Membrane Based Triethylene Glycol Separation and Recovery from ...

Membrane Based Triethylene Glycol Separation and Recovery
from Gas Separation Plant Wastewater
by
Pimchanok Khachonbun
A thesis submitted in partial fulfillment of the requirements for the
degree of Master of Engineering in
Environment Engineering and Management
Examination Committee: Prof. Chettiyappan Visvanathan (Chairperson)
Prof. Ajit P. Annachhatre
Dr. Romchat Rattanaoudom (External Expert)
Nationality: Thai
Previous Degree: Bachelor of Engineering in Environmental
Engineering
Suranaree University of Technology, Thailand
Scholarship Donor: Royal Thai Government – AIT Fellowship
Asian Institute of Technology
School of Environment, Resources and Development
Thailand
May 2013
i

Acknowledgements
I would like to express my heartfelt thanks and profound gratitude to my advisor, Prof. C.
Visvanathan, who has supported me throughout my thesis with his excellent guidance,
encouragement and valuable suggestions. Without his supervision and constructive
assistance, this study would not have been in its present shape.
Special appreciation is also extended to Prof. Ajit P. Annachhatre and Dr. R.
Rattanaoudom as the thesis committee members, who provided valuable comments,
support, suggestions and assistances toward the usefulness of the study.
I would like to gratefully acknowledge to Royal Thai Government (RTG) for scholarships
for the Master study in AIT. Moreover, my deep gratitude goes to Petroleum Authority of
Thailand (PTT), for providing technical support for my research.
I am thankful to Prof. C. Visvanathan’s research group for their support. Especially my
thanks go to Mr. P. Jacob and Mr. T. Rathnayake for their technical support and
encouragement to complete the research successfully.
In addition, my deep great gratitude also is extended to all my dear teachers, faculty
members and all staffs and technicians of EEM for their help, technical and moral support
and cooperation, which assisted me to complete this thesis.
I would like to express my deep thanks to my colleagues, Ms. Phontida, Mr. Supawat, Mr.
Phanwatt, Mr. Kiattisak, Mr. Duc, Mr. Ahmad, Mr. Siripong, Mr. Lalith, Ms. Kamala and
Ms. Tasawan for their generous support in technically as well as humanly during the entire
period of my study.
Finally, my achievement would never be possible unless there is hearty support from my
family. The deepest and sincere gratitude goes to my beloved parents, my younger sister
for their endless love, encouragement and understanding throughout the entire period of
my study.
ii

Abstract
Triethylene glycol (TEG) is absorption, involves the use of a liquid desiccant to remove
water content from the gas. This study investigated membrane filtration, pervaporation
process and design pre-treatment process to treat real wastewater from gas separation
plants. In membrane filtration experiment, four types of membrane (NF-TS40, NF-TS80,
RO-ACM5 and RO-NTR759HR) were tested with synthetic wastewater. NF-TS80 is the
best of nanofiltration membrane to recover TEG, with a 70% TEG recovery. Moreover,
RO-ACM5 was the most effective membrane of reverses osmosis membrane, with a 90%
TEG recovery which presented at low concentration applied (0.1%, 5% and 10% of TEG).
In case of permeate flux, the low permeate flux (0.01-0.16 L/m 2 .h) presented at high
concentration applied (20% and 30% of TEG) that was resulted from the effect of
concentration polarization and membrane fouling.
Pervaporation process was conducted with 0.1, 5 and 10% of TEG concentrations in
synthetic wastewater with temperature variation of 30, 40 and 70°C of each concentration.
In case of permeate flux, the high permeate flux 6.81 kg/m 2 .h presented at low
concentration (0.1% of TEG) and used high temperature (70°C). While the permeate flux
at a concentration of 10% was found with 0.58 kg/m 2 .h at 40°C. Also, the separation factor
was 698 for 10% TEG at 40°C. The flux and the separation factors obtained indicate that
pervaporation process with NaA Zeolite membrane is not attractive and the system does
not performed well at lower concentration of solutes.
In pre-treatment experiment, testing with real wastewater using RO-ACM5 and NF-TS80
membranes was necessary. However, the wastewater first needs be pretreated to protect
membrane from fouling by suspended solids and oil/grease by used microfiltration (MF)
and ultrafiltration (UF) membrane, respectively. Pre-treatment process coupled with
nanofiltration membrane (TS80) showed higher TEG removal than synthetic wastewater
experiments at 0.1% TEG concentration by approximately 73%. While reverse osmosis
membrane (ACM5) showed slightly higher removal for TEG than synthetic wastewater
experiments with 0.5% TEG concentration also by approximately 95%. In case of 8.3%
TEG concentration, nanofiltration (TS80) and reverse osmosis (ACM5) membrane showed
relatively equal to the value of synthetic wastewater experiments by approximately 47.15%
and 77.56%, respectively. Therefore, the pre-treatment process should be applied before
using membrane filtration with NF and RO membrane which are proposed for industrial
applications due to its high removal efficiency, high permeate flux with low TEG
concentrations.
iii

Table of Contents
Chapter Title Page
Title Page
Acknowledgements
Abstract
Table of Contents iv
List of Tables vi
List of Figures vii
List of Abbreviations viii
1 Introduction 1
1.1 Background of the Study
1.2 Objectives of the study
1.3 Scope of the Study
2 Literature Review 4
3
4
2.1 Triethylene Glycol Characteristics
2.1.1 General properties
2.1.2 Uses of TEG (Triethylene glycol)
2.1.3 Distribution in environment
2.1.4 Toxic effects
2.2 Gas Separation Plants (GSPs)
2.2.1 Characteristics of TEG in wastewater from gas
separation plant
2.3 Treatment Process
2.4 Membrane Filtration
2.4.1 Membrane applications
2.4.2 Introduction to membrane process
2.4.3 Type of filtration
2.4.4 Operational parameters
2.4.5 Factors affecting membrane filtration
2.4.6 Potential membrane filtration (NF/RO)
2.4.7 Pervaporation technology
Methodology
3.1 Phase I: High Pressure Membrane Filtration
3.1.1 Materials
3.1.2 Membrane tests unit
3.2 Phase II: Membrane of Pervaporation
3.2.1 Materials
3.2.2 Membrane tests unit
3.3 Phase III: Design Pre-Treatment Process to Treat
TEG wastewater
3.3.1 Materials
3.4 Indicative Methods for TEG
3.4.1 TEG analysis by gas chromatograph (GC)
Results and Discussions
iv
i
ii
iii
1
2
3
4
4
5
5
6
9
9
11
12
12
13
15
16
17
18
19
27
28
28
28
31
31
32
34
34
35
35
38

5
4.1 Phase I: High Pressure Membrane Filtration
4.1.1 Membrane properties
4.1.2 Permeate flux
4.1.3 Rejection
4.2 Phase II: Pervaporation Process
4.2.1 Permeate flux
4.2.2 Separation factor
4.2.3 Rejection
4.3 Phase III: Design Pre-Treatment Process for Treat
TEG Wastewater
4.3.1 Membrane properties
4.3.2 Efficiency of TEG wastewater before and after
pre-treatment process
4.3.3 Permeate flux of TEG in real wastewater
4.3.4 Rejection of TEG in real wastewater
4.3.5 Real wastewater characteristics after
NF and RO membrane treatment
Conclusions and Recommendations
5.1 Conclusions
5.2 Recommendations for Further Study
References
Appendix A
Appendix B
Appendix C
Appendix D
Appendix E
Appendix F
v
38
38
39
42
43
43
44
45
46
46
47
49
51
54
56
56
57
60
63
66
70
72
75
77

List of Table
Table Title Page
2.1 Physical and Chemical Properties of Triethylene Glycol 4
2.2 The Number of Facilities of Glycols was Used and The Number of
Employees Exposed
6
2.3 Surface Water Quality Guidelines for DEG and TEG
6
2.4 The Primary Method of Prevention and Medical Care of Human 8
2.5 The Composition of Natural Gas
9
2.6 Total Production Capacity of PTT’s Gas Separation Plant
10
2.7 Sources of TEG Wastewater Treatment Plant
11
2.8 Discharged Effluent Characteristics of Gas Separation Plants
12
2.9 Detail Explanation of Different Membrane Processes
16
2.10 Comparison of Rejection Efficiency of Constituents between NF
and RO
19
2.11 Summary of Pervaporation
20
2.12 Overview of Chosen Membrane Separation Processes
21
2.13 Types of Membrane for Pervaporation
22
2.14 Comparison of Pervaporation Modules
24
2.15 Selective and Transport Properties of Different Types of
Pervaporation Membranes
25
2.16 Permeate Flux and Separation Factor of Ethanol/Water Mixture 26
2.17 Comparison of Advantages and Disadvantages of Pervaporation 26
3.1 List of NF Membranes and Its Properties
28
3.2 List of RO Membranes and Its Properties
28
3.3 List of Pervaporation Membranes and Its Properties
31
3.4 List of MF Membranes and Its Properties
34
3.5 List of UF Membranes and Its Properties
35
4.1 Membrane Characteristics
38
4.2 Wastewater Characteristics of Real Wastewater from
Separation Plants
Gas 47
4.3 Wastewater Characteristics of Real Wastewater After MF
Membranes Pre-treatment
47
4.4 Wastewater Characteristics of Real Wastewater After UF 49
Membranes Pre-treatment
4.5 Wastewater Characteristics of Real Wastewater After NF 54
4.6
Membranes Pre-treatment
Wastewater Characteristics of Real Wastewater After RO
Membranes Pre-treatment
54
vi

List of Figure
Figure Title Page
2.1 Structures of Triethylene Glycol (TEG) 4
2.2 Major uses of TEG 5
2.3 Source of TEG wastewater in Gas Separation Plant of PTT
(Thailand)
10
2.4 Wastewater treatment plants
12
2.5 Demonstrates main characteristics of each membrane types
15
2.6 Membrane fouling
17
2.7 Schematic drawing of the pervaporation process with a downstream
vacuum or an inert carrier-gas
19
2.8 Hollow fiber modules
23
2.9 Plate-and-frame modules
24
2.10 Spiral wound module
24
2.11 Tubular modules
24
3.1 Experimental plans of study
27
3.2 Flow diagram of membrane experimental set up
29
3.3 Flowchart of membrane filtration experiment
30
3.4 Flowchart of pervaporation membrane experiment
32
3.5 Flow diagram of pervaporation experimental set up
33
4.1 Permeate fluxes of membrane filtrations
40
4.2 Normalized flux of direct filtration at different compound
concentrations
41
4.3 Membrane Fouling
42
4.4 Removal efficiency of synthetic wastewater thought membrane
filtration
42
4.5 Permeate fluxes of pervaporation process
44
4.6 Separation factor of pervaporation process
44
4.7 Removal efficiency of synthetic wastewater thought pervaporation
process
45
4.8 Design pre-treatment processes to treat TEG wastewater
48
4.9 Permeate fluxes of membrane filtrations with real TEG wastewater 51
4.10 Removal efficiency of real 0.5 and 8.3% of TEG wastewater
53
vii

List of Abbreviations
bw Brood War
CAS Chemical Abstracts Service
Da Dalton
DEG Diethylene glycol
EG Ethylene glycol
ESP Ethane Separation Plant
GC Gas Chromatography
GSPs Gas Separation Plants
KD Kilodalton
kPa Kilopascal
LD Lethal Dose
LD50 Median Lethal Dose
MBR Membrane bioreactor
MF Microfiltration
MMSCFD Million Standard Cubic Feet per Day
MSDS Material Safety Data Sheet
NF Nanofiltration
nm Nanometer
PC Personnel computer
ppm Parts per Million
PTT Petroleum Authority of Thailand
PV Pervaporation
R Compound Rejection
RO Reverse Osmosis
TEG Triethylene glycol
TREG Tetraethylene glycol
UF Ultrafiltration
U.S.EPA United States Environmental Protection Agency
wt Net Weight
μm Micrometer
viii

1.1 Background of the Study
Chapter 1
Introduction
One of the best glycol frequently used in dehydration of natural gas is TEG (Triethylene
glycol). TEG is a colorless, odorless and viscous liquid with molecular formula C6H14O4.
Advantages of using TEG are ease of regeneration and operation, minimal losses of drying
agent during operation, high affinity for water, chemical stability, high hygroscopicity and
low vapor pressure at the contact temperature.
In term of toxicity and bioaccumulation, TEG is listed as slightly toxic in acute rating from
U.S.EPA. (2003) and low bioconcentration and biomagnification. For human, when
considering exposure route of TEG on experiment conditions and works with this material
by inhalation, ingestion, skin and eyes contact, it has been identified as hazardous and for
potential acute and chronic health effects. Robertson et al. (1947) exposed rats to TEG in
their drinking water at 3,000 mg/kg bw/day for 13 months. No effects on mortality, body
weight, blood and urine composition, and gross and microscopic appearance of the major
organs was reported. Furthermore, Bossert et al. (1992) exposed mice to drinking water
containing TEG for 14 weeks. No effects were seen at 3,300 mg/kg bw/day, but increased
liver weight was observed at 6,800 mg/kg bw/day.
Apart from environmental contamination, their harmful effects on animal and human have
also been revealed in many studies. Regarding to animal studies, the effect on rats exposed
to the test material via a whole-body inhalation protocol and also receiving the chemical
via the oral and dermal routes appears to be low, with reported oral LD50 has value 17,000
mg/kg (MSDS, 2010). Moreover, this study has been repeated using a nose-only exposure
for 6 hours a day for 9 consecutive days. In this inhalation toxicity study, mean exposure
concentrations of 102, 517, or 1,036 mg/m 3 (approximately 0.1, 0.5, 1.0 mg/L/day)
triethylene glycol produced no treatment-related toxicities at any dose tested (McRae,
1998).
In the present, natural gas is one of the most important fuels in our life and one of the
principle sources of energy for day-to-day needs and activities. It is an important factor for
the development of countries that have strong economy because it is a source of energy for
household, industrial and commercial use, as well as to generate electricity. Most natural
gas producers use TEG to remove water in the dehydration process. When TEG is placed
into contact with natural gas it strips the water out of the gas. Thus, TEG is one of the
major components of the wastewater originates from a Gas Separation Plants (GSPs).
Therefore it is absolutely essential to recover and reuse TEG, back in the production
process and more reduces wastewater volume in GSPs.
Nowadays, membrane technologies are becoming more frequently used for separation of
wide varying mixtures in the petrochemical related industries and can complete
successfully with traditional. Membrane technology is widely used in wastewater treatment
processes recently, due to its high performance. Microfiltration (MF), ultrafiltration (UF),
nanofiltration (NF) and reverse osmosis (RO) are successfully used to produce high quality
water. Orecki et al. (2006) found that almost use membrane filtration for separation of EG
(ethylene glycol) from wastewater by nanofiltration. These studies were conducted using
1

the two membrane module configurations-spiral wound (equipped with membranes:
NF270-2540) and NF90-2540) and tubular (equipped with membranes AFC 30) for
separation of EG.
Wastewater in petrochemical industry is currently treated by activated sludge process with
pretreatment of oil/water separation (Ravanchi et al., 2009). Tightening effluent
regulations and increasing need for reuse of treated water have generated interest in the
treatment of petrochemical wastewater with the advanced membrane bio-reactor (MBR)
process.
Pervaporation (PV) is a membrane process used to separate liquid mixtures. In the
dehydration application, water is removed from its mixtures with organic components by
selective permeation through a dense hydrophilic membrane. The most relevant application
of PV is the separation of liquid azeotropes and close boiling point solvent-water mixtures.
Nik et al. (2005) found that inorganic membranes and particular zeolite membranes are
usually used for the dehydration of organic solvent by pervaporation (PV). In this study on
the pervaporation dehydration of EG/water mixtures using commercial nanoporous NaA
zeolite membranes.
A non-porous membrane separates the liquid feed from a downstream compartment to
which vacuum is applied. On the feed side, water is preferentially absorbed on the
membrane. On the permeate side, the water molecules are desorbed and removed, due to
the application of vacuum. The sorption of water on the hydrophilic membrane creates a
water concentration gradient, resulting in a diffusive flux across the membrane. Owing to
the vacuum applied at the permeate side of the membrane, permeate is in the vapors state,
so a phase change occurs from liquid on the feed side to vapor on the permeate side.
Therefore, when looking at membranes to enhance performance, there is often a trade-off
between separation factor and total flux.
1.2 Objectives of the Study
This study aims to develop alternative treatment method for separation and recovery of
concentrated TEG from wastewater in Gas Separation Plants before they are discharged.
The specific objectives of this study are:
1) To investigate efficiency of nanofiltration, reverse osmosis and pervaporation
for TEG separation and recovery;
2) To develop pre-treatment processes to treat real wastewater generated from
dehydration unit in Gas Separation Plant Wastewater (GSPs).
1.3 Scope of the Study
To accomplish the above objectives, scope of study was set as follows:
1) The study was comprised of 3 phases, and their scopes are:
Phase I: High pressure membrane filtration study was conducted in benchscale
with various membrane types (NF/RO) and varying compound
concentration.
2

Phase II: membrane of pervaporation study was conducted in bench-scale
with various membrane types and varying compound concentration.
Phase III: Design the pre-treatment process to organics and inorganics
compound separation in real wastewater from GSPs before pass through
membrane filtration (NF/RO) process.
2) The wastewater applied in this study of phase I and II was synthesized from
MiliQ® water, TEG used in Gas Separation Plants (GSPs).
3) The wastewater applied in this study of phase III was real wastewater generated
from dehydration unit in Gas Separation Plant Wastewater (GSPs).
3

2.1 Triethylene Glycol Characteristics
Chapter 2
Literature Review
Triethylene Glycol (also known as TEG, triglycol and trigen) is employed as a liquid
desiccant for the dehydration of natural gas. Molecular structures of glycols are mono-, di-
and triethylene glycols which are the first three members of a homologous series of
dihydroxyalcohols. The three glycols have many similar chemical properties. Differences
in their applications are due mainly to variations in physical properties such as viscosity,
hygroscopicity and boiling point.
2.1.1 General properties
Figure 2.1 Structures of Triethylene Glycol (TEG)
Physical form of TEG is a colorless, odorless and stable liquid with high viscosity and a
high boiling point. It is also soluble in ethanol, acetone, acetic acid, glycerin, pyridine and
aldehydes; slightly soluble in diethyl ether; and insoluble in oil, fat and hydrocarbons. The
physical and chemical properties of triethylene glycol are shown in Table 2.1.
Table 2.1 Physical and Chemical Properties of Triethylene glycol (TEG)
Parameter Unit Properties
Common name - Triethylene Glycol
Chemical name - Triethylene Glycol
CAS registry number - 112-27-6
Empirical formula - C6H14O4
Molecular weight g/mol 150.17
Density g/cm 3 1.10
Flash point (PMCC) °C (°F) 176 (350)
Ignition point, °C (˚F) °C (°F) 371 (700)
Distillation range at 760 mm Hg
Initial boiling point
Dry point
4
°C (°F)
278 (532)
300 (572)
Boiling point at 760 mm Hg °C (°F) 287.8 (550)
Freezing point °C (°F) -7.2 (19)
Coefficient of expansion per °C at 20°C - 0.00068
Surface tension at 20°C dyne/cm 45.2
Vapor pressure at 20°C mm Hg less than 0.01
Specific Gravity - 1.1274
Solubility - Highly miscible in water
Source: Material Safety Data Sheet (2012)

2.1.2 Uses of TEG (Triethylene glycol)
The main uses for triethylene glycol are based upon its hygroscopic quality. TEG used as
a dehydrating agent for natural gas pipelines where it removes the water from the gas
before being condensed and reused in the system. Moreover, TEG also has a
dehumidifying agent in air-conditioning units. TEGs used to make chemical intermediates
such as plasticizers and polyester resins. In addition, TEG is used in many products
including automotive antifreeze, brake fluids and industrial solvents (Leth and Gregersen,
2005), and TEG is also used as a solvent in many applications, including as a selective
solvent for aromatics, and a solvent in textile dyeing. Triethylene glycol also has mild
disinfectant qualities and, when volatized, is used as an air disinfectant for virus and
bacteria control.
Manufacture of
Ester
Derivatives, 12
Miscellaneous,
19
Solvent, 11
Figure 2.2 Major uses of TEG (Alberta Environment, 2012)
However, the usage of TEG as adsorbent in gas dehydration may affect human, animal and
contaminate in the environment. TEG may transport into soil, release into the river, and
accumulate in sediment at the bottom of the river by rapid run off during the rainy season
and finally affect aquatic and human health.
2.1.3 Distribution in environment
No information was found that would indicate DEG (diethylene glycol), TEG, or TREG
(tetraethylene glycol) occur naturally in the environment. Accordingly, their distribution in
the environment is expected to be strongly biased towards facilities where these
compounds are produced or used. The number of facilities where the Glycols are used is
significant. In the U.S., national surveys of occupational hazards were carried out in 1974
and 1983. The 1983 survey indicated that the number of facilities where these glycols was
used and the number of employees exposed to each was:
5
Vinyl
Pkasticizer, 13
Natural Gas
Dehydration,
45

Table 2.2 The Number of Facilities of Glycols was Used and The Number of
Employees Exposed
Glycol Number of Facilities Number of Employees Exposed
DEG 55,518 890,145
TEG 23,174 233,613
TREG 3,704 55,282
Source: Alberta Environment (2012)
The physical and chemical properties of these glycols (Table2.1) control the environmental
media in which they are likely to be found. All three glycols have very low vapor
pressures, and accordingly, their presence in the atmosphere will not be significant. All the
Glycols could potentially be present in soil, groundwater, and/or surface water (Table 2.3)
in the vicinity of facilities where they are used.
Glycol releases from oil and gas facilities can occur as a result of leaks from operating
equipment or through the improper disposal of wastes when glycol-using facilities are
maintained.
Spills and releases of DEG, TEG, and TREG at gas plants are remediated where possible.
In Alberta, frequency of spill reporting and concentrations of DEG are generally higher
than TEG and TREG, with TREG typically having concentrations less than 10 mg/kg or
non-detectable concentrations.
Table 2.3 Surface Water Quality Guidelines for DEG and TEG
Water Use DEG (mg/L) TEG (mg/L)
Human drinking water
(Source Guidance value for groundwater)
6 60
Freshwater aquatic life 150 350
Irrigation 1 n/c n/c
Livestock watering 2 n/c n/c
Wildlife watering 3 Source: Alberta Environment (2010)
Notes: n/c = not calculated
n/c n/c
1. Guideline protective of irrigation not calculated due to lack of toxicity data relevant to
irrigation.
2. Guideline not calculated due to the lack of toxicity information for livestock species.
3. Guideline not calculated due to the lack of toxicity information for wildlife species.
2.1.4 Toxic effects
TEG has been hazards Identification both of potential Acute Health Effects and Potential
Chronic Health Effects in human and animals are limited information from animal studies
reveals a range of acute toxic effects overlapping those for DEG (Alberta Environment,
2010). Smyth et al. (1941) found that rats and guinea pigs fed TEG at doses approaching
the LD50 appeared sluggish (possibly indicating depression of the central nervous system)
and gross examination revealed kidney damage. Oral LD50 values for laboratory animals
range from 8,800 to 22,000 mg/kg. Ocular and dermal studies found TEG to be non-irritant
6

or mildly irritating. Moreover, for chronic toxic Fitzhugh and Nelson (1946) exposed male
rats to 4% TEG in their diet (approximately 2,000 mg/kg bw/day) for 2 years. No effects
on mortality, body weight, blood and urine composition, and gross and microscopic
appearance of the major organs was reported.
In human are very hazardous in case of eye contact (irritant) of ingestion and slightly
hazardous in case of inhalation. Inflammation of the eye is characterized by redness,
watering, and itching, which there primary method of prevention and medical care is
showed in table 2.4. TEG has a very low order of acute toxicity by perioral, percutaneous
and inhalation (vapor and aerosol) routes of exposure. It does not produce primary skin
irritation. Acute eye contact with the liquid causes mild local transient irritation
(conjunctiva hyperemia and slight chemosis) but does not induce corneal injury. Robertson
et al (1947) exposed rats to TEG in their drinking water at 3,000 mg/kg bw/day for 13
months. No effects on mortality, body weight, blood and urine composition, and gross and
microscopic appearance of the major organs was reported. Bossert et al (1992) exposed
mice to drinking water containing TEG for 14 weeks. No effects were seen at 3,300 mg/kg
bw/day, but increased liver weight was observed at 6,800 mg/kg bw/day.
Animal maximization and human volunteer repeated insult patch tests studies have shown
that TEG does not cause skin sensitization (Ballantyne et al., 2007). The use patterns
suggest that exposure to TEG is mainly occupational, with limited exposures by
consumers. Exposure is normally by skin and eye contact. Local and systemic adverse
health effects by cutaneous exposure are likely not to occur, and eye contact will produce
transient irritation without corneal injury. The very low vapor pressure of TEG makes it
unlikely that significant vapor exposure will occur. Aerosol exposure is not a usual
exposure mode, and acute aerosol exposures are unlikely to be harmful, although a
peripheral sensory irritant effect may develop.
However, repeated exposures to a TEG aerosol may result in respiratory tract irritation,
with cough, shortness of breath and tightness of the chest. Recommended protective and
precautionary measures include protective gloves, goggles or safety glasses and
mechanical room ventilation. LC50 data to various fish, aquatic invertebrates and algae,
indicate that TEG is essentially nontoxic to aquatic organisms. Also, sustained exposure
studies have demonstrated that TEG is of a low order of chronic aquatic toxicity. The
bioconcentration potential, environmental hydrolysis and photolysis rates are low, and soil
mobility high. In the atmosphere TEG is degraded by reacting with photochemically
produced hydroxyl radicals. These considerations indicate that the potential for
ecotoxicological effects with TEG is low Carcinogenicity and Mutagenicity (Ballantyne et
al., 2007).
7

Table 2.4 The Primary Method of Prevention and Medical Care of Human
Identification of hazards Prevention
1. Potential Acute Health Effects:
Eye contact (irritant)
Inhalation (Slightly hazardous)
Skin contact
Ingestion
2. Potential Chronic Health Effects:
Carcinogenic effects
Mutagenic effects
Affecting organs inside the body.
Source: Material Safety Data Sheet (2012)
8
Check for and remove any contact lenses.
Immediately flush eyes with running water
for at least 15 minutes, keeping eyelids
open.
Cold water may be used.
Do not use an eye ointment.
Seek medical attention.
Allow the victim to rest in a well-ventilated
area.
Seek immediate medical attention
No known effect on skin contact, rinse with
water for a few minutes.
Do not induce vomiting.
Loosen tight clothing such as a collar, tie,
belt or waistband.
If the victim is not breathing, perform
mouth-to-mouth resuscitation.
Seek immediate medical attention.
Not available
Not available
The substance is toxic to kidneys, the
nervous system.
Repeated or prolonged exposure to the
substance can produce target organs
damage.

2.2 Gas Separation Plants (GSPs)
2.2.1 Characteristics of TEG in wastewater from gas separation plant
In the present, natural gas is one of the most important fuels in our life and one of the
principle sources of energy for many of our day-to-day needs and activities. It is an
important factor for the development of countries that have strong economy because it is a
source of energy for household, industrial and commercial use, as well as to generate
electricity. Most natural gas producers use TEG to remove water in the dehydration
process. When TEG is placed into contact with natural gas it strips the water out of the gas.
Thus, TEG is one of the major components of the wastewater originates from a Gas
Separation Plants (GSPs).
Moreover, the raw natural gas contains water vapor, hydrogen sulfide (H2S), carbon
dioxide, helium, nitrogen, and other compounds showed in table 2.5. In order to meet the
requirements for a clean, dry, wholly gaseous fuel suitable for transmission through
pipelines and distribution for burning by end users, the gas must go through several stages
of processing, including the removal of entrained liquids from the gas, followed by drying
to reduce water content.
Table 2.5 The Composition of Natural Gas
Components Symbol Percentage (%)
Methane CH4 70-90
Ethane C2H6
Propane C3H8
0-20
Butane C4H8
Carbon Dioxide CO2 0-8
Oxygen O2 0-0.2
Nitrogen N2 0-05
Hydrogen Sulphide H2S 0-5
Rare Gases He,Ne,Xe trace
Source: Composition of natural gas (2012)
In addition, the types of dehydration process used are absorption, adsorption, gas
permeation and refrigeration. The most widely dehydration processes used are which
usually involves one of two processes: either absorption, or adsorption. Absorption occurs
when the water vapor is taken out by a dehydrating agent. Adsorption occurs when the
water vapor is condensed and collected on the surface.
In part of TEG, The TEG adsorbs water from the wet gas and is passed to the glycol
regeneration unit where, very simply, adsorbed gases are flashed off and the water is
removed from the reboiler by heating the wet glycol to around 400ºF at atmospheric
conditions gas. The processes are continuous, that is glycol flow continuously through
dehydration unit where they come in contact and the glycol absorbs the water. The
regenerated TEG is then pumped back to the dehydration unit inlet. Thus, TEG is one of
the major components of the wastewater originates from a Gas Separation Plants (GSPs).
Therefore it is absolutely essential to recover and reuse TEG, back in the production
process.
9

Furthermore, in this study is case of PTT (Petroleum Authority of Thailand) which is the
largest operator of gas separation plants in Thailand. PTT’s gas separation plant unit 1 was
started operating on 1985, with unit 2 to 5 coming up later on. In addition, unit 1, 2, 3 and
5 are located in Rayong province and have production capacity of 390, 290, 390 and 530
MMSCFD (Million standard cubic feet per day respectively). Unit 4 is located in Kanhom,
Nakhon Srithammarat provinces and has current production capacity of 170.
PTT is having another two projects on construction in Rayong. The two new plants are the
ethane separation plant (ESP) and the gas separation plant unit 6. The ethane separation
plant’s purpose is to improve production of the gas separation plant unit 2 and 3. The gas
separation plant unit 6 has the production capacity of 800 MMSCFD. Both projects
encourage development of petrochemical industry and production of liquefied natural
(Cooking Gas) in response of the domestic demand. The total production capacity of
PTT’s gas separation plant will increase to 2,640 MMSCFD, which showed in table 2.6.
Table 2.6 Total Production Capacity of PTT’s Gas Separation Plant
Gas separation Capacity
(MMSCFD)
Production Capacity (Million Tons per Year)
GSP Unit 1-5 ESP and GSPs Total
1,770 870 2,640
Ethane 1.1 1.3 2.4
Propane & LPG 2.5 1.1 2.6
NGL 0.5 0.2 0.7
Total 4.1 2.6 6.7
Source: PTT Research & Technology Institute (2012)
Note: MMSCFD = Million standard cubic feet per day
Gas separation plants are located in Rayong of Thailand; there are 2 sources of TEG
wastewater as follow in table 2.7 and figure 2.3.
Figure 2.3 Source of TEG wastewater in GSPs of PTT (Thailand)
10

Table 2.7 Sources of TEG Wastewater Treatment Plant
Wastewater treatment plant Detail
Wastewater 1: (TEG low concentrations) - Volume 10-12 m 3 /day with concentration
of TEG 0.4%
11
- Half is send to the wastewater treatment
plant in industry which treatment with
AOP (Advanced Oxidation process)
system; another half is send external
disposal.
Wastewater 2: (TEG high concentrations) - Volume 1 m 3 /day with concentration of
TEG 5-70%
Source: PTT Research & Technology Institute (2012)
2.3 Treatment Process
- Send to Better world green company for
disposal (2,700 bath/tons)
TEG wastewater in PTT of Thailand uses conventional wastewater treatments. Moreover,
consisting process physical Treatment, minimizing Complex Structure of Organic
Compounds, biological treatment and MBR (Membrane Bio reaction) system, which have
effluent Characteristics are show in table 2.8.
Orecki et al., 2006 found that almost use membrane filtration for separation of EG
(ethylene glycol) from wastewater by nanofiltration. These studies was to use the two
membrane module configurations-spiral wound (equipped with membranes: NF270-2540)
and NF90-2540) and tubular (equipped with membranes AFC 30) for separation of EG.
Nik et al., 2005 found that inorganic membranes and particular zeolite membranes are
usually used for the dehydration of organic solvent by pervaporation (PV). In this study on
the pervaporation dehydration of EG/water mixtures using commercial nanoporous NaA
zeolite membranes.
Jehle et al., 1995 develop the evaporation (EV), for the concentration of the coolant liquid
from 25% up to 70% glycol. The ethylene glycol concentration in the overhead product
remains as low as 0.5% for this concentration range. Using two different pressures 13.3
and 133.3 mbar at 75°C. The tests of pervaporation (PV) were carried out with a mixture of
the original coolant liquid diluted with water at ethylene glycol concentrations in the range
of 70-95% at 75°C and using different pressure 20-30 mbar. The tests of reverse osmosis
(RO) were detailed with pressure between 15 and 70 bar and temperature between 15 and
40 °C which has the initial glycol feed concentration 0.5%-5%. Furthermore, reverse
osmosis and pervaporation to separation of glycol and water from coolant liquids which
have the pre-treatment process by gravity separation to free oil and settleable solids before
pass through membrane filtration.

Table 2.8 Discharged Effluent Characteristics of Gas Separation Plants
Parameter Unit Effluent Standard
pH - 7.9 5.5-9.0
TEG %
< 2 ppm
(at influent of ozone tank)
-
TDS mg/L 1254 3000
TSS mg/L 2.9 50
BOD mg/L 4 20
COD mg/L 42 120
Oil & Grease mg/L 0.5 5
Cl mg/L 417 -
TKN mg/L 2.7 100
Hg mg/L 0.0001 0.005
Zn µg/L 0.58 5
Total Coli form MPN 100 mL 220

mineral, pharmaceutical, electronics, beverages, beer/wine clarification, as well as
wastewater purification and water desalination. Membrane separation processes compete
with conventional processes such as carbon adsorption, solvent extraction, distillation,
centrifugation, flocculation followed by multimedia filtration, and ion-exchange.
Compared to conventional separation, membrane processes offers several advantages, such
as high quality products, the requirement for less chemical addition, and easier control of
operation and maintenance. However, membrane fouling is still hampering the growth of
industrial applications of membranes (Richard, 2012).
2.4.2 Introduction to membrane process
Membrane is receiving special recognition as alternatives to conventional water treatment
and as a means of polishing treated wastewater effluent especially in reuse applications. It
is defined as a thin film separation of two or more components from fluid flow and can be
classified differently on the basis of determined criteria like type of materials, fluid
movement, morphology, pore size etc. The need for more efficient treatment processes has
attracted the attention of environmental scientists and engineers towards pressure-driven
membrane techniques. The application of membrane filtration processes not only enables
high removal efficiencies, but also allows reuse of water and some of the valuable waste
constituents. In the last few years, technical and economic improvement has made the
treatment of industrial wastewater by membrane system even more advantageous.
Ultrafiltration has been successfully applied for recycling high molecular weight and
insoluble dyes, auxiliary chemicals and water. However, ultrafiltration does not remove
low molecular weight and soluble dyes (acid, direct, reactive and basic, etc.) but efficient
color removal has been achieved by nanofiltration. Its apparent benefits over other
advanced treatments are including continuous separation, low energy consumption, easy
combination with other existing technique, easy up-scaling, and no chemical cost.
Excepting water/wastewater treatment, membrane process can be found in all industrial
areas such as food and beverages, metallurgy, pulp and paper, textiles, pharmaceutical,
automotive, dairy, biotechnology and chemical industry. Membrane is widely used in
industrial process and used for chemical recovery.
As mentioned above, membrane can be manufactured by a wide variety of materials
included inorganic and organic membrane. The inorganic membranes may be distinguished
to 4 types such as ceramic, glass, metallic and zeolite membranes. Their advantages are
high chemical, mechanical and thermal stabilities but the disadvantages are very fragile
and expensive. The organic membranes are widely used in water and wastewater
applications they are more flexible and can be put in compact module. It can be made from
cellulose and synthetic polymer. The synthetic polymer can be manufactured for open
porous membranes, which are applied for microfiltration and ultrafiltration and dense
nonporous membrane, applied in gas separation and pervaporation. The summarized
details of each are explained as following.
Microfiltration (MF)
It is most similar to conventional coarse filtration, the pore size range from 100 - 1000 nm
and driving force pressure is less than 4 bars. It is mainly used to separate suspended and
colloidal particles by size sieving mechanism. It is applied for various purposes in industry
such as analytical application, sterilization in food and pharmaceuticals, ultrapure water
production in semiconductors, clarification, algae cell harvesting, water treatment and
13

membrane bioreactor in wastewater treatment. MF membranes are made from a number of
organic and inorganic materials, for example:
- Polymeric membranes: polyamide (PA), polysulphone (PS), polyethersulphone
(PES), polypropylene (PP), polycarbonate (PC).
- Ceramic membranes: alumina (Al2O3), zirconia.
MF is used primarily for separating macromolecules, large suspended particles, fungi and
bacteria. It is finding increased application as a pretreatment method to other membrane
processes, in pharmaceutical applications (Meltzer and Blakie, 1987) as a replacement for
conventional clarification and filtration technologies (Noble and Stern, 1995).
Ultrafiltration (UF)
The pore size is from 10–100 nm. Ultrafiltration (UF) is a variety of membrane filtration in
which hydrostatic pressure forces a liquid against a semipermeable membrane. Suspended
solids and solutes of high molecular weight are retained, while water and low molecular
weight solutes pass through the membrane. This separation process is used in industry and
research for purifying and concentrating macromolecular (10 3 -10 6 Da) solutions,
especially protein solutions. Ultrafiltration is not fundamentally different from
microfiltration and nanofiltration except in terms of size of molecules it retains. The
applications beyond microfiltration are including metallurgy (oil-water emulsion, electro
paint recovery), textile, etc.
UF has been accepted as an alternative to conventional pretreatment for brackish surface
water and sea water reverse osmosis (SWRO) systems (De et al., 2002). The use of UF
systems as RO pretreatment has some significant advantages over RO systems designed to
include conventional pretreatment:
- UF membrane systems take up less than 50% of the area of a conventional
pretreatment system, which results in reduced construction costs. This means that
a UF membrane system may be more favorable in cases where space is limited, or
where the costs of civil works are high.
- UF membranes system is easier to operate than some conventional filtration
processes.
- The operating costs of a UF membrane system may be lower than those for
conventional pretreatment systems.
- UF concentrated waste streams are easier to dispose of relative to those from
chemically enhanced conventional pretreatment processes.
- UF filtrate quality is usually better than that of conventional pretreatment process.
The colloidal fouling load to the RO is reduced, with a significantly lower Silt
Density Index (SDI) and turbidity in the feed water.
Nanofiltration (NF)
It is used for removal of low molecular weight solutes such as inorganic salts or small
organic molecules. Its pore size is in range of 1–10 nm and the operating pressure is 3-20
bars. The applications are including desalination of brackish water, removal of micro
pollutants, water softening, wastewater treatment, rejection of dyes, etc
14

Reverse osmosis (RO)
The pore size is almost similar with nanofiltration but percentages of salt rejection are
different. The driving pressure is in range of 10-100 bars. The applications are including
desalination of brackish and seawater, production of ultrapure water for electronic
industry, concentration of food juice, sugar and milk, etc.
Microfiltration
100 – 1000 nm
Colloids, Virus
Color
Hardness
Pesticides
Salt
Water
Figure 2.5 Demonstrates main characteristics of each membrane types
2.4.3 Types of filtration
Ultrafiltration
10 – 100 nm
Typically, membrane filtration can be classified to 2 types including cross flow and deadend
filtrations depending on application and module configuration. The prior provides
lower fouling rate and smaller flux decline than the later. Because of the cross-flow
operation can minimize fouling and cake layer formation on membrane with adjustment of
cross-flow velocity of feed. In case of dead-end filtration, even though it causes large
membrane fouling, its strength is high water recovery relative to cross flow type.
NF and RO are mostly applied with cross flow type because they tend to have fouling as
compared to other bigger pore of membranes. In case of MF, dead-end filtration is
frequently applied whereas both of cross flow and dead-end operations are applied in UF.
15
Nanofiltration
1 – 10 nm
Reverse Osmosis
< 10 nm
ΔP = 0.1-4 bar ΔP = 0.2-10 bar ΔP = 3-20 bar ΔP = 10-100 bar
Color
Hardness
Pesticides
Salt
Water
Salt
Water
Water

Table 2.9 Detail Explanation of Different Membrane Processes
Membrane
Pressure driven membrane processes
Microfiltration Ultrafiltration Nanofiltration Reverse Osmosis Piezodialysis
symmetric
porous
Asymmetric
porous
Thickness ≈ 10-150 µm ≈ 150µm
16
Composite
Sub layer ≈ 150
µm
Top layer

Clean Membrane Fouled Membrane
Figure 2.6 Membrane fouling
The selectivity of membrane toward diluted mixture is generally expressed by percentage
of rejection (R), demonstrated as follows;
C p
% R 1100
C
f
Where Cp = solute concentration in permeate
Cf = solute concentration in feed
2.4.5 Factors affecting membrane filtration
2.4.5.1 Hydrophobicity/hydrophilicity of membrane
17
Equation.2.2
Hydrophobicity/hydrophilicity of membrane is described for its ability to allow water
passing through. It is investigated by measurement of contact angle of water droplet on
membrane surface. Greater than 90˚ of contact angel indicates that the membrane has low
affinity to water (hydrophobicity) leading to low permeate flux as compared to hydrophilic
one. Moreover, hydrophobicity of membrane also affects removal of organic compound.
2.4.5.2 pH
pH of solution relates to presenting charge of membrane and a compound beside it
involves proton dissociation of functional group, attached on membrane surface or
composed in compounds. Thus, it directly affects electrostatic forces between compound
and membrane surface. Zeta potential is defined as power of charges showing on
membrane surface. The negatively charged membrane has been reported to highly reject
negatively charged organic compound through electrostatic repulsion (Bellona et al.,
2004). However, the electrostatic repulsion was reported to decrease with feed containing
some contaminants such as salts (Na + , Mg 2+ , etc.). It resulted because the positive ions

dissolved in solution might adsorb negative charge on membrane leading to decreasing
membrane rejection through electrostatic repulsion.
However, low rejection of negatively charged compound has also been observed with
negatively charged membrane. McCallum et al. (2008) demonstrated decreasing rejection
of estrogen processing negative charges by predominantly negative-charged polyamide
membrane.
2.4.5.3 Organic matter
From literature review, the presence of organic matter showed different effects on
membrane filtration as follows;
1. Decreasing rejection
A number of researches demonstrated adverse effect of organic matter on membrane
filtration of some organic pollutants. Yoon et al. (2006) found that natural organic matter
decreased rejection of nanofiltration. They explained that it might be resulted from
competition between natural organic matter and pollutants on sorption site of membrane.
Their explanation is similar with a number of researches that organic matter caused
pollutants (McCallum et al., 2008 and Zhang et al., 2006).
2. Increasing rejection
Comerton et al. (2008) found that rejection of pollutants prepared in filtered lake sample
was higher than in Milli-Q water with tight NF membrane. They concluded that in addition
to membrane pore size, water matrices play important role on rejection by improving
configuration or properties of membrane surface. Moreover, it is interesting to find that
feed prepared with secondary effluent from MBR showed significant membrane fouling
than natural water, even though it provided lower rejection (Comerton et al., 2008). Hence,
chemical properties of water matrices relates to fouling characteristics and membrane
rejection.
2.4.6 Potential membrane filtration (Nanofiltration and Reverse osmosis)
2.4.6.1 Reverse Osmosis/Nanofiltration (RO/NF)
There are only few researches that applied membranes (RO and NF) for TEG recovery in
wastewater. Due to in efficiency of conventional treatment systems, nanofiltration (NF)
frequently becomes the chosen treatment process. NF has been recognized having the
properties in between UF and reverse osmosis (RO) and thus offers significant advantages,
e.g. lower osmotic pressure difference, higher permeate flux, higher retention of
multivalent salt and molecular weight compounds (>300), relatively low investment and
low operation and maintenance costs. Koyuncu et al., 2004 utilized NF membrane to reuse
reactive dyehouse wastewater and the rejection of NaCl was about 12% while the 99.9% of
dye in the solution was removed. Comerton et al., 2008, Lee et al., 2008, Yoon et al., 2007,
Nghiem and Hawkes, 2007, Plakas et al., 2006 and Berg et al., 1997. These researches
investigated efficiency of reverse osmosis and nanofiltration on several kinds of those
compounds. In overviews, reverse osmosis showed greater than 90% of removal efficiency
whereas nanofiltration showed lower efficiencies.
18

Table 2.10 Comparison of Rejection Efficiency of Constituents Between NF and RO
Constitutes Unit NF RO
Total dissolved solids % 40-60 90-98
Total organic carbon % 90-98 90-98
Color % 90-96 90-96
Hardness % 80-85 90-98
Salts/chloride % 10-50 90-99
Salts/sulphate % 80-95 90-99
Nitrate % 10-30 84-96
Heavy Metals a % 40->50 85-95
Protein log 3-5 4-7
Pathogens (ex:bacteria) log 3-6 4-7
EDCs/PhACs % >10 >90
a = except Cd, Ag and Hg
Source: Asano et al.(2007), Lee at al.(2008) and Comerton, et al.(2008)
2.4.7 Pervaporation technology
2.4.7.1 Definition of pervaporation process
Pervaporation is a membrane process in which a pure liquid or mixture is in contact with
the membrane on the feed or upstream side at atmospheric pressure and where permeate is
removed as a vapor because of a low vapor pressure existing on permeate or downstream
side. This low (partial) vapor pressure can be achieved by employing a carrier gas or using
a vacuum pump. The (partial) downstream pressure must be lower than the saturation
pressure at least. A schematic drawing of this process is show in figure 2.7
Feed Retentate
Condenser
Permeate
Vacuum pump
Carrier gas
Figure 2.7 Schematic drawing of the pervaporation process with a downstream
vacuum or an inert carrier-gas
Essentially, the pervaporation process involves a sequence of the three steps:
Selective sorption into the membrane on feed side
Selective diffusion through the membrane
Desorption into a vapor phase on the permeate side
19
Feed
Condenser
Retentate
Permeate

The driving force for the mass transfer of permeates from the feed side to the permeate side
of the membrane is a gradient in chemical potential, which is established by applying a
difference in partial pressures of permeates across the membrane. The difference in partial
pressures can be created either by reducing the total pressure on the permeate side of the
membrane by using a vacuum pump system or by sweeping an inert gas on the permeate
side of the membrane.
Table 2.11 Summary of Pervaporation
Membranes:
Composite membranes with an elastomeric or glassy
polymeric top layer
Thickness: ≈ 0.1 to few μm (for top layer)
Pore size: Nonporous
Driving force: Partial vapors pressure or activity difference
Separation principle: Solution/Diffusion
Membrane material: Elastomeric and glassy polymer
Application: Dehydration of organic solvents
Removal of organic components from water
(alcohols, aromatics, chlorinated hydrocarbons)
Polar/Non-polar (e.g. alcohols/aliphatic or
alcohols/aromatics)
Saturated/Unsaturated (e.g. cyclohexane/
benzene)
Separation of isomers (e.g. C-8 isomers;
o-xylene, m-xylene, p-xylene, ethyl benzene, styrene)
Source: Reidel et al. (1996)
2.4.7.2 Definition of vapor permeation
Vapor permeation is similar in principle to pervaporation. The only difference concerns the
feed, which is a mixture of vapors or vapors and gases. As in pervaporation, the permeate
partial pressure is maintained by use of a vacuum or an inert sweep gas (table 2.11). There
is no change of phase involved in its operation. Thus, compared to pervaporation, the
addition of heat equivalent to the enthalpy of vaporization is not required in the membrane
unit and there is no temperature drop along the membrane (Kujawski, 2000). Operation in
the vapor phase also eliminates the effect of the concentration polarization prevalent in
liquid phase separations, such as pervaporation
20

Table 2.12 Overview of Chosen Membrane Separation Processes (Kujawski, 2000)
Membrane
process
Feed
phase/permeate
phase
Pervaporation liquid/vapor
Vapor
permeation
vapor/vapor
Pertraction liquid/liquid
Gas separation gas/gas
Membrane
distillation
liquid/vapor
Driving force Membrane
Chemical
potential
gradient
Chemical
potential
gradient
Concentration
gradient
Hydrostatic
pressure
gradient
Vapor pressure
gradient
21
Dense,
Hydrophobic
Dense,
Hydrophobic
Dense,
Hydrophobic
Porous or
Dense
Porous or
Dense
Main
Applications
Separation of
liquid mixtures
Separation of
vapor mixtures or
vapor from gases
Separation of
organic solutions
Separation of
gaseous mixtures
Ultrapure water,
concentration of
solution
Thus, in table 2.12 presents the main characteristics of chosen membrane processes which
resemble pervaporation or vapor permeation concerning either the membranes applied or
type of application. To avoid any misunderstandings it is quite important to know both the
differences and similarities of these processes. The performance of a given membrane in
pervaporation or vapor permeation is estimated in terms of its selectivity and the permeate
flux. The assessment is based on the mass transfer of the preferentially permeating species,
regardless of whether permeate or the retentate is the target product of the pervaporation
process (Kujawski, 2000).
2.4.7.3 Operational parameters
The selectivity of a given membrane can be estimated by using the following two
dimensionless parameters. The equation 2.3 is used to determine separation factor and
equation 2.1 for determine permeate flux as follows:
Separation Factor ()
water/ org
Cwater / Corg
Cwater / Corg
permeate
Equation 2.3
Where Corg = Denote the weight fraction of organic, gram (kg)
Cwater = Denote the weight fraction of water component, gram (kg)
feed

2.4.7.4 Variables that affect the performance of pervaporation.
Feed concentration
Due to the concentration of the preferentially permeating (usually minor) solution
component, being depleted in the process. There are two aspects to be considered the
activity of the target component in the feed and the solubility of the target component in
the membrane.
Membrane thickness
Refers to dry thickness because flux is inversely proportional to membrane thickness, thin
a membrane favors the overall flux but decrease selectivity. Moreover, thin membranes are
used for low swelling glassy membranes and thick membranes are used for high swelling
elastomeric membranes to maintain the selectivity.
Permeate pressure
Permeate pressure provides the driving force in pervaporation which the permeation rate of
any feed component increases as its partial permeate pressure is lowered. The highest
conceivable permeate pressure is the vapor pressure of the penetrant in the liquid feed.
Moreover, the effect of this parameter on pervaporation performance is dictated by the
magnitude of the vapor pressures encountered, and by the difference in vapor pressures
between them.
Temperature
Feed temperature or any other representative between feed and retentate streams. The feed
liquid provided the heat of vaporization of permeate, and in consequence there is a
temperature loss between the feed and retentate stream where the membrane act as a heat
exchanger barrier. Furthermore, temperature affects solubility and diffusivity of all
permeates, as well as the extent of mutual interaction between them. Favoring the flux and
having minor effect on selectivity.
2.4.7.5 Type of membranes and membrane modules
The choice of the membrane strongly depends on the type of application. It is important
which of the component should be separated from the mixture and whether this component
is water or an organic liquid.
Table 2.13 Types of Membrane for Pervaporation (Reidel et al., 1996)
Hydrophilic Hydrophobic
Polyacrylonitrile (PAN) Polydimethylsiloxane (PDMS)
Polyvinyl alcohol (PVA) Polyoctylmethylsiloxane (POMS)
Polyacrylic acid (PAA) Polyether block amide (PEBA)
Chitosan (CS)
22

Hollow fiber module
This module is used with an inside–out configuration to avoid increase in permeate
pressure within the fibers, but the outside–in configuration can be used with short fibers.
Another advantage of the inside-out configuration is that the thin top layer is better
protected but higher membrane area can be achieved with the outside-in configuration.
Plate and Frame module
Figure 2.8 Hollow fiber modules (Xu, 2001)
Two adjacent membrane pairs and then the feed solution flows through the membrane
between each pair of modules are composed of a double membrane or a sequence of
stacked layers horizontally. Moreover, the other devices to determine which making the
flow of retentate and permeated.
Spiral wound module
Figure 2.9 Plate-and-frame modules
This module is very similar to the plate and frame system but has a greater packing
density. This type of module is used with organophilic membranes to achieved organic–
organic separations.
23

Tubular modules
Figure 2.10 Spiral wound module (Xu, 2001)
Inorganic (ceramic) membranes are produced mainly as tubes, and then the obvious
module is the tube bundle for applications that used this kind of membranes. On the other
hand, for sweep gas pervaporation, tubular membranes conducting the gas-permeate
mixture are the only option.
Figure 2.11 Tubular modules (Xu, 2001)
The difference and similarity between different pervaporation modules are summarized in
table 2.13
Table 2.14 Comparison of Pervaporation Modules (Xu, 2001)
Hollow
Fine
Fibers
Capillary
Fibers
24
Spiral-
Wound
Plate-and-
Frame
Tubular
Manufacturing Cost
,($/m 2
)
5-20 20-100 30-100 100-300 50-200
Packing Density High Moderate Moderate Low Low
Resistance to fouling Very poor Good Moderate Good Very good
Parasitic pressure
drops
High Moderate Moderate Moderate Low
Suitable for high
Can be done
pressure operation Yes No No Yes with
difficulty
Limited to specific
types of membrane
Yes Yes No No No

2.4.7.6 Applications
Generally, the component with the smallest weight fraction in the mixture should
preferentially be transported across the membrane as follows the table 2.14.
Table 2.15 Selective and Transport Properties of Different Types of Pervaporation
Membranes (Kujawski, 2000).
Membrane
material
Polyvinyl
alcohol
Polyamide-6
Polyamide-6
Polyamide-
6/PAA
PESS Li+
PESS K+
Polypropylene
Silicone
Rubber
Silicone
Rubber
PDMS
PDMS
PEBAX
Polypyrole
Polypyrole
Zeolite NaA
Zeolite NaY
PERVATECH
PERVATECH
Binary
mixture A/B
Water/Ethanol
Water/Ethanol
Water/Dioxide
Water/Acetic
acid
Water/Isoprop
anol
Water/Isoprop
anol
Acetone/Water
Isopropanol/W
ater
Butanol/Water
Butyl
acetate/Water
MTBE/Water
Aniline/Water
Content of A
component in
feed (%wt)
25
Temperature
(˚C)
Hydrophilic polymeric membranes
0.1-8
30
50
8.7
11
11
90-100
80
35
15
25
25
Hydrophobic polymeric membranes
45
9-100
0.8
0.7
2
5.5
116
25
30
50
50
80
Membrane made of conducting polymers
Methanol/Tolu
ene
5
58
Methanol/Isopr
opanol
10
58
Inorganic membranes
Ethanol/Water 5
95
Methanol/MT
BE
10
50
Water/Acetic
acid
5
75
Water/Isoprop
anol
1
100
Selectivity
A,B
50-2000
2
45
82
40
60
3
9-22
45-65
370
280
198
590
2
5100
7600
Permeate
Flux
(kg m -2 h -1 )
0-2
1-1.5
0.04
0.005
0.087
0.026
0.1-1.2
0.03-0.11
For a given mixture a large variety in membrane performance can be observed with various
polymers. Table 2.15 gives the selectivity and fluxes of various homogenous membranes
for ethanol-water mixtures. It is seen that both the selectivity and flux can range from
extremely high to very low.
150
250

Table 2.16 Permeate Flux and Separation Factor of Ethanol/Water Mixture through
Different Homogeneous Membranes. Feed: 90 wt. % Ethanol.
Temperature: 70ºC. Membrane Thickness: = 50 μm (Kujawski, 2000)
Polymer Permeate Flux (kg/m 2 .h) Separation Factor
Polyacrylonitrile 0.03 12500
Polyacrylamide 0.42 2200
Polyvinylalcohol 0.38 140
Polyethersulfone 0.72 52
Polyhydrazide 1.65 19
Table 2.17 Comparison of Advantages and Disadvantages of Pervaporation (Xu, 2001)
Advantages Disadvantages
Low energy consumption
Low investment cost
Better selectivity without thermodynamic
limitations
Clean and close operation
No process wastes
Compact and scalable units
26
Scarce membrane market
Lack of information
Low permeate flows
Better selectivity without
thermodynamic limitations
Limited applications:
Organic substances dehydration
Recovery of volatile compounds at
low concentrations
Separation of azeotropic mixtures
However, pervaporation must be regarded as a young membrane process compared to
other membrane processes like reverse osmosis, ultrafiltration, dialysis and even electro
dialysis. There are several practical advantages of pervaporation and vapor permeation
when compared with other conventional technologies: simple operation and control,
reliable performance, high flexibility, unproblematic part-load operation, high product
purity (no contamination by entrained), no environmental pollution, high product yield,
low energy consumption, compact design (low space requirements), short erection time
and uncomplicated capacity enlargement. In general, pervaporation and vapor permeation
will especially be used in those cases where a small quantity has to be removed from a
large quantity. In all the above applications, the most successful processes require
integration with existing conventional separation unit operations. Nevertheless,
pervaporation and vapor permeation have been identified as areas of vast potential for
future research and commercial development.

Chapter 3
Methodology
This study comprised of two main phases namely: (1) High pressure membrane filtration
(2) membrane of pervaporation and (3) Design a pre-treatment process to treat wastewater.
Figure 3.1 demonstrates overall experimental study.
Phase I Phase II
Phase III
High Pressure Membrane Filtration
Preliminary test: 4 Types of Membranes
Comparison of NF and RO membrane
treatment efficiency
Determination of Optimum Concentration
of TEG (Triethylene Glycol)
- Use synthetic TEG wastewater
- Use real TEG wastewater from GSPs
Criteria of wastewater characteristics for pre-treatment
selection:
Figure 3.1 Experimental plan of study
The detail experiment of each phase is presented in the subsequent sections
27
Membrane of Pervaporation
Preliminary test: 1 Type of Membrane
Comparison of pervaporation membrane
treatment efficiency
Determination of Optimum Concentration
of TEG (Triethylene Glycol)
- Use synthetic TEG wastewater
Design a Pre-Treatment Process to treat TEG
wastewater
- Pre-Treatment is applied for organics and inorganics
removal from real wastewater before entering NF and
RO membrane

3.1 Phase I: High Pressure Membrane Filtration
3.1.1 Materials
The characteristics of NF and RO membrane were reported in Table 3.1 and 3.2
Table 3.1 List of NF Membranes and Its Properties, (Qin et al., 2007 and Halle, 2009)
Note: LMH = (L/m 2 Salt rejection (%NaCl and %MgSO4) 40-60 and 99 80-90 and 97.0
MWCO (DA) 200 150
ZETA potential at pH 7 (mV) -14±3 -14±3
Hydrophobic, Hydrophilic Hydrophilic Hydrophilic
Contact angle (˚) 48±2 48±2
Pure water flux (LMH/bar) 4.48 7.84
Polymer Polypiperazine amide Polyamide
pH range at 25˚C 2-11 2-11
Typical Flux/psi (GFD@PSI)
h)
20/110 20/110
Table 3.2 List of RO Membranes and Its Properties
Source: Jeżowska et al.(2006), Song and Kim (2000)
Note: LMH = (L/m 2 h)
3.1.2 Membrane tests unit
Properties TS-40 TS-80
Manufacturer TriSep TriSep
Properties NTR-759 HR ACM5
Pure water flux (LMH/bar) 1.7 5.75
Salt rejection (%NaCl 1.5 kg/m 3 ) 99.5 98.5
Hydrophobic, Hydrophilic Hydrophilic Hydrophilic
General Operating Pressure, bar 9.8-19.6 7.5
Maximum Operating Pressure, bar 29.4 41
Maximum Operating Temperature (˚C) 40 40
Feed pH range 2-10 2-10
Residual Chlorine (ppm) 0 0
5 liters of TEG (Triethylene Glycol) solution was poured inside double wall stainless steel
feed tank, in which 25±1°C of temperature was controlled using cooling tank. A Hydracell
piston pump (Model G-20, Wanner Engineering, INC., Minneapolis, MN), connected with
inverter (VS mini J7 Series, Yaskawa Electric Cooperation, Japan) for flow rate
adjustment, would deliver TEG solution from feed tank to membrane filtration unit at
approximately 2 L/min of flow rate. The stainless steel membrane unit has 32 cm 2 of
effective surface area. Pressure gauges were installed at feed and concentrate sides to
determine pressure. Moreover, membrane system was operated in recycle mode that
concentrate is sent back to feed tank. Permeate flux was measured by an electronic
balance.
28

Figure 3.2 Flow diagram of membrane experimental set up
29

Each experiment run was conducted about 1 day, which consist of 10 hours of
precompaction and 8 hours of membrane filtration run. The membrane experiment was
setup the pressure at 15 bar for NF and 20 bar for RO. The steps of experiment are
demonstrated in figure 3.3.
Before starting an experimental run, pre-compaction of membrane should be done.
A new membrane should be inserted in filtration unit.
To get constant permeate flux, system is operated with Mili-Q water for 10 hours.
The experimental run was conduct for 8 hours.
Permeate flux were collected every hours.
Permeate samples were collected at 8 hours.
TEG concentration
0.1 %vol, 5 %vol,
10 %vol, 20 %vol
NF RO
Feed
Feed
TEG solution
Fixed feed temperature
(25 o C)
Membrane filtration
Concentrate
30
Permeate
Run 8 hours
Run 8 hours
Permeate samples were collected at 8 hours
Analysis by Gas Chromatograph (GC)
Figure 3.3 Flowchart of membrane filtration experiment
Pressure at 15 bar for
NF and 20 bar for RO
Measurement
Permeate flux

The compound rejection (%) by membrane was calculated as follows:
C p
% R 1100
C
f
Where Cp = solute concentration in permeate, mg/L
Cf = solute concentration in feed, mg/L
The permeate flux (m 3 / m 2 .d.bar)) of compound was calculate as follows
31
Equation 3.1
Q
J Equation 3.2
AP .
Where Q = flow rate of permeate, m 3 /d
A = Active surface area membrane of membrane, m 2
P = Applied pressure, bar
Normalized flux (N) is ratio of permeate flux at time t to its initial value that is aimed to
study stability of permeate flux along the filtration cycle.
J
N
J
Where Jv = Permeate flux at time t (m 3 /m 2 .d.bar)
Jo = Initial permeate flux (m 3 /m 2 .d.bar)
3.2 Phase II: Membrane of Pervaporation
3.2.1 Materials
v Equation 3.3
The characteristics of pervaporation membrane were reported in Table 3.3
Table 3.3 List of Pervaporation Membranes and Its Properties
Source: (Sato and Nakane, 2007)
o
Properties NaA zeolite membrane
Module type Tubular
Hydrophobic, Hydrophilic Hydrophilic
Pure water flux, (kg/m 2 h) 4.0
Separation factor >5,000
Maximum operating temperature, (°C) 150
Maximum operating pressure, (bar) 0.98

3.2.2 Membrane tests unit
5 liters of TEG (Triethylene Glycol) solution was poured inside double wall stainless steel
feed tank, in which 30, 40, 50 and 70°C of temperature were controlled using heater. A
circulating pump connected with flow meter for flow rate adjustment, would deliver TEG
solution from feed tank to membrane module unit at approximately 1 L/min of flow rate.
The stainless steel membrane module unit has 0.03 m 2 of effective surface area. Pressure
gauges were installed at feed and concentrate sides to determine pressure. Moreover,
membrane system was operated in recycle mode that concentrate is sent back to feed tank.
During experiments the downstream pressure will be keep below 5 mbar by using a
vacuum pump. Permeate will be collect into cold trap and cooled by gel ice pack at
temperature below -10˚C. Permeation fluxes are determined by weighing permeate
collected over a given period of time in the cold traps. Composition of both the feed and
permeate mixtures will be determine by using gas chromatography. The steps of
experiment are demonstrated in figure 3.4.
TEG concentration
0.1 vol%, 5 vol%, 10 vol%
Zeolite Membrane
NaA zeolite
Membrane
Pervaporation
Feed
Concentrate Concentrate
TEG solution
Feed temperature
30°C, 40°C, 70˚C
Permeate
Permeate
Run 8 hours
Run 8 hours
32
Vacuum Controller
Valve
Vacuum
Pump
Permeate samples were collected at 8 hours
Analysis by Gas Chromatograph (GC)
Pressure at permeate side
below 5 mbar
Measurement Permeate flux
At cold trap use temp. below 0 ˚C
Digital Balance
Figure 3.4 Flowchart of pervaporation membrane experiment
Cold
Trap

Figure 3.5 Flow diagram of pervaporation experimental set up
33

Performance properties of a given pervaporation membrane were defined by the separation
factor (Eq.3.3) and permeate fluxes J (Eq.3.2)
Cwater / Corg
Cwater / Corg
permeate
water/ org Equation 3.3
Where Corg = Denote the weight fraction of organic, g
Cwater = Denote the weight fraction of water component, g
The membrane will be operating for at 8 hours with each concentration. Permeate samples
and permeate flux will be collected at 8 hours for TEG measurement, calculated by
equation 3.2.
3.3 Phase III: Design Pre-Treatment Process to Treat TEG Wastewater
3.3.1 Materials
The characteristics of microfiltration (MF) and ultrafiltration (UF) membrane were
reported in Table 3.4 and 3.5.
Table 3.4 List of MF Membranes and Its Properties
Model number
Membrane Properties
34
feed
Ceramic OBE Cartridge
Pore size (µm) 0.3
Area of membrane (m 2 )
Pure water flux (LMH/bar)
pH range
Module Diameter (mm)
Module Length (mm)
5.7
2,500
5.5-9.5
610
2,972
Temperature (°C) 5-38
Source: Mazuma Company (2013)

Table 3.5 List of UF Membranes and Its Properties
Model number
Standard
MWCO (KD)
Pure water flux (LMH/bar)
Area of membrane (m 2 )
pH range
Module Diameter (mm)
Module Length (mm)
Temperature (°C)
Membrane Properties
35
UFH-PST-90
4040
50-60
17.2
2.5
2-13
90
1,170
5-45
Source: Shanghai Megavision Membrane Engineering and Technology (2013)
Permeate flux can be enhanced by pretreating the feed. This technique is commonly used
either to remove particles that may cause clogging in the module or to prevent particles or
macromolecules from reaching and depositing on the membrane surface, or to reduce the
total contaminant load in downstream membrane modules.
The main objective of this phase was oil and grease, organics and inorganics compound
separation in real wastewater from GSPs before pass through membrane filtration
(NF/RO) process.
A real TEG wastewater should be found the wastewater characteristics of each
TEG concentrations.
To get concept of pre-treatment process to oil and grease, organics and inorganics
compound separation.
The first pre-treatment process use suction pump wastewater up from under the
tank which sending to microfiltration (MF) membrane with 0.3 µm. To remove
organics and inorganics compound such as TSS parameter.
After that use ultrafiltration (UF) membrane with 0.01-0.02 µm that can be treated
oil and greases before pass through membrane filtration (NF/RO) process.
3.4 Indicative Methods for TEG
3.4.1 TEG analysis by gas chromatograph (GC)
Indicative method for TEG (Triethylene glycol) measurement is analytical by gas
chromatograph (GC). However, the measurement was applied with concentrated and
methanol 99.9%. The steps of analysis are demonstrated in below.

Process of preparation
1. Sample dilution in the solvent Methanol when received the sample need to assess
the probability that the concentration of TEG in the calibration curve or not (0.1-
2%). Used the concentration 10% of TEG and then have to sample dilution 10 times
before injection by pipette the volume of sample 100 µL into vial that has size 1.5
mL and then adding more methanol 900 µL. After that analytical by gas
chromatograph (GC).
2. TEG sample to be analyzed must be stored in the refrigerator at 4 °C before
analyzed and should be left at room temperature for about one hour.
3. Appropriate sample volume for analysis should have a minimum volume of 3 ml.
Process of preparing a standard solution to Calibration curve
1. Preparation of standard solution concentration 10% TEG stock solution.
2. Diluted standard solution from the number 1 of process of preparation by various
concentrations from 0.1, 0.25, 0.5, 1.0 and 2.0%, respectively.
3. Triethylene Glycol compounds analyzed with GC Agilent HP 6890.
State of a GC Agilent HP 6890 for analysis of compounds triethylene glycol.
1. Detector 250°C
- Air and adjusting the pressure to 400 psi.
- H2 gas and adjusting the pressure to 40 psi.
- N2 gas and adjusting the pressure to 20 psi.
2. Temperature program
Parameter
Temperature
(°C)
Hold
(min)
Runtime
(h)
Initial 100 2 3
Ramp. 1, (25 °C/min) 250 10 18
3. Column : Restex Rxi 624 sil MS 30m x 0.25m x 1.4m
Mode: Constant Pressure
Flow: 1.2 ml/min
Outlet: Ambient
Average: 25 cm/sec time 18 min
4. Inlet
Inlet: Back
Mode: Splitless
Heater: 250 °C, 7.78 psi, flow 24.1 ml/min
Split vent: 19.9 ml/min at 0.1 ml
36

Analysis result
1. Preparation of Calibration Curve
Concentration (%) Peak area
0.1 1680.4
0.25 4181.3
0.5 9369.2
1 20126.4
2 40400.2
2. Determination the accuracy of the analysis by the TEG solution by injection 7 times.
3. The result from gas chromatograph will be displayed the value of rejection (%).
37

Chapter 4
Results and Discussions
The efficiency of membrane filtration, pervaporation process and pre-treatment process for
TEG (Triethylene The efficiency Glycol) separation and recovery as well as their
separation and recovery mechanism are presented in this chapter. In the high pressure
membrane filtration (Phase I), varying concentrations of TEG (Triethylene Glycol)
solution were tested with various membrane types. In pervaporation process (Phase II),
varying concentrations and temperatures of TEG (Triethylene Glycol) solution were tested
with zeolite membrane. Moreover, in the design pre-treatment process for treat TEG
wastewater (Phase III), using two types of membrane for pre-treatment wastewater before
entering NF and RO membrane. The suitable conditions derived from membrane filtration
and design a pre-treatment process was tested together. Finally, the details are presented in
the subsequent sections.
4.1 Phase I: High Pressure Membrane Filtration
4.1.1 Membrane properties
The properties of the membrane used in this study are presented in Table 4.1.
Table 4.1 Membrane Characteristics
Type Membrane
a
MWCO
Pure water
flux
Surface
Material of
Salt rejection
Membrane
b
(%)
(Da) (LMH/bar) NaCl MgSO4
NF TS40 200 4.48
Polypiperazine
amide
40-60 99
TS80 150 7.84 Polyamide 80-90 97
RO ACM5 - 5.75 - 98.5 -
NTR759HR - 1.70 - 99.5 -
a is from Manufacturer, b of 1,000 mg L -1 NaCl and 2,000 mg L -1 MgSO4
All there membranes are hydrophilic properties. The pure water fluxes of TS80 and TS40
are more as they have the biggest membrane pore in all the studied membranes. The main
difference in the two NF membranes was salt rejection rate. ACM5 and HTR759HR
completely removed salt, either monovalent or divalent ion, from the solution. Moreover,
TS40, TS80, ACM5 and NTR759HR were tested with different concentrations as: 0.1, 5,
10, 20 and 30 % of TEG concentrations. The membrane filtration operation was conducted
for 8 hours.
38

4.1.2 Permeate flux
The result of permeate flux of all tested membranes are presented in Figure 4.1.
Permeate Flux (L/m 2 .h.bar)
Permeate Flux (L/m 2 .h.bar)
2.06
1.38
0.7
0.02
8.04
6.04
4.04
2.04
0.04
0.1% TEG 5% TEG 10% TEG 20% TEG
0 1 2 3 4 5 6 7 8
Time (h)
(a) NF - TS40
0.1% TEG 5% TEG 10% TEG 20% TEG
0 1 2 3 4 5 6 7 8
Times (h)
(b) NF – TS80
39

Permeate Flux (L/m 2 .h.bar)
Permeate Flux (L/m 2 .h.bar)
6
4.8
3.6
2.4
1.2
0
1.6
1.28
0.96
0.64
0.32
0
0.1% TEG 5% TEG 10% TEG 20% TEG
0 1 2 3 4 5 6 7 8
Time (h)
(c) RO - ACM5
0.1% TEG 5% TEG 10% TEG 20% TEG
0 1 2 3 4 5 6 7 8
Time (h)
(d) RO – NTR 759 HR
Figure 4.1 Permeate fluxes of membrane filtrations
Flux reduction was observed with the filtration period. The detailed results of permeate
flux are mentioned in Appendix B (Table B-1, B-2. B-3 and B-4).At higher concentration,
lower permeate flux was observed that was corresponding with finding in the previous
40

study. Fast flux reduction resulted at initial period (around first 4 hours), and slowly
declined. The flux reduction might be resulted from progressive membrane fouling with
filtration period due to pore blocking and sorption of compound inside membrane pore or
on membrane surface. Moreover, the lower permeate flux also presented at higher
concentration applied. It might be resulted from more effect of concentration polarization
and membrane fouling at high concentration.
Figure 4.2 presents comparison of normalized flux at 8 th hours of filtration of all the
membranes.
Normalized Flux
1.2
1.0
0.8
0.6
0.4
0.2
0.0
TS40 TS80 ACM5 NTR759HR
0.1% TEG 0.91 0.70 0.78 0.53
5% TEG 0.64 0.72 0.30 0.76
10% TEG 0.86 0.79 0.33 0.50
20% TEG 0.38 0.80 0.62 0.56
Figure 4.2 Normalized flux of direct filtration at different compound concentrations
The detailed results of normalized flux are mentioned in Appendix B (Table B-6). As
presented in Figure 4.2, TS40 showed the lowest normalized flux at high concentration
applied (20 % TEG) as compared to other membrane used. It resulted because the pore of
TS40 membrane was very large (high MWCO) as compared to others. Therefore,
membrane fouling, which possibly blocked TS40 pore, might lead to permeate flux
reduction and consequently lowest normalized flux as compared to others. For RO
expected higher TEG (Triethylene Glycol) removal than NF. TS80 showed equally high
normalized flux in all experiments. At the low concentrations (5 and 10 %TEG), ACM5
showed lowest normalized flux as compare to other. Similarly, lower normalized flux of all
types of membranes at high concentrations might be resulted from membrane fouling.
Membrane fouling is illustrated in Figure 4.3.
41

4.1.3 Rejection
Figure 4.3 Membrane fouling
The rejections of synthetics TEG (Triethylene Glycol) with direct membrane filtration are
shown in Figure 4.4.
% Removal
100
80
60
40
20
0
Low concentration of TEG High concentration of TEG
NF-TS40 NF-TS80 RO-ACM5 RO-NTR 759 HR
0.1% TEG 5% TEG 10% TEG 20% TEG
Triethylene glycol Concentrations
Figure 4.4 Removal efficiency of synthetic wastewater thought membrane filtration
The lowest removal was observed at the highest concentration applied (20% TEG) in all
experiments. The detailed results of removal are mentioned in Appendix B (Table B-8). As
the MWCO of ACM5 and NTR759HR is smallest comparing with other membranes, the
highest removal efficiency of TEG can be expected. As the lowest TEG concentration (0.1
and 5 %TEG) NF-TS40 showed around 71-81% removal for different concentrations of
TEG. NF-TS80 showed around 60-67% removal for different concentrations of TEG.
42

Conversely, higher removal of TEG in RO-ACM5 and RO-NTR 759 HR were observed at
low concentration. The predominant removal mechanism of these membranes might be
adsorption of TEG on membrane. As the lowest TEG concentration (0.1 and 5 %TEG)
RO-ACM5 showed around 83-89% removal for different concentrations of TEG. RO-
NTR759HR showed around 87-96% removal for different concentrations of TEG. Hence,
lower membrane removal presented at high TEG concentration, which accelerated
membrane surface saturation at initial period. Higher removal of TEG was observed at
lowest concentration. It resulted because membrane fouling when increased
concentrations, developed at low concentration, reduced membrane pore size.
Consequently, higher removal of TEG was found at lowest concentration. Moreover, other
factors like surface charge and roughness of membrane might result higher TEG removal
in NF-TS40 and RO-NTR759HR.
Furthermore, lowest removal was observed at the highest concentration applied (20 %
TEG) in all experiments. It resulted because membrane fouling and pore absorption when
increased TEG concentrations and reduced membrane pore size. Moreover, the properties
of TEG will absorb water content in the natural gas. This means that, when in contact with
a stream of natural gas that contains water, TEG will serve to steal the water out of the gas
stream. This operation is called absorption (Asadollahi et al., 2010). As the TEG are a
highly viscous solvent in comparison to water and other solvent such as ethanol and
methanol. This may be relating to the Eq. (4.1), the viscosity of TEG to be high and hence
the result for permeate fluxes is slightly lower and in the pore of membrane had TEG
concentrations by pore absorption. Therefore, components of the permeated had amounts
of TEG concentrations which can pass through pore of membrane with water in permeate
side.
Where J = permeate flux, m 3 / m 2 .day
ΔP = Pressure difference
µ = Viscosity
RT = Resistance
4.2 Phase II: Pervaporation Process
P
J Equation 4.1
R
T
Pervaporation process was only tested with synthetic wastewater concentrations of 0.1, 5
and 10 % TEG with temperature variation of 30, 40 and 70 0 C. The permeate flux was
inadequate for definitive results since the beginning of the experiments. It was also
observed that at lower concentrations of TEG, membrane performance was inadequate and
thus further testing were not conducted using real wastewater as done with NF and RO
membranes. The results of permeate flux; separation factor and rejection are presented in
subsequent subsections 4.2.1, 4.2.2 and 4.2.3.
4.2.1 Permeate flux
As a general rule of thumb, in processes like pervaproration, vapor permeation and
membrane distillation, the permeate flux is measure in kg/m 2 .h. The permeate flux
measured for pervaporation is shown in figure 4.5. It can be observed that the flux is high
at 70 0 C but at other temperatures the flux is nearly negligible.
43

4.2.2 Separation factor
Figure 4.5 Permeate fluxes of pervaporation process
Separation factor is actually a ratio of ratios, and small changes in composition can lead to
large changes in the ratio, especially at low feed concentrations and high permeate
concentrations. It is a measure of performance of a system to separate two solutes. The
results of separation factor of TEG from water for all tested parameters are presented in
figure 4.6. It can be observe from figure 4.6 that 0.1 TEG at 70 0 C and 10 % TEG at 40 0 C
present a higher separation factor but as observed in literature for other organic compound
they are still quit less.
Separation Factor
Permeate Flux (kg/m 2 .h)
600
400
200
0
8
6
4
2
0
0.69
0.1%TEG at
30°C
55
0.1%TEG at
30°C
6.81
0.1%TEG at
70°C
487
0.1%TEG at
70°C
Figure 4.6 Separation factor of pervaporation process
44
0.53 0.47 0.58
5% TEG at
30°C
97
5% TEG at
30°C
10%TEG at
30°C
228
10%TEG at
30°C
10% TEG at
40°C
246
10% TEG at
40°C

From Figure 4.5 and 4.6, it is obvious that as the TEG concentration increases, the
permeate flux decreases. The detailed results of permeate flux are presented in Appendix D
(Table D-1).
The separation factor observed, slightly increase with increasing TEG concentration. The
detailed results of separation factor are mentioned in Appendix D (Table D-3). This is due
to the fact that the separation factor is actually a ratio (Equation 3.3), and small changes in
composition can lead to large changes in the ratio, especially at low feed concentrations
and high permeate concentrations.
Furthermore, the effect of temperature on the permeation flux and separation factor was
also studied. As seen in Figure 4.5 and 4.6, both the permeate flux and separation factor
increases with increasing feed temperature of 70°C. This may be due to the fact that as the
temperature increases permeate also increases significantly as a result, the separation factor
increases. In addition, the feed viscosity has a major impact on the transport resistances in
the module.
In PV membrane at concentration of solute 10% or less, the membrane becomes hardly any
selectivity is obtained. Thus the results are not reliable for any interpretation, the
separation factor and flux cannot be co-related in terms of diffusion characteristics but
temperature plays an important role in flux due to its influence in vapors pressure gradient.
4.2.3 Rejection
The overall TEG separation efficiency of pervaporation process for treatment of 0.1%, 5%
and 10% TEG concentrations is presented Figure 4.7.
Rejection (%)
80
70
60
50
40
30
20
10
0
33.16
5.39
Figure 4.7 Removal efficiency of synthetic wastewater thought pervaporation process
All of experiments were conducted at lowest TEG concentration with different the applied
temperature (30°C, 40°C and 70°C). The detailed results of removal are presented in
Appendix D (Table D-2). The lowest removal was observed at the lowest temperatures and
TEG concentrations applied (0.1%, 5% and 10%TEG at 30°C) in all experiments. The
detailed results of removal are accessible in Appendix B (Table B-3). At 30°C with 0.1%
45
11.19
71.02
49.58
0.1% TEG 5%TEG 10%TEG 10%TEG 0.1% TEG
30°C 40°C 70°C
Triethylene Glycol concentration and Temperature (°C)

and 5% of TEG concentration, removal varied in range of 5-33% for different TEG
concentrations.
Conversely, higher removal of TEG in pervaporation process was observed at higher
temperature (40°C and 70°C). At 40°C with 10% TEG concentration, removal was around
71% for 10% TEG concentration. Moreover, at 70°C with 0.1% TEG concentration around
50% removal for 0.1% concentrations of TEG was observed. Thus, the efficiency for
separation and recovery TEG wastewater by using pervaporation process depended on the
temperature values and the TEG concentrations.
In principle, permeation rate of a liquid depends on the interaction between polymeric
membrane and the penetrant. For a given liquid the flux will be influenced by the increased
interaction between the particular polymeric membrane and its affinity towards it. The
transport of liquid mixtures through a polymeric membrane is generally much more
complex. In binary liquids, the flux can be described in terms of solubility and diffusivity
but can be strongly influenced by both liquids in the binary solution.
4.3 Phase III: Design Pre-Treatment Process to Treat TEG wastewater
Membrane processes such as microfiltration (MF), ultrafiltration (UF) are increasingly
being applied for treating oily wastewater (Bhave and Fleming, 1988, Chen et al., 1991,
Daiminger et al., 1995). To treat real wastewater from the GSP, a pretreatment process was
deemed necessary to remove large suspended particles and oil/grease, especially when
membranes like NF and RO with thin-channel were employed to separate TEG from real
wastewater. NF and RO membrane are less tolerant to suspended solids, oil and grease.
Without a proper pretreatment membrane fouling will be the predominant force that
determines membrane performance.
4.3.1 Membrane properties
The pre-treatment processes in this study was essential as the second part of the research
focused on treating real wastewater from the GSP which contained suspended solids,
oil/grease and some detectable volatile compounds. Thus it was necessary to focusing on
the selection of proper pretreatment. Membrane material used for MF and UF were
narrowed down to be ideal for pretreatment due to their MWCO, pore size and its
distribution.
Permeate flux is an important parameter to characterize membrane separation efficiency
(Wu et al., 1999). With the development of polymer material science and technology,
many kinds of polymer membranes have been invented or improved in order to increase
permeate flux (Zaidi et al., 1992). In this section the properties of the membrane used for
pretreatment are presented. Pure water flux was estimated using Mili-Q water for both MF
and UF membrane.
Two membranes were used for pretreatment in the following series respectively:
1. Cartridge microfiltration membrane to remove suspended solids
2. Hollow fiber ultrafiltration membrane to remove oil and grease.
In table 4.2 and 4.3 characteristics of the microfiltration and ultrafiltration membrane are
presented.
46

4.3.2 Efficiency of TEG wastewater before and after pre-treatment process
For comparative reasons the wastewater characteristics of real TEG wastewater from Gas
Separation Plants are showed in Table 4.4. Subsequently the wastewater characteristics and
efficiency removal of this wastewater after MF and UF membranes pre-treatment are
showed in Table 4.3, 4.4, 4.5 and 4.6.
Table 4.2 Wastewater Characteristics of Real Wastewater from Gas Separation
Plants
Parameter Testing Unit
Test Results
0.5% TEG 8.3 %TEG
Mercury mg/L 0.001 0.002
Cadmium mg/L

Figure 4.8 Design pre-treatment processes to treat TEG wastewater
48

Table 4.4 Wastewater Characteristics of Real Wastewater After UF Membrane Pre-
Treatment
Parameter
Testing
Unit
Test Results
UF membrane Removal (%)
0.5% TEG 8.3% TEG 0.5% TEG 8.3% TEG
BOD5 mg/L 95 750 93.89 22.15
COD mg/L 5,667 6.60×10 4 31.45 31.25
Oil & Grease mg/L 57.8 78.9 86.2 89.49
TDS mg/L 3,467 7.88×10 4 38.03 21.98
TSS mg/L 36 14 76.62 97.22
4.3.3 Permeate flux of TEG in Real wastewater
To test with real wastewater using RO-ACM5 and NF-TS80 membranes, the wastewater
first needs be pretreated to protect membrane from fouling by suspended solids and
oil/grease. The pretreatment is done in two steps:
1. Suspended solids removal using cartridge microfiltration (MF) membrane.
2. Oil and grease removal employing a hollow fiber ultrafiltration (UF) membrane.
After pretreatment of real wastewater with 0.5 % and 8.3 % TEG infestation, the liquid is
sent to RO-ACM5 and NF-TS80 membranes separately. The resultant permeate flux for
RO-ACM5 and NF-TS80 membranes with 0.5 and 8.3 % TEG concentration are presented
in figure 4.9.
Permeate Flux (L/m 2 .h.bar)
8
7
6
5
4
3
2
1
0
0.1% of Synthetic wastewater 0.5% of Real wastewater
0 1 2 3 4 5 6 7 8
Time (h)
(a) NF – TS80 with Real 0.5% of real wastewater
49
67%

Permeate Flux (L/m 2 .h.bar)
6
5
4
3
2
1
0
0 1 2 3 4 5 6 7 8
(b) RO-ACM5 with Real 0.5% of real wastewater
Real wastewater showed low permeates flux as compared to synthetic wastewater. The
detailed results of permeate flux are presented in Appendix B (Table B-5). For NF-TS80
and RO-ACM5 with 0.5% of real TEG wastewater, there was a reduction of 67% and 56%
in permeate flux for real wastewater as compared with synthetic wastewater. The reduction
in flux is attributed to membrane fouling on membrane surfaces due to undetectable
volatile compounds present in the wastewater which could not be removed using
pretreatment.
Permeate Flux (L/m 2 .h.bar)
1.6
1.2
0.8
0.4
0
0.1% of Synthetic wastewater 0.5% of Real wastewater
Time (h)
10% of Synthetic wastewater 8.3% of Real wastewater
0 1 2 3 4
Time (h)
5 6 7 8
(c) NF-TS80 with Real 8.3% of real wastewater
50
56%
10.26%

Permeate Flux (L/m 2 .h.bar)
1
0.8
0.6
0.4
0.2
0
10% of Synthetic wastewater 8.3% of Reall wastewater
0 1 2 3 4 5 6 7 8
(d) RO-ACM5 with Real 8.3% of real wastewater
Figure 4.9 Permeate fluxes of membrane filtrations with real TEG wastewater
RO membrane showed similar reduced performance in permeate flux (10.26%) as NF-
TS80 (10.44%) at 8.3% TEG concentration than their permeate flux with synthetic
wastewater because the both of membranes had stronger sorption of suspended solid and
oil and grease on membrane surfaces.
4.3.4 Rejection of TEG in Real wastewater
Time (h)
The overall TEG removed efficiency are compared with synthetic wastewater and real
wastewater after pre-treatment processes for TS80, ACM5 with TEG concentration of 0.5
% and 8.3 % wastewater is presented in figure 4.10.
51
10.44%

Rejection (%) of TEG
Rejection (%) of TEG
60
45
30
15
80
60
40
20
0
0
60.00
(a) NF-TS80 with 0.5% of real wastewater
(b) NF-TS80 with 8.3% of real wastewater
The efficiency of pre-treatment process with NF-TS80 using real wastewater with 0.5% of
TEG concentrations was significantly higher than using the same membrane to treat
synthetic wastewater by approximately 73%. The detailed results of removal are described
in Appendix B (Table B-4).While using NF-TS80 with real wastewater containing 8.3%
TEG concentration, showed slightly lower efficiency than synthetic wastewater by
approximately 47.15%.
52
72.980
Synthetic wastewater Real wastewater
50.720
47.150
Synthetic wastewater Real wastewater

Rejection (%) of TEG
Rejection (%) of TEG
100
80
60
40
20
0
80
60
40
20
0
83.78
(c) RO-ACM5 with 0.5% of real wastewater
(d) RO-ACM5 with 8.3% of real wastewater
Figure 4.10 Removal efficiency of real 0.5 and 8.3% of TEG wastewater
In case of RO membrane with wastewater containing 0.5 and 8.3% TEG concentrations,
showed significantly higher removal than membrane filtration by approximately 95% and
78%, respectively but had very less permeate flux than NF membrane. However, permeate
flux of RO membrane after pre-treatment process is slightly lower than only membrane
filtration by approximately 10.44% and 56%, respectively. Thus, it might need frequent
53
94.79
Synthetic wastewater Real wastewater
76.060 77.560
Synthetic wastewater Real wastewater

membrane cleaning with pre-treatment membrane process when used real TEG
wastewater.
4.3.5 Real wastewater characteristics after NF and RO treatment
Parameters tested for real wastewater after pass through the pre-treatment process (MF and
UF membranes) and membrane filtration (NF and RO membranes) are presented in Table
4.5 and 4.6. The parameters included BOD, COD, Oil and Grease, TDS, TSS.
Table 4.5 Wastewater Characteristics of Real Wastewater After NF Membranes Pre-
Treatment
Parameter
Testing
BOD5
COD
Unit
NF membrane
54
Test Results
Removal
(%)
0.5% TEG 8.3% TEG 0.5% TEG 8.3% TEG
mg/L 65 300 31.58 60.00
mg/L 1,533 1.23×10 4 72.95 81.36
Oil and Grease mg/L 4.12 4.35 92.87 94.49
TDS
TSS
mg/L 5,163 1.02×10 4 84.54 87.06
mg/L 6 4 83.33 71.43
Table 4.6 Wastewater Characteristics of Real Wastewater After RO Membranes Pre-
Treatment
Parameter
Testing
BOD5
COD
Unit
RO membrane
Test Results
Removal
(%)
0.5% TEG 8.3% TEG 0.5% TEG 8.3% TEG
mg/L 40 100 57.89 86.67
mg/L 1,387 6,933 75.52 89.49
Oil and Grease mg/L 3.44 3.46 94.05 95.61
TDS
TSS
mg/L 4,277 9,887 87.19 87.43
mg/L 3.33 3.56 90.75 74.57
The wastewater characteristics after pre-treatment and membrane filtration using both NF-
TS80 and RO-ACM5 with 0.5% TEG and 8.3% TEG wastewater was significantly lower
than wastewater characteristics than original wastewater studied in the earlier section. The
detailed results of wastewater characteristics are tabulated in Table 4.2, 4.3, 4.4, 4.5 and
4.6. Thus, the pre-treatment process for treating TEG wastewater are particularly important

to protect membrane from fouling by suspended solids and oil/grease before tested with
real wastewater using RO-ACM5 and NF-TS80 membranes.
Therefore, the pre-treatment process should be applied before using membrane filtration
with NF and RO membrane which are proposed for industrial applications due to its high
recover efficiency, high permeate flux with low TEG concentrations. However, low
recover efficiency and low permeate flux was observed when experiments were done with
high TEG concentrations in range 20% TEG concentration in synthetic and real
wastewater. Hence, the pre-treatment process and membrane filtration are the interesting
option for application in terms of time used for operation (Triethylene glycol recovery) and
maintenance (membrane cleaning).
55

Chapter 5
Conclusions and Recommendations
The main objective of this study was to identify the effective technology for Triethylene
glycol (TEG) separation and recovery in wastewater from Gas Separation Plants. This
research comprised of three main phases, namely, Phase I: Membrane filtration, Phase II:
Pervaporation process and Phase III: Design pre-treatment process to treat TEG
wastewater. Moreover, the applicability of this research in the industrial sector was also
investigated.
5.1 Conclusions
In this research, it was found that the pre-treatment process for treat TEG wastewater
(Phase III) to protect membrane from fouling by suspended solids and oil/grease before
testing real wastewater using RO-ACM5 and NF-TS80 membranes. The studied
membranes had high efficiency to separate and recover TEG from real wastewater. Based
on the results obtained from testing synthetic wastewater with four membranes we could
optimize the treatment conditions like pressure application, membrane selection and select
the best two membranes to treat real wastewater. Moreover, a detailed study was
conducted in membrane filtration and pre-treatment processes to reveal their basic removal
mechanisms and efficiency.
Phase I: High Pressure Membrane Filtration
Nanofiltration membrane with high salt rejection (TS40) was the most effective membrane
for TEG recovery among membrane tested at low concentrations. It recovered more than
80% of TEG from the dilute stream. While NF membrane (TS80) with high salt rejection
also showed 60-67% TEG recovers. RO membrane (ACM5 and NTR759HR) removal
TEG in rang of 83-95%, in which the membrane having less MWCO showed higher
removal efficiency but compromising on flux. Moreover, NF membrane (TS80) showed
better performance in terms of permeate flux as compared to NF-TS40 membranes. While
in RO membrane (ACM5) performed better than RO-NTR759HR with synthetic
wastewater. It was uniformly observed that all the tested membrane performed well at
lower concentration but as the concentration increased to 20% TEG there was a sharp
reduction in flux with unstable rejection. The low permeate flux at high concentrations of
TEG can be attributed to concentration polarization and membrane fouling.
Phase II: Pervaporation Process
The pervaporation process was conducted with 0.1, 5 and 10% of TEG concentrations in
synthetic wastewater with temperature variation of 30, 40 and 70°C of each concentration.
The permeate flux of TEG/water mixture through a zeolite membrane was found to vary
from 0.47-0.69 kg/m 2 .h over a concentration range of 0.1-10% TEG at 30°C. Moreover,
the permeate flux at a concentration of 0.1% TEG at 70°C was found to be 6.81 kg/m 2 .h.
While the permeate flux at a concentration of 10% was found with 0.58 kg/m 2 .h at 40°C.
Also, the separation factor was 246 for 10% TEG at 40°C. The flux and the separation
factors obtained indicate that pervaporation process with NaA Zeolite membrane is not
attractive and the system does not performed well at lower concentration of solutes.
56

Phase III: Design Pre-Treatment Process to Treat TEG Wastewater
To accomplish objective 2, testing with real wastewater using RO-ACM5 and NF-TS80
membranes was necessary. But the wastewater first needs to be pretreated to protect
membrane from fouling by suspended solids and oil/grease. The pretreatment was carried
out in two steps; first step is suspended solids removal using cartridge microfiltration (MF)
membrane and second step is oil and grease removal employing a hollow fiber
ultrafiltration (UF) membrane. Desirable wastewater characteristics were achieved pretreatment
process where suspended solids and oil/grease were removed to a greater extent.
Pre-treatment process coupled with nanofiltration membrane (TS80) showed higher TEG
removal than synthetic wastewater experiments at 0.5% TEG concentration by
approximately 73%. While reverse osmosis membrane (ACM5) showed slightly higher
removal for TEG than synthetic wastewater experiments with 0.5% TEG concentration
also by approximately 95%. In case of 8.3% TEG concentration, nanofiltration (TS80) and
reverse osmosis (ACM5) membrane showed relatively equal to the value of synthetic
wastewater experiments by approximately 47.15% and 77.56%, respectively.
Therefore, the pre-treatment process should be applied before using membrane filtration
with NF and RO membrane which are proposed for industrial applications due to its high
removal efficiency, high permeate flux with low TEG concentrations. However, low
removal efficiency and low permeate flux was observed when experiments were done with
high TEG concentrations in range 20% TEG concentration in synthetic and real
wastewater. Hence, the pre-treatment process and membrane filtration are the interesting
option for application in terms of time used for operation (Triethylene glycol recovery) and
maintenance (membrane cleaning).
In light of this study it can be concluded that out of the studied membranes TS80 and
ACM5 are suitable for separating TEG from wastewater only at lower concentrations as in
higher concentrations membrane fouling and reduced permeate flux causes the system to
be not suitable for industrial applications.
5.2 Recommendations for Further Study
Methodology of membrane cleaning with NF and RO membrane for industrial
application in actual experiments. The results should be useful for saving cost of
membrane that used for experiments.
The longer filtration period should be applied with real wastewater experiments
which its can found period that membrane fouling. In addition, membrane cleaning
to get back the initial permeate flux, should be tested for long experiment run. It is
more similar with the actual treatment.
In this study, low concentrations (0.1% TEG, 5% TEG and 10% TEG
concentrations) of Triethylene glycol were applied. TEG concentrations above 30
% should be tested using PV which can result in higher separation, rejection and
improve efficiency of pervaporation process.
Optimize the membrane cleaning in zeolite membrane of pervaporation process for
operation periods of several days, weeks or months.
57

Investigate the effect of the backpulse technique on the performance of MF and
UF membranes in membrane modules of pre-treatment process.
Due to oil and grease, color and suspended solids have effect on the treatment and
TEG measurement, hence application of pre-treatment such as dissolve air
floatation (DAF) and membrane technology is recommended in the next study for
pervaporation process.
58

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62

Appendix A
Experimental setup
63

Cooling tank 25 ˚C
Dampener
Membrane Cell Module
Figure A-1 Membrane experimental setup
64
Inverter
Weight Balance

61.8 mm
Knob
3/8 in
180 mm
A
A
Concentrate Feed Water
86 mm
Figure A-2 Details of membrane module
Area = 229 mm 2
Figure A-2 Details of membrane module (Romchat, 2011)
65
126 mm
Victoria Coupling
Flat Sheet Membrane
Victoria Coupling
O-ring
Plate
Permeate Tube
Body

Appendix B
Experimental data for Membrane Filtration
66

Table B-1 Permeate Flux with Synthetic TEG Wastewater using NF-TS40
Run times
Permeate Flux (L/m
(h)
2 .h.bar)
0.1% TEG 5% TEG 10% TEG 20% TEG
0 1.78 0.96 0.227 0.12
1 1.91 0.88 0.223 0.11
2 1.87 0.84 0.294 0.10
3 1.93 0.78 0.342 0.09
4 1.89 0.70 0.302 0.08
5 1.79 0.73 0.288 0.07
6 1.85 0.69 0.244 0.05
7 1.78 0.66 0.217 0.05
8 1.62 0.61 0.196 0.04
Table B-2 Permeate Flux with Synthetics TEG Wastewater using NF-TS80
Run times
Permeate Flux (L/m
(h)
2 .h.bar)
0.1% TEG 5% TEG 10% TEG 20% TEG
0 7.58 2.61 0.690 0.15
1 7.00 2.46 0.604 0.13
2 6.54 2.35 0.656 0.16
3 6.25 2.19 0.625 0.18
4 6.12 2.16 0.575 0.15
5 5.87 2.06 0.552 0.14
6 5.70 1.97 0.544 0.13
7 5.45 1.92 0.547 0.13
8 5.33 1.87 0.546 0.12
Table B-3 Permeate Flux with Synthetics TEG Wastewater using RO-ACM5
Run times
Permeate Flux (L/m
(h)
2 .h.bar)
0.1% TEG 5% TEG 10% TEG 20% TEG
0 4.86 2.57 0.203 0.000
1 4.32 2.19 0.198 0.000
2 4.38 1.86 0.194 0.000
3 4.41 1.54 0.184 0.045
4 4.25 1.48 0.123 0.031
5 3.96 0.96 0.095 0.034
6 3.88 0.95 0.073 0.045
7 3.80 0.80 0.070 0.033
8 3.79 0.78 0.067 0.028
67

Table B-4 Permeate Flux with Synthetics TEG Wastewater using RO-NTR759HR
Run times
Permeate Flux (L/m
(h)
2 .h.bar)
0.1% TEG 5% TEG 10% TEG 20% TEG
0 1.33 0.89 0.078 0.000
1 1.25 0.87 0.075 0.000
2 1.17 0.88 0.072 0.041
3 1.08 0.85 0.070 0.038
4 1.00 0.83 0.061 0.045
5 0.96 0.82 0.053 0.041
6 0.83 0.73 0.048 0.033
7 0.75 0.70 0.045 0.031
8 0.71 0.68 0.039 0.023
Table B-5 Permeate Flux with Real Wastewater Infested TEG using NF-TS80 and
RO-ACM5
Run times
(h)
Permeate Flux (L/m 2 .h.bar)
NF-TS80 RO-ACM5
0.5% TEG 8.3% TEG 0.5% TEG 8.3% TEG
0 3.23 1.29 2.71 0.94
1 2.66 0.60 2.40 0.46
2 2.36 0.62 1.64 0.21
3 2.22 0.59 1.52 0.19
4 1.81 0.58 1.56 0.17
5 1.80 0.55 1.44 0.14
6 1.87 0.54 1.40 0.08
7 1.79 0.50 1.69 0.07
8 1.78 0.49 1.68 0.06
Table B-6 Normalized Flux at The End of Experiment with Synthetics TEG
Concentrations of Membrane Filtration
Initial TEG
Concentration
(%)
68
Membrane Type
TS40 TS80 ACM5 NTR 759 HR
0.1 0.91 0.70 0.78 0.53
5 0.64 0.72 0.30 0.76
10 0.86 0.79 0.33 0.50
20 0.38 0.80 0.62 0.56

Table B-7 Normalized Flux at The End of Experiment with Real TEG Wastewater of
Membrane Filtration
Initial TEG
Concentration
(%)
69
Membrane Type
TS80 ACM5
0.1 0.260 0.308
10 0.071 0.030
Table B-8 Rejection Efficiency of Membrane Filtration with Synthetic TEG
Wastewater
Initial TEG
concentration
(%)
TEG Rejection (%)
TS40 TS80 ACM5 NTR 759 HR
0.1 80.08 60.00 83.78 87.15
5 71.06 67.32 89.12 95.74
10 35.83 50.72 76.06 59.92
20 12.12 11.52 14.96 19.38
Table B-9 Rejection Efficiency of Membrane Filtration with Real TEG Wastewater
Initial TEG
Concentration
(%)
TEG Rejection (%)
TS80 ACM5
0.1 72.98 94.79
10 47.15 77.56

Appendix C
Experimental setup for Pervaporation Process
70

Cold Trap
Zeolite membrane module Feed Tank
Figure C-1 Pervaporation process setup
71
Temperature
adjustment
Vacuum pump Feed Pump
Silica Gel

Appendix D
Experimental Data in Pervaporation process
72

Table D-1 Permeate Fluxes at The End of Experiment with Synthetics TEG
Wastewater of Pervaporation Process
Unit: kg/m
Initial TEG
concentration
(%)
30
Temperatures (°C)
40 70
0.1 0.69 - 6.81
2 .h
5 0.53 - -
10 0.47 0.58 -
Table D-2 Efficiency of Pervaporation Process with Synthetics TEG Wastewater for
TEG Rejection
Unit: %
Initial TEG
concentration
(%)
30
Temperatures (°C)
40 70
0.1 33.16 - 49.58
5 5.39 - -
10 11.19 71.02 -
Table D-3 Separation Factors at The End of Experiment with Synthetics TEG
Wastewater of Pervaporation Process
Initial TEG
concentration
(%)
30
Temperatures (°C)
40 70
0.1 55 - 487
5 97 - -
10 228 246 -
Methodology to calculation the Separation factor
Performance properties of a given pervaporation membrane were defined by the separation
factor ()
water/ org
Cwater / Corg
Cwater / Corg
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permeate
Where Corg = Denote the weight fraction of organic, g
Cwater = Denote the weight fraction of water component, g
For the example
1. Initial TEG concentration of 0.1% with the temperature at 70°C
feed

Solve
From the formula:
water/ org
At the permeate side:
Cwater = 13,135.851 kg
Corg = 0.027 kg
At the feed side:
Cwater = 4.995 kg
Corg = 0.005 kg
Cwater / Corg
Cwater / Corg
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permeate
So, the value of separation factor of 10% of TEG with temperature at 40°C;
water / org
feed
13,135.851 0.027
4.995 0.005
= 487
2. Initial TEG concentration of 10% with the temperature at 40°C
Solve
From the formula:
water/ org
At the permeate side:
Cwater = 98.534 kg
Corg = 0.045 kg
At the feed side:
Cwater = 4.495 kg
Corg = 0.505 kg
Cwater / Corg
Cwater / Corg
permeate
So, the value of separation factor of 10% of TEG with temperature at 40°C;
water / org
98.534 0.045
4.495 0.505
= 246
feed

Appendix E
Experimental Details for Pre-Treatment Processes
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Microfiltration (MF)
Membrane
Figure E-1 Pre-treatment Processes
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Ultrafiltration (UF)
Membrane

Appendix F
Photos of the experiments with real wastewater
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0.1% TEG of real wastewater 10% TEG of real wastewater
Figure F-1 0.1% and 10% TEG of real wastewater
Synthetic wastewater Directly filtration by use real wastewater
after MF membrane
Pre-treatment 0.1% real wastewater by use
UF flat sheet membrane
Figure F-2 Pre-treatment process by use flat sheet membranes
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Pre-treatment 10% real wastewater by use
UF flat sheet membrane

NF-TS80 with 0.1% real wastewater after
MF and UF membrane pre-treatment
NF-TS80 with 10% real wastewater after
MF and UF membrane pre-treatment
Figure F-3 Results of experiments with real wastewater
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R0-ACM5 with 0.1% real wastewater
after MF and UF membrane pre-treatment
RO-ACM5 with 10% real wastewater
after MF and UF membrane pre-treatment