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e-ý ; .. ý . ý ý,
iý, t+urllat A1akstirttat AkaQelrilx. UNIVERSITI MALAYSIA SARAWAK
()4; 0O Kola Samarahan
P. KHIDMAT MAKLUMAT AKADEMIK UNIMAS
1111111111111111111111111111111 -
1000165885
REMOVAL OF PHOSPHORUS FROM AQUEOUS SOLUTIONS
USING SELECTED MATERIALS
TIONG PEI JEN
A thesis submitted in fulfillment of the requirements for the degree of Master of Science
Institute of Biodiversity and Environmental Conservation UNIVERSITI MALAYSIA SARAWAK
2007
Acknowledgements
I would like to sincerely express my utmost gratitude and appreciation to my research
supervisor, Prof. Dr. Lau Seng from Faculty of Resource Science and Technology,
Universiti Malaysia Sarawak, for his sustained interest, constructive criticisms,
guidance and invaluable support throughout my undertaking of this project.
I would also like to thank my parents, my brother and my sisters for their unrelenting
support, understanding, confidence, care and inspiration.
Besides that, my warmest thanks to all my friends, laboratory assistants, and all staff
from Institute of Biodiversity and Environmental Conservation (IBEC), Universiti
Malaysia Sarawak for their kind assistance through the course of my study.
I gratefully acknowledge the scholarship award by Kuok Foundation Berhad during the
course of my study. Last but not least, I would like to convey my heartiest gratitude and
appreciation to anyone who has in one way or another contribute towards the success of
this project.
i
Abstract
In Malaysia, eutrophication induced by excess phosphorus in water sources is one of the
major causes of water pollution. The sources of phosphorus include grey water and the
inefficiently treated effluents from septic tanks. The high concentration of phosphorus in
our grey water is due to the extensive usage of phosphate-based detergents for
laundering and other cleaning purposes. Conventional phosphorus removal methods (e. g.
chemical precipitation, reverse osmosis, ion exchange and electrodialysis) are either
energy and cost intensive or not environmentally sustainable. Biological phosphorus
removal has limited phosphate removal capacity. Thus, an efficient, energy and cost-
saving, as well as environmentally sustainable phosphorus removal process should be
established. In this study, the physical and chemical characteristics of three locally
available materials (limestone, red bricks, and degraded shale) were determined, and
their phosphorus (P) adsorption performance were examined using both batch and
column experiments. Desorption studies were carried out to determine the P adsorption
strength of the materials. The main objective of the study was to determine the efficiency
of three selected materials in removing phosphorus from aqueous solutions, and their
potential to be used as substrate in constructed wetland of an ecological sanitation
(ecosan) system. The physical characteristics determined include specific gravity and
particle density, bulk density and porosity, bed porosity, and pH values. For chemical
characterizations, P content, calcium carbonate, and metal contents (Ca, Mg, Fe and Al)
of the materials were determined. Batch experiments were carried out to ascertain the
adsorption of the various materials for phosphorus under different experimental
conditions (agitation time, pH, grain size, initial phosphorus concentration, mixture of
materials). Column experiments were carried out for the same factors as in batch
11
experiments in order to enable the comparison between results obtained from both
experiments. The phosphate-P adsorbed was determined using colorimetric method by
UV/VIS spectrometer. The results obtained show that among the three materials tested,
red bricks seemed to be the most porous, followed by limestone and degraded shale, with
porosity of 0.32, 0.29, and 0.17, respectively. Red brick was the most acidic (pH 4.26).
Degraded shale was almost neutral (pH 7.51), whereas limestone was the most alkaline
(pH 8.12). Both red bricks and degraded shale were found to fit into the pseudo-second
order kinetic models (R2>0.981). Limestone however, seemed to give the best fit into
pseudo-first order kinetic model. The Freundlich equation was observed to model the
phosphorus adsorption data better than Langmuir equation when considering all the
adsorbents investigated. Overall results from batch experiments show that when 10 mg
P/L of phosphate solution was applied to materials with 4-10 mm grain size, both red
bricks and limestone exhibit relatively high phosphorus adsorption percentage (>80%).
Meanwhile, degraded shale had very low phosphorus adsorption performance (<10%).
The mixture of materials exhibited lower phosphorus removal efficiencies than unmixed
materials except for degraded shale. Limestone used was found to accumulate up to
1635.93 mg P/kg material upon saturation while red bricks were found to accumulate
only 191.74 mg P/kg material when saturated. The studies on performance of materials
under repeated cycles show that limestone gave the best result under long run when
compared to red bricks and degraded shale. Low phosphorus desorbability was observed
for limestone and red bricks. Both materials exhibited desorbability of <10% at all pH
tested. Degraded shale was observed to have a high desorbability of about 32 - 50%,
except for pH 3 (about 15%). From the results obtained, it can be concluded that among
the materials tested, limestone has the greatest potential for phosphorus removal in
aqueous solution.
111
PENGASINGAN FOSFOR US DARI LAR UTAN AKUEUS MENGG UNAKAN
BAHAN TERPILIH
Abstrak
Di Malaysia, eutrofikasi yang disebabkan oleh kehadiran fosforus yang berlebihan di
sumber air merupakan salah satu faktor utama berlakunya pencemaran air. Sumber
fosforus tersebut adalah dart air buangan domestik dan air kumbahan tangki septik
yang tidak dirawat dengan sempurna. Kandungan fosforus yang tinggi dalam air
kumbahan domestik kita berpunca daripada penggunaan detergen berfosfat secara
berleluasa untuk pelbagai aktiviti pencucian. Cara konvensyen untuk pengeluaran
fosforus (contohnya: pemendakan kimia, osmosis pembalikan, penukaran ion, dan
elektrodialisis) sama ada memakan kos dan bekalan tenaga yang tinggi, atau tidak
mesra alam. Pengasingan fosforus dengan cara biologi pula didapati menipunyai
kapasiti pengeluaran fosforus yang terhad. Oleh itu, satu proses pengasingan fosforus
yang bukan sahaja menjimatkan kos dan bekalan tenaga tetapi juga mesra alam perlu
dicari. Dalam kajian ini, ciri-ciri fizikal dan kimia bagi tiga jenis bahan (batu kapur,
bata merah, dan batu `degraded shale) ditentukan. Keputusan penjerapa. n fosforus telah
diuji menggunakan eksperimen `batch' dan eksperimen turus. Eksperimen pendejerapan
juga dijalankan untuk menentukan kekuatan penjerapan fosforus bagi bahan kajian.
Tujuan utama kajian ini adalah untuk menentukan efisiensi bahan terpilih untuk
mengasingkan fosforus dart laru, tan akueus, dan potensi mereka untuk dijadikan sebagai
substrat bagi paya buatan dalam sistem `sanitasi ekologi : Ciri-ciri fizikal yang
ditentukan termasuk graviti tentu dan ketumpatan partikel, ketumpatan pukal dan
porositi, porositi dasar, dan nilai pH. Bagi ciri-ciri kimia, kandungan fosforus, kalsium
karbonat, dan unsur (Ca, Mg, Fe, dan Al) dalam bahan kajian tela. h ditentukan.
iv
Eksperimen `batch' telah dijalankan untuk menentukan penjerapan fosforus pada bahan
kajian di bawah keadaan eksperimen yang berbeza (Masa tindak balas, pH, saiz bahan,
kepekatan fosforus dalam larutan, campuran bahan). Eksperimen turus telah dijalankan
untuk mengkaji faktor-faktor yang sama dengan eksperimen `batch' agar perbandingan
dapat dibuat antara keputusan yang diperoleh daripada kedua-dua jenis eksperimen.
Fosforus yang terjerap ditentukan dengan kaedah kolorimetri menggunakan UV/VIS
spektrometer. Keputusan yang diperoleh menunjukkan antara tiga jenis bahan kajian
yang digunakan, bata merah adalah paling poros, diikuti dengan batu kapur dan
akhirnya batu `degraded shale; dengan porositi 0.32, 0.29, dan 0.17 masing-masing.
Bata merah adalah paling berasid (pH 4.26). Batu `degraded shale' adalah hampir
neutral (pH 7.51), manakala batu kapur adalah paling beralkali (pH 8.12). Kedu, a-dua
bata merah dan batu `degraded shale' adalah berpadanan dengan model kinetik pseudo-
second (R9>0.981). Batu kapur pula lebih sesuai untuk dipadankan dengan model kinetik
pseudo-first order: Persamaan Freundlich didapati dapat menggambarkan penjerapan
fosforus dengan lebih baik untuk semua bahan kajian berbandingpersamaan Langmu, ir.
Keputusan keseluruhan dart eksperimen `batch' menunjukkan bahawa apabila larutan
fosforus 10 mg P/L dan bahan kajian dengan saiz 4-10 mm digunakan, kedua-dua bata
merah dan batu kappur memberikan peratus penjerapan fosforus yang agak tinggi (? 80%).
Sementara itu, batu 'degraded shale' memberikan peratus penjerapan fosforus yang
rendah (<10%). Campuran bahan kajian memberikan kecekapan pengasingan fosforus
yang lebih rendah daripada bahan kajian yang tidak dicampur, kecuali batu `degraded
shale'. Batu kapur didapati mencapai takat tepu dengan 1635.93 mg P/kg bahan,
m, anakala bata merah mempunyai takat tepu pada 191.74 mg P/kg bahan. Keputusan
untuk persembahan bahan-bahan kajian dalam kitaran berulang menunjukkan bahawa
batu kapur memperlihatkan pengasingan fosforus yang paling baik untu. k jangka masa
V
panjang berbanding bata merah dan batu `degraded shale' Pendejerapan fosforus yang
rendah diperhatikan untuk kedua-dua batu kapur dan bata merah, di mana kedua-dua
bahan mempamerkan pendejerapan <10% pada sebarang pH yang dikaji. Batu `degraded
shale' diperhatikan mempunyai peratus pendejerapan yang tinggi, ia. itu lebih kurang 32
- 50%, kecuali pada pH 3 (lebih kurang 15%). Kesimpulannya, antara ketiga-tiga bahan
yang dikaji, batu kapur mempunyai potensi yang paling tinggi untuk pengasingan
fosforus dari larutan akueus.
vi
ruSat htlidnlat Milklumat Akaaemºw UNIVERSITI MALAYSIA SARAWAK u41(1() Kota Samarahaa
Table of Contents
Title
Acknowledgements
Abstract
Abstrak
Table of Contents
List of Tables
List of Figures List of Abbreviations
List of Symbols
Page
1
11
IV
vii
X1V
xvii
xxi
xxiii
Chapter 1 INTRODUCTION
1.1 The State of Water Pollution in Malaysia and Worldwide 1
1.2 Main Pollutants in Malaysia and Worldwide 5
1.3 Non Compliance of Discharges from Conventional 7
Treatment System to the Malaysian Water Quality Standard
1.4 Problem Statement and Potential Solution 10
1.5 Objectives of Study 15
1.6 Scope of Study 15
vii
Chapter 2 LITERATURE REVIEW
2.1 Wastewater 17
2.1.1 Composition of Wastewaters 20
2.1.2 Typical Composition of Grey Water 21
2.2 Nutrients in the Wastewater 22
2.2.1 Nitrogen 22
2.2.2 Phosphorus 24
2.2.2.1 Chemical Properties of Phosphorus 28
(a) Aqueous Chemistry 28
(b) Solid Phase/ Adsorption 31
(i) Kinetics of Phosphorus Adsorption 34
(ii) Phosphorus Adsorption Isotherms 37
2.3 Environmental Impacts of Phosphorus Usage
2.3.1 Impacts on Water Body
2.3.2 Impacts from Agriculture
2.3.3 Depletion of Phosphorus Resource
39
39
41
42
2.4 Wastewater Treatment 44
2.4.1 Conventional Treatment System 44
2.4.1.1 Phosphorus Removal Processes in 45
viii
Conventional Treatment System
(a) Biological Phosphorus Removal 45
(b) Chemical Precipitation 46
(i) Phosphate Precipitation with Calcium 47
(ii) Phosphate Precipitation with Aluminium 48
and Iron
2.4.2 Ecological Sanitation System 50
2.4.2.1 Constructed Wetland as Component in an 52
Ecological Sanitation System
(a) Surface Flow Constructed Wetland 54
(b) Subsurface Flow Constructed Wetland 54
2.4.2.2 Phosphorus Removal Mechanisms in 56
Constructed Wetland
(a) Removal of Phosphorus through 59
Adsorption and Precipitation
(b) Phosphorus Uptake by Plants 62
(c) Phosphorus Removal by Microorganisms 63
2.4.2.3 Strength and Weaknesses of Ecological 63
Sanitation System
(a) Strength of Ecological Sanitation System 63
(i) Economical and Affordable for All 63
(ii) Increasing Health and Dignity 64
(iii)Recycling and Reuse of Resources 64
(b) Weaknesses of Ecological Sanitation System 65
2.4.3 Media Materials Studied by Other Researchers 66
ix
Chapter 3 MATERIALS AND METHODS
3.1 Materials 68
3.2 Methodology 69
3.2.1 Experiment 1 (Characterizations of Media Materials) 69
3.2.1.1 Physical Characterizations 69
(a) Specific Gravity and Particle Density 69
(b) Bulk Density and Porosity 71
(c) Bed Porosity 74
(d) pH Values 75
3.2.1.2 Chemical Characterizations 76
(a) Calcium Carbonate Content in Media 76
Materials
(b) Metal (Fe, Ca, Mg, Al) and P Content 77
in Media Materials
3.2.2 Experiment 2 (Evaluation of the Performance of 77
Materials in Phosphorus Adsorption)
3.2.2.1 Batch Adsorption Experiments 78
(a) Studies on Adsorption Kinetics 80
(b) Studies on Adsorption Isotherm 81
(c) Effect of Initial Phosphorus Concentration 82
(d) Effect of pH 82
(e) Effect of Grain Size 83
(f) Effect of Mixture of Materials 84
3.2.3 Experiment 3 (Determination of P Accumulated 85
onto Materials)
3.2.4 Experiment 4 (Desorption Studies) 87
X
3.2.5 Experiment 5 (Column Adsorption Experiments) 88
(a) Studies on Retention Time 89
(b) Effect of Initial Phosphorus Concentration 90
(c) Effect of pH 91
(d) Effect of Grain Size 92
(e) Effect of Mixture of Materials 93
3.2.6 Experiment 6 (Studies on Performance of Materials under 93
Repeated Cycles)
3.3 Analytical Procedures 94
(a) Vanadomolybdophosphoric Acid 95
Colorimetric Method
(b) Ascorbic Acid Method 96
3.4 Statistical Analysis 98
Chapter 4 RESULTS AND DISCUSSION
4.1 Characteristics of Media Materials 99
4.1.1 Physical Characteristics of Media Materials 99
4.1.2 Chemical Characteristics of Media Materials 101
4.2 Batch Adsorption Experiments 103
4.2.1 Adsorption Kinetics 103
4.2.2 Adsorption Isotherms 111
4.2.3 Effect of Initial Phosphorus Concentration 115
X1
4.2.4 Effect of pH
4.2.5 Effect of Grain Size
4.2.6 Effect of Mixture of Materials
4.3 Determination of P Accumulated onto Materials
117
120
121
123
4.4 Desorption Studies 126
4.5 Column Adsorption Experiments
4.5.1 Effect of Retention Time
4.5.2 Effect of Initial Phosphorus Concentration
4.5.3 Effect of pH
4.5.4 Effect of Grain Size
4.5.5 Effect of Mixture of Materials
128
128
130
131
133
134
4.6 Studies on Performance of Materials under 135
Repeated Cycles
Chapter 5 CONCLUSION AND RECOMMENDATION
5.1 Conclusions
5.2 Recommendations for Further Research
138
140
xii
REFERENCES
APPENDICES
Appendix A
Appendix B
Appendix C
Appendix D
Appendix E
141
165
168
174
178
179
X111
List of Tables
Table 1.1 National Water Quality Standard for Malaysia.
Page
8-10
Table 2.1 Average daily production and nutrient content of urine and 18 faeces.
Table 2.2 Typical composition of grey water. 21
Table 2.3 Percentage of nutrients emission from grey water to the 22
environment.
Table 2.4 Typical Phosphorus Concentrations in Raw Domestic 24 Wastewater.
Table 2.5 Forms of phosphates depending on pH. 29
Table 2.6 Approximate nutrient composition of average sanitary 46
wastewater (mg/L) based on 120 gal per capita per day
(gpcd) (450 L/person. d).
Table 2.7 The possible calcium-phosphate minerals that might form 60
and their Ca/P molar ratio.
Table 4.1 Physical characteristics of different materials tested for 99
P-adsorption properties.
Table 4.2 Chemical characteristics of different materials tested for 101
P-adsorption properties.
Table 4.3 Values of adsorption rate constants, calculated qe and coefficient 107
of determination (R2) obtained from different kinetic models.
xiv
Table 4.4 Langmuir and Freundlich models regression constants. 112
Table 4.5 Desorbability of the adsorbed phosphate-P on selected 127
materials in DI water with different pH.
Table 4.6 Performance of mixture of materials for phosphorus adsorption. 134
Table Al Phosphorus adsorption with different agitation time. 165
Table A2 Phosphorus adsorption with different initial phosphorus 166
concentration.
Table A3 Phosphorus adsorption with different pH. 166
Table A4 Phosphorus adsorption with different grain size. 167
Table A5 Phosphorus adsorption by mixture of materials under 167
different pH.
Table Cl The calculated values of dimensionless separation factor (r) 177
called equilibrium parameter using Langmuir constant (b).
Table D 1 Phosphorus accumulated on limestone and red bricks under 178
repeated cycles of batch experiments using initial phosphorus
concentration of 200 mg/L.
Table El Phosphorus adsorption with different retention time. 179
Table E2 Phosphorus adsorption with different initial phosphorus 180
concentration.
Table E3 Phosphorus adsorption with different pH.
Table E4 Phosphorus adsorption with different grain size.
180
181
xv
Table E5 Phosphorus adsorption performance under repeated cycles. 182
xvi
List of Figures
Figure 2.1 Combined Wastewater.
Figure 2.2 Several Forms of Phosphate.
Page
19
25
Figure 2.3 Linear flows in a conventional sanitation system. 44
Figure 2.4 Circular flows in an Ecosan system. 51
Figure 2.5 Effect of pH on phosphate precipitation with different metal ions. 60
Figure 2.6 Effect of redox potential on phosphate precipitation with 61
different metal ions.
Figure 3.1 Conical flasks with materials in phosphate solution. 79
Figure 3.2 Experimental setup for batch experiments. 79
Figure 3.3 Perkin-Elmer Lambda 25 UV/VIS Spectrometer. 80
Figure 3.4 Experimental setup for column experiments. 89
Figure 4.1 Phosphorus adsorption kinetic data for selected materials. 103
Figure 4.2 Application of the intraparticle diffusion model to the 110
measured kinetic data for the studied materials.
Figure 4.3 P adsorption with respect to initial phosphorus concentration 116
(a) mg P adsorbed/ kg material in 4 different P concentrations (b) percentage P removal in solutions of different initial
P concentration.
xvii
Figure 4.4 Adsorption of P with respect to pH.
Figure 4.5 P adsorption with respect to grain size.
117
120
Figure 4.6 Adsorption of P with respect to mixture of materials. 121
Figure 4.7 Accumulated P (mg/kg) adsorbed by materials under
repeated cycles.
123
Figure 4.8 Limestone before phosphorus adsorption. 125
Figure 4.9 Limestone after phosphorus adsorption under repeated cycles. 125
Figure 4.10 Adsorption of P with respect to retention time. 129
Figure 4.11 Adsorption of P with respect to initial phosphorus concentration. 130
Figure 4.12 Adsorption of P with respect to pH.
Figure 4.13 Adsorption of P with respect to grain size.
131
133
Figure 4.14 Adsorption of P under repeated cycles. 136
Figure B1 Linearized form of pseudo-first order adsorption kinetics of 168
red bricks for phosphate-P. qe = P adsorbed by red bricks
at equilibrium; qt = P adsorbed by red bricks at time t
Figure B2 Linearized form of pseudo-second order adsorption kinetics of 168
red bricks for phosphate-P. t = time t; [Pit = P adsorbed by
red bricks at time t
Figure B3 Linearized form of Elovich adsorption kinetics of red bricks for 169
phosphate-P. q = amount of P adsorbed; t = adsorption time
xviii
Figure B4 Linearized form of power function adsorption kinetics of red 169
bricks for phosphate-P. t = time t; [P] = P adsorbed by red
bricks at time t
Figure B5 Linearized form of pseudo-first order adsorption kinetics of 170
limestone for phosphate-P. qe = P adsorbed by limestone at
equilibrium; qt = P adsorbed by limestone at time t
Figure B6 Linearized form of pseudo-second order adsorption kinetics of 170
limestone for phosphate-P. t = time t; [P]t = P adsorbed by
limestone at time t
Figure B7 Linearized form of Elovich adsorption kinetics of limestone for 171
phosphate-P. q = amount of P adsorbed; t = adsorption time
Figure B8 Linearized form of power function adsorption kinetics of 171
limestone for phosphate-P. t = time t; [P] = P adsorbed
by limestone at time t
Figure B9 Linearized form of pseudo-first order adsorption kinetics of 172
degraded shale for phosphate-P. qe = P adsorbed by degraded
shale at equilibrium; qt = P adsorbed by degraded shale at time t
Figure B10 Linearized form of pseudo-second order adsorption kinetics of 172
degraded shale for phosphate-P. t = time t; [P]t = P adsorbed
by degraded shale at time t
Figure B11 Linearized form of Elovich adsorption kinetics of degraded shale 173
for phosphate-P. q = amount of P adsorbed; t = adsorption time
Figure B12 Linearized form of power function adsorption kinetics of 173
degraded shale for phosphate-P. t = time t; [P] = P adsorbed
by degraded shale at time t
xix
Figure C1 Adsorption data for red bricks according to Langmuir (a) 174
and Freundlich (b) isotherms. qe = P adsorbed by red bricks;
C. = equilibrium P concentration in the solution
Figure C2 Adsorption data for limestone according to Langmuir (a) 175
and Freundlich (b) isotherms. qe = P adsorbed by limestone;
Ce = equilibrium P concentration in the solution
Figure C3 Adsorption data for degraded shale according to Langmuir (a) 176
and Freundlich (b) isotherms. qe = P adsorbed by degraded shale; Ce = equilibrium P concentration in the solution
xx
List of Abbreviations
ADP adenosine diphosphate
AES atomic emission spectroscopy/spectrometry
AGI acute gastrointestinal illness
AMP adenosine monophosphate APHA American Public Health Association
ATP adenosine triphosphate
BOD biochemical oxygen demand
COD chemical oxygen demand
CWS constructed wetland systems
DI deionized
DNA deoxyribonucleic acid
DO dissolved oxygen
DOE Department of Environment
Ecosan ecological sanitation
EPA Environmental Protection Agency
FWS free-water-surface
GTZ Gesellschaft für Technische Zusammenarbeit
HSFCW horizontal subsurface flow constructed wetland
ICP inductively coupled plasma
IHP International Hydrological Programme
LECA light-weight expanded clay aggregates
LWA light weight aggregates NREB Natural Resource and Environment Board
PVC polyvinyl chloride
RNA ribonucleic acid
SEPA State Environmental Protection Administration
SF subsurface flow
SS suspended solids TSS total suspended solids UK United Kingdom
UNESCO United Nations Educational, Scientific and Cultural Organization
U. S United States
xxi
USEPA United States Environmental Protection Agency
UV ultra violet
VIS visible
WHO World Health Organization
xxii
List of Symbols
< less than
> more than
< less than or equal to
2-D two dimensional
3-D three dimensional
µg microgram
°C degree Celsius or Centigrade
cm centimetre
cm3 centimetre cube
conc. concentration
d day
Eq equation
ft feet
g gram
gal gallon
ha hectare
hr hour
in. inch
kg kilogram
km kilometre
L litre
lb pound
m metre
M Molar
m2 metre square
mg milligram
min minute
mL millilitre
mm millimetre
pe redox potential
ppd person per day
ppm part per million
xxiii
