Effect of Algal Biofilm and Operational Conditions on Nitrogen Removal in Waste Stabilization Ponds

142 Pages·2011·3.02 MB·English

by  Mohammed Babu

EFFECT OF ALGAL BIOFILM
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AND OPERATIONAL
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A REMOVAL IN WASTEWATER
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IO STABILIZATION PONDS
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Discharge of nutrient rich wastewater causes eutrophication of surface water; C
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therefore wastewater treatment before discharge is required. Wastewater stabilization N
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ponds are low cost technology used by developing countries but not effective in IT
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nitrogen removal due to low nitrifier biomass in the water column. Introduction of
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surface area for attachment of nitrifiers has therefore been proposed. O
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This thesis reports the performance of pilot scale wastewater stabilization ponds IT
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fitted with baffles. The effect of baffles on nitrogen removal under tropical and two O
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operational conditions was investigated. Under TKN/BOD ratio of 0.67, the baffled N
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ponds performed better in nitrogen removal than the control pond. Total nitrogen E
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mass balances showed that nitrification-denitrification, algal uptake and sedimentation O
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were principle nitrogen removal mechanisms in biofilm waste stabilization ponds A
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IN
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This study shows the potential of biofilms in improving nitrogen removal in
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wastewater stabilization ponds. The BOD and TSS concentrations were sufficiently ST
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low to permit for reuse in irrigation. If the objective is reuse and optimization of W
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resources, the effluents from the ponds had sufficient nitrogen content for use in T
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agriculture. S
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This research was jointly funded by the Netherlands Fellowship Program and the IL
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EU-SWITCH project. SWITCH is supported by the European Commission A
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(6th Framework Programme) and contributes to the thematic priority area of IO
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“Global Change and Ecosystems”. P
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MOHAMMED BABU
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EFFECT OF ALGAL BIOFILM AND
OPERATIONAL CONDITIONS ON
NITROGEN REMOVAL IN
WASTEWATER STABILIZATION PONDS

MOHAMMED BABU
Thesis committee

Thesis supervisor
Prof. dr. H.J. Gijzen
Professor of Environmental Biotechnology
UNESCO-IHE Institute for Water Education
Delft, The Netherlands

Thesis co-supervisors
Dr. ir. N.P van der Steen
Senior Lecturer in Sanitary Engineering
UNESCO-IHE Institute for Water Education
Delft, The Netherlands

Dr. ir. C.M. Hooijmans
Senior Lecturer in Sanitary Engineering
UNESCO-IHE Institute for Water Education
Delft, The Netherlands

Other members
Prof. dr. ir. P.N.L. Lens
UNESCO-IHE Institute for Water Education
Delft, The Netherlands

Prof. dr. ir. H.H.M. Rijnaarts
Wageningen University
Wageningen, The Netherlands

Prof. dr. R. Haberl
University of Natural Resources and Life Sciences
Vienna, Austria
Prof. dr. F. Kansiime
Makerere University Institute of Environment and Natural Resources
Kampala, Uganda

This research was conducted under the auspices of the Wageningen University Institute
for Environment and Climate Research (WIMEK)
Effect of Algal Biofilm and Operational
Conditions on Nitrogen Removal in
Wastewater Stabilization Ponds

Thesis
Submitted in fulfilment of the requirements of
the Academic Board of Wageningen University and
the Academic Board of the UNESCO-IHE Institute of Water Education
for the degree of doctor
to be defended in public
on Friday 28 January 2011 at 10.00 a.m.
in Delft, the Netherlands

by

MOHAMMED BABU
Born in Mbale, Uganda
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Dedication
This thesis is dedicated to my late uncle Shantilal .A. Vyas
May God bless and rest your soul in peace
Acknowledgements
The author is extremely grateful to the Netherlands Government for providing financial
assistance through the Netherlands Fellowship Program. I would also wish to extend my
sincere thanks to the EU-SWITCH project for the financial assistance of my research
project.

I‟m very grateful to my promoter Professor Huub Gijzen for his kindness, guidance,
valuable discussions and comments during the writing of this dissertation. I greatly
appreciate his trips to Uganda and invaluable input and support in this study.

I‟m particularly indebted to my co-promoters Dr. Peter van der Steen and Dr. Tineke
Hooijmans for constructive ideas during the research period. I would greatly thank them
for accepting to come to Uganda and providing invaluable guidance. I extend my
heartfelt thanks to them for allocating time for meetings and critically reviewing the
manuscripts. Special thanks go to Dr. Henk Lubberding who mentored me during my
MSc study, kept in touch with me, notified and supported me when the PhD opportunity
became available.

Thanks to the Managing Director and management of National Water and Sewerage
Corporation for giving me permission and opportunity to use their facilities at the
Bugolobi Sewage Treatment Works. I‟m specifically grateful to Eng. Kiwanuka Sonko,
Dr. Kaggwa Rose and Mr. Kanyesige Christopher for their assistance and link to National
water.

I would wish to extend my appreciation to the Rector and Vice rector of Islamic
University in Uganda, Dr. A.K. Ssengendo and Dr. M. Mpeza for giving me the
opportunity and supporting me when pursuing this cause. Thanks to Dr. P.S.N.A
Ssekimpi for being parental and providing guidance throughout my under and
postgraduate studies. Thanks to my colleagues Dr. S. Nachuha and Mr. S. Okurut who
gave me courage and support during this period.

The laboratory staff of IHE Fred, Frank, Peter, Lyzette, Don and the rest; you did a great
job for me while I was in Delft. Thanks to Edwin Hes and Mushi .M. for their assistance
during experimental work while in Delft. I extend my appreciation to the laboratory staff
of BSTW especially Juliet, Nyombi .J. Mutyaba, C., Arra, K, Wetaga, H and Saazi Job
for supporting me in the lab. Not forgetting, my cousin Rama for accepting to do the dirty
work of pumping of wastewater daily into the anaerobic tank; thanks a lot dear! Thanks
to my PhD colleagues Kittiwet, K., Heyddy, L., Barreto C., Uwamariya V., Sekomo, C.,
Bagoth S; Ansa E and rest who made me feel at home while in Delft.

Special thanks to my beloved family; my mother, father and sisters who gave me the
courage and strength to move on. Great and heartfelt appreciation to my lovely wife
Samiha and her family, my sons Fesal and Irfan; I deeply appreciate your patience.
Thanks for tolerating my long hours in the lab and my absence from home for many
months. Finally, I acknowledge all those who helped me but whose names have not
appeared on this page. May God bless you all!
List of abbreviations
NH + Ammonium
4
NH + -N Ammonium nitrogen
4
et al and others
AT Anaerobic Tank
R Biofilm nitrification rate
bio
BOD Biochemical Oxygen Demand (5days)
5
BNR Biological Nitrogen Removal
BSTW Bugolobi Sewage Treatment Works
R Bulk water nitrification
bulk
cm Centimeters
COD Chemical Oxygen Demand
CFD Computational Fluid Dynamics
d-1 per day
DO Dissolved Oxygen
d Dispersion number
Eff Effluent
EU European Union
EPS Extra Polymeric Substance
FP Facultative ponds
Q Flow rate
g Grams
hrs Hours
HRT Hydraulic Retention time
Inf Influent
KjN Kjeldahl nitrogen
MP Maturation ponds
m Meters
µm Micro meters
mg Milligrams
mg l-1 Milligrams per liter
NO Nitrate
3
NO -N Nitrate nitrogen
3
NO Nitrite
2
NO -N Nitrite nitrogen
2
N Nitrogen gas
2
N O Nitrogen Oxides
2
Org-N Organic nitrogen
N Reactors in series
Pe Peclet number
pH Potentiometric hydrogen ion concentration
s Seconds
SPSS Statistical Package for Social Sciences
spp Species
T Temperature (oC)
TSS Total suspended Solids
UNEP United Nations Environmental Program
US$ US dollars
WSP Wastewater stabilization ponds

Greek
β Standard coefficient
µE Micro-Einstein‟s
α Index of short circuiting
2 Variance
Table of Contents

Chapter 1 Introduction ................................................................................................... 1

Chapter 2 The effect of baffles on algal-bacterial biofilm structure and composition of
zooplankton in wastewater stabilization ponds ........................................... 21

Chapter 3 Comparison of hydraulic flow patterns of four pilot scale baffled
wastewater stabilization ponds ................................................................... 49

Chapter 4 Nitrification in bulk water and biofilms of algae wastewater stabilization
ponds ........................................................................................................... 62

Chapter 5 Nitrification rates of algal-bacterial biofilms in wastewater stabilization
ponds under light and dark conditions ........................................................ 74

Chapter 6 Effect of operational conditions on the nitrogen removal in a pilot scale
baffled wastewater stabilization ponds under tropical conditions .............. 87

Chapter 7 Nitrogen mass balances for pilot scale biofilm stabilization ponds under
tropical conditions ..................................................................................... 100

Summary ......................................................................................................................... 119

Samenvatting ................................................................................................................... 124

Curriculum vitae