EVALUATION OF AQUATIC PLANTS FOR PHYTOREMEDIATION OF EUTROPHIC STORMWATERS

127 Pages·2009·2.47 MB·English

EVALUATION OF AQUATIC PLANTS FOR PHYTOREMEDIATION OF EUTROPHIC
STORMWATERS

By

QIN LU

A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY

UNIVERSITY OF FLORIDA

2009
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© 2009 Qin Lu

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To my husband, Diangao, and my son, Xuanning

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ACKNOWLEDGMENTS
First of all, I would like to express my deepest thanks to my advisor, Dr. Zhenli L. He, for
his encouragement, trust, and patience as my mentor. He has not only provided me professional
opportunities and offered me numerous insightful suggestions for my research, but also, as a role
model, he has shown me that hardworking and persistence as well as creativity and independent
thinking are ingredients of success. I am very grateful to my co-advisor, Dr. Donald A. Graetz.
He arranged for my airport pick up, social security number application, and first term
registration, all of which helped me adjust smoothly to a whole new environment and feel at
home. He has been giving invaluable suggestions and comments for my research. I would also
like to give my sincere thanks to Drs. Peter J. Stoffella, Yuncong Li and Samira Daroub for
serving on my advisory committee and making major contributions to my research. Special
thanks go to the late Dr. Dolen Morris, who had always been prompt in helping me improve my
writing. I profoundly appreciate South Florida Water Management District for funding the
research.
I thank Dr. Min Liu and Ms. Yu Wang, Lacey, Katrina, Leighton, and Brandon in Dr.
Graetz’s lab and Sampson and many other friends in Gainesville for their help and friendship
which made my stay in Gainesville a pleasant one. I wish to thank the faculty, staff, and students
of the Soil and Water Science Department for their assistance and support.
Dr. Charles A. Powell of Indian River Research and Education Center at the University of
Florida is acknowledged for making his laboratory facilities available for my use. I wish to thank
all the faculty, staff, and students, especially Mrs. Youjian Lin, Hai Lu, Mrs. Cuifeng Hu, Mrs.
Maria Solis, Drs. Peter J. Van Blokland and Sandra B. Wilson, at Indian River Research and
Education Center of University of Florida. Their kindness and help in many ways made my stay
in Fort Pierce a memorable one.
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I thank Dr. Xiaoe Yang for providing insight, expertise, and support. Special thanks go to
Drs. Guochao Chen, Jinyan Yang, Yuangen Yang, Frederico Vieira, Wenrong Chen, Yangbo
Wang, Mr. Douglas J. Banks, Mrs. Shaoqin Lu, and PhD students Jinghua Fan and Bruno Pereira
for providing assistance in laboratory analysis, expertise and laughter over the past three years.
Without their help, successful completion of my PhD study is impossible. I have always felt
fortunate to be part of Dr. He’s group where I have learned, enjoyed and benefited from team
work.
I wish to express my appreciation to Dr. Xiaochang Wang for his continued interest in my
progress, encouragement and support.
I am very grateful to my parents, parents-in-law, and siblings for their love, support,
encouragement, and confidence in me, which have been the driving force for me to pursue my
dreams.
I am greatly indebted to my loving husband, Diangao, who has sacrificed so much to be
with me here in the United States and helped me in the field and in the lab. I thank my adorable
son, Xuanning, who has brought so much joy and happiness into our life. They are the endless
source of strength I can always rely on.
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TABLE OF CONTENTS

page
ACKNOWLEDGMENTS ...............................................................................................................4 
LIST OF TABLES ...........................................................................................................................9 
LIST OF FIGURES .......................................................................................................................10 
ABSTRACT ...................................................................................................................................12
CHAPTER
1 LITERATURE REVIEW .......................................................................................................14 
Water Quality: A Worldwide Concern ...................................................................................14 
Phytoremediation of Contaminated Water Using Aquatic Plants ..........................................17 
Stormwater Treatment with Floating Aquatic Plants .............................................................22 
Growth Factors of Aquatic Plants ...........................................................................................23 
Research Objectives ................................................................................................................25 
2 NUTRIENT REMOVAL POTENTIAL OF WATER LETTUCE (PISTIA STRATIOTES
L.) FROM STORMWATER IN DETENTION SYSTEMS ..................................................27 
Introduction .............................................................................................................................27 
Materials and Methods ...........................................................................................................28 
Experimental Design .......................................................................................................28 
Chemical Analysis ...........................................................................................................31 
Data Treatment and Data Analysis ..................................................................................32 
Results and Discussion ...........................................................................................................33 
General Water Quality Improvement ..............................................................................33 
Nitrogen and P Concentration Reduction ........................................................................39 
Nitrogen and P Removal Potential by Plant Uptake .......................................................46 
Physiological Limits ........................................................................................................48 
System Management .......................................................................................................49 
Conclusions .............................................................................................................................50 
3 METAL REMOVAL POTENTIAL OF WATER LETTUCE (PISTIA STRATIOTES L.)
FROM STORMWATER IN DETENTION SYSTEMS ........................................................51 
Introduction .............................................................................................................................51 
Materials and Methods ...........................................................................................................54 
Chemical Analysis ...........................................................................................................55 
Data Treatment ................................................................................................................55 
Results .....................................................................................................................................56 
Metal Concentration Reduction in Water ........................................................................56 
Metal Accumulation by Plant Root .................................................................................61 
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Metal Distribution in Plant ..............................................................................................61 
Estimation of Annual Metal Removal .............................................................................62 
Metal Uptake and Surface Adsorption ............................................................................63 
Metal Bio-concentrated by Plant .....................................................................................64 
Discussion ...............................................................................................................................66 
Conclusions .............................................................................................................................68 
4 NITROGEN REQUIREMENT FOR WATER LETTUCE AND COMMON
SALVINIA .............................................................................................................................69 
Introduction .............................................................................................................................69 
Materials and Methods ...........................................................................................................70 
Experimental Design .......................................................................................................70 
Chemical Analysis ...........................................................................................................71 
Statistical Analysis ..........................................................................................................71 
Results and Discussion ...........................................................................................................71 
Relationship between Plant Biomass Yield and N Concentration ..................................71 
Relationship between Plant N and Solution N Concentration .........................................75 
Plant Critical N Concentration ........................................................................................78 
Conclusions .............................................................................................................................78 
5 PHOSPHORUS REQUIREMENT FOR WATER LETTUCE AND common
SALVINIA .............................................................................................................................80 
Introduction .............................................................................................................................80 
Materials and Methods ...........................................................................................................81 
Experimental Design .......................................................................................................81 
Chemical Analysis ...........................................................................................................82 
Statistical Analysis ..........................................................................................................82 
Results and Discussion ...........................................................................................................82 
Relationship between Plant Biomass Yield and Solution P Concentration ....................82 
Relationship between Plant P Concentration and Solution P Concentration ..................87 
Plant Critical P Concentration .........................................................................................90 
Conclusions .............................................................................................................................90 
6 EFFECT OF SALINITY ON GROWTH OF WATER LETTUCE .......................................92 
Introduction .............................................................................................................................92 
Materials and Methods ...........................................................................................................93 
Experimental Design .......................................................................................................93 
Chemical Analysis ...........................................................................................................94 
Statistical Analysis ..........................................................................................................95 
Results and Discussion ...........................................................................................................95 
Plant Growth as Affected by a Salinity Gradient ............................................................95 
Plant Biomass in Different Salinity .................................................................................95 
Plant Nutrient Status under Different Salinity Conditions ..............................................98 
Conclusions ...........................................................................................................................100 
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7 EFFECT OF PH ON GROWTH OF WATER LETTUCE ..................................................101 
Introduction ...........................................................................................................................101 
Materials and Methods .........................................................................................................102 
Experimental Design .....................................................................................................102 
Chemical Analysis .........................................................................................................103 
Statistical Analysis ........................................................................................................103 
Results and Discussion .........................................................................................................103 
Plant Growth in Water at Different pH .........................................................................103 
Plant Biomass Yield at Different pH Treatments ..........................................................105 
Plant Nutrition Status at Different pH Treatments ........................................................105 
Conclusions ...........................................................................................................................109 
8 SUMMARY AND CONCLUSIONS ...................................................................................111 
LIST OF REFERENCES .............................................................................................................115 
BIOGRAPHICAL SKETCH .......................................................................................................127 

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LIST OF TABLES
Table page

2-1 Water quality improvement in the treatment plots of the East and West Ponds. ...............36 
2-2 Annual removal amounts of plant dry biomass, N, and P from the East and West
Ponds. .................................................................................................................................47 
3-1 Annual metal removal rates by periodic harvesting of water lettuce. ................................65 
4-1 Nutrient solution composition for N requirement study. ...................................................70 
5-1 Nutrient solution composition for P requirement hydroponic study. ................................81 
6-1 EC and ions contributing to water salinity in the waters of the East and West Ponds. .....92 
6-2 Nutrient solution composition for the salinity tolerance study. .........................................93 
7-1 Chemical composition of nutrient solution for pH effect study. .....................................102 
7-2 Nutrient concentration and related properties of the nutrient solution at different pH
levels. ...............................................................................................................................110 

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LIST OF FIGURES
Figure page

2-1 Experimental set up in the West Pond and the East Pond. ................................................30 
2-2 Total solid concentrations in the waters of the East and West Ponds. ...............................34 
2-3 Turbidity in the East and West Ponds. ...............................................................................35 
2-4 Water samples from treatment plot and control plot. ........................................................37 
2-5 Water EC in the East and West Ponds. ..............................................................................38 
2-6 Water pH in the East and West Ponds. ..............................................................................39 
2-7 Nitrate-N in the waters of the East and West Ponds. .........................................................40 
2-8 Ammonium-N in the waters of the East and West Ponds. .................................................41 
2-9 Total Kjeldhal N in the waters of the East and West Ponds. .............................................42 
2-10 Water PO -P in the East and West Ponds. .........................................................................43 
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2-11 Total dissolved P in the waters of the East and West Ponds. ............................................44 
2-12 Total P in the waters of the East and West Ponds. .............................................................45 
2-13 Nitrogen concentrations in plant roots and shoots from the East and West Ponds. ...........47 
2-14 Phosphorus concentrations in plant roots and shoots from the East and West Ponds. ......48 
3-1 Total dissolved metal concentrations in the treatment and control plots of the East
and West Ponds during 2005-2007 (n=122).. ....................................................................56 
3-2 Plant metal concentration factors (CFs) in the East and West Ponds. ...............................61 
3-3 Metal root/shoot ratio in concentration of the East and West Ponds. ................................62 
3-4 Distribution of metals outside and inside of water lettuce root. ........................................64 
3-5 Plant metal bio-concentration factors (BCFs) in the East and West Ponds. ......................66 
4-1 The growth performance of water lettuce and common salvinia under different N
levels. .................................................................................................................................73 
4-2 Plant dry biomass yield at different N level treatments. ....................................................73 
4-3 The shoot/root ratio of water lettuce dry biomass at different N levels. ............................74 
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