universiti putra malaysia the introduction of …the introduction of eichhornia crassipes into the...
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UNIVERSITI PUTRA MALAYSIA
THE INTRODUCTION OF EICHHORNIA CRASSIPES INTO THE HIGH RATE ALGAL POND
TO REMOVE NITROGEN FROM WASTEWATER
NGUYEN NGOC BICH
FSAS 1998 34
THE INTRODUCTION OF EICHHORNIA CRASSIPES INTO THE HIGH RATE ALGAL POND
TO REMOVE NITROGEN FROM WASTEWATER
by
NGUYEN NGOC BICH
Thes i s Submi t ted in Fulfi lment of the Requirements
for the Degree of Master of Science
in the Facul ty of Science and Environmental Studies
Universiti Putra Malaysia
Apri l 1 9 98
Affectionately dedicated to
TRAN THI HONG NHUNG
Of Lai Khe, Ben Cat, Binh Duong
VIETNAM
ACKNOWLEDGEMENTS
This study is sponsored by the Technical Assistance
Programme (TAP) from the government of Malaysia to the
government of Vietnam. The programme is brought into
effect by co-operation between the Rubber Research
Institute of Malaysia (RRIM) and the Rubber Research
Institute of Vietnam (RRIV).
The Directorates of RRIM and RRIV, led by Datuk Dr.
Abdul Aziz b. S. A. Kadir and Mr. Mai Van Son, and
particularly the gentlemen in charge of administration of
the programme, Dr. Ismail Hashim and Dr. Dang Duy So, are
profoundly thanked for their nomination and support.
Deep gratitude goes to Assoc. Prof. Dr. Mohammad
Ismail Yaziz of Faculty of Science and Environmental
Studies (FSES), Universiti Putra Malaysia (UPM) , who has
given his excellent guidance and aid during the study.
Appreciation is due to Ir. Dr. Nordin Abdul Kadir Bakti
of Applied Chemistry and Processing Division (ACPD) of
RRIM, for his valuable advice and provision of
facilities. Thanks are also due to Assoc. Prof. Dr.
Nasiman Sapari of FSES, UPM for his worthy comments on
iii
the manuscript. Staff of the ACPD's Effluent Research
Unit of RRIM are also thanked for their warm assistance,
amongst them are Dr. Zaid Isa, Mr. Mohd. Zin Karim, Mr.
Mohd. Idris Haj i Noor, and Mr. Wan Mohd. Mukhtar.
Many other RRIM employees have been friendly and
helpful. They belong to Crop Improvement and Protection
Division (CIPD), Biotechnology and Strategic Research
Division (BSRD), and Crop Management Division (CMD). It
is impossible to highlight their respectable names, as
the list would be too long . Neither is it possible, for
the same reason, to detail lecturers and assistants in
Department of Environmental Science and Department of
Biology, Faculty of Science and Environmental Studies,
and Department of Soil Science, Faculty of Agriculture,
UPM, who have provided their help whenever asked. Mr.
Godwin Singam and friends at Centre for Environmental
Technologies (CETEC), Kuala Lumpur were always ready to
lend a hand, particularly in searching paperwork. Bui Nhu
Phuong at Centre for Water and Environment (CEFINEA),
Poly technique University, Hochiminh City, also provided
information.
iv
The author would like to take this opportunity to
express his devotion to his beloved parents, Mr. and Mrs.
Nguyen Nghia and Vo Thi Xuan Lan, whose infinite love has
motivated him to present accomplishment. He is thankful
to his brothers - Minh Dat and Viet Hung are amongst
those seven - who have backed him with their love and
sympathy and trust. His brothers-in-law and sisters-in
law are also thanked for their love and care and
compassion, of whom Hoang Thy and Hong An will be
remembered for their delightful letters that were
heartening in hours of need.
The author would like to apologise for his failure -
due to lack of space - in demonstrating each and every
gentle person who has, materially or spiritually,
directly or indirectly, contributed to this study.
'\,
TABLE OF CONTENTS
Page
ACKNOWLEDGEMENTS . . . . ........... . .. . . . . . . . . . . . . . . iii ix
x xiii
xiv xv
xviii
LIST OF TABLES . . . . . . . . ...... . .... . ... . ... . ..... .
LIST OF FIGURES ...... . .. . .............. . ....... .
LIST OF PLATES . .............. . . . . . . ....... . .... . LIST OF ABBREVIATIONS .... . ..................... . ABSTRACT ... . . , . . . . . . . . .. . . . . .... . .......... . . . . . ABSTRAK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CHAPTER
I
II
III
INTRODUCTION ............. . ... . ...... . . 1
LITERATURE REVIEW . . . . . . . . . . . . . . . . . . . . . 4
Nitrogen Removal from Wastewater . . . . .. 4 Aquatic Chemistry of Nitrogen . . . ... 4
The Need to Control Nitrogen . ...... 5 The Nitrogen Cycle .... . ......... . .. 7 Biological Control of Nitrogen in Wastewater . . ................. . .. 9
Treatment of Wastewater Using Algal Culture . . . . . . . . . . . ... . . . .... . .. . .. . .. . 1 1
Biology of the Algae . ....... . .... . . 1 1 Symbiosis between Algae and Bacteria ... . . . . . . . . . . . . . . . . . . . . . . . . 13 The High Rate Algal Pond . . . ... . .... 14 Algae Removal Techniques ... . . . . . . . . 2 2 Characteristics of Algae Removal Techniques . .... . . . . . . . . . . . . . . . . . . .. 2 7
Treatment of Wastewater Using Water-
hyacinth ... . . . ... . . .. . .... . .. . . . . . . . . . 2 9 Biology of Waterhyacinth . . ....... . . 2 9 Nitrogen Removal Using Water-hyacinth . ..... . . . .. . . . . .... . ... . . .. 31' Effluent Polishing Using Water-hyacinth ... . . . .. . . . . . ... . ..... . . . . . 3 3
Summary of the Literature Review ... . . . 34
MATERIALS AND METHODS . . . . . . . . . . . . . . . . . 36 Materials ... . . . .. . . .... . . . .. . . . . . ..... 36
HRAP Experimental Models . . . . .. . . . . . 36 Wastewater ............... . . . . . . . . . . 3 9
Algal Culture . . . . . . . . .. . . . . . . . . . . . . 3 9
Waterhyacinth Culture ... . . . . . . . . . . . 40
vi
TABLE OF CONTENTS
Page
l\<:lC�OVllJ�!)C3����1rEl ............................... . iii ix
x xiii
xiv xv
xviii
lJIEl1r OF 1r.ABlJ�El ................................. . lJIEl1r OF FIC3UR�El ................................ . lJIEl1r OF PlJl\1r�El ................................. .
lJIEl1r OF .ABBR�VIl\1rIO�El .......................... . .ABEl1rAA<:1r ....................................... .
.ABEl1rAAlC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CHAPTER
I
II
III
I�1rRO!)U<:1rIO� ......................... . 1
lJI1r�AA1rUR� R�VI�Vl .................... . 4 �itrogen Removal from Vlastewater . . . . . . 4
l\quatic <:hemistry of Nitrogen . . . . . . 4 1rhe Need to Control Nitrogen ....... 5 1rhe �itrogen <:ycle . . . . . . . . . . . . . . . . . 7 Biological Control of Nitrogen
in Vlastewater . . . . . . . . . . . . . .. . . . . . . . 9 1rreatment of Vlastewater Using l\lgal Culture . . . . . . . . ... . . . . . . . .. . . . . . . . . .. . 1 1
Biology of the l\lgae . . . .. . . . . . . . . . . 11 Elymbiosis between l\lgae and Bacteria .. . .. . . . . . . . ...... . .. . . . . . . 13 1rhe High Rate l\lgal Pond ... .. . ... . . 14 l\lgae Removal 1rechniques . . . . . . . . . . . 2 2 Characteristics of l\lgae Removal 1rechniques . . . . . . . . . . . . . . . . . . . . . . . . . 2 7
1rreatment of Vlastewater Using Vlater-hyacinth . . . . . . . . . .. . . . . . . . . . . .. . . . . . . . 2 9
Biology of Vlaterhyacinth .... . .. . . . . 2 9 �itrogen Removal Using Vlater-hyacinth . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1 �ffluent Polishing Using Vlater-hyacinth . . . . . . . . . . . . . . .. . . . . . . . . . . . 3 3
Elummary of the lJiterature Review . . . . . . 34
�1r�RIl\lJEl �!) ��1rHO!)El ................ .
�aterials ............................ .
HAAP Experimental �odels .......... .
3 6 3 6 3 6
Wastewater .. . . . .. . . . . . . . ... . . . . . . . . 3 9 l\lgal Culture ............ . . . . . . . . . . 3 9 Vlaterhyacinth Culture .... . . ... . . . . . 4 0
vi
IV
V
Methods ... . . . ... . . . . . ......... . ....... 4 2 Experimental Design . . . . . . . . . . . . . . . . 4 2 Sampling and Analysis .. . . ...... . ... 4 8 Mass Balance of Nitrogen ........... 5 0 Statistical Analysis . . . . . . . . . . . . . . . 5 2
RESULTS AND DISCUSSIONS 53 Preliminary Experiment . ... . .. . . . . . . . . . 5 3
Characteristics of Rubber Skim Serum ... . .......... . . . . ... . . . .... . . 5 3 Tolerance of Algae to Raw Rubber Wastewater . . . . . . . ... . . . . . . . . . . . .. . . 5 5 Tolerance of Waterhyacinth to Raw Rubber Wastewater . . . . . . . . . . . . . . . . . . 5 6 Maximum Density of Waterhyacinth Growing in Raw Rubber Wastewater . . . 5 7
Batch Mode Experiment ..... .... . .. . . ... 5 7 Effect of Waterhyacinth on Growth of Algae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 7 Effect of Algal Growth on Growth of Waterhyacinth . . . . . . . . . . . . . . . . . . . 6 2 Removal of Total Kj eldahl Nitrogen . 6 3 Removal of Ammoniacal Nitrogen .. . . . 6 6 Removal of Organic Nitrogen ........ 6 8 Presence of Oxidised Nitrogen ...... 6 9 Configuration of Nitrogen Removal . . 7 1 Effect of Waterhyacinth on Nitrogen Removal Structure ...... . . . 7 6 Effect of Waterhyacinth on Nitrogen Removal Efficiency .......... . .... . . 7 8 Effect of Waterhyacinth on Nitrogen Transformations . . . . . . . . . . . . . . . . . . . . 7 9 Effect of the Components on Environ-mental Parameters . . . . . . . . . . . . . . . . . . 8 0 Performance of the Batch Mode . . . . .. 8 6
Continuous Mode Experiment . . . . . . . . . . . . 8 8 COD Removal Rate . . . .. . .. . . .. . . . .. . . 8 8 Performance of the Continuous Mode . 9 2
SUMMARY AND CONCLUSIONS .............. . 9 5
BIBLIOGRAPHY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 9
vii
APPENDICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 5
A B
Laboratory Methods of Analysis ....... . Additional Tables .................... .
115 1 3 8
VITA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
viii
LIST OF TABLES
Tab le Page
1 Typical Wastewaters Treated by the HRAP ................................... . 1 9
2 Typical Algal Species Used in the HRAP .. 2 1
3 Characteristics of Typical Algae Removal Techniques ............................. . 2 8
4 Description of Runs in Batch Mode 4 5
5 Description of Runs in Continuous Mode .. 4 8
6 Characteristics of Latex Concentrate Skim
7
8
Serum ........... . ....... . ............... 5 5
Tolerance of Algae and Waterhyacinth to Raw Rubber Wastewater .................. .
Effect of Waterhyacinth Coverage on TKN Removal in the Batch Mode Experiment ....
5 6
66
9 Characteristics of the Treated Wastewater in the Batch Mode Experiment . . . . . . . . . . . . 8 7
1 0 Characteristics of the Treated Wastewater
1 1
12
13
14
in the Continuous Mode Experiment . . . . . . . 94
Meteorological Data at RRIM Experiment Station in Sungai Buloh from January to September 1 9 9 7 . . . . . . . . . . . . . . . . . . . . . . . . . .
Effect of 2 5 % Surface Coverage of Waterhyacinth on Performance of the HRAP in Batch Mode .......................... .
Effect of 7 5 % Surface Coverage of Waterhyacinth on Performance of the HRAP in Batch Mode .......................... .
Effect of 1 0 0 % Surface Coverage of Waterhyacinth on Performance of the HRAP
in Batch Mode .......................... .
ix
1 3 9
14 0
14 1
1 4 2
LIST OF FIGURES
Figure
1 The Simplified Nitrogen Cycle .......... .
2 The Symbiosis of Algae and Bacteria
3 Schematic Diagram of the High Rate Algal Pond ................................... .
4 Schematic Diagram of Effluent Treatment Model Used in Batch Mode ............... .
5 Schematic Diagram of Effluent Treatment Model Used in Continuous Mode .......... ,
6 Graphical Presentation of the Batch Mode Experimental Set-up .................... .
7 Variations of VSS in the Batch Mode with Waterhyacinth Introduced at the Middle of
Page
8
14
15
3 7
3 8
44
the Experimental Runs ........ . . . . . . . . . . . 6 0
8
9
1 0
1 1
12
1 3
14
Correlation Between Chlorophyll a Concentration and VSS in the Batch Experiment ............................. .
Variations of VSS in the Batch Mode with Waterhyacinth Introduced at the Start of the Experimental Runs .................. .
Relationship between Growth of Algae and Growth of Waterhyacinth ................ .
Growth Rate of Waterhyacinth in the HRAP Model .................................. .
TKN Removal with Waterhyacinth Introduced at the Middle of the Experimental Runs ..
TKN Removal with Waterhyacinth Introduced at the Start of the Experimental Runs ...
AN Removal with Waterhyacinth Introduced at the Middle of the Experimental Runs ..
x
6 1
6 1
6 3
6 3
64
6 5
6 7
15
1 6
1 7
1 8
1 9
2 0
2 1
2 2
2 3
2 4
2 5
2 6
2 7
2 8
2 9
3 0
AN Removal with Waterhyacinth Introduced at the Start of the Experimental Runs . . .
Organic N Removal with and without Waterhyac inth Coverage . . . . . . . . . . . . . . . . . .
NO) -N in Introduced
the HRAP with Waterhyacinth at the Start o f the
6 7
6 8
Experimental Runs . . . . . . . . . . . . . . . . . . . . . . . 7 0
Ef fect of Init ial Waterhyacinth Coverage on the Mechanism of N Removal . . . . . . . . . . . 7 7
Ef fect o f Midway Waterhyac inth Coverage on the Mechanism of N Removal . . . . . . . . . . . 7 7
Effect of Initial Waterhyacinth Coverage on N Removal Effic iency . . . . . . . . . . . . . . . . . 7 8
Effect of Midway Waterhyacinth Coverage on N Removal Effic iency . . . . . . . . . . . . . . . . . 7 9
Effect o f Algae and Waterhyacinth o n pH . 8 1
Effect o f Init ial Waterhyac inth Coverage on pH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 1
Ef fect o f Midway Waterhyacinth Coverage on pH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2
Effect o f Algae and Waterhyacinth on DO Concentrat ion . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
E f fect of Init ial Waterhyac inth Coverage on DO Concentrat ion . . . . . . . . . . . . . . . . . . . . . 84
Ef fect of Midway Waterhyacinth Coverage on DO Concentrat ion . . . . . . . . . . . . . . . . . . . . . 8 5
COD Removal Rate Us ing 9 - day Retent ion Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 8
COD Removal Rate Us ing 6 - day Retent ion Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 9
COD Removal Rate Us ing 3- day Retent ion Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 0
xi
3 1 Definit ion Sket ch Analys is for Cont inuous Reactor
for a Mass Balance a Completely -mixe d ,
xi i
9 1
Plate
1
2
3
4
5
6
LIST OF PLATES
Chiarella vulgaris ( spherical cel l ) and Scenedesmus acuminatus ( e l ongated cel l )
Roots o f Eichhornia crassipes . . . . . . . . . . .
Batch-mode Experiment . . . . . . . . . . . . . . . . . . .
Cont inuous - mode Experiment . . . . . . . . . . . . . .
Roots of Waterhyac inth Growing in a Pond Wi thout Algae . . . . . . . . . . . . . . . . . . . . . . . . . . .
Roots of Waterhyac inth Af ter 10 Days of Growth in the HRAP Mode l . . . . . . . . . . . . . . . .
xi i i
Page
4 1
4 1
4 7
4 7
5 9
5 9
AN
APHA
BOD
COD
CV
DO
HRAP
HRT
N
N02 -N
N03 -N
P
r
TKN
TSS
VSS
WSP
LIST OF ABBREVIATIONS
Ammoniacal Nitrogen
American Publ ic Health Assoc iat ion
Biochemical Oxygen Demand
Chemical Oxygen Demand
Coe f f ic ient of Variat ion
Dis solved Oxygen
High Rate Algal Pond
Hydraulic Retention Time
Nit rogen
Ni trite Nitrogen
Ni trate Nitrogen
Level of signi f icance
Correlat ion coe f f i cient
Total Kj eldahl Nitrogen
Total Suspended Sol ids
Volat ile Suspended Sol ids
Waste Stabilisat ion Pond
xiv
Abstract of the s i s submitted to t he Senate of Univers i t i Put ra Malays ia in ful f i lment
of the requirement s for the degree of Master of Science
THE INTRODUCTION OF EICHHORNIA CRASSIPES INTO THE HIGH RATE ALGAL POND
TO REMOVE NITROGEN FROM WASTEWATER
By
NGUYEN NGOC BICH
April 1 9 9 8
Chai rman: As soc . Prof . Dr . Mohammad I smai l Yaz i z
Faculty: Science and Environmental Studies
The treatment of wastewater us ing algal cul tures has
been researched and developed s ince 1 9 5 0 . The High Rate
Algal Pond (HRAP ) is the most e f f i cient of this type of
treatment , part icularly for nitrogen removal . However ,
the main problem with the HRAP i s the high level of
organic suspended sol ids in the treated wastewater .
Furthermore , nut rient s released from the lys i s of algal
cells may give rise to eutrophi cat ion in the rece iving
water .
xv
A laboratory- scale experiment was carried out uSlng
the HRAP in the company of an aquatic plant ,
waterhyac inth Eichhornia crassipes, as an integrated
sys tem to remove nitrogen from wastewater . The dominant
algal species used was Chlorella vulgaris.
Twenty runs in the batch mode were operated under
the convent ional HRAP and the HRAP -waterhyac inth
combinat ion syst em . Three runs were operated in the
cont inuous mode us ing t he HRAP -waterhyac inth system with
5 0 % surface area coverage and 3 di f ferent retent ion t imes
( 3 days , 6 days , and 9 days ) .
Comparison of the convent ional HRAP and the HRAP
waterhyac inth system for treat ing di luted raw wastewater
from rubber latex concentrate process ing revealed better
nitrogen removal e f f i c iency by the HRAP-waterhyacinth
sys tem . Total Kjeldahl Nitrogen in the treated wastewater
was 2 3 % lower in the HRAP with waterhyac inth than that in
the normal HRAP . Signi f icant reduct ion of suspended
sol ids was also recorded . Total Suspended Sol ids of the
eff luent in t he HRAP -waterhyacinth system was generally
less than 50 mg/L whereas it was greater t han 4 5 0 mg/L in
the convent ional HRAP .
xvi
Within one reactor , t he algae and t he waterhyac inth
could co - exi st wel l . The algae did not show any
inhibi t ion towards growth of the waterhyac int h , whi l s t
the latter allowed the algae to grow as long as there
were nut rient s and space for photosynthes i s .
The mas s balance of nitrogen depicted a part it ioning
of nit rogen removal in the HRAP -waterhyacinth system .
This might be attributed to nitrogen assimi lat ion by
algae and bacteria , nitrogen uptake by waterhyac inth ,
biologi cal nitrif icat ion - denitrificat ion , and the
volat i l i sat ion of ammonia . In the convent ional HRAP ,
nit rogen removal was mainly due to ammonia vol at i l i sat ion
and assimilation .
These findings indicate that the introduct ion of
Eichhornia crassipes into the HRAP may bring about better
treatment of the wastewat er , in terms of nitrogen and
sol ids removal . However , further study is necessary to
determine the opt imum des ign and operat ion of such a
system .
xvi i
Abstrak Tes i s Dikemukakan Kepada Senat Univers i t i Putra Malaysia Sebagai Memenuhi
Keperluan Untuk I j azah Master Sains
PENGUNAAN EICHHORNIA CRASSIPES DI DALAM KOLAM ALGA KADAR TINGGI
UNTUK PENGURANGAN NITROGEN DARI AIR S I SA
Oleh
NGUYEN NGOC BICH
April 1 9 9 8
Pengerusi : Prof . Madya Dr . Mohammad I smai l Yaziz
Fakulti: Sains dan Alam Sekitar
Pengolahan air s i sa menggunakan kul tur alga telah
disel idik dan dimaj ukan sej ak 1 9 5 0 . Kolam Alga Kadar
Tinggi ( KAKT ) merupakan cara pengolahan yang pal ing cekap
bagi pengol ahan cara ini , terutama nya untuk pengurangan
nit rogen . Walau bagaimanapun , masaalah utama s i stem KAKT
adalah paras pepej al terampai organik yang t inggi di
dalam air s i sa yang telah dirawat . Tambahan , zat makanan
yang ter ke luar dari pada sel alga yang mat i boleh
menyebabkan eutrof ikas i di dalam sungai yang menerima air
sisa tersebut .
xvi i i
Suatu kajian makmal menggunakan KAKT yang
mengandungi keladi bunt ing Eichhornia crassipes sebagai
s i stem bersepadu telah dij alankan untuk mene l i t i
pengurangan nitrogen dari a i r s i sa . Alga yang dominan
yang digunakan ialah Chlorella vulgaris .
Sebanyak dua puluh percubaan secara kelompok ( batch)
telah dij alankan menggunakan si stem KAKT biasa dan si stem
KAKT - keladi bunt ing. Tiga percubaan berterusan
( cont inuous ) j uga dij alankan di mana 5 0 % permukaan air
s i sa di tumbuhi keladi bunting dan menggunakan tempoh
penahanan hidraulik yang berlainan .
Perbandingan kedua - dua s i stem untuk mengolah air
s i sa cecair dari ki lang pemprosesan get ah pekat
menunj ukkan si stem KAKT - ke l adi bunt ing memberi
pengurangan nitrogen yang lebih baik . Kandungan Total
Kj eldahl Nitrogen di dalam air s i sa yang telah diolah
secara KAKT - keladi bunt ing adalah 2 3 % lebih rendah
daripada yang diolah oleh s i stem KAKT biasa . Pengurangan
kandungan pepej al terampai yang lebih baik j uga di
catatkan . Amnya , kandungan pepe j al t erampai di dalam
KAKT-keladi bunting adalah kurang daripada 5 0 mg/L
manakala di dalam KAKT biasa adalah melebihi 4 5 0 mg/L .
xix
Alga boleh bertumbuh bersama dengan kel adi bunt ing .
Alga didapat i tidak menghalang pertumbuhan kel adi bunt ing
sementara ke ladi bunting pula t idak menghalang
pertumbuhan alga selagi zat makanan dan ruang untuk
fotos int e s i s mencukupi .
Perimbangan j i sim nitrogen menunj ukkan pemetakan
pengurangan nitrogen di dalam sistem KAKT- keladi bunt ing .
Pengurangan nit rogen berlaku me lalui as imi lasi oleh alga
dan bakteria , permakanan oleh keladi bunt ing , nitrif ikasi
dan deni tri f ikasi , dan pemeruapan amonia . Dalam s i stem
KAKT bias a , pengurangan nitrogen berlaku me lalui
pemeruapan amonia dan asimilas i .
Penemuan -penemuan ini menunj ukkan penanaman
Eichhornia crassipes di dalam KAKT boleh menghas i lkan
pengolahan yang baik untuk pengurangan kandungan nitrogen
dan pepe j al . Walau , tambahan perlu di j al ankan untuk
mengena bagaimana pun pasti rekabentuk s i stem yang sesuai
serta cara operas i s i stem berkanaan .
xx
CHAPTER I
INTRODUCTION
The treatment of wastes using algal cultures has
been researched and developed s ince 1 9 5 0 ( Oswald et al . ,
1 9 5 7 ) . The High Rate Algal Pond ( HRAP ) has proven to be
the most e f f i c ient of thi s type of treatment ,
part icularly for nitrogen removal ( Fallowf ield et al . ,
1 9 8 5 ; Picot et al . , 1 9 9 2 ) . However , s ince the main
funct ion of the pond is the ass imilat ion of nut rient s in
wastewater by algae through their metabol ism, thi s leads
to the development of organi c suspended sol ids in the
pond . Therefore , further treatment i s needed to remove
algae from the treated e f f luent ( Gaudy and Gaudy , 1 9 8 1 ) .
Many separation and harvest ing t echniques have been
developed to remove algae from the treated e f f luent , the
most promis ing amongs t t hem be ing centri fugat ion ,
chemical coagulation , and autof locculat ion ( Oswald and
1
2
Golueke , 1 9 6 0 ) . Other algae removal t echniques include
ion exchange , f lotat ion , microstraining , e l ectric charge
field, sand f i l trat ion , pond operat ion techniques , land
applicat ion , aquacul ture , f loat ing plant s , and rock
f i l ters ( Golueke and Oswald, 1 9 6 5 ; McGarry and
Tongkasame , 1 9 7 1 ; Middlebrooks et al . , 1 9 74 ; Harris et
al . , 1 9 7 7 ; Dinges , 1 9 78 a , 1 9 7 8b ; Wolverton and McDonald ,
1 9 7 9 ; El l i s , 1 9 8 3 ; Fal lowf ield and Garrett , 1 9 8 5 ;
Nordin , 1 9 94 ) . However , unle s s the algae produced have
economic value , mos t of the harvest ing methods are cost ly
and/or complicated due to their requirements of energy ,
chemicals and other material s , complex t echnology , and
sophi sti cated equipment ( Fallowfield and Garrett , 1 9 85) .
Amongst aquat ic plant s that have been used in
wastewater treatment for the purpose of nutrients removal
and e f f luent upgrading , water hyac inth ( Ei chhornia
crassipes ) is one of the most e f fect ive macrophytes
(Hauser , 1 9 84 ; Reedy and De Busk , 1 9 85) . However , no past
study has ment ioned the co - exi stence of waterhyacinth and
algae within a common treatment reactor .
Thi s study was aimed at inves t igating the
poss ibi l i ty of us ing an integrated treatment system
3
created by the introduct ion of waterhyac inth into the
HRAP to remove nitrogen f rom wastewater . The st ructure of
nitrogen removal in such a system would al so be s tudied .