This study investigated the concentration of heavy metals in oil field produced water
from Niger Delta, before and after treatment with locally sourced agricultural
wastes. Two produced water samples were investigated for different metal ions such
as; Lead, Nickel, Cadmium, Copper, Iron, Magnesium, Chromium, Zinc,
Manganese, Calcium, Arsenic, Boron, Tin and Barium. The produced water samples
were treated with four different adsorbents which are; Orange peels, Banana peels,
Palm Kernel Fiber and Luffa Cylindrica. These adsorbents were used at different
particle sizes of 63 and 150 microns. Ten of these metals were analyzed using the
atomic absorption spectrophotometer (AAS) and the remaining four were analyzed
using the UV-Visible spectrophotometer. The analysis was carried out (in line with
the industrial standard) in order to determine the concentration of the metals in the
produced water samples.
The results obtained from the analysis showed that the concentration of the metal
ions investigated reduced drastically after treating. For example, the concentration
of lead, iron and zinc reduced from 0.095ppm, 0.045ppm, 0.108ppm to 0.018ppm,
0.001ppm and 0.002ppm respectively in sample X. The physical and chemical
properties as well as other contaminants of the produced water samples such as
chloride content, total dissolved solids and density were also determined before and
after treatment. There were reductions in the concentrations of these properties.
This showed that the produced water from the oil and gas activities should be treated
for metal ions present that may have concentrations higher than standard limits set
by regulatory bodies before disposal and/or re-use due to their negative effects to
man and its environment.
LIST OF FIGURES
Figure 1.0: Petroleum hydrocarbon reservoir. ........................................................... 3
Figure 1.1. Steps involved in the dynamics of adsorption. ........................................ 9
Figure 3.0 Raw luffa cylindrica fiber and raw palm kernel fiber. ...........................24
Figure 3.1 Raw banana peels and raw orange peels. ...............................................25
Figure 3.2: Crushed and sieved banana peels. .........................................................26
Figure 3.3 Crushed and sieved orange peels............................................................26
Figure 3.4 Crushed and sieved palm kernel fiber. ...................................................27
Figure 3.5 Crushed and sieved luffa cylindrica. ......................................................27
Figure 3.6 Drying of the adsorbents in the oven after treatment with HNO3. ........28
Figure 3.7 Produced water samples and Adsorption process with the adsorbents. .28
Figure 3.8 Atomic absorption spectrophotometer (AAS). .......................................30
Figure 3.9 UV-Visible spectrophotometer (spectrumlab 752s). ..............................35
Figure 3.10 Standard stock solutions for determining the concentration of arsenic,
boron, tin and barium in the samples. ......................................................................35
Figure 3.11 Filling the burette with the silver nitrate solution ................................37
Figure 3.12 Appearance of a reddish brown precipitate to determine the chloride
concentration. ...........................................................................................................38
Figure 3.13 Determination of the carbonates and biocarbonates concentration. ....40
Figure 3.14 Drying the evaporating dish filled with sample in the oven. ...............42
Figure 3.15 Sample of the filter paper with residue. ...............................................43
Figure 3.16 Taking the pH values from the pH meter. ............................................44
Figure 3.17 Pycnometer bottles used for density determination. ............................45
Figure 3.18 Electronic weighing balance. ...............................................................45
Figure 4.2.1 Calibration Curve of Absorbance vs Conc. Of Arsenic (mg/l). ..........55
Figure 4.2.2 Calibration Curve of Absorbance vs Conc. of Boron .........................57
Figure 4.2.3: Calibration Curve of Absorbance vs Conc. of Tin (mg/l)..................60
Figure 4.2.4 Calibration Curve of Absorbance vs Conc. of Barium (mg/l) ............62
Figure 4.4.1 Calibration Curve of Absorbance vs. Conc of Sulphate .....................66
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LIST OF TABLES
Table 1.0: Composition of oilfield produced water ................................................... 5
Table 1.1 Production Chemicals in oil and gas fields produced water...................... 6
Table 1.2. Oil adsorption capacities of different adsorbents ...................................11
Table 3.1 Flame-gas combination for metal ion analysis by AAS. .........................30
Table 4.1.1 Concentration of metals in the untreated sample X (Nembe Field). ....46
Table 4.1.2 Concentration of metals in the untreated sample Y (Colo Creek Field).
..................................................................................................................................47
Table 4.1.3 Concentration of metals in the treated sample X (using the adsorbents
individually). ............................................................................................................48
Table 4.1.4 Concentration of metals in the treated sample Y (using the adsorbents
individually). ............................................................................................................49
Table 4.1.5 Concentration of metals in the treated sample X (Concurrent mixture-
63 microns). .............................................................................................................50
Table 4.1.6 Concentration of metals in the treated sample X (Concurrent mixture-
150 microns). ...........................................................................................................51
Table 4.1.7 Concentration of metals in the treated sample Y (Concurrent mixture –
63 microns). .............................................................................................................52
Table 4.1.8 Concentration of metals in the treated sample Y (Concurrent mixture-
150 microns). ...........................................................................................................53
Table 4.2.1 UV-Vis Spectrophotometer Absorbance Reading For Arsenic ...........54
Table 4.2.1.1 Concentration of Arsenic Ion in the Untreated Produced Water. ......55
Table 4.2.1.2 Concentration of Arsenic Ion in the Treated Samples. ......................56
Table 4.2.2 UV-Vis Spectrophotometer Absorbance Readings for Boron. ............57
Table 4.2.2.1 Concentration of Boron Ion in the Untreated Produced Water. ........58
Table 4.2.2.2 Concentration of Boron Ion in the Treated Samples. ........................58
Table 4.2.3 UV-Vis Spectrophotometer Absorbance Readings for Tin ..................59
Table 4.2.3.1 Concentration of Tin Ion in the Untreated Produced Water..............60
Table 4.2.3.2 Concentration of Tin Ion in the Treated Samples..............................61
Table 4.2.4 UV-Vis Spectrophotometer Absorbance Readings for Barium. ..........62
Table 4.2.4.1 Concentration of Barium Ion in the Untreated Produced Water. ......63
Table 4.2.4.2 Concentration of Barium Ion in the Treated Samples. ......................63
Table 4.3.1 Table Showing the Volume of Silver Nitrate Sample Used. ................64
Table 4.3.2 Chloride Concentration in the Untreated Produced Water. ..................65
Table 4.3.3 Chloride Concentration in the Treated Samples. ..................................65
Table 4.4.1 UV-Vis Spectrophotometer Absorbance Readings for Sulphate. ........66
ix
Table 4.4.2 Sulphate Concentration in the Untreated Produced Water. ..................67
Table 4.4.3 Sulphate Concentration in the Treated Samples. ..................................67
Table 4.5.1 Table Showing the Volume of Sulfuric Acid Used. .............................68
Table 4.5.2 Table Showing the Volume of Sulphuric Acid Used. ..........................69
Table 4.5.3 Concentration of Carbonates and Bicarbonates in the Untreated
Produced Water. .......................................................................................................69
Table 4.5.4 Concentration of Carbonates and Bicarbonates in the Treated Samples.
..................................................................................................................................70
Table 4.6.1 Table Showing the Amount of the Total Dissolved Solids in the
Untreated Samples. ..................................................................................................71
Table 4.6.2 Table Showing the Amount of the Total Suspended Solids in the
Treated Samples. ......................................................................................................71
Table 4.7.1 Table Showing the Amount of the Total Suspended Solids in the
Untreated Samples. ..................................................................................................72
Table 4.7.2 Table Showing the Amount of the Total Suspended Solids in the
Treated Samples. ......................................................................................................73
Table 4.8.1 Table Showing the pH Values of the Untreated Samples. ...................74
Table 4.8.2 Table Showing the pH Values of the Treated Samples. .......................74
Table 4.9.1 Table Showing the Density Values of the Untreated Produced Water
Samples. ...................................................................................................................75
Table 4.9.2 Table Showing the Density Values of the Treated Samples. ...............75
x
TABLE OF CONTENTS
DECLARATION ........................................................................................................i
CERTIFICATION .................................................................................................... ii
DEDICATION ......................................................................................................... iii
ACKNOWLEDGEMENT ....................................................................................... iv
ABSTRACT ............................................................................................................... v
LIST OF FIGURES ................................................................................................ vii
LIST OF TABLES ................................................................................................. viii
TABLE OF CONTENTS ........................................................................................... x
CHAPTER ONE ........................................................................................................ 1
1.0Introduction ................................................................................................... 1
1.1Background of Study ..................................................................................... 1
1.2Origin of Produced Water ............................................................................. 2
1.3 Composition of Produced Water ................................................................ 4
1.4Effects of Produced Water ............................................................................ 6
1.5Treatment Technologies ................................................................................ 7
1.5.1Technologies for Removing Oil from Water ....................................... 7
1.5.2Technologies for Removing Salt from Water ...................................... 8
1.6Adsorption ..................................................................................................... 8
1.7Aims and Objectives of this Research Work ..............................................12
1.8Problem Statement ...................................................................................... 12
1.9Significance of Work .................................................................................. 12
1.10Expected Results ...................................................................................... 13
CHAPTER TWO ..................................................................................................... 14
2.0Literature Review ........................................................................................ 14
CHAPTER THREE ................................................................................................. 23
3.0Materials and Methodology ........................................................................ 23
3.1Experimental ............................................................................................... 23
3.2Materials and Equipment ............................................................................ 23
xi
3.2.1Materials ............................................................................................23
3.2.2Equipment .......................................................................................... 23
3.2.3Collection of Materials ...................................................................... 24
3.3Experimental Procedure ..............................................................................25
3.3.1Preparation of the Adsorbents (Banana Peels, Orange Peels, Luffa
Cylindrica and Palm Kernel Fiber) ..................................................................25
3.4Atomic Absorption Spectroscopy (AAS) ....................................................29
3.4.1Procedure to Determine the Concentration of the Metal Ions Using
AAS ............................................................................................................31
3.4.2Reagents and Chemicals .................................................................... 31
3.5Laboratory Experiments to Determine the Concentration of the Metals in
the Samples Using UV-Vis Spectrophotometer ..................................................31
3.5.1Determination of Arsenic (As) Concentration ...................................31
3.5.2Determination of Boron (B) Concentration ....................................... 32
3.5.3Determination of Tin (Sn) Concentration .......................................... 33
3.5.4Determination of Barium (Ba) Concentration ................................... 34
3.6Laboratory Experiments to Determine Some Anions and Other Contents of
the Produced Water ..............................................................................................36
3.6.1Determination of the Chloride Concentration in the Produced Water
Samples ............................................................................................................36
3.6.2Determination of the Concentration of Carbonates and Bicarbonates in
the Produced Water Samples ...........................................................................38
3.6.3Determination of the Sulphate Concentration in the Produced Water
Samples ............................................................................................................40
3.6.4Determination of the Amount of Total Dissolved Solids Content in the
Produced Water Samples .................................................................................41
3.6.5Determination of the Amount of Total Suspended Solids in Produced
Water Samples .................................................................................................42
3.6.6Determination of the pH Value of the Produced Water Samples ...... 43
3.6.7Determination of the Density of the Produced Water Samples ......... 44
CHAPTER FOUR .................................................................................................... 46
xii
4.0Results and Discussion ................................................................................ 46
4.1Results ......................................................................................................... 46
4.1.1Concentration of Metals in Both the Untreated and Treated Samples
Using AAS .......................................................................................................46
4.2Concentration of Metal Ions in the Samples Using the UV-Vis
Spectrophotometer ...............................................................................................54
4.2.1Analysis of Arsenic (As) ....................................................................54
4.2.2Analysis of Boron (B) ........................................................................57
4.2.3Analysis of Tin (Sn) ........................................................................... 59
4.2.4Analysis of Barium (Ba) .................................................................... 62
4.3Results Showing the Chloride Content of both Treated and Untreated
Produced Water Sample .......................................................................................64
4.4Results Showing the Sulphate Concentration in both the Treated and
Untreated Produced Water Samples ....................................................................66
4.5Results Showing the Concentration of Carbonates and Bicarbonates in
both the Treated and Untreated Produced Water Samples ..................................68
4.6Results Showing the Total Dissolved Solids in both the Treated and
Untreated Produced Water Samples ....................................................................71
4.7Results Showing the Total Suspended Solids in both the Treated and
Untreated Produced Water Samples ....................................................................72
4.8Results showing the pH Values of both the Treated and Untreated
Produced Water Samples .....................................................................................73
4.9Results Showing the Density of both the Treated and Untreated
Produced Water Samples .....................................................................................74
4.10Discussion ................................................................................................ 76
CHAPTER FIVE ..................................................................................................... 77
5.0Conclusion and Recommendations ............................................................. 77
5.1Conclusion ................................................................................................... 77
5.2Recommendations ....................................................................................... 78
REFERENCES ........................................................................................................ 79
APPENDIX A .......................................................................................................... 84
xiii
APPENDIX B .......................................................................................................... 90
APPENDIX C .......................................................................................................... 95
APPENDIX D .......................................................................................................... 98
APPENDIX E ........................................................................................................ 103
APPENDIX F ......................................................................................................... 110
APPENDIX G ........................................................................................................ 115
