Integration of Anaerobic Digestion and Composting Facilities by Golnaz Arab A thesis submitted in

283 Pages·2017·9.96 MB·English

by  Golnaz Arab

Integration of Anaerobic Digestion and Composting Facilities

by

Golnaz Arab

A thesis submitted in partial fulfillment of the requirements for the degree of

Doctor of Philosophy

in

Environmental Engineering

Department of Civil and Environmental Engineering

University of Alberta

©Golnaz Arab, 2017
ABSTRACT

Interest in organic waste treatment has increased in recent years due to growing rate
of organic waste generation. Implementing biotransformation technologies helps to divert
organic waste from landfill, reduce greenhouse gas emission, and produce valuable final
products. This research was conducted in two parts. The general goal of the first part was
to extend the overall knowledge in organic waste characterization, generation rate,
sources, and sampling. While in the second part, which is the main part of the
dissertation, the focus was on anaerobic digestion and composting processes and
integration of these two biotransformation technologies.
In the first part (Chapter 2), a sampling methodology was proposed for higher
education institutions (HEI’s), as one of the main generators in institutional, commercial,
and industrial (ICI) sectors. Representative organic waste was collected according to the
proposed methodology and characterized in terms of their physical, chemical, and
biological properties.
In the second part, different options of digestate post treatment were investigated in
an integrated anaerobic digestion and composting system. Co-composting of digestate
and organic fraction of municipal solid waste (OFMSW) was studied in terms of
physicochemical parameters and microbial population dynamics in Chapter 3 and 4,
respectively. Digestate was prepared by running a high solid anaerobic digestion (HSAD)
reactor with the working volume of 500 L. Then it was mixed with OFMSW in eight
different mixing ratios; 0, 10, 20, 30, 40, 50, 75, or 100% (wet mass). Composting
reactors with working volume of 25 L were monitored for 100 days including 30 days of
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aeration and 70 days of curing. Monitored parameters were temperature, mass changes,
total solids, organic matter, pH, and electrical conductivity. Stability and maturity
endpoints were also quantified by running respirometry, C:N ratio, ammonium to nitrate
ratio, and Solvita® tests. The results revealed that the reactors with 20 to 40% (%ww)
digestate had better performance in terms of organic matter (OM) removal, temperature
evolution, and also stability time. Results also showed that total ammonia nitrogen (TAN)
available in the digestate could be an effective parameter in organic matter degradation
and composting performance. Concentration above 5000 TAN mg.kg-1 DM found to be
unfavorable for the biological activities where the improvement in composting
performance was observed in the lower concentrations of TAN. OFMSW could also
enhance the physicochemical properties of the digestate by balancing free air space,
moisture content, and C:N ratio parameters. Simpson index calculated from
pyrosequencing results also showed that microbial diversity was higher in the reactors
with better performance. Proper mixing ratio of the digestate and OFMSW, 20 to 40%,
(%ww) probably provided the most favourable condition for bacteria and fungi activities.
Higher relative abundance of the two bacterial phyla, Thermoactinomycetaceae and
Actinomycetales, in the reactors with 20 to 40% digestate indicated a potential of high
efficient and rapid composting. In the fungal community, Galactomyces, Pichia,
Chaetomium, and Acremonium were the four genera probably involved in higher OM
degradation in the reactors with better performance.
In Chapter 5, co-composting of polished digestate and composted OFMSW was
studied as another option for further treatment of digestate. 8-day aerated digestate was
mixed with composted OFMSW in eight different mixing ratios; 0, 20, 30, 40, 50, 60, 80,
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or 100% (wet mass) as feedstock for the curing process. Curing process was monitored
during 100 days, with the same physicochemical analyses applied in the previous options.
The results demonstrated that the two main feedstocks could not take advantages of each
other and composting performance decreased when the digestate portion increased. This
could be due to loss of N during aeration of the digestate and/or inappropriate inoculation
time.
Overall, comparing all the investigated options demonstrated that co-composting of
the digestate and OFMSW with the mixing ratio of 20 to 40% was associated with higher
OM degradation, higher temperature generation, and shorter stability time. Therefore co-
composting of digestate with the OFMSW is suggested as a reliable and robust method
for further treatment of the digestate.

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PREFACE
The research completed in this dissertation was planned, designed, conducted,
analyzed, interpreted, and compiled by myself, under supervision of Dr. Daryl
McCartney in the Department of Civil and Environmental Engineering at the University
of Alberta.
A version of Chapter 2 of this thesis has been submitted as a case study research
article of G. Arab and D. McCartney entitled “Organic Waste Characterization at Large
Post-Secondary Institutions” in Waste and Biomass Vaporization jounal. I was
responsible for experimental measurements, data analysis, and manuscript composition.
Mr. Kentson Yan and Mr. Shahid Malik helped me with sample collection and
preparation. This work was supported by University of Alberta, Energy Management &
Sustainable Operations.
The pilot-scale composting setup referred to in Chapters 3, 4 and 5 were designed
and operated by myself. Composting reactors were repaired with the assistance of
Christine Heyregers. The environmental chamber was constructed by Curtis Faucher. The
high solids anaerobic digestion pilot scale was operated at Alberta Innovates-Technology
Futures (AI-TF).
A version of Chapter 3 of this thesis has been accepted as a research article of G.
Arab and D. McCartney entitled “Benefits to Decomposition Rates When Using
Digestate as Compost Feedstock: Part I - Focus on Physicochemical Parameters” in
Waste Management journal. I was responsible for the composter reactor operation,
experimental measurements, data collection, and data analysis for the manuscript
composition. This work was supported by the City of Edmonton and Mitacs-Accelerate
(ITO4535).
A version of Chapter 4 of this thesis has been submitted as a research article of G.
Arab, V. Razaviarani, Y. Liu, Z. Sheng, and D. McCartney entitled “Benefits to
Decomposition Rates When Using Digestate as Compost Feedstock: Part II - Focus on
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Microbial Community Dynamics” in Waste Management journal. I was responsible for
the composter reactor operation, data collection, and experimental measurements. DNA
extraction was conducted in Dr. Yang Liu’s microbiology lab with assistance of Dr.
Zhiya Sheng at the University of Alberta. Dr. Vahid Razaviarani assisted me with data
analysis. He also contributed in discussion section of the manuscript. This work was
supported by the City of Edmonton, Edmonton Waste Management Centre of Excellence
(EWMCE), and Mitacs-Accelerate (ITO4535).
A version of Chapter 5 of this thesis has been submitted as a research article of G.
Arab and D. McCartney entitled “Effects of digestate co-composting on curing phase of
composting” in Waste Management journal. I was responsible for the composter reactor
operation, data collection and analysis, and experimental measurements for the
manuscript composition. This work was supported by the City of Edmonton and Mitacs-
Accelerate (ITO4535).

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DEDICATION

I dedicate this dissertation to my beloved family, who are the world to me.

A special gratitude to my loving parents, Mina and Ali, for their invaluable
support and dedicated partnership for success throughout my life.

A very special thanks to my lovely brother, Kourosh, for his forever love, support,
and encouragement.

In spite of our long distance, you have been always with me in every step of this
way, through all the good and bad times. Thank you for all the unconditional love. This
journey would not have been possible without your support.

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ACKNOWLEDGEMENTS
First and foremost, I would like to sincerely appreciate my supervisor, Dr. Daryl
McCartney, for his generous guidance, continuous encouragement, and invaluable
support through my PhD studies. He has been a great supervisor and mentor.
I am sincerely thankful to Dr. Christian Felske for giving me the chance to run my
experiments according to the City of Edmonton full-scale facility and always helping me
with the technical aspects of the research. I also acknowledge my defense committee
members: Dr. Ian Buchanan, Dr. Yang Liu, Dr. Bipro R. Dhar, Dr. Samer Adeeb, Dr.
Christian Felske, and Dr. Grant Clark.
I highly appreciate the contribution of my co-author Dr. Vahid Razaviarani. Thank
you for being such a supportive friend and a great source of inspiration.
I deeply thank to Dr. Yang Liu and Dr. Zhiya Shang for providing the lab equipment
and helping with DNA extraction; Alberta Innovates - Technology Futures (AI-TF) for
supplying the digestate by running high solids anaerobic digestion (HSAD); and the
operations and laboratory staff at University of Alberta, and city of Edmonton, specially
Christine Hereygers, Perry Fedun, and Jennifer Chiang.
I would also like to express my gratitude to the Edmonton Waste Management Center of
Excellence (EWMCE). It was my pleasure to work at the Centre and get inspired by every
single employee there. A special thanks to Kristine Wichuk and Curtis Faucher for their
valuable assistance throughout the project, and more importantly for their friendship.
I would like to acknowledge the financial support received from University of Alberta
(Energy Management & Sustainable Operations), City of Edmonton, EWMCE, and
Mitacs-Accelerate (ITO4535).
Finally, a special thanks to my dearest family for their invaluable supports and sacrifices
throughout the course of this journey.
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Table of Contents

CHAPTER 1: BACKGROUND INFORMATION AND RESEARCH OBJECTIVES .... 1
1.1 Organic waste ........................................................................................................................ 1
1.2 ICI waste in Edmonton Capital Region ................................................................................ 2
1.3 Higher education institutional waste ..................................................................................... 3
1.4 Organic waste treatment technologies .................................................................................. 7
1.4.1 Anaerobic digestion ....................................................................................................... 7
1.4.2 Composting .................................................................................................................... 9
1.5 Problem statement and research objectives ......................................................................... 18
1.6 Thesis outline ...................................................................................................................... 21
1.7 References ........................................................................................................................... 23
CHAPTER 2: ORGANIC WASTE CHARACTERIZATION AT LARGE POST-
SECONDARY INSTITUTIONS ...................................................................................... 29
2.1 Introduction ......................................................................................................................... 29
2.1.1 Background .................................................................................................................. 29
2.1.2 Study location .............................................................................................................. 33
2.2 Materials and Methods ........................................................................................................ 33
2.2.1 Sample collection and processing ................................................................................ 33
2.2.2 Samples characterizations ............................................................................................ 40
2.2.3 Weighted-Average Calculation Method ...................................................................... 41
2.3 Results and discussion ........................................................................................................ 43
2.3.1 Physical and chemical properties ................................................................................. 43
2.3.2 Biological property ...................................................................................................... 45
2.3.3 Sampling methodology discussion .............................................................................. 46
2.4 Summary and conclusions................................................................................................... 47
2.5 References ........................................................................................................................... 49
CHAPTER 3: BENEFITS TO DECOMPOSITION RATES WHEN USING
DIGESTATE AS COMPOST FEEDSTOCK: PART I - FOCUS ON
PHYSICOCHEMICAL PARAMETERS ......................................................................... 52
3.1 Introduction ......................................................................................................................... 52
3.2 Materials and methods ........................................................................................................ 54
3.2.1 Anaerobic digestion equipment ................................................................................... 54
3.2.2 Anaerobic digestion feedstock ..................................................................................... 55
3.2.3 Composting equipment & operation ............................................................................ 56
3.2.4 Composting feedstock ................................................................................................. 58
3.2.5 Analytical methods ...................................................................................................... 60
3.3 Results and discussion ........................................................................................................ 62
3.3.1 Typical performance parameters ................................................................................. 63
3.3.2 Initial C/N ratio ............................................................................................................ 65
3.3.3 Total biodegradable carbon (C ) ................................................................................ 66
bio
3.3.4 Mineral forms of N (ammonia-N and nitrate-N) and their ratio .................................. 66
3.3.5 pH and EC.................................................................................................................... 68
3.3.6 Solvita® ....................................................................................................................... 70
3.3.7 A summary of key observations based on the monitored parameters.......................... 71
3.3.8 Possible benefits of OFMSW on digestate composting ............................................... 74
3.4 Conclusions ......................................................................................................................... 75
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3.5 References ........................................................................................................................... 76
CHAPTER 4: BENEFITS TO DECOMPOSITION RATES WHEN USING
DIGESTATE AS COMPOST FEEDSTOCK: PART II - FOCUS ON MICROBIAL
COMMUNITY DYNAMICS .......................................................................................... 79
4.1 Introduction ......................................................................................................................... 79
4.2 Methodology ....................................................................................................................... 81
4.2.1 Material used, equipment and operation ...................................................................... 81
4.2.2 Microbial community analysis ..................................................................................... 83
4.2.3 Statistical Analysis ....................................................................................................... 85
4.3 Results and discussion ........................................................................................................ 85
4.3.1 Reactors’ performance ................................................................................................. 85
4.3.2 Microbial community profile and dynamics ................................................................ 85
4.3.3 Correlation between bacterial-fungal communities and environmental variables ....... 97
4.4 Conclusions ....................................................................................................................... 102
4.5 References ......................................................................................................................... 104
CHAPTER 5: EFFECTS OF DIGESTATE CO-COMPOSTING ON CURING PHASE
OF COMPOSTING ....................................................................................................... 108
5.1 Introduction ....................................................................................................................... 108
5.2 Materials and methods ...................................................................................................... 110
5.2.1 Equipment and operation ........................................................................................... 110
5.2.2 Feedstock ................................................................................................................... 111
5.2.3 Analytical methods .................................................................................................... 114
5.3 Results and discussion ...................................................................................................... 116
5.3.1 Process performance parameters (temperature, RHG, ROR, and SOUR) ................. 116
5.3.2 Inorganic nitrogen (NH -N and NO -N) .................................................................... 119
4 3
5.3.3 pH and EC.................................................................................................................. 121
5.3.4 Solvita® maturity index ............................................................................................. 122
5.3.5 Total biodegradable carbon (C ) .............................................................................. 123
bio
5.3.6 Correlations among the process and maturity indices ............................................... 124
5.4 Conclusions and recommendation .................................................................................... 126
5.5 References ......................................................................................................................... 128
CHAPTER 6: GENERAL CONCLUSIONS AND RECOMMENDATIONS .............. 130
6.1 Thesis overview ................................................................................................................ 130
6.2 Conclusions ....................................................................................................................... 131
6.3 Future research and Recommendations............................................................................. 133
BIBLIOGRAPHY ........................................................................................................... 135
APPENDIX A: Photographic records ............................................................................. 146
APPENDIX B: Chapter 2 Supplementary Data.............................................................. 149
APPENDIX C: Chapter 3 Supplementary Data.............................................................. 167
APPENDIX D: Chapter 4 Supplementary Data ............................................................. 217
APPENDIX E: Chapter 5 Supplementary Data .............................................................. 236

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