"elation of OTE or a-value with Influencing Factors in Aeration
Due to complex mechanisms underlying oxygen transfer in aeration systems, OTE
and a-value could be affected by three groups of factors including equipment factors,
operation factors and wastewater conditions as listed in Table 2. The information was
obtained from U.s. EPA (1989) EPA/ASCE Design Manual on Fine Pore Aeration.
9
Table 2. Factors Affecting Oxygen Transfer in Aeration Systems
Equipment Factors Diffuser type Diffuser density Diffuser submergence Diffuser layout Diffuser age Flow regime Basin geometry
Operation Factors Solids retention time/nitrification Food to microorganisms ratio Airflow rate per diffuser Mixed liquor DO Diffuser fouling
Wastewater Conditions Wastewater characteristics Mixed liquor temperature
Some correlations linking oxygen transfer and aerobic biological system
characteristics are found in CASP in the literature, depending on the parameters
considered.
Mueller et aI. (2000) found that solution-phase COD (SCOD) concentration is a
principal factor influencing OTE and alpha for the plug-flow systems. In this study, OTE
was measured with the membrane diffusers utilizing the off-gas technique. The difference
in a-values was correlated with the impact of SCOD on the individual station OTE2o
values (tank weighted avemge process OTE at zero DO and 20°C) as shown in Fig. 1. An
increase in SCOD leads to a decrease in OTE2o.
30 ,--------------------------------------------,
o
'" W I-o 10
OTE,. = -0.405 SCOD + 5 1.1
a L-~ __ ~ __ ~ __ ~ __ ~ __ ~ __ ~ __ ~ __ ~~ __ ~ __ -"
a 20 40 60 80 100 120
seOD (mgll)
Fig. 1. Effect ofSCOD Values on OTE2o
10
Stenstrom (1989) observed a good correlation between ML VSS concentration and a-
value in the full-scale study of 6 conventional WWTPs. Process oxygen transfer rates
were determined using off-gas analysis and different fine pore diffusers were evaluated.
A trend for a-value to increase with ML VSS at the aeration basin inlet is shown in Fig. 2
while the correlating equation wasn't given.
o~,-----------------------------------,
.. .., 1.5 0.20
:I .~
l: 15
0.15
0 :z:= • II 10 .... 0.10 .. 0 0 oD If: ..
D 0.0$ CI~ .....
0.00 400 SOD 800 1000 1200
MLVSS (mgIL)
Fig. 2. Alpha-value as a function ofMLVSS concentration
Rosso et a1. (2005) summarized 15 years ofOTE measurements of fine-pore diffusers
using the off-gas technique. The dataset was based on 30 nationwide conventional
activated sludge plants treating municipal wastewater with mean cell retention time
(MCRT) ranging from 1.6 to 36 days. The normalized airflow rates QN and MCRT were
correlated with a and aSOTE as follows:
aSOTE = 5.717 ·logX - 6.815
a = 0.172 ·logX -0.131
II
where:
MCRT 'X,=--
QN
Q _ AFR
N-a·ND ·z
AFR = air flow rate, m3 Is
a = diffuser specific area, m2
N D = total diffuser number
Z = diffuser submergence, m
In MBR process, biomass and membranes interact in a number of ways and mass
transfer interactions are different, making it difficult to extrapolate phenomena and
correlations known from CASP. However, the affecting factors mentioned above can still
be taken into account when research is carried out to explore the correlations between
oxygen transfer and potential influencing parameters in MBRs.
Recently some investigations have been performed to identify the effect of MLSS
concentration on oxygen transfer rates, particularly on a-values in MBRs (Cornel et a1.,
2003; GOnder and Krauth, 1999; GOnder, 2001; Krampe and Krauth, 2003; Muller et a1.,
1995; and Wagner et a1., 2002). As reviewed in Table 3, different magnitudes of a-values
at high MLSS were reported in the literature.
These studies observed an exponential relationship between a-value and MLSS
concentration. The results are summarized in Fig. 3. Despite the differences between the
systems and the sludge type, high solids concentrations affected the oxygen transfer in
the same way. Muller et a1. (1995), found a-values of 0.98, 0.5, 0.3, and 0.2 for MLSS
concentrations of3, 16,26 and 39 g.L·' respectively, but didn't correlate a to MLSS. An
exponential equation representing the impact of the solids concentrations on the a-value
was calculated from this data.
12
Table 3. Review of the Effect of MLSS Concentration on Oxygen Transfer for MBR Systems
Reactor Config. Membrane MLSS Aeration OTE Determination Measured Ana[yzed Sludge Reference and Scale Modu[es Range (gIL) System(s) Method a-value Properties
Ranl!e EMBRa UFandMF 3-39 A diffused air Not specified 0.98-0.2 MLSS& Muller et aI., (pilot scale) system Particle size [995
5MBR6 Plate, Hollow (pilot scale) fiber 8-25 Fine-bubb[e. Not specified 0.5-0.15 MLSS GOnder and
Coarse-bubble. Krauth, 1999 EMBR Tubu[ar Surface (pilot sca[e)
Single-tank 5MBR (full scale). Not specified 7-17 Fine-bubb[e Clean water (adsorption). 0.7-0.4 MLSS& Wagner et aI .• Dual-tank 5MBR mixed liquor (adsorption) Viscosity 2002 (full scale)
Single-tank 5MBR (full scale). Not specified 7-17 Fine-bubble Clean water (adsorption), 0.7-0.4 MLSS. Cornel et aI., Dual-tank 5MBR mixed liquor (off-gas. Viscosity, 2003 (full scale) adsorption) Air f10wrate &
Surfactant conc.
Pilot scale. Several activated Not specified 8-28 Fine-bubble, Clean water (adsorption). 0.5-0.1 MLSS, ML VSS, Krampe and sludge types lajector mixed liquor (adsorption) Viscosity. EPS. Krauth, 2003
CST". Polymer contents &
Surface tension
a EMBR = external MBR b 5MBR = submerged MBR • CST = capillary suction time
13
1.0 ~--------------------,
Gl = e,o.017l ·MISS (Gunder, 2001) 0.8+-~~~
Gl = e,O.0446 ·MLSS (Muller et al,1995) ., ::J Oi 0.6
(Wagner et aI, 2002; Cornel et ai, 2003) a = e,O.046 ·MLSS %
.<:
~0.4 Gl = e ,0.082 . MLSS
.lGunder an~ Krauth,I9921n _ ~~~:::::~~~~~] a = e,O.08788 ·MLSS
0.2
(Krampe and Krauth,2003) 0.0 +---~-~~c.:...:.~-----~::":"~~--~------l
o 5 10 15 20
MLSS concentration (gil)
25 30
Fig. 3. Alpha-MLSS concentration relationships for fine-bubble systems in MBRs
All of the evidence exists that MBRs, which operate at high MLSS concentrations,
have suppressed a-values, and that a-value is inversely proportional to MLSS. However,
the decrease rate of a with MLSS varies among studies.
Wagner et aI. (2002) and Cornel et aI. (2003) determined a-values for the fine-bubble
aeration systems in full-scale municipal MBRs. They indicate that a-value decreases
from 0.6 to 0.4 in the MLSS concentration range of 10 to 20 gIL. Daily a-value variations
in the range of ± 0.1 were detected, which were attributed to varying surfactant loading.
Additionally, the coarse bubble "cross-flow" aeration system was found indicating no
dependence of a-value and MLSS.
Cornel et aI. (2003) also obtained the relationship between MLSS and specific
oxygen transfer efficiency. Fig. 4 shows the specific oxygen transfer efficiency as a
function of MLSS, which means the oxygen transfer efficiency per unit depth of aeration
tank.
14
10
co 6 ui b o 4 !5 Q) Co en 2
------------ ----------------------~
TJ = 9.00-S.63x 10-4 MLSS+2.56xI0-s MLSS2
O+---,----,--~---,----r_--._--~--_r--~
o 2000 4000 6000 8000 10000 12000 14000 16000 18000
MLSS (mg/L)
Fig. 4. Specific oxygen transfer efficiency as a function of MLSS
Furthennore, some researchers evaluated the effect of mixed-liquor viscosity on ex-
value. GUnder (2001) and Krampe and Krauth (2003) formulated equations linking the a-
value to the viscosity at a shear rate of 40 S·1 in activated sludge with high MLSS
concentrations (Fig. 5). An increase in viscosity has been shown to have a negative
influence on the oxygen transfer. The same trend was also observed by Wagner et aI.
(2002) while the correlating equation wasn't given.
In these studies, a-value was correlated better with viscosity than with MLSS
concentration, which suggests that the effect of MLSS on a might be better explained in
terms of the influence of MLSS on viscosity. Explanations concerning this phenomenon
have been given in the literature (WERF, 2004). High viscosity may lower a by
increasing the rate of bubble coalescence, and thus reducing the interfacial area of oxygen
transfer. Additionally, the ability of bubbles to induce turbulence and mixing decreases
with viscosity.
15
1.2 -- - ------------------
1.0
~ 0.8
a = I1r.40 ·0456 (Krampe and Krauth, 2003)
:./ --- ------
~ IV 0.6 .£: Q.
;( 0.4 a= I1r.40 -OAS (Gunder, 2001)
I 0.2 ---- ---j 0.0
0 20 40 60 80 100 120
ll,40 [mPa . sl
Fig. 5. Alpha-Viscosity relationships for fine-bubble systems
So far some limited work has been done to observe the impact of other biomass
properties besides MLSS and viscosity on aeration efficiency in MBR process. Krampe
and Krause (2003) analyzed the sludge in regard to MLSS, viscosity, polymer contents,
EPS components and capillary suction time (CSn. However, only the solid contents and
the viscosity were found to be possible parameters to describe the relations. In this study,
all sludge types were gradually diluted in order to get a series of solids contents. This is
very different than growing or accumulating sludge in the aeration tank and obtaining the
desired solids contents in sequence gradually. The dilution method wouldn't be expected
to accurately capture sludge characteristics under different growth conditions.
In conclusion, although several practical experiences and data are available for MBR
aeration processes, no systematic and comprehensive investigation has been conducted so
far on other sludge properties such as OUR, PSD, TOS, SCOD, SMP and EPS in addition
to MLSS and viscosity. The influence of other sludge properties on oxygen transfer still
remains unclear. Therefore additional or further studies are needed to determine how
other variables affect the a-MLSS concentration relationship in MBRs.
16
CHAPTER 3 SCOPE AND OBJECTIVES OF WORK
The pilot-scale aeration study was conducted under existing operating conditions at
Honouliuli WWTP located at Ewa beach, Honolulu, Hawaii, where an investigation of
parallel pilot MBR systems is underway. A 20 ft tall pilot column had been constructed
for aeration testing and was filled with clean or process water. Clean water tests were
performed with 3 different 9-inch diameter fine-pore diffusers, ceramic, membrane, and
high density polyethylene (HDPE) types, to determine standard oxygen transfer
efficiency (SOTE) under specific airflow rates. This was followed by off-gas testing with
process water at varied MLSS concentrations (5, 7.5, 10, 12.5, IS, 17.5, and 20 gIL) to
determine OTE. The process water consisted of mixed liquor from a MBR pilot. An off-
gas analyzer was constructed to measure OTE under steady-state conditions. In addition,
the comprehensive analyses of the activated sludge were carried out to investigate the
relationship between the sludge properties and a-value.
The main goal of the study was to determine a-value and provide better
understanding for more efficient fine-bubble aeration system design of full-scale MBRs.
The specific objectives included:
1. To acquire good data on OTE and a-values at the high MLSS concentrations in a
MBRsystem.
2. To systematically examine the effects of aeration intensity, diffuser type, and
various sludge characteristics, such as TSS, VSS, viscosity, SMP, EPS, PDS,
OUR, SCOD and TDS, on oxygen transfer; identify potential factors affecting
OTE and a-value.
3. To obtain better correlations of these identified factors with a-value in MBRs.
17
CHAPTER 4 FUNDAMENTALS OF OXYGEN TRANSFER TESTS
4.1 Fundamentals of the non-steady state method
Interfacial oxygen transfer involves transport from the bulk gas phase to the interface,
and then from the interface into the liquid. For sparingly soluble gases, such as oxygen,
mass transfer on the gas side of the interface is much quicker; therefore, transfer on the
liquid side is expected to control oxygen transfer at the interface. Then oxygen transfer
can be described by the following two-resistance mass transfer model, which is most
commonly used to predict oxygen transfer in water (Aeration A Wastewater Treatment
Process, 1988; ASeE, 2000):
(4.1)
where:
e = DO concentration, mg I L
e: = DO saturation concentration, mg I L
KLa = apparent volumetric mass transfer coefficient, S-I
t = time, s
The method for determining KLa and e: in clean water is the unsteady adsorption
method, which involves first removing dissolved oxygen (DO) from the water volume by
the addition of a chemical reductant (normally sodium sulfite) and then re-oxygenating
the water to near the saturation level using the specific aeration device. The KLa and e: values are estimated by regression analysis of the measured DO data using the integrated
form of Equation (4.1), which is shown in Equation (4.2):
(4.2)
18
where:
Co = DO concentration at time zero, mg I L
The values of KLa and C: are dependent on water temperature and the barometric
pressure (under process conditions) and they are adjusted to standard conditions. The
standard oxygen transfer efficiency (SOTE) is obtained as follows:
(4.3)
where:
C:ao = equilibrium DO concentration at 20 °C, I atm and zero salinity, mg/L
KLaao = apparent volumetric mass transfer coefficient at 20 °C, 5-1
V = liquid volume of water in the test tan k, m3
W 02 = mass flow of oxygen in air stream, kg I s
The equilibrium DO concentration C:ao and apparent volumetric mass transfer
coefficient KLa aO are calculated as follows:
where:
• • ( I ) C"ao = CooT to
K a - K a·e(20-T) L 20 - L
(4.4)
(4.5)
C:T = equilibrium DO concentration at temperature T,I atm and zero salinity, mg/L
KL a = apparent volumetric mass transfer coefficient at the test temperature, S-1
t = temperature correction factor
o = barometric pressure correction factor
e = empirical temperature correction factor
19
T = temperature, °C
The pressure correction factor n accounts for the effect of non-standard barometric
pressures. It is calculated as follows for basins less than 6.1 m (20 ft) deep:
where:
n = Ph P,
Pb = barometric pressure during the test, psi
(4.6)
P, = standard atmosphere pressure 14.7 psi at I 00% relative humidity
The influence of temperature on the oxygen transfer coefficient and oxygen saturation
value can be expressed in terms of the factors e and 1", defined by:
e(T -20) = KL aT
K La 20
(4.7)
(4.8)
The influence of temperature on the various oxygen saturation concentrations will be
similar. Therefore, 1" can be calculated based on published DO surface saturation values:
where:
C' ST
(4.9)
= tabular value of DO saturation conc. at 20°C, I atm and 100% relative humidity, mg/L
= tabular value of DO saturation conc. at the test temperature, 1 atm and 100% relative humidity, mg/L
Values of e reported in the literature have ranged from 1.008 to 1.047 and are
influenced by geometry, turbulence level, and type of aeration device. The clean water
20
test standard recommends that the value of e be taken to1.024 unless experimental data
for the particular aeration system indicate conclusively that the value is significantly
different from 1.024 (Aeration A Wastewater Treatment Process, 1988).
4.2 Fundamentals of the off-gas method
4.2.1 Theory of analysis
The off-gas method is based on a gas-phase mass balance, which measures the change
in oxygen content of the air entering and exiting an aeration tank. By comparing the
composition of the off-gas to that of the gas entering an aeration tank, it is possible to
calculate the oxygen transfer occurring within the tank. If the flow rates of gas entering
an exiting the fluid are known, then the following mass balance can be made (Stenstrom
1997; Stenstrom 2005):
(4.10)
where:
p = density of oxygen at temperature and pressure of gas flow, kg! m 3
q;,qo = total volumetric gas flow rates of inlet and outlet gasses, m3 !s
YR, YOg = mole fractions (equivalent to volumetric fractions) of oxygen in
the inlet and exit gasses
KLa = volumetric oxygen transfer coefficient, 5-1
C: = equilibrium DO concentration in the test liquid at the given conditions, mgIL
C = oxygen concentration, mgIL
v = liquid volume, m3
21
Vo = gas hold-up volume, m3
At steady state the equation reduces to:
(4.11)
Since it is often difficult to measure the entering gas flow rate to an aeration system, a
procedure which does not rely on gas flow rates is needed. If one assumes that the inert
portions of the entering gas stream do not change, a mole fraction approach can be
developed which does not require gas flow rate. This assumption means that the
nitrogen, argon, and inert trace gases do not change as they pass through the aeration
system. The new technique (Redmon et aI., 1983) relies upon this assumption to
calculate oxygen transfer efficiency (aTE). It must be further assumed that the transfer at
the fluid surface and the atmosphere is negligible when compared to the transfer caused
by the aeration system, and that steady state conditions exist during the test. Both
assumptions are very good for the wastewater treatment systems.
aTE expressed as a fraction, can be derived as follows:
where:
OTE = mass O2 in - mass O2 out mass O2 in
MRo/i -MRog/i
MRo/i (4.12)
= mass rate of inerts, which is constant (by assumption) in both the inlet and off-gas streams, kg I s
= molecular weights of oxygen and inerts, respectively
22
MRo1;, MRogii = mole ratio of oxygen to inerts in the inlet and off-gas streams
The mole ratio of oxygen to inerts is calculated by subtracting the mole fractions of
oxygen, carbon dioxide and water vapor, as follows:
(4.13)
Yog MRog/i = -;-1---;Y-;-o-g~-Y;-;C-O-2--'(::"og-)--~Y'--W-(O-g-) (4.14)
where:
= mole fractions of C02 in the reference gas(R), or
off-gas (og)
YW(R) , YW(og) = mole fractions of water vapor in the reference gas (R)
and off-gas (og)
The value of YR is the mole ratio of oxygen in air, and can be calculated by
subtracting the humidity from the known (handbook) mole fraction of oxygen in dry air
as follows:
YR = 0.2095(J.-YW(R» (4.15)
To use Equations (4.12) through (4.15) to calculate OTE, it is necessary to measure
water vapor, CO2 , and O2 partial pressure in the inlet air and in the off-gas (six
measurements). The water and CO2 vapor pressures can be reduced to zero by drying
and adsorption, which can reduce the number of measurements to two (only YR , YOg need
to be determined). Using this more convenient method, the value of YR should be exactly
20.95% and equation (4.13) and (4.14) reduce to:
Y MRo,; =--R-=0.2650
l-YR
23
(4.16)
Vag MRagli = I-V
og
4.2.2 Correction to standard conditions
(4.17)
If the mixed-liquor dissolved oxygen, temperature and IDS are measured at the same
time OTE is measured, and if the equilibrium DO concentration (C:) is known, it is
possible to calculate aSOTE. The correction is made in the same way as clean water data
are corrected to standard conditions, as follows:
(4.18)
where:
DO = operating DO concentration, mg/L
~ = correction factor for salinity
If the standard oxygen transfer efficiency (SOTE) of the aeration systems is known
from clean water tests, the a-value can be calculated as follows:
aSOTE a
SOTE
24
(4.19)
CHAPTERS MATERIALS AND METHODS
5.1 Pilot Aeration Column
A pilot column (30-inch diameter, 20 ft tall) has been constructed and used for
aeration testing. Column leveling and leakage tests were conducted before the experiment
started. Rubber hoses and silicone were used to eliminate the leaks at the bottom.
5.2 Diffusers
Three different fme-pore diffusers - membrane, ceramic and HDPE disc were tested
throughout the course of the experiment.
The membrane and ceramic disc diffusers are both manufactured by Aeration
Engineering Resources Corporation (AERCOR). The membrane diffuser kit consists of
three pieces: one glass filled reinforced polypropylene membrane support plate; one glass
filled reinforced polypropylene rise ring and one 9" diameter EPDM (Ethylene Propylene
Diene Monomer) disc membrane. The orifice diameter of the membrane is WI. The
ceramic disc diffuser is 9.187" diameterxO.75" thick. The orifice diameter is also \4".
Discs are provided with a simple adapter gasket to fit existing ceramic holders.
The 250mm (9.8425") diameter fine bubble disc diffuser is provided by Lakeside
Equipment Corporation.
5.3 Apparatus
The YSI Model 52 Dissolved Oxygen Meters and 5739 Field Probes were adopted for
DO concentration and water temperature measurement. Two craftsman air compressors
25
(Shp, 20 gal, single cylinder/oil-free) supplied compressed air to the diffuser. Two
rotameters for gas flow measurement were connected to the compressors.
For performance of the off-gas method, an off-gas analyzer has been constructed to
measure OTE under steady-state conditions. As shown in Fig. 6, the off-gas instrument
includes a fuel cell gaseous oxygen analyzer (Teledyne Model 320P) and a carbon
dioxide and water vapor sorption column (SP Refillable Indicating Moisture Trap). The
oxygen mole fraction is measured with Model 320P, which provides a signal proportional
to mole fraction, and can be calibrated directly at the pressure of the inlet air.
I t I Outlet
Oxygen Analyzer
{(
0 D Inlet P A
Stripper Column Manometer Amp Meter
Fig. 6. Schematic of the Off-gas Analyzer Structure
The stripper column was installed and operated in the vertical mode. It's filled with
the adsorbent - drierite (Anhydrous CaS04 Hammond) as well as the mixture of glass
beads & granular NaOH. As the gas flows through the absorber column, moisture is
adsorbed with drierite and C02 is absorbed with sodium hydroxide. Drierite changes
dramatically from bright blue to pink as the gas stream approaches 40% relative
humidity.
26
In addition, a differential pressure manometer, Extech Model 407910, was employed
to indicate gas pressure. Model 320P is provided with an external output of 0-100 m V
DC. A Fluke Model 87 True RMS Digital Multimeter was used as an external recorder to
supplement the detector cell's integral meter. After removal of moisture and C02 from
the sample stream, the 02 partial pressure results in a DC current output from the fuel
cell.
5.4 MBR pilot description
The activated sludge used in the second-phase testing came from an existing pilot-
scale 5MBR system treating raw domestic wastewater at the Honouliuli WWTP, which is
supplied by Enviroquip Inc., USA. The main equipment specifications for this unit are
summarized in Table 4.
Table 4. Enviroquip 5MBR Pilot System Snmmary
Membrane Module Type Flat-Plate Membrane Location Aeration Basin (Cartridge)
Membrane Type Microfiltration Membrane Arrangement Vertical
Membrane Material Chlorinated Effective Filtration Area 630 ft" Polyethylene
Support Material ABS Flow Rate 2.5 gal/d
Cartridge Dimensions 19"X39"xO.25" Design Flux 14.7GFD
Cartridge Membrane 8.6 ft" TMP 0.1 - 4 psi Surface Area Cartridge Dry Weight 106 oz. Air Use 3.0 CFMlIOO ft'
Mean Pore Diameter 0.4 11m Operating Mode Continuous air scour and Permeation relax
Acceptable PH Range 1 - 10 Recommended SoC -40°C Temperature Range
27
An Enviroquip membrane cartridge,
as shown in Fig. 7, is constructed by
ultrasonicall y welding sheets of polymer
to the back and front of a support panel.
Between the panel and the membranes,
a porous spacer material serves to
di stribute filtered water into a series of
grooves that lead to a nozzle on top of
the cartridge. Membrane cartridges are
housed in membrane unit.
Anatomy of the Membrane Cartridge
Nozzle
Membrane P1'Inei
Spacer
Microstructure
Mixed Liquor Flow
Permeate
Fig. 7. Anatomy or lhe Membrane Cartridge
Each membrane unit is comprised of a lower diffuser case and an upper membrane
cassette. In the MBR, several submerged membrane units are connected via common
permeate, air supply and flushing lines as shown in Fig. 8.
Fig. 8. Cutaway Illustration of Membrane Unit
28
The Enviroquip MBR treatment system operated at the Honouliuli WWTP consists of
a penneate pump, a membrane tank, a blower, mixed liquor re-circulation equipment,
anoxic and aerobic tanks as shown in Fig. 9. The anoxic zone is un-aerated, and is
equipped with surface mixers where the DO concentration is maintained below 0.5 mgIL
and the majority of denitrification occurs.
Fig. 9 illustrates the process flow diagram of the MBR pilot in nonnal operation
mode. The influent wastewater is pumped to the headworks where it passes through a 3-
mm traveling band screen. The screen is employed for pre-treatment to protect the
membranes from abrasive and stringy waste components (hair in particular). The
wastewater then flows through the anoxic tank for biological nitrogen removal.
Raw Wastewater
Fine Screen Blower
______ v_
Mixer
o 0
o 0
o 0
Mixed Li uor Recirculation
Suction Pump
oO~ o 0 0cJ-0~.lI CO 00
i
Permeate
Anoxic Zone MBR Re-circulation Pump
Fig. 9. Process Flow Diagram of the Enviroquip MBR
Then the wastewater goes to the membrane bioreactor where the membrane modules
are submerged in the activated sludge compartment. Air is introduced into the system to
scour the membranes, drive the biological treatment, and uniformly distribute suspended
29
solids throughout the aeration tank. Mixed liquor was pumped from the bottom of the
MBR and re-circulated to the anoxic zone. A slight vacuum is applied through a permeate
pump downstream of the membranes to allow for the solid-liquid separation process to
occur.
During the second-phase experiment of this study, in order to achieve the desired
solids concentrations in sequence, the activated sludge was completely retained in the
MBR without being discharged or recirculated.
5.5 Methods
The sludge in the membrane tank was characterized by measuring TSS, VSS,
viscosity, SMP, EPS, PDS, OUR, SCOD and IDS. Analysis of TSS, VSS, IDS and
OUR for the mixed liquor samples was conducted using the procedures described in
Standard methods (APHA, 1992). Soluble COD was determined on samples filtered
through a 0.45 J.11l1 filter.
Measurement of OUR
In this study, OUR was measured in situ using the BOD bottle technique. From the
slope of the DO reduction vs. time the OUR can be calculated using following equation:
where:
OUR = 8C 8t
8C = change in DO concentration, mgIL
8t = timeframe of measurement, h
The specific procedures of OUR measurement are described in Chapter 6.
30
Measurement ofViscositv
The viscosity of mixed liquor samples was determined with the Brookfield DV
II+Pro programmable Viscometer which measures fluid viscosity at given shear rates.
The principal of operation of the DV -JI+Pro is to drive a spindle (which is immersed in
the test fluid) through a calibrated spring. The viscous drag of the fluid against the
spindle is measured by the spring deflection. Spring deflection is measured with a rotary
transducer.
As the rheological behavior of the activated sludge mixed liquor correlates to that of a
non-Newtonian, shear thinning liquid, the Herschel-Bulkley model is suggested for the
analysis of viscometer data (Krampe and Krauth, 2003). However, due to the
unreasonable values obtained by this approach, the viscometer data were analyzed by the
Bingham plastic fluid model instead which gave the more realistic results:
11=11. +1]'1
where:
II = shear stress, mPa
II. = yield stress, mPa
1 = shear strain rate imposed on the sample, S-I
1] = viscosity, mPa·s
The viscosity of mixed liquor samples was measured under the selected viscometer
speed of 10, 20, 30, 40, 50, 60, 70, 80, 90 and 100 RPM. The corresponding shear rates
were 12.23,24.46,36.69,48.92,61.15,73.38,85.61,97.84, 110.07 and 122.30 S·I. Then
the measured viscosity data were analyzed using the Bingham model.
31
Measurement of SMP and EPS content
EPS is most commonly measured by analyzing the supernatant of a centrifuged
sludge that has been treated with one or more of the following techniques: heat,
sonication, EDT A or formaldehyde, cation exchange resin (CER), sodium hydroxide. The
most widely used extraction method is by CER treatment that removes bridging divalent
cations (Ca2+, Mg2~ from the sludge matrix and releases the EPS into solution. This
method provides a high yield of extracted EPS without denaturing protein
macromolecules by heating, and it minimizes cell lyses (Frolund et al., 1996).
In this study, EPS was extracted from microbial floc using the CER method. A mixed
liquor (ML) sample was immediately cooled to 4°C to minimize microbial activity. The
exchange resin (70 g of CERlg VSS) was added to a SO-mL sample and mixed at 600
rpm using a single blade paddle for 2 h at 4°C. The mixture (8 mL) was centrifuged for
IS min at 12,000 g to remove MLSS. Supernatant carbohydrate and protein were
measured colorimetrically.
At the same time, 8 mL of untreated ML was centrifuged for 15 min at 12,000 g, and
the protein and carbohydrate concentrations were determined on the supernatant to
represent the soluble fraction (SMP).
The centrifuged supernatant of the untreated ML sample represented the SMP
concentration and the centrifuged supernatant of the sample after CER addition
represented the sum of SMP and EPS concentrations. The difference between these
measurements was the EPS concentrations.
EPS concentrations were determined as the sum of carbohydrates and proteins
because they are the dominant components typically found in EPS (Frolund et al., 1996;
32
Lee et aI., 2003). Carbohydrates were detennined by the phenol-sulphuric acid method of
Dubois et aI. (1956). Glucose was used for standard and samples were analyzed at the
wavelength of 490 nm. To determine protein concentrations, the Folin method proposed
by Lowry et aI. (1951), modified by Frolund et aI. (1996) was applied. Bovine serum
albumin (BSA) was used as a standard.
Measurement ofPSD
Particle size distribution of the mixed liquor samples was analyzed with the Lasentec
M 1 00 Particle System Characterization Monitor. The instrument utilizes a technique
called focused-beam reflectance measurement (FBRM) to measure the size distributions
of sludge particles that flow by the probe window. Specifically, it uses a laser diode
source and measures the light scattered off individual particles suspended in a liquid.
FBRM is a real-time, in-process measure of particle count and dimension by chord
length distribution. The chord length distribution is a function of the shape and dimension
of the particles and particle structures as they exist in the process. The Lasentec MIOO
provides a continuous, high-speed count of particle population by dimension, making it
possible to track the rate and degree of change of solids composition in activated sludge
on the basis of both particle count and particle dimension. The particles ranging from 0.8
to 1000 IlII1 in diameter are measured.
5.6 Chemicals
During this study, many chemicals were used for the deoxygenation of clean water in
the field testing and for the analytical analysis of sludge properties in the lab. The name
or molecular formula and function of each chemical are presented in Table 5.
33
Table 5. Chemicals Used in the Experiments
Name
NazS03
CoCh.6HzO
Phenol
Sulfuric acid
Glucose
Folin-phenol
NazC03
CuSO •. 5HzO
NaK Tartrate
NaOH
Bovine serum albumin (BSA)
Granular NaOH
Orierite
Fnnction
Deoxygenation
Catalyst of the deoxygenation reaction
Carbohydrate measurement
Carbohydrate measurement
Carbohydrate standard
Protein measurement
Protein measurement
Protein measurement
Protein measurement
Protein measurement
Protein standard
Adsorbent of COz
Adsorbent of moisture
SCOD measurement
MBR Membrane cleaning
34
CHAPTER 6 DESCRIPTION OF FIELD STUDIES
Two types of column test were performed at the Honouliuli WWTP. Clean water tests
were conducted using tap water obtained from a fresh water supply at the WWTP. Hoses
were used to transport the water to the column. Tests were also performed using process
water. The column was located near the existing pilot MBR units.
6.1 Clean water aeration column testing
Clean water testing began on Dec. 14th, 2005 and ended on Jan. 30th, 2006. A total of
18 tests were conducted with fresh tap water. Clean water process efficiency was
measured for several flow rates with each diffuser following the ASCE (2000) standard
procedures. Airflow rates per diffuser were those typical values suggested by
manufacturers. Because of the small scale of the test column, as compared to a full-scale
aeration tank, only two probes were used. Clean water tests have been conducted with
each diffuser in triplicate at multiple specific airflow rates.
The ASCE 2-91 protocol specifies a non-linear regression technique (DOPAR) to
solve for KLa and C:. What we need to do is to enter DO and time data, get the values of
KLa, andC:, and calculate SOTE using equation (4.3).
The experimental setup is schematically represented in Fig. 10. A fine-pore diffuser
was installed at the bottom of the column. In this test, 3 types of different air diffusers
were included. The column was fitted with 2 DO probes mounted upside down. One was
placed at the 1/3 depth of the column water, and the other at the 2/3 depth of the column
water. The water depth over the diffuser (submergence) was 15 feet. It's important to
3S
place the sensor facing upward so that air bubbles do not cause DO readings to fluctuate
during the tests.
-- - ----~----
00 Sensors
DO Meters
Compressor Test Column
Fig. 10. Aeration Column Setup for Clean Water Testing
The following experimental procedures were carried out:
- Fill the column with tap water.
- Place the diffuser in the column. Take the dimension of water depth and submergence.
- Calibrate each DO meter.
Place sensors in a beaker of tap water. Adjust DO meters to ensure each meter reads
same DO concentration. Record and label actual position of each sensor. Then take
initial DO reading.
- Prepare deoxygenation chemicals.
10-15 mg/L of Na2S03 is required for per 1.0 mg/L DO. A solution of cobalt
catalyst is needed to achieve a soluble cobalt concentration of 0.50 mg/L in the test
water. Completely dissolve each amount in hot water outside the column prior to its
addition.
- Remove 02 from the water by adding deoxygenation chemicals.
36
Pour cobalt chloride into column first. The cobalt catalyst was added once for each
run. For unifonn distribution, the cobalt solution was dispersed throughout the tank by
operating the aeration system for 30 minutes upon each addition. Then gradually add
sufficient sulfite solution to depress the DO level below 0.10 mgIL at all points in the
test water. A pump was used to distribute sulfite solution unifonnly into the column.
- Re-aerate the water using the air diffuser and take the DO readings.
Tum on and set the compressors at the desired airflow rate. Record DO
concentrations from the two DO meters every 10 seconds until 98% DO saturation is
reached.
Repeat above procedures for each type of diffuser with varied airflow rates in triplicate.
6.2 Process water aeration column testing
In the second phase of the research, OTE was measured utilizing the off-gas
technique at different MLSS concentrations. Over 250 tests were completed during the 3-
month investigation period. Since the tests were perfonned in a pilot column and the
entire off-gas flow can be captured, no flow weight averaging is required in this case.
Fig. 11 shows the column set up for process water testing. For perfonnance of the off
gas method a supplementary gas analyzer and an off-gas collection system were required.
The sealed wooden cover on the top was used to obtain representative off-gas samples of
the column. Off-gas is a quantity of gas being released from the surface of the aerated
mixed liquor. This gas was collected from the Teflon PTFE pipe in the center of the
cover that ultimately necked down for the stripper column connection. By the hose
connection the off-gas and the ambient air reached the gas analyzer, where the oxygen
partial pressure (equivalent to mole fraction) had to be measured. The C02 and water
37
vapor in reference air and off-gas was removed from the gas by a stripper column prior to
analysis as described previously.
Cover
Overflow .---~==----i~H-... ·.- .... :!V! ••••
PilotMBR
o o 0
o o o
Test Column
Air
Off gas
DO Meter
Valves i-L __ -.J Gas Analyzer
Fig. 11. Aeration Column Setup for Process Water Testing
A lower DO sensor was put in the column to measure the operating DO concentration
and water temperature. The mixed liquor from the MBR unit was continuously pumped
into the bottom of the column. Overflow from the column was returned to the MBR. The
airflow through the diffuser was adjusted to the desired value after the liquid level
stabilizes. The column was allowed to come to steady state. The DO and off-gas were
analyzed throughout the course of the experiment.
The process water tests were performed at varied MLSS concentration. A MLSS
concentration of5, 7.5,10,12.5, IS, 17.5 to 20 gIL in the MBR was targeted; however,
the actual readings fluctuated between 3 and 18 gIL. The sludge had been accumulated in
38
the MBR without being discharged or recycles and was transported into the aeration
column for testing.
At each MLSS concentration, the following experimental steps were realized:
I. Take the in-situ OUR measurement of the mixed liquor.
OUR was determined immediately after activated sludge samples were collected
from the Enviroquip MBR as follows.
Calibrate the DO probe and set up the magnetic stirring bar equipment.
Collect sludge sample from the aeration tank. Pour the sample into a 500-rnL
sample bottle. Increase DO cone. of sample by shaking it vigorously for
approximately 30 seconds in the partially filled bottle.
Fill the BOD bottle completely to the top. Immediately insert the DO probe,
making sure that the probe tightly seals the sludge from the atmosphere. Activate
probe stirring mechanism and magnetic stirrer.
- After the meter reading has stabilized, record the initial DO and temperature
reading. Record levels at time intervals of 10 seconds. Record data over a 15-
minute period or until the DO is less than 1.0 mgIL. Record the final temperature.
2. Perform off-gas testing for the mixed liquor in the column with 3 types of diffusers.
Pump the mixed liquor from the aeration tank to the column. Put the calibrated DO
probe and the diffuser (connected to the compressors) into the column. Then cover the
column with the hood. Make sure the hood is sealed well.
We planed to test each diffuser over the same range of airflow rates applied to the
clean water testing. However, due to higher pressure drop in the process water, the
airflow rate of3 SCFM couldn't be achieved.
39
For each diffuser under a specific air flow rate:
- Take the partial oxygen fraction of reference gas (air) and off-gas.
Connect the gas hose to the off-gas analyzer. The gas sample passed through the
stripper column and then flew over the oxygen cell using the accessory flow-through
adapter. A radial connector was used as the inlet considering the high gas flow rates.
Record the ampere reading in IlA on the Model 87 Digital Multimeter until the Ch
partial pressure stabilized. To diminish the effect of the variability in the off-gas
oxygen concentration readings, a reference gas followed by an off-gas reading were
taken for each condition 3-5 times. Oxygen cell calibration was conducted prior to each
test at various times. Control the reference gas flow to maintain the same pressure
reading (recorded by the monometer) as under the off-gas flow.
- Measure operating DO concentration and temperature of the mixed-liquor in the
column under each condition. A YSI Model 52 DO probe was used for mixed liquor
DO and temperature measurements.
According to the acquired off-gas analysis data, MRo/i and MRog/i , the mole ratio of
oxygen to inerts in the inlet and off-gas streams were calculated using Equation (4.16),
(4.17) respectively. Then the oxygen transfer rate at process conditions, OTE, was
obtained through Equation (4.12). The salinity correction factor p was determined based
on conductivity of the mixed liquor samples because accurate conductivity can be easily
measured from a field measurement. In addition, since the standardized C:20 and SOTE
were already known from the clean water tests, andC:T (the equilibrium DO
concentration at test temperature, 1 atm and zero salinity) can be deduced from C :20
40
using Equation (4.4) and (4.9), the values of aSOTE and corresponding a under each
condition were obtained with equation (4.18) and (4.19) respectively. The data of the off
gas testing was summarized in Appendix II.
In addition to the OUR measurements and oxygen transfer tests in the field, we
conducted the comprehensive analyses of the activated sludge in the lab, in order to
observe the changes of the a-value in dependence on the sludge properties. During the
variation of the MLSS concentration, besides those known parameters such as MLSS,
MLVSS and viscosity, many other parameters were measured including SMP, EPS, PSD,
TDS, and SCOD.
41
CHAPTER 7 RESULTS AND DISCUSSION
7.1 Clean Water Aeration Test
Clean water aeration test results summary in Table 16 (Appendix II) presents all of
the data collected in clean water testing. The table shows the standard oxygen transfer
efficiency SOTE, the mass transfer coefficient KLazo and the equilibrium DO
concentration C:20 for the three diffusers. Each diffuser was tested over a range of two or
three flow rates suggested by the manufacturers.
Fig. 12 gives the average overall KLazo for the three different diffusers. Fig. 13 shows
the average values of SOTE determined. These data generally compare well with vendor
literature and were used to determine the alpha factor in the following off-gas testing of
mixed liquor.
30 -+- Membrane Dlffuer __ Ceramic Diffuser
25 -+- HOPE Diffuser
c E 20 ~ ~
0
~ 15
flO 5
0 0.5 1 1~ 2 ~5 3 3.5
Air Flow Rate (SCFM)
Fig. 12. Average mass transfer coefficient for three fine pore diffusers
42
5 __ Membrane Diffuser
i~ _.- .. __ .
----~-. -
__ Ceramic Diffuser
......... HOPE Diffuser I-
~ /. .. \ ... -- --------
1.5 f--- ..
1 o 0.5 1 1.5 2 2.5 3 3.5
Air Flow Rate (SCFM)
Fig. 13. Average SOTE per foot of submergence for three fine pore diffusers
7.2 Process Water Aeration Test
Summaries for off-gas analysis (I) to (8) in Appendix II show all of the data collected
in off gas testing. including the calculated OTEs and a-values for the various process
conditions. The properties of mixed liquor of varied concentrations are presented in Table
2S (Appendix 11).
7.2.1. Evaluation of Diffuser Type on a-value
Table 6. Comparison of a-value of 3 Diffusers
MLSS AFR' a a AFR a a AFR a a (mg/L) (SCFM) (Memb.) (Cera.) (SCFM) (Memb.) (Cera.) (SCFM) (Cer .. ) (HDPE)
3082 I 0.32 0.04 2 0.58 0.40 1.5 0.16 0.27
3867 I 0.53 0.17 2 0.36 0.27 1.5 0.16 0.19
5436 I 0.22 0.09 2 0.21 0.21 1.5 0.12 0.16
8367 I 0.19 0.13 2 0.29 0.27 1.5 0.13 0.18
10533 I 0.17 0.09 2 0.17 0.14 1.5 0.08 0.11
11967 I 0.16 0.09 2 0.14 0.12 1.5 0.07 0.10
14760 I 0.14 0.06 2 0.11 0.09 1.5 0.05 0.08
17667 I 0.12 0.05 2 0.09 0.08 1.5 0.05 0.05
• AFR - all" flow rate.
43
The a-values of the 3 different fine-pore diffusers are compared in Table 6. We can
see that diffuser type has an effect on oxygen transfer. Under the same airflow at a certain
MLSS concentration, a-value changed with different diffusers.
7.2.2. Evaluation of Air Flow on a-value
The influence of air flow on a-value with the membrane and ceramic diffuser is
depicted in Fig. 14 and 15. We were unable to see the influence of AFR variation on a-
value of the HDPE diffuser because the AFR of 3 SCFM couldn't be achieved in the
process water testing. For the same reason, the dependence of a-value on AFR variation
from 2 to 3 SCFM wasn't observed for the membrane diffuser either.
0.6 .-------------:------,
0.55 ---=---0.5 -
0.45 +--
gj 0.4+--iii > 0.35 d! ii 0.3
« 0.25
__ MLSS = 3082 mg/l
---MLSS = 3867 mg/l __ MLSS " 5436 mg/l
--*'" MLSS = 8367 mg/l --lIf- MLSS = 10533 mg/l ___ MLSS = 11967 mg/l
0.2
0.15
0.1
--+- MLSS " 14760 mg/l i - MLSS " 17667 mg/l
0.05 +---.--------r---.------1 0.5 1 1.5 2 2.5
Air Flow Rate (SCFM)
Fig. 14. Alpha-value of the membrane diffuser at varied AFR
Fig. 14 shows that with the membrane diffuser at the MLSS concentration of 3867,
5436, 10533, 11967, 14760 and 17667 mgIL, a-value decreased or remained the same
when the air flow rate increased from 1 to 2 SCFM. The exceptions occurred at the
MLSS concentration of 3082 and 8367 mgIL where a increased with airflow.
44
0.45
0.4
0.35 +----------I'-----------j
CD 0.3 +-------+-----j ::J
1 0.25 •
{ 02
« 0.15 t------;;=::;~~~~--1 0.1
0.05
O+---r---.---r------j 0.5 1 1.5 2 2.5
Air Flow Rate (SCFM)
__ MLSS = 3082 mgll ___ MLSS " 3867 mgll
--.- MLSS " 6436 mgll
--*"" MLSS " 8367 mgll --lI!- MLSS " 10533 mgll --+- MLSS " 11967 mgll -+- MLSS " 14760 mgll - MLSS = 17667 mgll
Fig. 15. Alpha-value of the ceramic diffuser at varied AFR
Fig. 15 shows that with the ceramic diffuser, a-value declined or remained the same
as the air flow changed from I to 1.5 SCFM, and then increased as the air flow rose to 2
SCFM at the MLSS concentration of3867, 8367,10533,11967,14760 and 17667 mgIL.
The exceptions occurred at the MLSS concentration of 3082 and 5436 mgIL where a-
value continuously rose with air flow. The optimum air flow rate for the ceramic diffuser
was 2 SCFM.
The discrepancies observed in the effect of air flow on a-value with both of the
diffusers at the MLSS concentration of 3082 mgIL could be explained by the different
sludge behavior at low MLSS concentrations, whereas the ones occurred under other
process conditions might be caused by experiment errors.
7.2.3. Evaluation of MLSS and ML VSS concentration on a-value
Fig. 16 and 17 summarizes the average a-values in dependence of MLSS or ML VSS
concentration over the study.
45
0.6 IJ
0.5
_. )I(
0.2 - -.. 0.1
o 2500
IJ
-- ------ --
x
r ! .. )I( ..
5000
---- -[J- ---- --
x
. -----~-
--
• • .. ~ IJ X .. ..
7500 10000 12500
MLSS (mglL)
• Membrane 1 SCFM
IJ Membrane 2 SCFM
.. Ceramic 1.5 SCFM
x Ceramic 2 SCFM
)I( HOPE 1.5 SCFM
- -- --- - --- ---- - -- -- ! I I I
- ------------- --- ------ -- -i
~ • ~
--5!
--
.. • 15000 17500 20000
Fig. 16. Comparison of the a-value under different process conditions via MLSS
0.6
0.5
0.4 gj
~ i! 0.3 Q.
« 0.2
0.1
o
~---- --- ---
o 2000
IJ
IJ
• -----)I( X
• )I( .. .. )I( ..
4000
- ------- ------ -- - --
• Membrane 1 SCFM
IJ Membrane 2 SCFM
.. Ceramic 1.5 SCFM
x Ceramic 2 SCFM
)I( HOPE 1.5 SCFM
IJ X
--_._- -r • ~ .. x • )I( X IJ • -.. .. lI! ~ .. • 6000 8000 10000 12000 14000 16000
MLVSS (mglL)
Fig. 17. Comparison of the a-value under different process conditions via ML VSS
The results of each diffuser under various AFR show the same tendencies as expected
that a-values declined with MLSS or ML VSS concentration, which confirm the
46
conclusions drawn in the literature (Chapter 2). No appreciable correlation between a-
value and MLSS or ML VSS was found with the ceramic diffuser under 1 SCFM of air
flowmte.
Due to the low DO concentmtion maintained in the test column and the low re-
circulation of mixed liquor realized between the column and the MBR during the process
water testing, lower a-values were obtained in this study in comparison with the values
reported in the literature.
As shown in Fig. 18 and 19, the correlation between MLSS or MLVSS concentmtion
and a-value under each process condition is expressed by an exponential equation. The
regression coefficients (R2) of the correlating curves in both figures are 0.94 (Membrane
I SCFM), 0.87 (Membrane 2 SCFM), 0.93 (Cemmic I.S SCFM), 0.89 (Cemmic 2
SCFM) and 0.93 (HOPE 1.5 SCFM), respectively.
0.50,-------
0.45 +-------------------1 --Membrane 1 SCFM ........ Membrane 2 SCFM
- .. - ... ceramI<: 1.5 SCFM .... a =O.3366e-6E-05.MLSS
0.40 +---,,"" o:---r--------------I a =O.5868e ... oool
•MLSS ----·ceraml<: 2SCFM
0.35 +-------j'--"-~------,1~---------I
!!l 0.30
1 0.25 .t::
~ 020
0.15
0.10
0.05
-'- -.
..... '. '.
-'-'-'HDPE 1.5SCFM __ _ ____ . '--===-:c--==' '. .... a = 0.4592e ...... " "LIS
~.~-;-;-;:-
". a = O.325Se ... ·OOOI •MLSS '" '" ---" ... , ........... -..... ", ------ ~;:~~~~~~~~=== ------~.~---- .. -.. -:::..~~.:~~~ -:~~=~--~- -~ .... ~~.~ .......
a = O.2162e'O£,,,,MLSS .-.. - .. - .. - .. _ .. ~~:_ '---'-' ----. ---,-"=--=-- .. :::.--' -"".:;.;:....-0.00 +---,---~--~--~-~~---,----,----,------j
2000 4000 6000 8000 10000 12000 14000 16000 16000 20000
MLSS (rTlJIL)
Fig. 18. Correlation of MLSS and a-value
47
0.50 ------------ -------------'. a = 0.61 S1 e-O001"· MLVSS --N'embrane1 SCFM
0.45 +-~.c:... .. " .. :-... ----/+----------------l ........ N'embrane2SCFM
0.40 +----.. ...: ... ~-d--------------_1 -··-··Ceramlcl.5SCFM " ······t.. a =0.4792e;ooo, . .,LVSS ----. Ceramic 2 SCFM
,:: >--- '-;;j ,':-"-j :: :---:'--'-::-:~:~--::-~:~Z~:'~"7~-'-
0.15 -'/'-."_"_"_"_"_"_"_ -.-._._._._._._ '----1. 0.10 +--_____ '_" '-'-'-'- /I '--. -"-.. -.-.-a =0.223ge ... ·...,'·MLVSS - •• - •• - •• - •• - •• - •• _ •• _ •• _.
0.05
0.00 +----~--~-----r"---~---~---,.---__I 2000 4000 6000 8000 10000 12000 14000 16000
ML VSS (mgJL)
Fig. 19. Correlation ofMLVSS and a-value
7.2.4. Evaluation of ViscosiJy on a-value
Fig. 20 distinctly shows that viscosity of activated sludge is linearly dependent on
MLSS concentration. An increase in solids content leads to a higher viscosity of sludge.
14
12
'El: 10 S ::L 8 ~ <II
6 3 <II :> 4
2
0 2000
-------- --_.- --------,
p - 0.0008 MLSS-1.9481 2
4000 6000 6000 10000 12000 14000 16000 18000 20000
M.SS (mgIL)
Fig. 20. Correlation of MLSS and viscosity
48
As shown in Fig. 21, as viscosity increased, a-values decreased accordingly under
different process conditions over the study. In Fig. 22, a-value is correlated well with
viscosity for each process condition in tenns of a power law equation.
0.6
0.5
., 0.4
'" "iii
0 • tlembrane 1 SCFM
o tlembrane 2 SCFM
.. Ceramic 1.5 SCFM
x Ceramic 2 SCFM 0 )I( HOPE 1.5 SCFM
• =;t 0.3 ii
0 - ~ -- - ----------- _._----_. ---
x x
:1(1 t
&)1( • • <C
0.2
0.1 .. x 0 • .. x ~4- -- -1- • . .
51 I .. .. .. • I o o 2 4 6 8 10 12 14
Viscosity (cp)
Fig. 21. Comparison of the a-value under different process conditions via viscosity
0.45 --r===========~~ --Wembrane1 SCFM ......... Wembrane 2 SCFM
a = 0.4399.11-<>625 0.40 +----'r----"'-=-"'/~=--------___1
·······Ceramlc 1.5 SCFM 0.35 +----:..: .. -..;--cr---------------1 _____ Ceramlc2SCFM
t ----:\""":·.···t· ."::-_---"a'-=_0'-'.5J4:..:.9-"7jJ!::. .. _·_ .... _______ -L...::-...::.-::..: . .::.-.:...'HD~P=E.:1.5~SC~F~M~J-j
1 :: ,::~ _~-':::L: _a ~!_2~-o37M :.:: ~___ ,-.::.:~.t:~ .. ,-.~.~ ~~~~~~~:~. _ .. ~:~.:.:.::.~.~.~~~~.~ ......... :.: .... ':~'c~_-I . I"~ "'''1,;.'''- -.--.-.-.-._._ --- - --
a = 0.30 16jJ-<> 5849 ,\' ._ ........... - ... _ •• _ •• _ ... :~' - ~ --'-.-. -~-.-. -.-. 0.05 m \ ... _- .. - •• - •• _ •••••
a = 0.2077 p-o.S404 0.00 +---~-----.=:........;:..=.:.:...:...!.=-r----~--~---~----I
o 2 4 6 8
Viscosity ~ (cp) 10
Fig. 22. Correlation of viscosity and a-value
49
12 14
The regression coefficients (R2) of the correlating functions in Fig. 22 are 0.92
(Membrane 1 SCFM), 0.83 (Membrane 2 SCFM), 0.92 (Ceramic 1.5 SCFM), 0.86
(Ceramic 2 SCFM) and 0.85 (HDPE 1.5 SCFM), respectively. No dependence of a-value
on viscosity was observed with the ceramic diffuser under 1 SCFM of AFR.
The solids concentration in a MBR system can be adjusted around a targeted value
through controlling the amount of sludge wasted. The low viscosity of mixed liquor can
be kept by maintaining the low solids concentration in the system, leading to a better
oxygen transfer.
7.2.5. Evaluation of OUR on a-value
M.-~~~~~~~~~~~~~~~~~~~~~,
50
~ 45 .c ~40 .§. 35
0::30 :::l 0 25
--~--~
•
.--~ ____ OUK=()'J~41 MLSS°.s08
• R2 = 0.91
2O~-
15+-~~~~~~~~~~~-'~~~r---~.-----~
2500 5000 7500 10000 12500 15000 17500 20000
MLSS (mgIL)
Fig. 23. Correlation of OUR and MLSS
Fig. 23 shows that the parameter of OUR of activated sludge is a function of MLSS
concentration. An increase in wastewater strength leads to an increase in micro-organism
metabolic activity and higher OUR. As shown in Fig. 24, decreasing a-values were
observed at increasing OUR over the study except for the ceramic diffuser under I SCFM
of air flow rate.
50
0.6 a • IIfoembrane 1 SCFM
0.5 a IIfoembrane 2 SCFM
• Ceramic 1.5 SCFM
x Ceramic 2 SCFM a )I( HOPE 1.5 SCFM
-- . • a -
)I( X x
0.4 !!! ~ Jl! 0.3 c.
0.2 It ----_._-l{ t---
• • )I( • ~ •• x • )I( • x t--- --- --- ------- ----)(1-•
«
0.1
• • o
15 20 25 30 35 40 45 50 55
OUR (mg/L.hr)
Fig. 24. Comparison of the a-value under different process conditions via OUR
0.60
a = 56.344 OUR -1.'415
0.50
0.40
,
, ............ / a = 107.87 OUR-I 716
.. :::I iil ~ 0.30
.<: c. ;;:
0.20
0.10
0.00 15 20 25 30 35 40
OUR (rrg/L.h)
Fig. 25. Correlation of OUR and a-value
--Membrane 1 SCFM i,
........ Membrane 2 SCFM
-"·"·Ceramlc 1.SSCFM ~ - - - -. Ceramic 2 SCFM
-·-·_·HDPE 1.5SCFM
45 50 55
In Fig. 25, good correlations are observed between a-value and OUR for each process
condition. The regression coefficients (R2) of the correlating curves are 0.88 (Membrane
51
I SCFM). 0.91 (Membrane 2 SCFM). 0.90 (Ceramic 1.5 SCFM). 0.92 (Ceramic 2
SCFM) and 0.83 (HDPE I.S SCFM). respectively.
The observed relationship between a-value and OUR can be interpreted by the effect
ofMLSS concentration on oxygen transfer. In Fig. 23. the OUR is shown to increase with
MLSS because bacterial activity is highly related to the substrate concentration. As
discussed previously. a lower a-value is obtained at a higher MLSS concentration due to
the higher viscosity of the activated sludge. Thus a-value displays a correlation with
OUR.
The treatment efficiency of the ASP depends heavily on the metabolic activity of the
viable microorganisms in the mixed liquor. However. present control practices in the
treatment plants still depend mainly on a determination of MLSS or ML VSS. Because of
their inability to express the dynamic behavior of the active biomass in the mixed liquor.
routine monitoring methods (such as MLSS and ML VSS) should be supplemented by
additional rapid biochemical tests (Liu. 1983).
OUR can be measured directly in real time and is a meaningful indicator of the viable
organism concentration. From the relationship of it to process performance (a-value)
obtained in this study. OUR is suggested to be used as an on-line control parameter of
treatment processes where tests having a much more rapid response time and indicative
of reaction rates are essential.
It must be pointed out that the sludge samples for OUR measurement in this study
were collected from the MBR aeration tank. not from the test column. The suggestion of
measuring the OUR of the mixed liquor in the test column under various process
conditions could be made to explore the more dynamic correlation between a and OUR.
52
7.1.6. Evaluation of PSD on ex-value
PSD data had been analyzed for the sludge samples of varied concentrations in the
study. Particle size was investigated in the range of 0.8-1000 JI.m. As shown in Fig. 26,
wider PSD dimensions were observed at higher MLSS concentrations, and median
particle sizes generally decreased as MLSS increased.
1400
1200
'"' ()
1000 c:
'" :0 0"
'" ~ u. 800 ~ Q) .0 E :0 600 z Q)
13 t 400 '" !l.
200
0
1 10 100
Particle Diameter (pm)
--- MLSS = 3082 mg/L
-a- MLSS = 3867 mg/L
-+- MLSS = 5436 mg/L
--><- MLSS = 8367 mg/L
--lI!- MLSS = 10533 mg/L
--MLSS = 11967 mg/L
MLSS = 14760 mg/L
- MLSS = 17667 mg/L
1000
Fig. 26. Particle size distributions at various MLSS concentrations
As previously described in Chapter 5, the activated sludge was completely retained in
the MBR without being wasted or recirculated during the study, to achieve the desired
solids contents. Consequently, the longer the sludge retention time (SRT) and
accordingly the higher solids concentration, the broader the size range of the biomass
particles.
53
Median particle sizes at MLSS of3082, 3867, 5436, 8367, 10533, 11967, 14760 and
17667 mgIL were 55.0,55.7,37.7,33.5,33.3,33.9,29.4 and 29.1 !JlIl, respectively. The
correlation between median particle size and MLSS concentration is depicted in Fig. 27.
60
Cii 55
1 50 'SE 45 Je"::4Q
~ 35 30
-- ----
• '\
" 1--
--
D -1169.4 MLSs-O.3831 R2 - 0.89
~ -
• ----• ....... • 25
2500 5000 7500 10000 12500 15000 17500 20000
MLSS (rTWLl
Fig. 27. Correlation of median particle size and MLSS
Small particles in the activated sludge could either come from the influent or from the
cellular debris generated by cell decay and break-up. In the Enviroquip MBR pilot, the
membrane pores (nominal 0.4 !JlIl in diameter) are small enough to retain significant
amounts of colloidal material that most colloids remain in the mixed liquor. Due to the
complete sludge retention during the study, more non-aggregate small particles could be
retained in the reactor at prolonged SRTs and higher MLSS concentrations. This is a
possible explanation for the phenomenon observed in the study that increased solids
content leads to an increase in fine population of biomass.
The relationships between a-value and median particle size under different process
conditions over the study are summarized in Fig. 28. Decreasing a-values were observed
at increasing median particle size, except for the ceramic diffuser under I SCFM of air
flow rate. In Fig. 29, a-value and median particle size are correlated for each process
condition. The regression coefficients (R2) of the correlating functions are 0.84
54
Membrane I SCFM), 0.78 (Membrane 2 SCFM), 0.85 (Ceramic I.S SCFM), 0.74
(Ceramic 2 SCFM) and 0.79 (HDPE 1.5 SCFM), respectively.
0.6 c • Membrane 1 SCFM
0.5 c Membrane 2 SCFM • • Ceramic 1.5 SCFM
x Ceramic 2 SCFM 0.4
~ x HOPE 1.5 SCFM c
~ 0.3 t • -[]
--- --------x xx
« 0.2 --- L--~ ----_._--_.
.! • x
0.1 • ~ ~ • 51 - -
•• .. 0
25 30 35 40 45 50 65 60
Median Particle DIameter (101m)
Fig. 28. Comparison of the a-value under different process conditions via particle size
0.5
0.5
0.4
0.4
§ 0.3
;.,~ 0.3 .r: ~ 02
02
0.1
0.1
0.0
--- ----- ---_._. ----------- -- ----
Membmne 1 SCFM a = 0.000 W, + 0.OOO8D + 0.16f!9
.•...••• Membmne 2 SCFM ..
a = -0.OOO2D' + 0.030 W -0.6077 .. ' -"-"'Ceramlc 1.5SCFM
.. ' -p
~ ..... <--- -- - - - - Ceramic 2 SCFM .' ,.' ... -- ... • ~ ---m~"_ ~ I
.. n. - ---- _-~c.-.-··~- --. _ _ -------........ -:., ,.' ..... I
a =-O.0004D' _+0.0452D ....,.._-: ....... _ .. ___ . . _ _ _ ._ .• - .. -' -0.8697 "-.... -' ...... "-"-"7
~' ..... ..- .......... -~~ .... ~ .. _.,- I
,,'~.~. ...,.- a = -o.ooow' + 0.0242D - 0.4525 ~.,,~ .' .......... ,.. . ' -.-
~ .... -._._._ ........
" .-.-..... -..... -~~ ,'" r-- ." -' ,. ....... a =-O.OOO4D' +0.036D-0.6856
25 30 35 40 45 50 55 eo Median Particle Diameter (~m)
Fig. 29. Correlation of particle size and a-value
55
The influence of MLSS concentration on oxygen transfer can account for the
observed relationship between a-value and particle size. Since increased solids content
results in an increase in fine biomass population and median particle diameter decreases
with solids concentration, a-value displays a correlation with particle size.
7.2.7. Evaluation of SMP, EPS, SeOD and TDS on a-value
The contents of seOD, IDS, total SMP and total EPS in mixed liquor were also
evaluated. Each of these parameters is plotted against MLSS concentration. As shown in
Fig. 30, 31 and 32, the data points are highly scattered and no appreciable trend is
observed of seOD, TDS or total SMP with MLSS. And accordingly no dependence of a-
value on these parameters was discovered over the study.
In Fig. 33, a trend is observed that the total EPS content increased and then decreased
with solids content. At the MLSS concentration of 8367 mg/L, the minimum value of
total EPS was obtained. This interesting phenomenon might be interpreted by the
biological activity of the microorganisms in the sludge.
00,-------------------------------------------, !
50
~ E 40 f-----~
c • • 030 -!;l
---------.--------- ~--~ •
20 - • ----- • 10~--~--~--~----~--~--~--~--~----~__,
o 2000 4000 0000 0000 10000 12000 14000 16000 16000 20000
MLSS concentration (mg/L)
Fig. 30. Relationship between SCOD and MLSS
S6
1050
1000
950
~ 900 --
g 850 rJl g 800
750
700
650 0
30
25
~ e20 ~
a. 15 ::;; rJl
~ 10 f"
5
0 0
350
-
100
50
• . --
• •
• ••
--~-~-. --- • • 2000 4000 6000 6000 10000 12000 14000 16000 16000 20000
MLSS concentration (mgIL)
Fig. 31. Relationship between IDS and MLSS
• •
~~~~~----.. • •
.-~~--~ • • ---
2000 4000 6000 6000 10000 12000 14000 16000 16000 20000
MLSS concentration (mgIL)
Fig. 32. Relationship between total SMP and MLSS
• -
-
• • ..
• • • -
020004000 6000 6000 100001200014000160001600020000
MLSS concentration (mgIL)
Fig. 33. Relationship between total EPS and MLSS concentration
57
7.2.8. Evaluation ojMLSS, MLVSS, Viscosity, OUR and PSD on OTE
The effect of sludge properties on OTE was only observed for the membrane diffuser
with 1 SCFM of air flow rate. Under other process conditions, no clear trend was
obtained.
In the following graphs. volumetric OTE (VOTE) is plotted versus and correlated to
MLSS. MLVSS. viscosity. OUR and particle size. separately.
0.10 ,.-----------------------------,
0.09
'" 0.08 f------=-.""=~c_-----------__;;_:;o_;_;_____,-----___1 E VOTE = 3.5955 MLS~·4m • R2 = 0.98 ~ 0.07
I!! 0.06
o ~~~~::::~~==:====_---> 0.05 r---VOTE =4.2264 MLVSS-0 4802
• R2 = 0.98 0.04 ... a·
0.03 '---~--~--~-~--~--~-~--~-----'
2000 4000 6000 8000 10000 12000 14000 16000 18000 20000
MLSS or MLVSS concentration (mgIL)
Fig. 34. Correlation ofMLSS. MLVSS and VOTE
Fig. 34 shows that VOTE decreased as MLSS (or MLVSS) increased. Good
correlations were observed between VOTE and MLSS (or ML VSS) concentration.
0.10
0.09
iW)' 0.08
~0.Q7 I':! 0.06
~ 0.05
0.04
• . ---. _ .. _. - . --------------,
..... _-- -----------
VOTE = 0.1014 ,u-OJ289.R 2 = 0.95 - -- -----------j
• 0.03 '--~-~-~~-~-~--~-~-~~-~-~----'
o 2 4 6 8
Vlscoslly ~ (cp)
10
Fig. 35. Correlation of viscosity and VOTE
58
12 14
In Fig. 35, it is shown that VOTE decreased as mixed liquor viscosity increasing,
which is expressed by a power function.
0.10 ,---,---
0.09
C") 0.08
~ 0.07
I!! 0.06 o > 0.05
0.04 ---------+
• ---~ 0.03 +---~--~--~--~---~--~--~--__I
15 20 25 30 35 40 45 50 55
OUR (mgll.h)
Fig. 36. Correlation of OUR and VOTE
Fig. 36 shows that decreasing VOTE was observed at increasing OUR. A power law
function is formulated to correlate VOTE and OUR.
0.10
0.09
M' 0.08 +-----~ 0.07
I!! 0.06 -o > 0.05
0.04 +---
• yOT~ = 0.0015 D'D334 ... R2 = 0.84
• •
0.03 +---~---,---~--~~--~--~--_____4 25 30 35 40 45 50 55 50
MedIan Particle Diameter (pm)
Fig. 37. Correlation of particle size and VOTE
In Fig. 37, increasing VOTE was observed at increasing particle diameter. The
relationship is also expressed by a power law function.
S9
CHAPTER 8 CONCLUSIONS, LIMITATIONS AND RECOMMENDATIONS
8.1 Conclusious from the study
Within the scope of the presented investigations, the 4-month pilot-scale aemtion tests
were performed in an aemtion column. The research was successful in meeting its
objective of exploring the dependence of a-value and oxygen tmnsfer efficiency on
possible factors in MBR systems, including diffuser type, air flow mte and sludge
properties. Several new parameters such as IDS, SCOD, OUR, PSD, SMP and EPS
content of sludge have been tried to correlate with a-value and OTE. Off-gas technique
was utilized for OTE measurements in the wastewater. From the completed experiments,
the following conclusions can be drawn:
(1) Supplied air flow rate influences a-value.
(2) Diffuser type is another factor affecting a-value.
(3) Among the tested properties of activated sludge, the possible parameters identified to
correlate a-value or oxygen tmnsfer efficiency are MLSS or ML VSS concentmtion,
viscosity, OUR and median particle size.
(4) No dependence of a-value on total SMP, SCOD or IDS was observed over the study.
(5) An interesting trend was observed that the total EPS content increased and then
decreased with solids content. At the MLSS concentration of 8367 mgIL, the
minimum value of total EPS was obtained.
(6) The a-values observed in this investigation are lower than those reported in the
litemture.
60
8.2 Limitations of the study
The limitations of the study are summarized as follows:
(I) Low DO concentration was maintained in the test column during the process water
testing.
DO concentration in the column is the most important parameter in converting OTE
to aSOTE and thus is critical in the successful operation of a-value measurement.
Low DO concentration provided by the low air flow of each diffuser in this study
couldn't maintain proper process conditions in the test column. This caused the
biological conditions in the column to be different than in the MBR aeration tank.
And Iowa-values were obtained accordingly. The inaccuracy oftest results increased
with MLSS concentration.
(2) Low mixed liquor re-circulation rate was realized between the column and the MBR.
The low mixed liquor re-circulation was caused by the imperfection in the re
circulation system design. This limitation also contributed to low DO in the column.
(3) Old membranes were used in the MBR pilot.
The membranes immersed in the aeration tank of Enviroquip system have been used
over 3 years. And the system was used as a sludge thickener for a period of time
before this study. Although the membranes were physically and chemically cleaned
(using hypo chloride acid), the irreversible fouling could have existed and influenced
the solids build up and sludge properties in the aeration tank.
Although this study has the limitations listed above, it still provides a possible starting
point and insights for similar work.
61
8.3 Recommendations/or future research
Based on the limitations in this study, the following modifications of the experiment
system are recommended to improve the accuracy ofOTE or a-value measurement:
(1) Simulate the actuaI operation in the aeration tank as more as possible.
This can be accomplished through the both improvements:
i. Control the DO level in the test column.
The number of diffusers employed at a time in the test column and the air flow per
diffuser must be in a range that provides adequate DO concentration for
maintaining proper process conditions as well as providing accurate test results.
And it should be noted that if the air flow rate is too high, high a-values may result
from column tests operating at excessive DO concentration.
ii. Increase the re-circulation rate and shorten the HRT of mixed liquor in the column.
To achieve this purpose, a big feeding hose and a powerful re-circulation pump may
need to be used in the experiment.
(2) Employ new membranes in the MBR units during the research to avoid the adverse
effect of membrane fouling on the activated sludge.
It's also recommended to employ different types of MBR units in the study to
compare the results between the activated sludge of the different systems and investigate
if there is dependence of a-value or OTE on activated sludge type.
62
Testing Date: 12121105 Local Temp: 79 of
Time Time DOl D02
(sec) (min) (mgIL) (mgIL)
o 10
20
30
40
SO 60
70
80
90
100
110
120
130
140
ISO 160
170
180
190
200
0.00
0.17
033
0.50
0.67
0.83
1.00
1.17
133
1.50
1.67
1.83
2.00
2.17
233
2.50
2.67
2.83
3.00
3.17
333
0.05 0.09
O.OS 0.08
0.Q7 0.70
0.19 1.47
0.09 135
0.05 1.01
0.03 0.90
033 0.91
0.60 0.64
127 0.51
1.42 0.53
1.47 0.56
1.13 0.64
1.01 0.73
\38 139
2.26 1.56
1.49 1.43
2.05 1.48
225 1.84
2.05 2.12
2.56 1.98
APPENDIX I: RAW DATA TABLETS
TABLE 7. Clean Water Test (1) Raw Data
Diffuser Type: Membrane Disc Local Barometric Pressure: 29.84 in Hg
TIme Time DOl D02
(sec) (miD) (mgIL) (mgIL)
210
220
230
240
250
260
270
280
290
300
310
320
330
340
3SO 360
370
380
390
400
410
3.50 2.63 2.05
3.67 2.65 3.48
3.83 2.91 3.19
4.00 2.44 3.08
4.17 2.43 2.94
433 2.51 3.13
4.50 2.61 3.50
4.67 2.74 3.52
4.83 2.86 3.77
5.00 3.03 331
5.17 3.09 320
533 3.19 320
5.50 328 3.29
5.67 3.40 3.41
5.83 3.48 3.77
6.00 3.61 3.93
6.17 3.74 3.77
633 3.75 4.13
6.50 3.79 4.56
6.67 3.91 4.74
6.83 4.02 4.89
63
Air Flow: I SCFM Water Temp: 25.0 DC
Time Time DOl D02
(see) (mID) (mgIL) (mgIL)
420
430
440
450
460
470
480
490
500
510
520
530
540
550
560
570
580
590
600
610
620
7.00 4.10 4.75
7.17 4.16 4.59
7.33 4.37 4.44
7.50 4.73 430
7.67 4.57 434
7.83 4.57 437
8.00 4.74 4.75
8.17 4.89 5.44
833 4.94 5.44
8.50 5.17 5.53
8.67 530 5.08
8.83 5.55 4.99
9.OQ 530 4.92
9.17 5.17 4.89
933 5.29 5.00
9.50 528 5.06
9.67 5.83 5.18
9.83 5.87 526
10.00 5.55 525
10.17 5.59 524
1033 5.73 527
TIme
(sec)
630
640
650
660
670
680
690
700
710
720
730
740
750
760
770
780
790
800
810
820
830
TIme DOl D02
(miD) (mgIL) (mgIL)
10.50 5.79 5.33
10.67 5.65 539
10.83 5.60 5.68
11.00 5.90 5.99
11.17 5.78 5.89
1133 5.84 5.71
11.50 5.90 6.08
11.67 5.86 5.84
11.83 5.84 5.77
12.00 5.% 6.01
12.17 6.13 6.07
12.33 6.10 6.10
12.50 6.12 5.95
12.67 6.14 6.\6
12.83 6.19 6.45
\3.00 6.40 621
\3.17 638 6.18
1333 6.67 620
\3.50 6.44 624
13.67 6.41 628
13.83 6.46 6.54
TIme TIme DOl DOl
(sec) (min) (mg/L) (mg/L)
840 14.00 6.47 6.43
850 14.17 6.48 6.38
860 14.33 6.54 6.45
870 14.50 6.56 6.40
880 14.67 6.58 6.42
890 14.83 6.63 6.83
900 15.00 6.81 6.94
910 15.17 7.04 6.97
920 15.33 7.02 7.04
930 15.50 6.88 6.91
940 15.67 6.85 6.78
9SO 15.83 6.87 6.95
960 16.00 6.89 7.07
970 16.17 6.94 7.15
980 16.33 7.04 7.07
990 16.SO 7.04 7.06
1000 16.67 6.97 7.07
1010 16.83 7.09 7.22
1020 17.00 7.08 7.11
1030 17.17 721 7.10
1050 17.SO 7.40 7.06
1060 17.67 729 724
1070 17.83 727 7.36
1080 18.00 7.32 7.64
1090 18.17 7.31 8.30
1100 18.33 727 8.43
TABLE 7. (Continued) Clean Water Test (1) Raw Data
TIme TIme DOl DOl
(sec) (min) (mg/L) (mg/L)
1110 18.50 7.35 827
1120 18.67 7.42 7.63
1130 18.83 7.35 7.60
1140 19.00 7.48 7.89
1150 19.17 7.53 7.77
1160 19.33 7.59 7.56
1170 19.50 7.57 7.46
1180 19.67 7.61 7.37
1190 19.83 7.74 7.36
1200 20.00 7.67 7.52
1210 20.17 7.66 7.62
1220 20.33 7.74 7.66
1230 2O.SO 7.75 7.66
1240 20.67 7.78 7.59
1250 20.83 7.79 7.51
1260 21.00 7.78 7.46
1270 21.17 7.81 7.54
1280 21.33 7.85 7.59
1290 21.SO 7.83 7.62
1300 21.67 7.82 7.71
1310 21.83 7.78 7.72
1320 2200 7.82 8.12
1330 2217 7.83 7.92
1340 2233 7.80 7.88
1350 2250 7.81 7.81
1360 2267 7.88 7.81
TIme TIme DOl DOl
(sec) (min) (mg/L) (mg/L)
1370 22.83 7.91 7.73
1380 23.00 7.87 7.96
1390 23.17 7.93 7.90
1400 23.33 7.96 8.01
1410 23.50 7.92 8.02
1420 23.67 7.98 8.62
1430 23.83 8.03 8.05
1440 24.00 7.99 7.97
1450 24.17 7.97 8.11
1460 24.33 8.00 7.93
1470 24.50 8.02 7.96
1480 24.67 8.04 7.94
1490 24.83 8.00 7.97
1500 25.00 8.01 7.95
1510 25.17 8.05 7.85
1520 25.33 8.06 7.96
1530 25.SO 8.03 7.96
1540 25.67 8.07 8.00
15SO 25.83 8.16 7.97
1560 26.00 821 8.05
1570 26.17 8.22 8.02
1580 26.33 8.17 8.19
1590 26.50 829 8.31
1600 26.67 8.38 827
1610 26.83 8.44 8.08
1620 27.00 8.40 823
64
TIme TIme DOl DOl
(se<) (min) (mg/L) (mg/L)
1630 27.17 8.39
1640 27.33 8.38
1650 27.50 8.43
1660 27.67 8.43
1670 27.83 8.35
1680 28.00 8.32
1690 28.17 8.41
1700 28.33 8.42
1710 28.50 8.40
1720 28.67 8.44
1730 28.83 8.43
1740 29.00 8.43
1750 29.17 8.42
1760 29.33 8.52
1770 29.SO 8.57
1780 29.67 8.51
1790 29.83 8.49
1800 30.00 8.56
1810 30.17 8.53
1820 30.33 8.46
1830 30.SO 8.51
1840 30.67 8.52
1850 30.83 8.51
1860 31.00 8.55
1870 31.17 8.57
1880 31.33 8.58
8.15
8.01
8.13
8.12
824
8.43
8.31
821
8.22
8.38
827
8.32
8.38
8.36
8.46
8.68
8.55
8.44
8.47
8.41
828
829
8.30
8.32
8.31
8.45
TIme
(se<)
1890
1900
1910
1920
1930
1940
1950
1960
1970
1980
1990
2000
2010
2020
2030
2040
2OSO
2060
2070
2080
2090
2100
2110
2120
2130
2140
TIme DOl D02
(min) (mg/L) (mg/L)
31.50 8.62 8.49
31.67 8.69 8.62
31.83 8.61 8.73
32.00 8.67 8.72
32.17 8.72 8.75
32.33 8.69 8.63
32.SO 8.55 8.52
32.67 8.64 8.35
32.83 8.68 8.47
33.00 8.70 8.51
33.17 8.66 8.63
33.33 8.63 8.62
33.50 8.65 8.63
33.67 8.78 8.47
33.83 8.78 8.49
34.00 8.86 8.55
34.17 8.82 8.55
34.33 8.71 8.58
34.50 8.79 8.61
34.67 8.80 8.67
34.83 8.69 8.64
35.00 8.66 8.46
35.17 8.69 8.64
35.33 8.78 8.87
35.50 8.76 8.83
35.67 8.69 8.64
Table 7. (Continued) Clean Water Test 1 Raw Data
TIme TIme DOl DOl Time Time DOl DOl
(sec) (miD) (mgIL) (mgIL) (sec) (miD) (mgIL) (mgIL)
2150 35.83 8.73 8.61 2380 39.67 8.99 8.85
2160 36.00 8.74 8.59 2390 39.83 8.92 8.76
2170 36.17 8.74 8.51 2400 40.00 8.96 8.73
2180 36.33 8.80 8.53 2410 40.17 8.96 8.79
2190 36.50 8.80 8.55
2200 36.67 8.80 8.57
2210 36.83 8.77 8.71
2220 37.00 8.81 8.73
2230 37.17 8.80 8.68
2240 37.33 8.77 8.71
2250 37.50 8.78 8.58
2260 37.67 8.87 8.60
2270 37.83 8.89 8.77
2280 38.00 8.87 8.68
2290 38.17 8.86 8.62
2300 38.33 8.89 8.66
2310 38.50 8.90 8.68
2320 38.67 8.87 8.78
2330 38.83 8.88 8.64
2340 39.00 8.90 8.64
2350 39.17 8.91 8.72
2360 39.33 8.94 8.27
2370 39.50 9.02 8.80
6S
Table 8. In Sitn OUR Test (1) Raw Data
Testing Date: 5126/06 MLSS = 3082 mgIL Initial T ..... = 28.7 °C Final T ..... = 322°C
TIme TIme DO TIme TIme DO TIme TIme DO TIme TIme DO
(see) (miD) (mg/L) (see) (miD) (mg/L) (sec) (miD) (mg/L) (see) (mID) (mg/L)
0 0.00 824 230 3.83 5.65 460 7.67 4.43 690 11.50 321
10 0.17 7.33 240 4.00 5.60 470 7.83 4.37 700 11.67 3.16
20 0.33 7.11 250 4.17 5.55 480 8.00 4.32 710 11.83 3.10
30 0.50 6.96 260 4.33 5.50 490 8.17 428 720 12.00 3.05
40 0.67 6.83 270 4.50 5.43 500 8.33 422 730 12.17 3.00
50 0.83 6.73 280 4.67 5.39 510 8.50 4.17 740 12.33 2.95
60 1.00 6.65 290 4.83 5.34 520 8.67 4.11 750 12.50 2.89
70 1.17 6.56 300 5.00 529 530 8.83 4.06 760 12.67 2.84
80 1.33 6.50 310 5.17 523 540 9.00 4.01 770 12.83 2.79
90 1.50 6.43 320 5.33 5.18 550 9.17 3.95 780 13.00 2.74
100 1.67 639 330 5.50 5.13 560 933 3.89 790 13.17 2.69
110 1.83 634 J40 5.67 5.06 570 9.50 3.84 800 13.33 2.64
120 2.00 627 350 5.83 5.01 580 9.67 3.80 810 13.50 2.58
130 2.17 622 360 6.00 4.96 590 9.83 3.74 820 13.67 2.53
140 2.33 6.15 370 6.17 4.91 600 10.00 3.68 830 13.83 2.48
150 2.50 6.07 380 633 4.85 610 10.17 3.63 840 14.00 2.43
160 2.67 6.04 390 6.50 4.80 620 10.33 3.58 850 14.17 238
170 2.83 5.99 400 6.67 4.75 630 10.50 3.53 860 14.33 233
180 3.00 5.93 410 6.83 4.69 640 10.67 3.47 870 14.50 228
190 3.17 5.87 420 7.00 4.64 650 10.83 3.41 880 14.67 222
200 333 5.82 430 7.17 4.59 660 11.00 3.37 890 14.83 2.17
210 3.50 5.71 440 7.33 4.53 670 11.17 3.32 900 15.00 2.12
220 3.67 5.72 450 7.50 4.48 680 11.33 326
66
Table 9. In Situ OUR Test (2) Raw Data
Testing Date: 6/9/06 MLSS = 3867 mgIL Initial T....., = 24.5 °C Final T....., = 24.4 °C
Time TIme DO TIme TIme DO TIme TIme DO TIme Time DO
(sec) (miD) (mgIL) (-) (miD) (mgIL) (-) (miD) (mgIL) (-) (mIo) (mgIL)
0 0.00 8.12 230 3.83 5.99 46() 7.67 4.36 690 ILSO 2.83
10 0.17 7.88 240 4.00 5.92 470 7.83 429 700 11.67 2.76
20 0.33 7.77 250 4.17 5.85 480 8.00 422 710 11.83 2.68
30 0.50 7.65 260 4.33 5.77 490 8.17 4.15 720 12.00 2.61
40 0.67 7.54 270 4.50 5.70 500 8.33 4.11 730 1217 2.55
50 0.83 7.46 280 4.67 5.63 510 8.50 4.04 740 1233 2.48
60 1.00 7.37 290 4.83 5.56 520 8.67 3.95 750 1250 2.42
70 1.17 727 300 5.00 5.49 530 8.83 3.88 760 1267 2.35
80 1.33 7.18 310 5.17 5.42 S40 9.00 3.81 770 12.83 229
90 1.50 7.07 320 5.33 5.35 550 9.17 3.74 780 13.00 222
100 1.67 6.98 330 5.50 527 560 9.33 3.67 790 13.17 2.16
110 1.83 6.90 340 5.67 520 570 9.50 3.61 800 13.33 2.09
120 2.00 6.82 350 5.83 5.13 580 9.67 3.56 810 13.50 2.03
130 2.17 6.75 360 6.00 5.06 590 9.83 3.50 820 13.67 1.97
140 2.33 6.66 370 6.17 4.99 600 10.00 3.44 830 13.83 1.90
150 2.50 6.58 380 6.33 4.91 610 10.17 3.36 840 14.00 1.84
160 2.67 6.51 390 6.50 4.84 620 10.33 327 850 14.17 1.77
170 2.83 6.43 400 6.67 4.77 630 10.50 322 860 14.33 1.71
180 3.00 6.36 410 6.83 4.70 640 10.67 3.16 870 14.50 1.65
190 3.17 628 420 7.00 4.63 650 10.83 3.10 880 14.67 1.59
200 3.33 621 430 7.17 4.56 660 11.00 3.03 890 14.83 1.52
210 3.50 6.14 440 7.33 4.49 670 11.17 2.% 900 15.00 1.46
220 3.67 6.06 450 7.50 4.42 680 11.33 2.89
67
Table 10. In Situ OUR Test (3) Raw Data
Testing Date: 6130/06 MLSS = 5436 mgIL Initial T-., = 29.4·C Final T.-= 29.6·C
TIme TIme DO TIme TIme DO TIme TIme DO
(sec) (miD) (mgIL) (see) (miD) (mglLl (sec) (miD) (mgIL)
0 0.00 6.84 230 3.83 4.51 460 7.67 2.72
10 0.17 6.61 240 4.00 4.42 470 7.83 2.64
20 033 6.48 250 4.17 434 480 8.00 2.57
30 0.50 6.35 260 4.33 427 490 8.17 2.50
40 0.67 622 270 4.50 4.19 500 8.33 2.41
50 0.83 6.09 280 4.67 4.11 510 8.50 234
60 1.00 5.98 290 4.83 4.03 520 8.67 227
70 1.17 5.87 300 5.00 3.95 530 8.83 2.19
80 1.33 5.75 310 5.17 3.87 S40 9.00 2.12
90 1.50 5.67 320 533 3.79 550 9.17 2.04
100 1.67 5.58 330 5.50 3.72 560 9.33 1.%
110 1.83 5.49 340 5.67 3.63 570 9.50 1.89
120 2.00 5.41 350 5.83 3.56 580 9.67 1.81
130 2.17 529 360 6.00 3.48 590 9.83 1.74
140 2.33 523 370 6.17 3.41 600 10.00 1.66
150 2.50 5.15 380 6.33 332 610 10.17 1.58
160 2.67 5.07 390 6.50 325 620 10.33 1.51
170 2.83 4.99 400 6.67 3.18 630 10.50 1.44
180 3.00 4.91 410 6.83 3.10 640 10.67 1.36
190 3.17 4.83 420 7.00 3.03 650 10.83 129
200 333 4.74 430 7.17 2.95 660 11.00 121
210 3.50 4.66 440 733 2.88 670 11.I7 1.14
220 3.67 4.58 450 7.50 2.79 680 11.33 1.06
68
Table 11. In Situ OUR Test (4) Raw Data
Testing Date: 7t1.8/06 MLSS = 8367 mgIL Initial T""" = 29.8 ·C Final T""" = 29.9 ·C
TIme TIme DO TIme TIme DO TIme TIme DO
(sec' (miD' (mgIL) (see) (min, (mgIL, (sec' (min' (mgIL)
0 0.00 6.89 230 3.83 4.75 460 7.67 2.84
10 0.17 6.69 240 4.00 4.67 470 7.83 2.75
20 0.33 6.55 250 4.17 4.59 480 8.00 2.67
30 0.50 6.43 260 4.33 4.52 490 8.17 2.59
40 0.67 6.33 270 4.50 4.43 500 8.33 2.51
50 0.83 625 2SO 4.67 4.35 510 8.50 2.43
60 1.00 6.15 290 4.83 428 520 8.67 2.35
70 1.17 6.04 300 5.00 420 530 8.83 227
80 1.33 5.96 310 5.17 4.04 540 9.00 2.19
90 1.50 5.87 320 5.33 3.96 550 9.17 2.11
100 1.67 5.79 330 5.50 3.87 560 9.33 2.03
110 1.83 5.70 340 5.67 3.80 570 9.50 1.95
120 2.00 5.63 350 5.83 3.72 5SO 9.67 1.86
130 2.17 5.S4 360 6.00 3.64 590 9.83 1.78
140 2.33 5.46 370 6.17 3.56 600 10.00 1.70
ISO 2.50 5.38 3SO 6.33 3.48 610 10.17 1.61
160 2.67 5.31 390 6.50 3.40 620 10.33 1.54
170 2.S3 523 400 6.67 3.32 630 10.50 1.46
ISO 3.00 5.15 410 6.S3 324 640 10.67 1.37
190 3.17 5.07 420 7.00 3.16 650 10.83 129
200 3.33 4.99 430 7.17 3.0S 660 11.00 121
210 3.50 4.91 440 7.33 3.00 670 11.17 1.13
220 3.67 4.83 450 7.50 2.92 680 11.33 1.05
69
Table 12. In Situ OUR Test (5) Raw Data
Testing Date: 8110/06 MLSS = 10533 mgIL Initial T ..... = 29.4 °C FinaIT ..... =29.l oC
Time TIme 00 Time Time 00 Time Time DO
(-) (miD) (mgIL) (sec) (miD) (mgIL) (sec) (miD) (mgIL)
0 0.00 6.36 230 3.83 3.94 460 7.67 1.48
10 0.17 6.26 240 4.00 3.83 470 7.83 1.37
20 0.33 6.15 250 4.17 3.73 480 8.00 1.27
30 0.s0 6.05 260 4.33 3.61 490 8.17 1.16
40 0.67 5.94 270 4.50 3.51 500 8.33 1.06
50 0.83 5.84 280 4.67 3.40
60 1.00 5.73 290 4.83 3.30
70 1.17 5.63 300 5.00 3.19
80 1.33 5.52 310 5.17 3.08
90 LSO 5.41 320 5.33 2.98
100 1.67 5.31 330 5.s0 2.87
110 1.83 5.20 340 5.67 2.76
120 2.00 5.10 350 5.83 2.66
130 2.17 5.00 360 6.00 2.s5 140 2.33 4.89 370 6.17 2.44
150 2.50 4.78 380 6.33 2.33
160 2.67 4.68 390 6.s0 2.23
170 2.83 4.58 400 6.67 2.12
180 3.00 4.46 410 6.83 2.01
190 3.17 4.36 420 7.00 1.90
200 3.33 4.26 430 7.17 1.79
210 3.50 4.15 440 7.33 1.69
220 3.67 4.04 450 7.50 1.58
70
Table 13. In Situ OUR Test (6) Raw Data
Testing Date: 8/17/06 MLSS = 11967 mgIL Initial T __ = 32.9 °C Final T ..... = 30.9 °C
Time Time DO TIme Time DO
(sec) (miD) (mg/L) (see) (miD) (mg/L)
0 0.00 6.13 230 3.S3 3.44
10 0.17 6.0S 240 4.00 3.30
20 0.33 6.02 250 4.17 3.16
30 0.50 5.97 260 4.33 3.02
40 0.67 5.S7 270 4.50 2.88
50 0.83 5.7S 280 4.67 2.74
60 1.00 5.67 290 4.S3 2.60
70 1.17 5.56 300 5.00 2.46
80 1.33 5.44 310 5.17 2.32
90 1.50 5.31 320 5.33 2.IS
100 1.67 5.1S 330 5.50 2.04
liO 1.83 5.06 340 5.67 1.90
120 2.00 4.93 350 5.S3 1.75
130 2.17 4.S1 360 6.00 1.62
140 2.33 4.67 370 6.17 1.47
ISO 2.50 4.54 380 6.33 1.33
160 2.67 4.39 390 6.50 1.19
170 2.83 427 400 6.67 1.05
ISO 3.00 4.12
190 3.17 3.9S
200 3.33 3.S5
210 3.50 3.71
220 3.67 3.57
71
Table 14. In Situ OUR Test (7) Raw Data
Testing Date: 8131106 MLSS = 14760 mgIL Initial T .... (test 7.1) =32.2 °C Final T __ (test 7.1) = 30.S °C Initial T ..... (test 7.2) = 33.S °C Fina\T __ (test7.2)= 32.loC
Test7.! Time Time DO Time Time DO Test 7·2 Time TIme DO Time Time DO
(sec) (min) (mgIL) (sec) (min) (mgIL) (sec) (min) (mgIL) (see) (min) (mgIL)
0 0.00 526 150 2.50 3.45 0 0.00 526 150 2.50 3.45
10 0.17 5.18 160 2.67 327 10 0.17 5.18 160 2.67 327
20 033 5.10 110 2.83 3.11 20 033 5.10 110 2.83 3.11
30 0.50 4.98 180 3.00 2.95 30 0.50 4.98 180 3.00 2.95
40 0.61 4.88 190 3.17 2.19 40 0.61 4.88 190 3.11 2.19
50 0.83 4.14 200 333 2.62 50 0.83 4.74 200 333 2.62
60 1.00 4.66 210 3.50 2.44 60 1.00 4.66 210 3.50 2.44
70 1.11 4.55 220 3.67 221 70 1.11 4.55 220 3.61 227
80 133 4.44 230 3.83 2.11 80 133 4.44 230 3.83 2.11
90 1.50 432 240 4.00 1.95 90 1.50 432 240 4.00 1.95
100 1.67 420 250 4.17 1.19 100 1.61 420 250 4.17 1.19
110 1.83 4.06 260 433 1.63 110 1.83 4.06 260 433 1.63
120 2.00 3.92 210 4.50 1.46 120 2.00 3.92 210 4.50 1.46
130 2.11 3.16 280 4.61 130 130 2.11 3.16 280 4.61 1.30
140 233 3.62 290 4.83 1.13 140 233 3.62 290 4.83 1.13
Note: The OUR of activated sludge at this MLSS concentration was tested twice in·situ. The reported value in this study is an average.
72
Table 15. In Situ OUR Test (8) Raw Data
Testing Date: 9f14f06 MLSS = 17667 mgfL Initial T __ = 32.8 °C Final T __ = 30.4 °C
TIme TIme DO Time Time DO
(sec) (min) (mg/L) (sec) (min) (mg/L)
0 0.00 5.69 230 3.83 2.80
10 0.17 5.55 240 4.00 2.66
20 0.33 5.41 250 4.17 2.54
30 0.50 5.30 260 4.33 2.41
40 0.67 5.20 270 4.50 2.28
50 0.83 5.09 280 4.67 2.15
60 1.00 4.% 290 4.83 2.02
70 1.17 4.84 300 5.00 1.88
80 1.33 4.70 310 5.17 1.75
90 1.50 4.56 320 5.33 1.63
100 1.67 4.45 330 S.50 1.50
110 1.83 4.32 340 5.67 1.36
120 200 4.20 350 5.83 1.23
130 2.17 4.07 360 6.00 1.11
140 2.33 3.95
ISO 2.50 3.83
160 2.67 3.70
170 2.83 3.57
180 3.00 3.45
190 3-17 3.32
200 3.33 3.18
210 3.50 3.06
220 3.67 2.93
73
APPENDIX n: DATA SUMMARIES
TABLE 16. Clean Water Aeration Column Test ResuIfli Snmmary
Clean Water Test ResuItJ -- I No. I Dimlser Air Oowratc I Local T""", WaterT""", KLa" 1 I Kt.8" 2 I C.,. 1 C." 2 SOTE 1 SOTE2
AECOR
AECOR
1 "2 T 4
5
SCFM degF in Hg degj IIhr IIhr mg/L mg/L % % (Probe 1) - (probe 2) (probe 1 (probe 2) (pJOIiC 1) -~
1 79 29.84 25.0 5.043 5.090 10.003 9.835 23.876 1 73 29.92 24.6 5.490 5.860 10.016 10.603 26.025 , 2 76 29.77 25.0 14.387 13.235 10.269 10.991 34.962 ' 2 71 29.80 24.1 IS.991. ~504 9.Sll 10.381 35.993 3 29.91 24.2 40.774
29.84 24.4 42.961 Ceramic 1 I 69 I 29.91 23.5 72.445 Ceramic ----I 69 - --- 29.91 25.6 12.180 11.253 11.188 11.278 64.496 60.070
I ~ Ceramic 1 76 29.90 25.8 8.614 7.893 10.924 10.417 44.540 38.916 I .n Ceramic 1 74 29.91 25.6 7.349 7.173 9.668 10.406 33.628 38.332
Ceramic 1.5 71 29.94 24.5 23.449 20.833 10.324 10.908 76.389 71.707 I " Ceramic 1.5 71 29.94 25.1 18.956 17.357 10.269 10.703 61.423 58.621 I 13 Ceramic 2 74 29.96 24.2 18.230 16.893 10.137 10.853 43.733 43.390 I 14 Ceramic 2 74 29.96 24.4 18.m 15.392 8.540 10.934 37.947 39.829
15 HOPE 1.5 77 29.92 25.6 15.172 16 HOPE 1.5 74 29.91 24.6 17 HDPE 3 72 29.Tl 24.0 I ~".I.I~ ~~"'J I IV • .., ...... I .WIN'" JO~J .11 • .-, I
I III' unDI:' '::t "'0 29.77 24~J..... ....... ..., n" I ...... " .. I Oft 1ft.<'" ", .... ..JIj - I
I Clean Water 1 _ Difflrser Q .. Avg. C'." I Avg. Kca" I Avg. SOTE Avg.SOTE
(SCFM) (mgIL) (11hr) (%) per II of
1.11~ 1 5.370 1 25.752 ± 1.717 ~ I IU..... . 14.780 35.868 _~J.9.1
12 i2 27.148 43.906 I 2.927 Ceramic I 10.556 10.499 52.886 3.526 I I I I I Ceramic 1.5 10.551 20.419 67.035 4.469 I I I I I Ceramic 2 10.116 17.423 41.225 2.748 HOPE 1.5 10.536 14.738 47.954 3.197 HOPE 3 10.419 25.404 41.747 2.783
Note: Probe I is the upper DO probe in the aeration column and probe 2 is the lower one. The di1fuser submergence is 15 Il
74
Testing Date: May 26, 2006 Air Temp ("F): 92 Barom Pres (in Hg): 29.99
DiflUser Airflow Test Rate No. (SCFM)
1 Memb. 1
2 Memb. 1
3 Memb. 1
4 Memb. 2
5 Memb. 2
6 Memb. 2
7 Memb. 2
8 Ceramic 1
9 Ceramic I
10 Ceramic 1
11 Ceramic 1.5
12 Ceramic 1.5
13 Ceramic 1.5
14 Ceramic 2
15 Ceramic 2
16 Ceramic 2
17 HOPE 1.5
18 HOPE 1.5
19 HOPE 1.5
20 HOPE 1.5
Water 00 Temp. (mgIL) ("C)
30.0 1.11
30.1 636
30.1 3.76
30.0 5.06
29.9 7.04
28.4 5.84
TABLE 17. Off-gas Analysis (1) Data Summary
MLSS = 3082 mgIL Theta = 1.024
Ref-gas Off-gas M Ampere Ampere Fra<lion
(pA) (pA) Off-gas
557 527 0.1982
563 528 0.1%5
565 528 0.1958
567 539 0.1992
564 542 0.2013
557 533 0.2005
545 524 0.2014
525 516 0.2059
513 508 0.2075
51\ 508 0.2083
491 472 0.2014
490 471 0.2014
489 471 0.2018
480 466 0.2034
477 469 0.2060
478 470 0.2060
534 518 0.2032
538 516 0.2009
538 518 0.2017
539 517 02009
75
YR =0.2095 MR oIi = 0.2650
MRatio C.T Off-gas (mgIL)
0.2472
0.2445 8.40
0.2434
0.2487
0.2521 8.53
0.2S07
0.2522
0.2593
0.2618 8.75
0.2631
0.2522
0.2522 8.76
0.2528
0.2553
0.2594 8.41
0.2594
0.2551
0.2515 8.99
0.2527
0.2515
C." (mgIL)
10.11
10.29
10.56
10.55
10.12
10.54
aTE OTE aSOTE SaTE Alpha (%) a>g. avg. avg. avg.
("10) ("10) (%)
6.72
7.74 7.53 8.34 25.75 032
8.14
6.17
4.88 532 20.66 35.87 0.58
539
4.83
2.16
123 \38 2.34 52.89 0.04
0.74
4.85
4.86 4.77 10.99 67.04 0.16
4.61
3.66
2.11 2.63 16.36 4123 0.40
2.11
3.76
5.12 4.66 13.15 47.95 0.27
4.66
5.11
Testing Date: June 9, 2006 Air Temp ("F): 95 Barom Pres (in Hg): 30.01
Test Diffuser Airflow No. Rate
(SCFM)
1 Memb. 1
2 Memb. 1
3 Memb. 1
4 Memb. 1
5 Memb. 2
6 Memb. 2
7 Memb. 2
8 Memb. 2
9 Memb. 2
10 Commie 1
11 Commie 1
12 Commie 1
13 Commie 1
14 Ceramic 1.5
15 Commie 1.5
16 Commie 1.5
17 Cemmic 1.5
Water 00
~~. (mg/L)
30.3 4.43
30.5 6.45
31.0 4.56
31.1 5.14
- ..
TABLE 18. Off-gas Analysis (2) Data Summary
MLSS = 3867 mg/L Theta = 1.024
Ref_ 00_
~;;e ~e 634 600
634 603
638 604
639 604
603 588
596 578
579 567
576 562
570 557
524 510
530 51!
531 511
531 510
520 501
522 502
521 503
522 503
M Fraction 00_ 0.1983
0.1993
0.1983
0.1980
02043
02032
02052
02044
02047
02039
02020
02016
02012
02018
02015
02023
02019
76
VR =02095 MR"" =02650
MRalio C'T 00_ (mg/L)
02473
02488 8.36
0.2474
02469
02567
025SO
02581 8.47
02569
02574
02561
02531 8.61
02525
02519
02529
02523 8.60
02535
02529
C.,. (mg/L)
10.11
10.29
10.56
10.55
OTE Avg. oSOTE SOTE Alpha ("10) OTE ("10) (%)
('Vol
6.69
6.11 6.57 13.53 25.75 0.53
6.65
6.83
3.13
3.79
2.61 3.09 12.81 35.87 0.36
3.06
2.87
3.36
4.49 4.38 8.99 52.89 0.17
4.72
4.95
4.58
4.80 4.57 10.98 67.04 0.16
4.33
4.56
TABLE 18. (Continued) Off-gas Analysis (2) Data Summary
Test Airflow Water 00 Ref-gas Off-gas M MRatio C'T C." OTE Avg. aSOTE SOTE No. Diffuser Rate ~e~r (1llfIL) Ampere Ampere Fradion Off-gas (1llfIL) (mg/L) ("/0) OTE ("/0) ("/0)
Alpha (SCFM) (..A) (~A) Off-gas (%)
18 Ceramic 2 513 501 0.2046 0.2572 2.94
19 Ceramic 2 514 501 0.2042 O~ 3.18 31.3 6.07 8.22 10.12 3.00 11.23 41.23 0.27
20 Ceramic 2 513 501 0.2046 0.2572 2.94
21 Ceramic 2 513 501 0.2046 0.2572 2.94
22 HOPE 1.5 495 478 0.2023 0.2536 4.31
2J HOPE 1.5 495 478 0.2023 0.2536 4.31 31.5 4.90 8.53 10.54 4.12 9.32 47.95 0.19
24 HOPE 1.5 493 478 0.2031 0.2549 3.82
25 HOPE 1.5 494 478 02027 0.2543 4.06
77
Testing Date: June 30, 2006 Air Temp ("F): 98 Barom Pres (in Hg): 29.97
Test D_ Airtlow No. Rate
(SCFM)
I Memb. I
2 Memb. I
3 Memb. 1
4 Memb. 1
5 Memb. 1
6 Memb. 2
7 Memb. 2
8 Memb. 2
9 Memb. 2
10 Memb. 2
11 Memb. 2
12 Memb. 2
13 Ceramic 1
14 Ceramic 1
15 Ceramic 1
16 Ceramic 1
17 Ceramic I
18 Ceramic 1.5
19 Ceramic 1.5
20 Ceramic 1.5
21 Ceramic 1.5
W_ OO Temp. rci
(mtVL)
29.3 0.10
29.5 420
29.7 0.65
29.8 2.08
TABLE 19. Off-gas Analysis (3) Data Summary
MLSS = 5436 mgIL Theta = 1.024
Ref-gas Off-gas
~:;. ~= 578 551
569 542
570 542
573 545
581 557
576 555
576 557
575 557
578 558
577 560
581 564
581 563
589 571
589 568
591 567
590 566
590 56S
589 559
589 559
588 557
587 556
M Fraction Off ..... 0.1997
0.1996
0.1992
0.1993
02008
02019
02026
02029
02023
02033
02034
02030
02031
02020
02010
02010
02006
0.1988
0.1988
0.1985
0.1984
78
Ya =0.2095 MR .. =0.2650
M Ratio C _r Off-gas (mtVL)
02496
02493
02488 8.50
02488
02513
02529
02541
02546
02535 8.62
02552
02553
02547
02549
02532
02516 8.81
02515
02510
02482
02482 8.79
02476
02476
C ,'" (mgIL)
10.114
10288
10.556
10.551
OTE Avg. oSOTE SOTE Alpha ("10) OTE ("10) ("10)
(%1
5.84
5.93
6.13 5.83 5.69 25.75 022
6.10
5.17
4.57
4.14
3.93
4.34 4.03 7.64 35.87 021
3.70
3.67
3.89
3.83
4.47
5.08 4.76 4.95 52.89 0.09
5.09
5.30
6.36
6.36 6.47 8.17 67.04 0.12
6.58
6.59
TABLE 19 (Continued). otT-gas Analysis (3) Data Summary
Test Airflow w_ oo Rcf-gas OO-gas M
M Ratio CoT C.", OTE
Avg. oSOTE SOTE Ditfuser Rate Temp. ~ ;:re Fraction (mgIL) (mgIL) OTE Alpha
No. (SCFM) ('ci (mgIL) 00_ OO-gas ('10) ('10) (%) (%)
22 Ceramic 2 569 551 02029 02545 3.97
23 Ceramic 2 573 554 02026 02S40 4.16
24 Ceramic 2 30.0 4.60 575 556 02026 02540 8.40 10.116 4.14 3.99 8.57 4123 021
2S Ceramic 2 573 556 02033 02552 3.72
26 Ceramic 2 574 556 02029 0.2546 3.93
27 HOPE 1.5 535 514 02013 02520 4.91
28 HOPE 1.5 535 512 02005 0.2508 5.38
29 HOPE 1.5 302 3.00 534 512 02009 02514 8.72 10.536 5.16 528 7.75 47.95 0.16
30 HOPE 1.5 536 512 02001 02502 5.60
31 HOPE 1.5 535 512 02005 02S08 5.38
79
Testing Date: July 28, 2006 AirTemp("F): 99 Barom Pres (in Hg): 30.00
Test DiflUser Airflow No. ~ I Memb. I
2 Memb. I
3 Memb. I
4 Memb. I
5 Memb. I
6 Memb. I
7 Memb. I
8 Memb. 2
9 Memb. 2
10 Memb. 2
11 Memb. 2
12 Memb. 2
13 Ceramic I
14 Ceramic I
15 Ceramic I
16 Ceramic I
17 Ceramic I
w_ 00g/L) Temp. I"ci
29.9 0.18
30.0 420
30.2 1.80
TABLE 20. Off-gas Analysis (4) Data Summary
MLSS = 8367 mgIL Theta = 1.024
Ref-gas OIT-gas
~;'ie "(:je S63 541
567 543
567 545
S68 547
578 554
575 556
575 551
592 566
593 S66
596 569
597 572
59S 570
570 549
570 545
570 543
571 S44
570 543
M Fraction OIT-gas
020)3
02006
02014
02018
02008
02026
02008
02003
02000
02000
02007
02007
02018
02003
0.1996
0.1996
0.1996
80
VR =0.2095 MR oIi = 0.2650
MRatio C .T OIT-gas (mgIL)
02521
02510
02521
02527 8.41
02513
02540
02512
02S05
02499
02500 8.54
02511
02511
02528
0250S
02493 8.73
02494
02493
C"" (mgIL)
10.114
10.288
10.556
OTE Avg. aSOTE SOTE Alpha COA,) OTE COA,) COA,)
(%)
4.89
5.30
4.86
4.63 4.89 4.80 25.752 0.19
520
4.14
522
5.49
5.69
5.66 5.47 1M3 35.868 029
524
526
4.62
5.48
5.92 5.57 6.75 52.886 0.13
5.91
5.92
TABLE 20. (Continued) Off-gas Analysis (4) Data Summary
Test Airflow Water Rol_ Off_ M MRatio C _y C-.,. Avg. oSOTE SOTE
Diffuser RlIk ~~r COWL) ;;:ee ;;:ee FlBdion (mg/L) (mg/L) OTE OTE Alpha No. (SCFM) Off_ Off_ ("16) (%)
(%) (%)
18 Ceramic 1.5 570 547 02010 02516 5.05
19 Ceramic 1.5 574 550 02007 0.2512 5.23
20 Ceramic 1.5 577 554 02011 02518 4.99
21 Ceramic 1.5 582 556 02001 02502 5.59 30.3 3.30 8.72 10.551 5.51 8.54 67.035 0.13
22 Ceramic 1.5 582 556 02001 02502 5.59
23 Ceramic 1.5 579 552 0.1997 02496 5.83
24 Ceramic 1.5 581 553 0.1994 02491 6.02
25 Ceramic 1.5 582 555 0.1998 02497 5.80
26 Ceramic 2 570 552 02029 02S45 3.96
27 Ceramic 2 570 551 02025 02539 4.18
28 Ceramic 2 568 554 02043 02568 3.10
29 Ceramic 2 30.4 5.82 571 555 02036 02557 8.34 10.116 3.52 3.38 10.97 41225 027
30 Ceramic 2 577 564 02048 02575 2.83
31 Ceramic 2 581 567 02045 02570 3.03
32 Ceramic 2 583 569 02045 02570 3.02
33 HOPE 1.5 564 541 02010 02515 5.10
34 HOPE 1.5 563 539 02006 02509 5.33
35 HOPE 1.5 562 539 02009 02514 5.12
36 HOPE 1.5 562 S40 02013 02520 4.90 30.5 3.68 8.67 10.536 5.01 8.39 47.954 0.18
37 HDPE 1.5 566 S44 02014 02521 4.87
38 HOPE 1.5 573 550 02011 02517 5.02
39 HOPE 1.5 576 555 02019 02529 4.57
40 HOPE 1.5 583 559 02009 02514 5.15
81
Testing Date: August 10,2006 Air Temp ("F): 99 Barom Pres (in Hg): 30.00
Test Diffuser Airflow No.
~ I Memb. I
2 Memb. I
3 Mcmb. I
4 Memb. I
5 Memb. I
6 Memb. 2
7 Memb. 2
8 Mcmb. 2
9 Memb. 2
10 Mcmb. 2
II Mcmb. 2
12 Cenunic I
13 Cenunic I
14 Cenunic I
IS Ceramic I
16 Cenunic I
17 Cenunic I
18 Cenunic I
Water 00 Temp. (mg/L) ("q
29.8 0.07
30 l.05
30.2 0.10
.--
TABLE 21. Off-gas Analysis (5) Data Summary
MLSS = 10533 mgIL Theta = 1.024
Ref-gas Off-gas
~: ~: 582 559
580 560
582 561
582 561
582 561
600 573
604 576
60S 577
60S 578
60S 578
60S 578
626 603
631 608
639 613
640 613
643 618
650 620
646 615
M Fraction Off ....
02012
02023
02019
02019
02019
02001
0.1998
0.1998
02002
02002
02002
02018
02019
02010
02007
02014
0.1998
0.1994
82
Va =0.2095 MR ali = 0.2650
MRatio C .T Off-gas (mg/L)
02519
02536
02530 8.43
02530
02530
02501
0.2497
0.2497 8.54
02502
02502
0.2502
0.2528
02529
02515
02510 8.73
0.2521
02497
0.2491
C.'" (mg/L)
10.114
10.288
10.556
--
OTE Avv,. aSOTE SOTE Alpha ("k) OTE ("16) (%)
("16)
4.95
4.32
4.52 4.57 4.43 25.752 0.17
4.52
4.52
5.63
5.79
5.78 5.66 6.20 35.868 0.17
5.58
5.58
5.58
4.60
4.57
5.09
5.28 5.17 5.02 52.886 0.09
4.87
5.77
5.99 -
TABLE 21 (Continued). otT-gas Analysis (5) Data Summary
Test Airflow Water 00 Ref-gas Off-gBS M MRatio ~} c.,.
OTE Avg.
aSOTE SOTE No. Diffuser (~ T~. (mgIL)
Ampere ~
Fnu:tioo Off-gas (mgIL) (,A» ~Z (,A» ('A» Alpha
("C (Ju\) Off-gas
19 Ceramic I.S 600 S74 0.2004 0.2S07 S.42
20 Ceramic I.S 600 S73 0.2001 0.2S01 S.63 30.3 0.20 8.72 10.SSI S.63 S52 67.03S 0.08
21 Cemmic 15 600 S72 0.1997 0.2496 S.83
22 Ceramic 15 S98 S71 0.2000 0.2S01 S.64
23 Ceramic 2 S90 S68 0.2017 0.2S26 4.67
24 O:nmtic 2 S91 S69 0.2017 0.2S27 4.66
2S Ceramic 2 30.4 1.93 S92 S70 0.2017 0.2S27 8.34 10.116 4.66 4.61 5.76 41.22S 0.14
26 Ceramic 2 S93 S71 0.2017 0.2S27 4.6S
27 Ceramic 2 594 S73 0.2021 0.2S33 4.43
28 HOPE 15 S80 5S6 0.2008 0.2S13 S.l8
29 HOPE I.S S78 SS3 0.2004 0.2S07 S.41
30 HOPE I.S 30.S 0.24 S77 SSI 0.2001 0.2S01 8.67 10.S36 S.63 S.47 5.38 47.954 0.11
31 HOPE I.S S7S S49 0.2000 O.2Soo S.6S
32 HOPE 15 573 S48 0.2004 0.2S06 S.46
83
Testing Date: August 17, 2006 Air Temp ("F): 99 Barom Pres (in Hg): 30.00
Test Dif!iJser Airflow No. Rate
(SCFMl
I Mo:mb. I
2 Mcomb. I
3 Mcomb. I
4 Mcomb. I
5 Mcomb. I
6 Memb. I
6 Mo:mb. 2
7 Mo:mb. 2
8 Mcomb. 2
9 Mcomb. 2
10 Mcomb. 2
II Memb. 2
12 Mcomb. 2
13 Cemmic I
14 Cemmic I
IS Cemmic I
16 Cemmic I
17 Cemmic I
18 Cemmic I
19 Ceramic I
20 Cemmic I
w_ oo
~6' (mgIL)
30.3 026
30.5 0.45
30.7 0.42
TABLE 22. Off-gas Analysis (6) Data Summary
MLSS = 11967 mgIL Theta = 1.024
Ref-gas Oft'-gas
~ ~::;. 610 590
609 590
610 589
609 589
610 589
610 589
610 586
610 586
610 586
609 585
608 584
608 583
607 583
595 574
594 573
595 572
594 571
593 568
591 566
588 565
586 563
M Fraetion Off .....
02026
02030
02023
02026
02023
02023
02013
02013
02013
02012
02012
02009
02012
02021
02021
02014
02014
02007
02006
02013
02013
84
VR =0.2095 MR ali = 0.2650
MRalio Cor Oft'-gas (mgIL)
02541
02546
02536 8.36
02541
02536
02536
02520
02520
02520
02519 8.47
02519
02514
02519
02533
02533
02522
02522 8.66
02510
02510
02520
02520
C." (mgIL)
10.114
10288
10.556
OTE Avg. oSOTE SOTE Alpha ("/0) OTE (%) ("/0)
{"!ol
4.11
3.91
4.32 4.18 4.13 25.752 0.16
4.12
4.32
4.32
4.93
4.93
4.93
4.93 4.% 5.01 35.868 0.14
4.94
5.15
4.95
4.42
4.43
4.84
4.85 4.87 4.89 52886 0.09
527
529
4.90
4.91
TABLE 22. (Continued) Off-gas Analysis (6) Data Summary
Test Airflow Water 00 Ref_ 00_ M M Ratio C .T :;,,~) OTE Ayg. .sOTE SOTE No. Diftilser Rate T~. (mgIL) ~ =- Fraction 00_ (mgIL)
("/0) OTE (";.,) ("/0) Alpha (SCFM) 00_ {"/oj
21 Ceramic 1.5 579 558 02019 02530 4.54
22 Caamic 1.5 580 556 02008 02513 5.18 30.9 0.40 8.63 10.551 4.92 4.92 67.035 0.07
23 Ceramic 1.5 578 555 0.2012 02518 4.98
24 Ceramic 1.5 577 554 02011 02518 4.99
2S Ceramic 2 570 547 02010 02516 5.05
26 Ceramic 2 S69 S46 02010 02516 5.06 31.0 0.38 826 10.116 5.12 5.12 41225 0.12
27 Ceramic 2 568 545 02010 02516 5.07
28 Ceramic 2 567 543 02006 02510 5.30
29 IIDPE 1.5 529 511 02024 02537 427
30 IIDPE 1.5 528 509 I
02020 02531 4.51 I
31 IIDPE 1.5 31.2 0.32 527 507 02015 02524 8.57 10.536 4.75 4.66 4.61 47.954 0.10
32 IIDPE 1.5 526 506 02015 02524 4.76
33 IIDPE 1.5 S2S 504 02011 02518 5.01
85
Testing Date: August 31, 2006 Air Temp ("F): 99 Barom Pres (in Hg): 30.00
Test Diffuser Airtlow No. Rate
(SCFM)
1 Memb. 1
2 Memb. 1
3 Memb. 1
6 Memb. 2
7 Memb. 2
8 Memb. 2
13 Ceramic I
14 Ceramic I
15 Ceramic 1
21 Ceramic 1.5
22 Ceramic 1.5
23 Ceramic 1.5
2S Ceramic 2
26 Ceramic 2
27 Ceramic 2
29 HOPE 1.5
30 HOPE 1.5
31 HOPE I.S "---
Water 00
~~r (mg/L)
31.4 022
31.6 0.72
31.7 0.30
31.6 0.38
31.6 0.63
31.3 028
-- - L.
TABLE 23. Off-gas Analysis (7) Data Summary
MLSS = 14760 mgIL Theta = 1.024
Ref-gas Off-gas
~: '7::e
495 480
495 480
495 480
490 476
491 476
491 476
444 432
444 432
444 432
441 428
441 428
441 428
436 423
436 423
436 423
431 418
431 419
432 419
M Fraction Off ......
02032
02032
02032
02035
02031
02031
02038
02038
02038
02033
02033
02033
02033
02033
02033
02032
02037
02032
86
VR =02095 MR oil = 02650
MRatio C.T Off-gas (mgIL)
02S49
02549 820
02S49
02555
02S49 8.31
02549
02560
02S60 8.52
02560
02552
02S52 8.S3
02552
025S1
02551 8.18
02SS1
02550
025SS 8.56
02550
C.,. (mg/L)
10.114
10.288
10.556
10.551
10.116
10.536
OTE A.g. aSOTE SOTE Alpha (%) OTE (%) (%)
("10)
3.80
3.80 3.80 3.71 25.752 0.14
3.80
3.59
3.83 3.75 3.90 35.868 0.11
3.83
3.39
3.39 3.39 3.33 52.886 0.06
3.39
3.70
3.70 3.70 3.68 67.035 0.05
3.70
3.74
3.74 3.74 3.85 41225 0.09
3.74
3.79
3.50 3.69 3.63 47.954 0.08
3.78 - '----- --
Testing Date: September 14, 2006 Air Temp ("F): 99 Barom Pres (in Hg): 30.00
Test DiIliJser AiJIlow Water No.
~ Temp. ("ci
I Memb. I
2 Memb. I
3 Memb. I 30.0
4 Memb. I
5 Memb. I
6 Memb. 2
7 Memb. 2
8 Memb. 2 30.2
9 Memb. 2
10 Memb. 2
13 Ceramic 1
14 Ceramic 1
15 Ceramic 1 30.2
16 Ceramic 1
17 Ceramic 1
18 Ceramic 1
21 Ceramic 1.5
22 Ceramic 1.5 30.2
23 Ceramic 1.5
24 Ceramic 1.5 -
00 (mg/L)
0.19
0.22
0.28
029
TABLE 24. otT-gas Analysis (8) Data Summary
MLSS = 17667 mWL Theta = 1.024
Ref-gas Q1I.glIS
'(:ie ~:;e 581 566
585 571
590 575
594 579
597 582
613 601
613 599
613 597
612 595
608 591
556 S44
554 543
5SJ 542
5S2 S40
552 539
551 538
S44 531
545 531
545 532
S46 532
M Fm:tion Off-gas
0.2041
0.2045
0.2042
0.2042
0.2042
0.2054
0.2047
0.2040
0.2037
0.2036
0.2050
0.2053
0.2053
0.2049
0.2046
0.2046
02045
02041
02045
0.2041
87
YR =0.2095 MR ali = 02650
MRalio C .T
Off-gas (mgIL)
0.2564
0.2570
0.2566 8.40
0.2566
0.2567
0.2585
0.2574
0.2563 8S1
0.2558
0.2557
0.2578
0.2584
0.2584 8.73
0.2578
0.2572
0.2572
0.2571
0.2S6S 8.73
0.2571
0.2S6S
C • ., (mgIL)
10.114
10.288
10.556
10.551
OTE Avg. aSOTE SOTE Alpha (%) ~: (%) ("10)
3.24
3.01
3.19 3.16 3.10 25.752 0.12
3.17
3.16
2.46
2.87
3.2S 3.12 3.07 35.868 0.09
3.49
3S1
2.71
2.50
2.50 2.73 2.71 52.886 0.05
2.73
2.96
2.97
3.00
3.23 3.11 3.08 67.035 0.05
3.00
3.22
TABLE 24. (Continued) Off-gas Analysis (8) Data Summary
Test Airflow Water 00 Ref_ Off_ M M Ratio c"oT c·..,lIl OTE Avg. aSOTE SOTE DiIJilser ~ ~d· ::;ae =- Fraction OTE Alpha
No. (mg/L) Off ..... Off_ (mg/L) (mg/L) (%) ("/0)
("/0) ("/0)
25 Ceramic 2 543 528 02037 02558 3.47
26 Ceramic 2 541 527 02041 02564 325 30.3 0.30 8.36 10.116 3.31 3.29 41225 0.08
27 Ceramic 2 S40 526 02041 02564 326
28 Ceramic 2 539 52S 02041 02564 326
29 HOPE 1.5 541 532 02060 02595 2.10
30 HOPE 1.5 542 532 02056 02589 232 0.05 30.3 029 8.7 10.536 2.32 2.30 47.954
31 HOPE 1.5 542 532 02056 02589 2.32
32 HOPE 1.5 542 531 02052 02583 2.55
88
TABLE 25. Sludge Properties at Varied MLSS Concentrations
SampUIIg TSS vss VIscosity Carbobydrate ProteiD SMP EPS TOS SCOD OUR MediaD Date (mg/L) (mg/L) «p) (mg/L) (mg/L) (mg/L) (mg/L) (mglL.b) ParDd.
SMP EPS SMP EPS Slzo
(mg/L) (mg/L) (mg/L) (mg/L) (Jim)
05126106 3082 2661 1.57 11.43 196.27 2.82 53.63 14.25 249.90 740 25.4 19.86 54.97
06109106 3867 3290 1.63 4.12 16.42 2.02 17.34 6.14 33.76 738 22.2 25.37 55.70
06/30106 5436 4521 2.02 19.87 14.40 4.44 100.40 24.31 114.80 1005 50.4 28.84 37.65
07128106 8367 6700 3.98 4.70 24.29 3.63 81.05 8.33 105.34 670 34.8 29.83 33.52
08110106 10533 8233 6.09 4.97 34.63 2.82 100.40 7.79 135.03 973 33.4 38.27 33.31
08117106 11967 9633 8.37 7.25 37.59 4.44 131.86 11.69 169.45 691 29.5 47.65 33.91
08131106 14760 11491 10.7 5.25 32.55 4.44 263.31 9.69 295.86 789 17.5 51.05 29.39
09114106 17667 13900 13.1 5.80 69.24 4.84 184.67 10.64 253.92 879 30.3 45.85 29.06
89
APPENDIX III: PHOTOGRAPHS
Picture 1. Column set-up
90
Picture 2. Clean water testing
91
Sealed cover
Picture 3. Process water testing
92
Picture 4. Diffuser in the test column
Picture 5. Aeration in the test column
93
Picture 6. Membrane disc diffuser
Picture 7. Ceramic disc diffuser
94
Picture 8. HOPE disc diffuser
Picture 9. OfT-gas analyzer being used in testing
95
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99