The 9th International Symposium
on Water Environment Systems---with Perspective of Global Safety(November 25th – 26th, 2021)

Department of Civil and Environmental Engineering
Graduate School of Engineering
Tohoku University

Sponsors
International Joint Graduate Program in
Resilience and Safety Studies of Tohoku University
http://gp-rss.tohoku.ac.jp/

WISE Program for Sustainability in the Dynamic
Earth of Tohoku University
https://syde.tohoku.ac.jp/
Department of Civil and Environmental
Engineering, Graduate School of Engineering,Tohoku University
http://www.eng.tohoku.ac.jp/

ORGANIZERSDr. So KAZAMA(Professor, Tohoku University)

Dr. Yu-You LI(Professor, Tohoku University)

Dr. Daisuke SANO(Professor, Tohoku University)

Dr. Daisuke KOMORI(Associate Professor, Tohoku University)

Dr. Kengo KUBOTA(Associate Professor, Tohoku University)

SECRETARIATS
Assistant Professor, Dr. Yoshiya TOUGE
yoshiya.touge.a6@tohoku.ac.jp
Assistant Professor, Dr. Yu QIN
yu.qin.e8@tohoku.ac.jp

PARTICIPANTS
Tohoku university
Name
Shuka KAGEMASA
Luhur Akbar DEVIANTO
Tianjie WANG
Gaoxuefeng FENG
Chen WANG
Zibin LUO
Kampachiro URASAKI
Junhao SHEN
Shitong ZHOUKe Shi
Vempi Satriya
Mohammad Naser Sediqi
Amalia Nafisah Rahmani Irawan
Huang Qin
Hayata Yanagihara
The Hong Kong Polytechnic University
Name
Hongxing YANG

Japan
Identity
Student
Student
Student
Student
Student
Student
Student
Student
Student
Student
Student
Student
Student
Student
Student
China
Identity
Professor

Westlake University
Name
Feng JU

Identity
Professor

University of Nottingham
Name
Chris Gibbins
Matthew Johnson
Faith Chan
Thomas Stanton

UK, China, Malaysia
Identity
Professor
Associate Professor
Associate Professor
Lecturer

Kasetsart University
Name
Prem RangsiwanichpongXi'an University of Architecture and Technology
Name
Yu LI
Ziwen JIA

China

Thailand
Identity
Lecturer
China
Identity
Student
Student

China Agricultural University
Name
Mengmeng JIANG
Zhiyue WU
Shanghai University
Name
Jinghuan LUO
Bohan YU

China
Identity
Student
Student
China
Identity
Postdoctoral Researcher
Student

Schedule (GMT+9)
25 Nov (Thu)
10:00 ~ 12:00 Online Fieldwork
Topic: AnMBR&Anammox pilot‐scale plant

26 Nov (Fri)9:00 ~

9:05 Opening speech

9:05 ~

9:10 Group photo

Session I Oral session I
9:10 ~

9:40 The Power of Biology in River Environments
Matthew Johnson, University of Nottingham

9:40 ~ 10:10 Sustainable urban water management strategies in Chinese cities –the Sponge City Program (SCP): the case of Ningbo
Faith Chan, University of Nottingham
10:10 ~ 10:40 Linking Remote Sensing Data and Soil‐Bioengineering Technique for
Erosion Control in Sop Moei district, Thailand
Prem Rangsiwanichpong, Kasetsart University
10:40 ~ 10:50 Coffee break
10:50 ~ 11:10 Defining Global Fire Patterns and Quantifying Climate Influence on
Ke Shi, Tohoku University
11:10 ~ 11:30 The spatial and temporal response of wet crops to agricultural drought: A casestudy in Indonesia
Amalia Nafisah Rahmani Irawan, Tohoku University
11:30 ~ 11:50 Evaluation of historical and future simulations of precipitation andtemperature in Afghanistan from CMIP6 climate models
Mohammad Naser Sediqi, Tohoku University
11:50 ~ 13:00 Lunch break
13:00 ~ 14:30 Poster session
Poster exhibition (Room A)・ Global‐scale analysis of crop response pattern to different droughttimescales
Vempi Satriya, Tohoku University

・ Evaluate the dynamic change of burn‐ability by observing the fuelmoisture content in Japan
Huang Qin, Tohoku University

・ Changes in exposed population to heavy rainfall disasters associatedwith population decline in Japan
Hayata Yanagihara, Tohoku University

P1

Poster exhibition (Room B)

・ Assessment of long‐term operation performance in mesophilicanaerobic co‐digestion of Lipid and Food Waste
Chen WANG, Tohoku University

・ Influence of ammonia concentration on the treatment performance ofpilot‐scale one‐stage PN/Anammox process
Zibin LUO, Tohoku University

・ Development of a BrISH for environmental microorganisms
Kampachiro URASAKI, Tohoku University

・ Methane fermentation performance of pig manure treatment by apilot‐scale self‐agitated anaerobic baffled reactor
Junhao SHEN, Tohoku University

・ Enhancement Effect of Two Novel Pretreatment Methods on
Anaerobic Digestion of Waste Activated Sludge with Thermophilic
Shitong ZHOU, Tohoku University

Session II Plenary lectures
14:30 ~ 15:00 Applications of Solar Photovoltaics and Offshore Wind Power towards
Carbon Neutrality in Coastline Cities
Hongxing YANG, The Hong Kong Polytechnic University
15:00 ~ 15:30 Exploring Microbiome Assembly and Antibiotic Resistome in
Wastewater Treatment Plants
Feng JU, Westlake University

Session III Oral session II
15:30 ~ 15:45 Diversity and genomic information of Patescibacteria in activatedShuka KAGEMASA, Tohoku University
15:45 ~ 16:00 Sewage concentration for detecting public health biomarkers in
Luhur Akbar DEVIANTO, Tohoku University
16:00 ~ 16:15 Influence of temperature on treatment performance of municipal
wastewater by a pilot‐scale Anaerobic Membrane Bioreactor (AnMBR)
Tianjie WANG, Tohoku University
16:15 ~ 16:30 AnMBR treating swine waste : from lab‐scale to pilot‐scale
Yu LI, Xi'an University of Architecture and Technology
16:30 ~ 16:45 Mitigation of membrane fouling in a thermophilic hybrid AnMBR
treating food waste
Mengmeng JIANG, China Agricultural University
16:45 ~ 17:00 Elucidating fouling charactization in a high solid anaerobic membranebioreactor treating OFMSW leachate
Zhiyue WU, China Agricultural University
17:00 ~ 17:15 Effective enrichment of anammox granules for high‐loading landfill
leachate treatment: Research progress
Jinghuan LUO, Shanghai UniversityP2

17:15 ~ 17:30 Biochar enhances partial denitrification/anammox by sustaining highrates of nitrate to nitrite reduction
Ziwen JIA, Xi'an University of Architecture and Technology
17:30 ~ 17:45 Enhancing phosphorus recovery from sewage sludge using anaerobic‐
based processes: Current status and perspectives
Bohan YU, Shanghai University
17:45 ~ 18:00 Mainstream Nitrogen Removal by a Partial nitritation‐anammox
Reactor with HAP Syntrophic Granules after an AnMBR
Gaoxuefeng FENG, Tohoku University
18:00 ~ 18:10 Closing speech

P3

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GP‐RSS & SyDe

(Nov. 25th ~ 26th , 2021)

Tohoku University‐‐‐‐‐ with Perspective of Global Safety

The Power of Biology in River Environments○ Matthew JOHNSON1*
1

School of Geography, University of Nottingham, NG7 2RD, UK.
*
E-mail: M.Johnson@nottingham.ac.uk

Abstract
Our knowledge of river processes is dominated by engineering and physics approaches focused on the hydraulicpower of water and its ability to move the mineral sediment that constitutes river beds and banks. This excludes
the role of living organisms, many of which burrow into river beds and banks, redistribute sediments whenmoving and foraging, or stabilize sediments through roots, mucous or silk. Here, experimental and field data areused to compare the energy in the biological community to the hydraulic energy to compare potential sources ofpower for geomorphological work. Experiments also show that Signal Crayfish, an invasive species, movesediment whilst expending much lower energy than would be expected by the hydraulic flow required to moveequivalent grains. The paper discusses the implications of these findings to fluvial geomorphology and channel
form.
Keywords: 1. Ecosystem engineering, 2. Biogeomorphology, 3. Signal Crayfish, 4. Stream Power, 5.
Channel dynamics.
leniusculus) were investigated in mesocosm and field
experiments. Signal Crayfish are an invasive species, native
to the west coast of the USA, and invasive through northern
Europe and Japan. They burrow extensively into river-beds
and banks, causing bank collapse and damage toinfrastructure including flood defenses. Past experiments
have shown these animals can double bedload transport
rates of gravels due to their redistribution of sediment grains
across sediment surfaces [1] and field work has found they
can increased fine sediment transport in rivers by 30% dueto their burrowing activity [2].

1 Introduction
Organisms living in rivers have adapted to survive, utilize
and modify fluvial environment. There are numerous
examples of living organisms altering river channels;
however, that knowledge is not well integrated into
geomorphological systems.
Sediment transport and channel change is typically related
to the hydraulic power of water i.e. the stream power. It is
proposed here that stream power is supplemented orretarded by biological power associated with, for example,
burrowing animals and stabilization by plant roots,
respectively. Framing the interaction of organisms and theenvironment as an energy transfer may be an informative
way of integrating ecological processes into moreestablished knowledge frameworks and assessing therelative significance of animals in comparison to purely
physical processes.

2 Materials and methods
The potential relative significance of animals in controlling
river processes was investigated at two scales. First, thestream power per unit width along three rivers wasmodelled using existing topographic, discharge and site
survey data. In these rivers, there were also repeatedspecies-level macroinvertebrate samples. Information on thecalorific content of the collected species was collated fromthe literature, which was used to represent the theoreticalmaximal energy available for modifying environments. A
comparison could then be made between the maximal
biological power and the maximal hydraulic power,
seasonally, at sites along rivers

Fig. 1. A Signal Crayfish on the experimental sediment.
Here, Signal Crayfish were held in sealed aquaria and theirenergy expenditure was estimated as a function of their
respiration rate. As a validation, videography of grain
movements was used to estimate energy expenditureassociated with sediment reworking by multiplying theenergy required to move a single grain by the estimateddistance the grain was moved. By using an experimental

Second, a higher resolution study was performed toinvestigate a specific example of a bio-geomorphic energy
exchange. To further investigate the role of animals in
sediment transport, Signal Crayfish (Pacifastacus

1The 9th International Symposium on Water Environment Systems

GP‐RSS & SyDe

(Nov. 25th ~ 26th , 2021)

Tohoku University‐‐‐‐‐ with Perspective of Global Safety
substrate where all grains were of identical weight and size,
calculations could accurately estimate the energy required tomodify sediment positions (Figure 1).

potential to do significant geomorphological work, and thatusing metrics of energy expenditure and power may offer auseful framework for better integrating biological processes
into river science.
.

3 Results and discussion

References

The unit power (Watts/m2) associated with invertebrates atthe sampling sites was consistently an order of magnitude
higher than the stream power associated with Q10 flows.
Only a small proportion of the biological energy associatedwith the invertebrate community would be used for
sediment alterations; however, the same is also true of theunit stream power. Therefore, this result indicates thepotential significance of invertebrate animals as a source ofpower for geomorphological work.

[1] Johnson, M.F., Rice, S.P. and Reid, I. (2011) Increasein coarse sediment transport associated with disturbance ofgravel river beds by signal crayfish (Pacifastacus
leniusulus). Earth Surface Processes and Landforms 36:
1680-1692.
[2] .Rice, S.P., Johnson M.F., Mathers, K., Reeds, J., andExtence, C. (2016) The importance of biological biotic
entrainment for base flow fluvial sediment transport.
Journal of Geophysical Research: Earth Surface 121:
890-896.

Fig. 2. The unit power associated with the invertebrate
community in spring and autumn, and the equivalentstream power for the Q10, Q50 and Q95, representing
the largest, median and lowest flows, respectively.
Oxygen measurements indicated that crayfish expended
approximately 6 Joules per hour (i.e. 0.0017 Watts/m2),
confirmed by videography that found crayfish moved 300
grains an average of 6 grain diameters, indicating a powerof 0.0015 Watts/m2. Extrapolating to crayfish populations
recorded in the River Nene, UK, crayfish would expend
0.08 W m Watts/m2 per night, which is much lower than therecorded stream power associated with the Q10 flow (37 W
m Watts/m2). However, crayfish were found to movesediments up to 40 mm in diameter, which according tostandard size-power relationships would require flows of 30
W m Watts/m2 to mobilise. Therefore, crayfish are more
efficient than the flow in moving sediments, requiring
smaller powers to have the same geomorphological impact.

4 Conclusions
Biological power is much more efficient at moving
sediment than stream power, complicating directcomparisons between biological and physical processes.
However, it is clear that the biological power associatedwith invertebrate animals in rivers is substantial with the2The 9th International Symposium on Water Environment Systems‐‐‐‐‐ with Perspective of Global Safety (Nov. 25th ~ 26th, 2021)

GP‐RSS & SyDe
Tohoku University

Sustainable urban water management strategies in Chinese cities – theSponge City Program (SCP): the case of Ningbo○ Faith Ka Shun CHAN1,2*, Lei LI1 & Miran LU3
1School of Geographical Sciences, University of Nottingham Ningbo China, Ningbo 315100, China.

2

Water@Leeds Research Institute, University of Leeds, Leeds LS29JT, United Kingdom.

3

Faculty of Science Department of Statistics and Applied Probability, National University of Singapore, Blk

S16, Level 7, 6 Science Drive 2 Singapore 117546, Singapore.
*E-mail: faith.chan@nottingham.edu.cn

Abstract‘Sponge City’ is the term used to describe the Chinese government’s approach to urban surface water management.
The concept was conceived in 2014 in response to an increasing incidence of urban surface flooding in many
Chinese cities. While ambitious and far-reaching in its aim (of reducing national flood risk, increasing water supply
and improving water quality), the initiative must be implemented by individual sub-provincial or municipal-levelgovernment entities. Thus, while the concept is similar to Blue-Green Cities (BGCs). Indeed, the increasing use ofnational rather than international examples of best practice reflects a growing body of knowledge that has evolved
since the start of the Sponge City initiative. In this session, we will discuss about the interpretation and developmentof the latest SCP guidelines by using the case of Ningbo, Zhejiang Province. In this study, we principally looking
at the public perception and participation, and found that the influence on social media and communication channels
between the according authorities have been initiated on the SCP development from the case of Ningbo. The
communities have ways to express their opinions towards the SCP practice and operations for the improvements
and adjustments. These findings will help to improve the current 3rd stage development of the Program until 2030s
and beyond.
Keywords: Sponge City 1; Urban surface water flooding 2; Blue-Green Infrastructure 3; Climate Change 4;
Public Participation 5.
Wuhan in 2020 and 2016, Ningbo in 2021 and 2013,
Shenzhen in 2014 and 2013, and Beijing in 2012 (Griffiths etal., 2020, Xiao, 2021). These events caused causalities,
injuries and huge economic impacts alarmed the Central
National Government (CNG) to take according actions on
urban flood relief.
The Sponge City Program (SCP) was initiated in 2013 andaimed to alleviate urban water floods, which reduce urban
runoff discharge, infiltrate and storing urban stormwater by
Blue-Green Infrastructure (BGI) to achieve 1-in-30 years
protection level (Chan et al., 2018). Likewise, the SCP(selected 30 pilot cities across China) to restore naturalhydrological function by improving soil infiltration,
stormwater retention, storage, purification, but also retrofit toupgrade traditional engineering drainage systems via hybrid(green-grey) measures (e.g. artificial wetlands, ponds, green-

1 Introduction
China has experienced rapid social-economic developmentin the recent decades. Substantial landuse changes andurbanisation enhanced several urban water issues, such asurban floods and water pollution (Xia et al., 2017). The
natural hydrological cycle has been interrupted by removing
green spaces (e.g. farmland, suburb land, wetland, etc.),
which deficient 40-50% of stormwater intake in naturalenvironment. Urban runoff coefficient has been significantly
increased due to soil sealing and urban transformation with
infrastructures (Yin et al., 2017). However, the existing landdrainage system only withstand at 1-in-1 to 1-in-5 years
return period. Unfortunately, Chinese cities suffer severe
urban (surface water) floods because of insufficient drainage
capacity. For example, Zhengzhou flood in July 2021,

3

The 9th International Symposium on Water Environment Systems

Tohoku University‐‐‐‐‐ with Perspective of Global Safety (Nov. 25th ~ 26th, 2021)
roofs, bio-swales, rain gardens, etc.) and achieving multiple
benefits on improving the urban ecosystem services (Xie etal., 2020).
Ningbo is selected as one of the pilot cities in 2015 andundertaking several SCP infrastructure sites (e.g. Ecocorridor and Cicheng Park, etc.) (Fig.1). The city isfrequently suffered with typhoon-enhanced storm surges andintensive rainstorms, over 80% of annual precipitation forabout 1700-2200mm from May to September (Tang et al.,2015). The city was inundated severely in Typhoon Fitow
during 2013, the municipal government integrated with thestrategic scheme, namely “Five Water Management” Plan,
which includes (i) sewage discharge treatment; (ii) flood
control; (iii) waterlogging discharge; (iv) freshwater supplyand (v) water conservation that is supported by the Zhejiang
Provincial and Ningbo municipal governments. These
practices co-produce with the SCP and targeting to deliver
better urban water management and sustainability goals forthe communities. These practices and policies have been
established for several years and yet to know the conditions
on public perceptions, understanding and awareness, but also
the participation. The authorities have spent efforts on
improving the communication channels (e.g. some popularsocial media platform in China).
This study aims to investigate current SCP and Five Water
Management Plan in the case of Ningbo. We provide
justification from our interviews and questionnaires andtriangulate and validate current practices in Ningbo.

GP‐RSS & SyDe

questionnaires. All survey data were statistically analysedusing Excel and R software.
Whilst, the interviews were helpful to understand more indepth perspectives from the communities of the SCP and Five
Water Management practices in Ningbo. The interviewees
were selected randomly and each interview were about 10
minutes each conducted during November 2019 that aims toarticulate the perception from the communities from the 2017
survey data set. The data was transcribed and translated. The
analyses based on the ground theory, and the researchers
undertook manual coding that match with the key research
themes in this study. All data from the questionnaire survey
and interviews have been undertaken the approved ethics
application. All interviewees have been informed and agreed
with the consent. All information to be deleted after the
project completion.
Table 1 Interviewees’ information
Participant ID(Interviewees)

Age, gender andoccupationA

Elderly (F), 60,
retiredFlowersalesperson in South
Business District, 35
Elderly (F), 55,
retiredHousewife (F), 40
Primaryschoolteacher (M), 30
Student (F), 20 inSouthBusiness
District
Waitress (F), 35 in
Nantang Old Street
Elderly (M), 60,
retiredBusinessman (M),55, at reside aroundthe Tianyi Square
Student (M) 20,
reside around the
Tianyi Square

B
C
D
E
F
G
H
I
J

Interviewees’
homelocation (within 3km
radius at the relevant SCP
sites)NET Eco-corridor
Yinzhou Park
Sanjiangkou Park
Cicheng Park
Cicheng Park
Yinzhou Park
Nantang
Old
Sanjiangkou Park
Nantang
Old
Sanjiangkou Park
Nantang
Old
Sanjiangkou Park
Nantang
Old
Sanjiangkou Park

Street,Street,Street,Street,3 Results and discussion
Fig. 1. SCP site locations in Ningbo as interviews and questionnaire sites for thisIn this questionnaire, we have conducted some other issues
such as general information, perception on Fiver Water
Management Plan, SCP, sustainability issues and future
foresights about these programs.
In this section, we mostly focused on illustrating the resultsthat responding our major research questions that conductedfive specific questions in the questionnaire set on theperception issue (see Fig.2) and listed here:

study (Locations A: New East Town; B: Ci Cheng Park; C: Sanjiangkou Park; D:
Yinzhou Park; E: Nan Tang Old Street) (Source: authors).

2 Materials and methods
In this study, we adopted the questionnaire survey and semistructured interviews all conducted by face-to-face in the
public space (e.g. surrounding the SCP parks, coffee shops,
café, etc.). The survey sites for questionnaires were selectedfrom the SCP projects location in Ningbo (see Fig.1) as forinvestigating the communities who are living in that area orcommonly using these SCP facilities (e.g. Sponge urban
parks, sponge healthy running tracks, Sponge artificial ponds
and wetlands.). The survey was conducted from June toAugust 2017. Due to the limited labour resources andweather conditions, this study managed to conduct 110“11. Ningbo has done a lot of works on urban riverrestoration under the 5-water management plan, are you
familiar of this policy/what are the 5-water management
about?
a.
Not at all, b. little, c. modest, d. fully understood
12.
Do you think it is useful to promote urban riverrestoration in Ningbo?
a.
Not at all, b. a little, c. modest, d. very useful4The 9th International Symposium on Water Environment Systems

GP‐RSS & SyDe
Tohoku University‐‐‐‐‐ with Perspective of Global Safety (Nov. 25th ~ 26th, 2021)
13.
Do you think there are any connections between
Five Water Management Plan with sponge city projects?
a.
Not at all, b. a little, c. modest, d. a lot of
connections
14.
Do you think more areas in Ningbo other than East
town (Jiangdong) and North district (Jiangbei) need to beundertaken sponge city and urban river restoration projects?
a.
No, b. Yes
15.
Do you think current awareness and participation
are enough to public for these projects?
a.
Not at all, b. a little, c. modest, d. enough”

100%
80%
60%

2
6
16

32

35

10
49

20

0%
11

We have found the results (see Fig.2) demonstrated thecommunities were not too familiar about the urban riverrestoration under Five Water Management Plan and urbanriver restoration (Q11) as 33.64% participants responded
unfamiliar and another 44.55% respondent expressed withlittle understanding on the Five Water Management Plan.
In fact, we found that the communities also have rather
conservative viewpoints on the usefulness of promoting
urban river restoration in Ningbo (Q12) as only at about 9%
participants expressed that promoting urban river restorationin Ningbo was very useful, but majority were expressed not
useful or only little useful. Interestingly, we also found thatmajority of participants found no connection (3.64%) or onlywith little connection (about 27%) between Five Water
Management Plan with SCP in Ningbo (Q13).
Participants believed it was not too useful to promote theurban river restoration and expressed only a little connection
between Five Water Management Plan, urban riverrestoration and SCP as according to the analysis of theconnection among these practices (Q12 and Q13), whichreflected the public perception to the functions and benefits
in urban ecology, water management and urban flood risk
management and climate change adaption with these threemain strategies from the data set in 2017 were yet understood
the Science and technical aspects well.
That findings were implied by Q14 and Q15, which
majority of community residents expressed that the SCP andurban river restoration should still be promoted andcontinuously expanded Five Water Management should still
be undertaken (over 65%), but majority of participants
admitted that their own awareness and participation were notenough (with about total 58% expressed not at all or a little
awareness and participation) for these practices. That
reflected the awareness and participation issues might
influence the perceptions on the urban water management
issues in Ningbo (include Five Water Management and SCP)
from the 2017 questionnaire data set.

0

1
10
29

21
37

35

26

40%
20%

36

39

30

3
12

4
13

A

B

C

71
35
3
14
D

15

N

Figure 2 Public perception on urban river restoration, Sponge City Program andFive Water Management (note perception on these questions refer as above: Blue:
Not at all (for Q11-13, 15)/Yes (Q14), Orange: a little (for Q11-13, 15)/No (Q14),
Grey: Modest (Q11-13, 15), Yellow: fully understood (Q11)/very useful (Q12)/lotsof connection (Q13)/enough (Q15), Green: Answer not valid/incomplete/not
answered.

For such findings on public perceptions, we justified withthe 2019 interview data with the local community and foundthat there were some evident afterwards. For some reasons,such as lacking of education and promotion, especially toelderlies, an elderly interviewee living around the Yinzhou
Park responded (interviewee A): “…I have not heard too
much on these programs, because I am getting old at this age,
do not pay attention…” Another elderly interviewee(interviewee H) also responded: “…read and understood it(these programs/strategies) via the newspaper but can't
remember it clearly, found these are helpful policies”.
Moreover, we interviewed some interviewees who
understood these schemes via social media channels, such as
via the mobile apps that the elderlies might found theirdifficulties to adapt the implications from technology. Two
students ex-pressed (interviewee F, resided at South Business
district close to Yinzhou Park) “Heard it in the car radio andreceived relevant publicity via SMS.”; another student(interviewee J, living around the Tianyi Square close to
Sanjiangkou Park) expressed that “…Saw (these programs)
on app news…”
For the work professional age that a flower-seller operated
the shops at a shopping mall around the Yinzhou Park
(interviewee B) expressed that: “…saw related information
on mobile phone text messages…”; another interviewee
working as a primary school teacher (interviewee E, Ci
Cheng Park) expressed he understood about these urban
water management strategies via television channels“…understanding (these programs) from TV news, three outof five water management are remembered: sewage,
drainage water and flood.”
From these justifications in the 2019 interviews, we canunderstand that the Municipal Government has actually used
and adopted multiple channels on these urban water
management strategies by TV, newspaper and lately via
mobile apps, internet sources for enhancing promotion andimprovement on public awareness and participation. We
recommend the government may engage with thecommunities in several age groups for gathering them for

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The 9th International Symposium on Water Environment Systems‐‐‐‐‐ with Perspective of Global Safety (Nov. 25th ~ 26th, 2021)
some local education activities or community engagement
activities to enhance further public participation.

4 Conclusions
Ningbo Municipal Government has spent tremendous
efforts on improving urban water issues by implementing
SCP, Five Water Management and undertaking the largescale urban river restoration schemes during the last few
years. Despite more time is needed to see the performanceand effects based on the regular monitoring and review. The
optimistic effects at this early stage is reflected in the supportof these schemes in 2017 from the communities and public.
These showed the current challenges of reflecting the latest
situation and phenomenon of these schemes as the data has
been finalised after only a few years of implementation.
Public perception can be improved by using several
channels and adopt “fit-for-purpose” approach such as
looking after different age groups’ understanding andlearning of these strategies (i.e. elderly and other age groups).
These lessons will be vitally important to improve urban
water management strategies holistically providing good
lessons for other Chinese cities that faced potential water
risks from climate change and rapid urbanisation factors.

Reference
CHAN, F. K. S., GRIFFITHS, J. A., HIGGITT, D., XU, S., ZHU, F.,
TANG, Y. T. & THORNE, C. R. 2018. “Sponge City” in
China—A breakthrough of planning and flood risk
management in the urban context. Land Use Policy, 76, 772.
GRIFFITHS, J., CHAN, F. K. S., SHAO, M., ZHU, F. & HIGGITT, D.
L. 2020. Interpretation and application of Sponge City
guidelines in China. Philos Trans A Math Phys Eng Sci, 378,
20190222.
TANG, Y.-T., CHAN, F. K. S. & GRIFFITHS, J. 2015. City profile:
Ningbo. Cities, 42, Part A, 97-108.
XIA, J., ZHANG, Y., XIONG, L., HE, S., WANG, L. & YU, Z. J. S. C.
E. S. 2017. Science China Earth Sciences, 60, 652.
XIAO, E. 2021. Death Toll From China Flood Jumps to More Than 300.
Wall Street Journal - Online Edition, N.PAG-N.PAG.
XIE, X., QIN, S., GOU, Z. & YI, M. 2020. Engaging professionals inurban stormwater management: the case of China’s Sponge
City. Building Research & Information, 48, 719-730.
YIN, H.-L., ZHAO, Z.-C., WANG, R., XU, Z.-X. & LI, H.-Z. 2017.
Determination of urban runoff coefficient using time series
inverse modeling. Journal of Hydrodynamics, 29, 898-901.

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Linking Remote Sensing Data and Soil-Bioengineering Technique for
Erosion Control in Sop Moei district, Thailand○ Prem Rangsiwanichpong1*, Chatchai Ngernsaengsaruay2, Nisa Leksungnoen3,
and Apiniti Jotisankasa4
1

Department of Water Resources Engineering, Faculty of Engineering,
Kasetsart University, Bangkok 19000, Thailand.
2Department of Botany, Faculty of Science, Kasetsart University, Bangkok 19000, Thailand.
3
Department of Forest Biology, Faculty of Forestry, Kasetsart University, Bangkok 19000, Thailand.
4
Department of Civil Engineering, Faculty of Engineering, Kasetsart University, Bangkok 19000, Thailand.
Correspondence to: Prem Rangsiwanichpong (Prem.R@ku.th)

Abstract
There is a potential for landslide hazards in the Sop Moei area, southernmost district of Mae Hong Son province,
Thailand. Landside happen by the combination factors such as earthquake, monsoon, and human activities. Water
erosion is the one of main factors that leading to soil detachment and landslide event in high slope area. Therefore,
the objective of this research is to estimation annual soil loss and generate a soil erosion potential map using GIS
technique based on the Revised Universal Soil Loss Equation (RUSLE). The results shown that the high potentialof soil erosion areas have also higher risk of landslide event. It involves identification of soil erosion hazard areas
and rising community awareness of soil erosion risk, study of plants with potentials for bio-slope stabilization, inorder better prepare the community for prevention and mitigation of soil erosion hazard in high slope areas ofThailand.
Keywords: GIS; Hazard map; RUSLE; Soil Bio-Engineering; Thailand.
forest (Fig.1.). The area of forest is approximately 87.5% of
the provincial area. There are mountains along the northsouth parallel. (Fig. 2.)

1 Introduction
Soil Erosion is the first step in the sedimentation routes
which consist of erosion, transportation and deposition of
sediment [1]. Soil losses from water erosion, and the host of
linked problems associated with occurred landslide events inhigh slope areas, are currently major environmental issues inThailand. Therefore, the method for estimating soil erosion
is an important for erosion control. In this century, numerical,
empirical, and field experiments have been developed forassessing soil erosion. The RUSLE is widely used for
estimating annual soil erosion rates. Several publications
have used RUSLE method to estimate soil erosion rates forlong term ([2], [3]). Currently, the erosion control using
herbaceous and woody plants through soil bio-engineering
remains a new challenge. Soil Bio-Engineering is the use ofplants with engineering technique for control of landslide anderosion. Generally, plant life tend to be stronger and morestable with time as roots penetrate deeper, which engineering
structure only deteriorates with time. Nevertheless, soilbioengineering technique can be prevent only shallow
landslide and surface erosion with depth of failure less than
3 meters [4].
This research aims to generate soil erosion hazard map by
remote sensing data and using soil bio-engineering techniquefor erosion control in Sop Moei area. Moreover, this researchalso study plants which are of potential for preventing soil
erosion and landslide in high land area with community
participation.

Fig. 1. Topography of Sop Moei district.

2 Study Area
Sop Moei district is located on the south end of Mae Hong
Son province. This area is 192 km. far from Mae Hong Son
Mueang district (downtown). Topography, Most of Sop Moei
area is a high mountain complex and still a richness naturalFig. 2. Land use of Sop Moei district.

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The results indicate that the potential of average annual soil
erosion rate in Sop Moei project is 86 tons/year. Furthermore,
the erosion rate were correlated with topography and slope,with higher erosion rate associated with mountainous andhigher slope areas. In addition, the results shown thatdifferent magnitudes of soil erosion occurring in every partof the studied areas but also significantly higher magnitudes
occur in agriculture area without soil & water conservation
practice, especially upland rice and maize (Fig.4.). Moreover,this research also compares the soil erosion hazard map withoccurrence of landslides by the location of landslide areasfrom field survey data (Fig.9.). We found that the high

3 Methodology and Data
This research aimed to generate the soil erosion hazard map
by remote sensing data and Geographic Information System(GIS) technique. The RUSLE method was used to analyze
magnitude of soil erosion in each grid cell with 30 m.
resolution. The RUSLE method is an empirical soil loss
model [5] which can be expressed as:
𝐴 = 𝑅 × 𝐾 × 𝐿𝑆 × 𝐶 × 𝑃(1)

where:A is the mean annual soil loss per unit area, R is the rainfall
erosivity factor, K is the soil erodibility factor, LS is the
topographic factor, C is the cover-management factor, and P
is the conservation practice factor.
In this research, we used 20 rain gauge stations operated by
the Highland Research and Development Institute (HRDI) to
observe daily rainfall data during 2010 to 2020 (10 Years).
The annual rainfall in Sop Moei is 1100 mm. per year. For
extreme daily rainfall, we found that the extreme daily
rainfall for Sop Moei ranges from 59 to 76 mm. with higher
values occurring in the southern part of the district (Fig.3.).
Moreover, Geologic map data obtained from the Land
Development Department of Thailand (LDD).

potential of soil erosion have also greater risk of landslide
occurrence. According to the highland community, the main
reasons of such gully formations are agricultural activities,
heavy rainfall, and lack of immediate treatment while gullies
start to form. Fig.5. shows some of the gullies formed andsoil being lost every year in the Sop Moei district. Moreover,the local community showed their good awareness of thelocal problems, as they were able to give useful information,
guide the researchers and discuss about the way to mitigate
the soil erosion problem (Fig. 8.)

Fig. 4. Agricultural land and soil erosion hazard map.

Fig. 3. Geological data and extreme daily rainfall map.

4 Results
The average annual soil erosion for each of the five studied
areas was evaluated using the Revised Universal Soil Loss
Equation (RUSLE) method with daily rainfall data between
2010 and 2020. The magnitude of erosion were divided into
5 levels: lowest, low, moderate, high and highest respectively.

8

In the studied area, the forest type is lower montane. The
plant species were chosen to study root tensile strength. The
criteria for species selection were based on the habitat of thespecies with both native and exotic species along with theobservation of the farmers with the experiences of the HRDI
officers. Moreover, the species selection for soil erosion

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reduction has to be based on the benefits of the species on thetimber, economic, as well as soil and water conservation.
However, the native habitat of the species is equallyimportant for consideration because even some species havehigh ability to reduce soil erosion, species introduced to the
new area have to adapt to the new environments. They might
adapt and survive but growth might not be normal or theymight be able to adapt so well and rapidly take over the native
species resulting in invasive species in the area.
Results from root tensile strength clarified that the strength
decreased when the diameter of root increased. Root tensile
strength also depended on root size, root moisture, root healthand root storage, and root age etc.
Plants with high root tensile strength at root diameter of 1
millimeter were Persea americana (Avocado) (Fig.6.),
Litsea cubeba, (Fig.7.), Coffea arabica (Arabian coffee), andPrunus mume (Plum) which most of them are exotic species
that are not native to Thailand (apart from L. cubeba). The
exotic species were introduced to Thailand for food withgood economic benefits and they also serve the soil erosion
control as well as soil and water conservation. We consideredthose species to have full potential for soil-bioengineering.

Fig. 7. Root of L. cubeba at Wadokro village(2/8/2020)

Fig. 5. Gully formations and surface soil loss
at Sop Moei area (27/8/2020)

Fig. 8. Soil Erosion field survey
at Huai Nam Sai village (27/8/2020)
The treatment of soil surface for protecting soil erosion in
Sop Moei district can be done based on 2 levels of erosion
problem as follows.
1. For areas where erosion just started or moderate erosion,
vetiver system should be used along the contour, with 0.5m
spacing between the rows, according to the standard drawingof Department of Highways or Department of Rural Roads.
2. For areas with severe erosion on side slope or back slope,soil bio-engineering technique including, flapped soil bag,micro pile with live stake can be used. More detailed soil

Fig. 6. Root of P. americana (Avocado)
at Wadokro village (1/8/2020)

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investigation, slope geometry and other limitations should be
performed to make detail designs.

5 Conclusions
The result of soil erosion hazard map in the Sop Moei
district Extension Areas indicated that high potential of soil
erosion areas mostly occurred in high slope area especially
20 to 30 degrees with sedimentary rock geology, namely,siltstone, mudstone, and sandstone as well as igneous rock.
The rainfall are under influence of the monsoon seasonal
winds i.e. southwest monsoon and northeast monsoon as wellas, orographic rainfall effect. These conditions accelerated

soil erosion leads to landslide events in this area. In studiedarea, soil erosion occurring in every part of the Sop Moei
district but also significantly higher magnitudes occur inagriculture area without soil & water conservation andnatural forest upstream with steep slope and highprecipitation.
The recommended slope stabilization and erosion control
techniques depends on the community conditions and othersurrounding factors, which can be categorized in 3 groups,
related to the level of engineering technique combined withplants (for lowest to highest), namely, 1) Vegetation
technique 2) Soil bag and vegetation and 3) Engineering
technique and vegetation.

Fig. 9. Comparison of soil erosion risk map and location of landslide at Sop Moei district. (27-30/8/2020)

Acknowledgment
This project was supported by the Highland Research and Development Institute (HRDI). Valuable assistance provided by Dr.
Jarunee Pilumwong and staffs at the HRDI. The authors wish to thank the Land Development Department of Thailand (LDD)
for providing the geological data.

Reference[1] Ouyang D., Bartholic J., Predicting Sediment Delivery Ratio in Saginaw Bay Watershed, Proceedings of the 22 nd National
Association of Environmental Professionals Conference, Orlando, (1997), pp. 659-671.
[2] Sahu, A., Baghel, T., Sinha, M. K., Ahmad, I., Verma, M.K., Soil Erosion Modeling using Rusle and GIS on Dudhawa
Catchment, International Journal of Applied Environmental Sciences, 12(6), (2017), pp.1147-1158.
[3] Rangsiwanichpong, P., Kazama, S., Gunawardhana, L., Assessment of sediment yield in Thailand using revised universal
soil loss equation and geographic information system techniques, River Research and Application, 34(9), (2018), pp. 1113-1122.

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Tohoku University----- with Perspective of Global Safety[4] Jotisankasa, A., Taworn, D., Chumchey, N., Sukolrat, J., Quantification of root reinforcement in bio-slope stabilization:
laboratory and field studies, Proceedings of the 4th International Conference on Rehabilitation and Maintenance in Civil
Engineering (ICRMCE 2018), 195 (2018), pp. 1-11.
[5] Renard, K., Foster, G., Weesies, G., McCool, D., Yoder, D., Predicting soil erosion by water: a guide to conservation
planning with the Revised Universal Soil Loss Equation (RUSLE), USDA Agriculture Handbook, 703. (1997)

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Tohoku University‐‐‐‐‐ with Perspective of Global Safety

Defining Global Fire Patterns and Quantifying Climate Influence on Fire
○ Ke SHI1* & Yoshiya TOUGE1
1

Department of Water Environment, Engineering University, Miyagi 980-8579, Japan.
*
E-mail: shi.ke.s5@dc.tohoku.ac.jp.

Abstract
Fires are widespread disasters worldwide and are concurrently influenced by multiple global climatic drivers.
The teleconnections between different regional fires and the underlying climatic cause mechanisms have not been
fully explored. Determining a suite of global climatic drivers that explain most of the variations in different
homogeneous fire regions will be of great significance for fire management, fire prediction, and global fireclimatology. Therefore, this study first identified spatiotemporally homogeneous regions of burned area
worldwide during 2001~2019 using a distinct empirical orthogonal function. Additionally, the cross wavelet
transform and wavelet coherence were used to analyze the relationships between major patterns of fire burned
area and various global climatic drivers. The three most significant global climatic drivers that strongly impacted
each of the eight major fire patterns were identified. Then, the potential mechanisms of the global climatic drivers
for specific regions were discussed. These results provide a reference for future exploration of the connection
between fire and climate.
Keywords: Global fire patterns; Climate Influence; Teleconnection.
1 Introduction
Fire, which is strongly responsive to climatic drivers, is a
critical component of the natural earth system’s ecologicalprocess at scales ranging from local to global. Higher
temperatures, more rain-free days, more fire events, andmore fire-affected areas induce significant fire danger
variations. An apparent increase in catastrophic fires has
been found globally in recent years.
One of the critical factors affecting fires is climate. One of
the best known of these mechanisms is the El
Niño-Southern Oscillation (ENSO)-fire dynamic in InsularSoutheast Asia [1]. Strong correlations were found between
fires and the ENSO index (Southern Oscillation Index andNiño 3.4 index) in equatorial forests. The impact of the
Arctic Oscillation (AO) pattern on interannual firevariability in Central Siberia was found by Balzter et al. [2].
Overall, climate variability could influence fire behavior
and account for the variability in fire severity at various
temporal and spatial scales. Therefore, substantial research
has focused on the relationship between climate weather
and fire from local to global levels. Aldersley et al. [3]analyzed the relationship between the burned area andmeteorological elements such as high temperature andintermediate annual rainfall in fourteen global
subcontinental regions. However, these studies mainly
focused on gridpoint-specific meteorological elements andfire burned area relationship analysis. Global climatic
drivers such were not considered from a more in-depth
perspective in their global fire study. Indeed, global climatic
drivers are often the most fundamental factor that affects
meteorological elements such as precipitation andtemperature, which in turn affects global fires. But there is
still a gap in the comprehensive understanding of therelationship between global climatic drivers and fire, andeven finding the teleconnections between different regionalfires can be expected implying that same global climatic
driver affecting fire in several regions.
Until now, previous studies have not filled gaps in
exploring the spatiotemporally homogeneous regions of

12

global burned areas and multiple climatic influences.
Therefore, a comprehensive study of global fire patterns
will help us better understand global fires. Considering thatthe causes of fires are intricate and usually influenced bymultiple factors, it is essential to study multivariablecoherence to better reveal the salient features of fires from a
global perspective. Therefore, the main aim of this study
was to analyze the relationships between major fire patterns
and various global climatic drivers.

2 Materials and methods
In this study burned area data is from Fire CCI v5.1 [4]dataset during 2001~2019 at the 1°×1° resolution on themonthly scale. Then, log-transformation was performed forburned area time series. Also, the monthly log-transformed
burned area anomalies (logBAA) were subsequently
calculated to indicate the abnormal fire condition every
month. As for global climatic drivers, in this paper, sixteen
global climatic drivers that may have impacts on fires wereselected. To explore the diversity of climate causes, bothoceanic indices such as the Oceanic Niño Index andcontinental teleconnection patterns such as the East
Atlantic/Western Russia Pattern were considered. These
global climatic drivers were sourced from the National
Oceanic and Atmospheric Administration (NOAA):
https://www.noaa.gov/ (last access: 11 May 2021).
As for methods, the distinct empirical orthogonal function(DEOF) analysis was utilized to identify the global patternof logBAA. In the DEOF, a continuous spectrum of spatial
patterns resulting from a stochastic process can be
represented by EOF modes, where some spatial structures
will be more dominant than others. Based on the isotropic
diffusion null hypothesis, the EOF modes (DEOFs) can befound by rotating the leading EOF modes, corresponding to
the distinguished principal components (DPCs). The details
about DEOF can be found in Dommenget [5]. Additionally,
the cross wavelet transform (XWT) and wavelet coherence(WCO) [6] can examine the relationship between the DPCs
and the global climatic driving factor. WCO reveals local
similarities between two time series and may be found to be

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Tohoku University‐‐‐‐‐ with Perspective of Global Safety
a local correlation coefficient in the time-frequency plane;that is, their possible teleconnection can be identified by
WCO [6]. The specific XWT and WCO analysis methods
can also be found in Torrence et al. [6]. Notably, wavelet
analysis brings about a cone of influence (COI) that delimitsa region of the WPS beyond which the edge effects become
significant, which means outcomes outside COI should besuspected [6].

fire and global climatic drivers. Furthermore, some regions
were ignored in our identified global fire patterns.

3 Results and discussion
The DEOF calculation used the logBAA time series ofeach 1°×1° grid cell on a monthly scale. The first eight
DEOFs represented 30.0% of the total variance. Figure 1
displays the spatial patterns of DEOF1~8. Different DEOFs
represented different abnormal characteristics of fire burned
areas. Specifically, EOF values greater than (less than) 80%of the total are considered high positive (low negative)
loading. For example, in DEOF2, the spatial distribution
illustrated that low negative loadings occurred in Part ofRussia and Ukraine. Meanwhile, the high positive loadings
were mainly concentrated in northern Kazakhstan, which
also meant that these regions had opposite characteristics as
those of the negative loading regions.
Figure 1 also shows the defined region of the three global
climatic drivers that have the most significant influence on
DEOF1~8. Some regions frequently appeared in different
DEOF patterns. The hotspot-1 (around Ukraine andKazakhstan) was found in DEOF1~3. Although the threemost dominant global climatic drivers changed with the
DEOF patterns, Atlantic multidecadal Oscillation (AMO),
Pacific/North Pacific Oscillation (EP/NP) and Pacific North
American Pattern (PNA) were the strongest influencing
drivers among these five climatic drivers, indicating thatthese three global climatic drivers had a relatively strong
impact on the hotspot-1. EP/NP, PNA, East
Atlantic/Western Russia Pattern (EA/WR) were thedominant global climatic drivers among DEOF2, DEOF4
and DEOF8, where hotspot-2 (southern Africa) appeared
concentrated. For DEOF3, DEOF5 and DEOF8, there were
three different combinations of global climatic drivers
affectingthehotspot-3(Australia):
Multivariate
Niño/Southern
Oscillation
Index(MEI)-DEOF3,
AO-DEOF5 and EA/WR-DEOF8. The global climatic
drivers that affect the hotspot-4 (Brazil) have become very
diverse, where they were found to be affected by ten
different global climatic drivers. Affected by ten climatic
drivers, PNA, Arctic Oscillation (AO), Polar/Eurasia
Pattern(POL) and EA/WR were the dominant global
climatic drivers in the hotspot-4 of DEOF4~7.
Overall, our teleconnection analysis has revealed how
global climatic drivers affect global burned area patterns,
which provides a possibility for informing the anticipationof burned area. As for global burned area patterns,
regionality is greatly evident. These hotspots, such asaround Ukraine and Kazakhstan, southern Africa, Australia
and Brazil, frequently appear in different global burned area
patterns. While, even if the around Ukrainian region did notshow a large burned area, it showed significant burned area
anomalies. Similarly, the United States, where fires
frequently occurred, was also insignificant in our global
burned area patterns. The study's limitations include thelack of validation for the physical mechanism between the13

Fig. 1. The location distribution of the top three global
climatic drivers with the strongest influence on DEOF
patterns.

4 Conclusions
This paper establishes the teleconnection between global
climatic drivers and logBAA patterns for the first time andexplores the physical mechanism behind theirteleconnection from a global perspective. The results of thispaper are conducive to a better understanding of thespatiotemporal characteristics of global fire burned areas.
Due to the changing climate, atmosphere and ocean
scenarios, focusing on global climate drivers provides anefficient and promising reference for predicting fire burned
area anomalies. The conclusions will also be valuable forfire management, fire prevention, and global fire ecologicalclimatology.

Reference[1] Fuller, D. O. et al. The ENSO-fire dynamic in insularSoutheast Asia. Climatic Change. 74(2006), 435–455.
[2] Balzter, H. et al. Impact of the Arctic Oscillation
pattern on interannual forest fire variability in Central
Siberia. Geophysical Research Letters. 32(2005), 1–4.
[3] Aldersley, A. et al. Global and regional analysis ofclimate and human drivers of fire. Science of the Total
Environment. 409(2011), 3472–3481.
[4] Chuvieco, E. et al. ESA Fire Climate Change Initiative(Fire_cci): MODIS Fire_cci Burned Area Pixel product,
version 5.1[dataset]. Centre for Environmental Data
Analysis: Didcot. (2018).
[5] Dommenget, D. Evaluating EOF modes against a
stochastic null hypothesis. Climate Dynamics. 28(2007),
517–531.
[6] Torrence, C. et al. A Practical Guide to Wavelet
Analysis. Bulletin of the American Meteorological society.
79(1998), 61–78.

Acknowledgements
This study was jointly supported by Grant-in Aid for
Scientific Research (B), 2020-2023 (20H02248, Yoshiya
Touge).

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The spatial and temporal response of wet crops to agricultural drought:
A case study in Indonesia○ Amalia Nafisah Rahmani IRAWAN1*, Daisuke KOMORI1,2 & Vempi Satriya Adi HENDRAWAN1
1

Graduate School of Environmental Studies, Tohoku University, Miyagi 980-8577, Japan.
Department of Civil and Environmental Engineering, Tohoku University, Miyagi 980-8577, Japan.
*
E-mail: amalia.nafisah.rahmani.irawan.q3@dc.tohoku.ac.jp.

2

Abstract
Wet crop (e.g., paddy) is one of the primary food sources in the world, including in Indonesia. Located in thetropical-humid region, as the main agricultural production, planting season for paddy is divided into the wet
cropping season and the dry cropping season. The crop productivity is relatively higher in the dry cropping period
due to the availability of sunlight and less clouds which support the crop growth. But there is a high risk ofdrought that could affect the crop production because the water supply often relies on precipitation especiallyduring the rainy season. Standardized Precipitation Index (SPI) is a well-known drought assessment method foundby McKee et al., in 1993 which only requires long term precipitation data for the input, and it can be used toassess the agricultural drought. The SPI analysis was conducted using GSMaP which has 0.1° x 0.1° spatial
resolution. According to the correlation analysis between SPI index and drought affected areas on city-scale,
SPI-3 in August is the most suitable to assess the agricultural drought in Indonesia. Based on the correlation
analysis between SPI-3 and crop yield, the agricultural drought assessment is more suitable to be conducted on agrid-scale because of many local characteristics on fragmented agricultural areas which contribute to the responseof wet crops to drought. For the spatial response, the lower crop yield loss is found in the area below the thresholdvalue (r-value ≤ 0.6) or the region where drought is not the main driver of crop yield loss, even in the area thatwas hit by drought the hardest because there is the existence of irrigation system. But still in the region whichmore vulnerable to drought or has a high correlation (r-value > 0.6), the existence of irrigation systems cannot
withstand the drought event resulting in higher crop yield loss when hit by more severe drought.
Keywords: Agricultural Drought; SPI; Wet Crop; Dry Cropping Season; Temporal Scale; Spatial Scale.
1 Introduction
Agricultural drought started from the lack of precipitation(meteorological drought) that damaged the agriculture area
and affected the crop production. Standardized Precipitation
Index (SPI) was found by McKee et al., in 1993 that it can beused for drought assessment and only needs the long-term
precipitation data (minimum 20-30 years). By using theprobability density function and normalization, the SPI canassess the wet and dry conditions over any regions (drought
occurred where SPI ≦ -1). Another benefit of SPI is the
temporal versatility so it can be calculated for various
timescale according to user’s interest (WMO, 2012).
Many researchers have also used SPI for agricultural
drought assessment, but there is no general agreement
reached to determine the most appropriate timescale to be
utilized. For example, Ali (2001) and Ji and Peters (2003)
found that SPI-3 is suitable in Turkey and U.S. Great Plains
respectively. Meanwhile Iglesian and Quiroga (2017) use
SPI-12 as a climate indicator for measuring the climatic risk
to cereal production. Still, there is less discussion related tothe agricultural drought on wet crops (e.g., paddy). Locatedin the tropical-humid region, paddy is the main agricultural
production in Indonesia. The crop productivity is relatively
higher in the dry cropping period due to the availability ofsunlight and less clouds which support the crop growth. But
there is a high risk of drought that could affect the crop
production because the water supply often relies on
precipitation especially during the rainy season.
In this research, the objectives are i) to determine the mostsuitable SPI index to be utilized for agricultural application

14

in the tropical-humid region, ii) examine the spatial responseof wet crop to agricultural drought on city-scale andgrid-scale. Specifically, this study was focused on the wetcrop during the dry cropping period.
This research was conducted in West Java as one of thelargest rice producers in Indonesia with the rainy season from
October - March and the dry season from April - September.
According to the World Bank in 2016, 31.46% of the land is
agricultural land, dominated by paddy fields, which is very
vulnerable to drought events. The results of this study will be
helpful to get a better understanding about agricultural
drought impact on wet crops.

2 Materials and methods
The precipitation data collected from Japan Aerospace
Exploration Agency (JAXA) provides near real-time rainfall
data on their product called Global Satellite Mapping ofPrecipitation (GSMaP). The daily precipitation data are
available from March 2000 - present date and were retrieved
across West Java with 0.1° x 0.1° resolution. The agricultural
statistical dataset in this study, drought-affected areas during
the dry season and the crop yield (annually and monthly),
were obtained from the Ministry of Agriculture and theAgricultural Agency of West Java respectively.
SPI was calculated based on the GSMaP precipitation
dataset for various timescale (SPI-1, SPI-3, SPI-6, SPI-9, andSPI-12) with different month reference from January December which is associated with the dry cropping season.
To determine the most suitable SPI index, Pearson
correlation analysis was assessed between various SPI index
and drought-affected areas on the city-scale. For theThe 9th International Symposium on Water Environment Systems

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Tohoku University----- with Perspective of Global Safetygrid-scale analysis, crop yield estimation model was
generated using stepwise multilinear regression model fromthe vegetation indices or the Normalized Difference
Vegetation Index (NDVI) obtained from MODIS/TERRA
with 250-m resolutions. Then, the correlation analysis was
conducted between SPI-3 and detrended crop yield to assess
the impact of drought on paddy in Indonesia.

3 Results and discussion

Fig. 1. Heatmap of Mean of Correlation Value between
SPI Index and Drought-Affected Areas
Figure 1 showed the heatmap of average correlation value
where vertical axis indicated the SPI aggregation timescaleand horizontal axis indicated the month reference. The
shaded area on the heatmap involved only a wet season
which is not a target period of this study, so the result is notincluded. Based on the heatmap, the correlation resulted innegative values, indicated by the red colour, meaning that thedecrease of SPI index, or a dry condition, is associated with
the increase of drought-affected areas in the agriculture area.
In addition, the highest correlation was found during the
SPI-3 in August thus in this study SPI-3 was selected as themost suitable index to be utilized. This finding is consistent
with study by Ali in 2013 which stated that SPI-3 issensitive to the reduction in soil moisture that affects crop
growth and with study by Ji&Peters in 2002 which statedthat vegetation has a time lag response to precipitation andthat the impact of water deficits is cumulative.

Fig. 3. Correlation between Detrended Crop Yield andSPI-3 in 2019 on Grid-Scale
For the grid-scale analysis, 2019 was selected to be thefocus period because of the occurrence of most extreme
drought year. Based on the characteristics of the data fromgrid-scale analysis, it was observed that almost all the grid
located in region with r-value ≥ 0.6 experience crop yield
loss with various SPI index values indicating the drought
event as the main driver of crop yield loss, thus the thresholdfor r-value was set at 0.6. Figure 3 showed the result fromgrid-scale analysis with 4 main findings: (1) The irrigation
system was installed in the area which was hit by drought thehardest (more to the left). (2) Region with r-value ≥ 0.6 wasmore vulnerable to drought proven by the red circle marker,
the high crop yield loss occurred in the irrigated area when
hit by the hardest drought meaning that there might be failure
in delivering an adequate amount of water. (3) Region withr-value < 0.6 was more resilient to drought proven by theblue circle marker which has low crop yield loss even after
hit by severe drought. (4) Meanwhile the region which is still
irrigated by local water resources (cross shaped marker),even though it is not located in the extreme dry region, thewater availability is still very dependent with precipitationthat might be dangerous in the future because of climatechange impact.

4 Conclusions

Fig. 2. Spatial Distribution of r-Value between Detrended
Crop Yield and SPI-3 on City-Scale
After the most suitable SPI index was determined, thecorrelation between crop yield and SPI-3 was assessed oncity scale. The result did not produce a high significant
correlation caused by the spatial scale of the assessment andthe uncertainty in the subround dataset. But the different
response in the northern area (irrigated by dam) and southernarea (irrigated by river or wells) was observed. This result
indicates the importance of an advanced irrigation system. In
the northern part, severe drought events did not result in ahigh crop yield loss because there is still water supply for
agricultural activity resulted in negative correlation.

15

This study was conducted to assess the spatial andtemporal response of the wet crop to the agriculture drought
during the dry cropping season. SPI-3 in August is the mostsuitable index to be utilized and the assessment isrecommended to be conducted on grid-scale because there
are many local characteristics in fragmented agricultureareas. Based on the correlation between SPI-3 and crop
yield, the threshold for r-value was set for 0.6. For theregion which more vulnerable (r-value ≥ 0.6), the existenceof irrigation systems cannot withstand the drought event
resulting in higher crop yield loss when hit by more severe
drought. Meanwhile, for the area which more resistant(r-value < 0.6), the low crop yield loss was observed both inirrigated and non-irrigated agricultural areas.

Reference[1]
World
MeteorologicalOrganization,
2012:
Standardized Precipitation Index User Guide (M. Svoboda,
M. Hayes and D. Wood). (WMO-No. 1090), Geneva.
[2] Ji, L., & Peters, A. J. (2003). Assessing vegetation
response to drought in the northern Great Plains using
vegetation and drought indices. Remote Sensing ofEnvironment, 87(1), 85–98.

The 9th International Symposium on Water Environment Systems

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Tohoku University----- with Perspective of Global Safety

Evaluation of historical and future simulations of precipitation andtemperature in Afghanistan from CMIP6 climate models○ Mohammad Naser Sediqi1*, Daisuke Komori 1,2
1

Graduate School of Environmental Studies, Tohoku University, Miyagi 980-0845, Japan.
2
Graduate School of Engineering, Tohoku University, Miyagi 980-0845, Japan.
*E-mail: mohammad.naser.sediqi.p4@dc.tohoku.ac.jp.

Abstract
The coupled Model Intercomparison Project phase 6 (CMIP6) dataset was used to assess the spatio-temporalprojected changes in precipitation and temperature over Afghanistan under latest three Shared Socioeconomic
Pathways (SSPs) emission scenarios (SSP1-2.6, SSP2-4.5 and SSP5-8.5) for the three period, near future (20202044), mid future (2045-2067) and far future (2075-2099). Statistical metric was used for ranking the models to
select appropriate GCMs based on their ability to simulate historical monthly average precipitation, maximum andminimum temperature for the period of (1990-2014). Three model namely MPI-ESM1-2-LR, ACCESS-CM2 andFIO-ESM-2-0 were found high ranked models based on past performance for simulating the all three variables.
Mean ensemble of selected GCMs revealed an in-crease in maximum temperature in the range of 1.7-4.5 oC, 2.75.3 oC, and 4.5-6.8 oC and minimum temperature in the range of 1.8-9.8 oC, 3.2-9.9 oC and 5.6-10.7 oC and average
precipitation change in the range of -4.9-10.23 %, -2.4-22.6 % and -1.4-29.8 % under SSP1-2.6, SSP2-4.5 and SSP58.5 scenarios, respectively during far future (2075-2099). Northeast of the country (Himalayas region) were
projected higher increase in temperature, where, higher change in average precipitation were projected in the southand southwest (desert region) of Afghanistan.
Keywords: Climate projections; global climate model; CMIP6; Afghanistan
1 Introduction
Global Climate Models (GCMs) can be used to predict
future climate information. The GCMs project future climatebased on different assumptions of future changes ofgreenhouse gas (GHG) emissions, land use and socioeconomy [1]. The change in global GHG re-leases andsocioeconomic is related to the political strategies at national,
regional and global levels.
Afghanistan is located in cross road of central and south
Asia, and has divided to different climate zones (Figure 1).
Decades of political fighting has faced many different
environ-mental issues, mostly in water sector [2]. According
global climate risk index (2017) ranked 12th most vulnerable
to climate change and has already experienced prolonged
droughts. i.e. drought 1998-2002 [3].
In Afghanistan 98 % of water resource is used for
agriculture, similarly, more than 80 % of the population get
their income from agricultural practices. Therefore, rapid
declination of renewable water resources has caused asignificant impact on water resources, agriculture andlivelihood of the vast populace of the country.
The mean annual temperature in the country has increased
by 0.13 to 0.29 °C/decade in the last five decades.
Understanding possible climate changes are crucial for thecountry to anticipate future water stress, aridity and theirimplications to agriculture and economy.
The objective of the present study is to assess the relative
historical performance and future projections of the CMIP6GCMs in Afghanistan. Nineteen GCMs based on theiravailability for the study area are used for this purpose. The
capability of the models was assessed in simulating the
spatial and temporal variability of climate for annual scale.

16

Fig. 1. Afghanistan with its different climate zones.

2 Materials and methods
CRU gridded dataset from the University of East Anglia
Climatic Research Unit, was used for assessing GCM's
performance in simulating historical monthly rainfall,
maximum temperature (Tmax) and minimum temperature(Tmin) with resolution of 1.0 × 1.0.
Nineteen CMIP6 GCM's were used to assess the futureclimate projection for three different future scenarios overAfghanistan. The GCMs were selected based on availabilityof projections of three main climate variables rainfall, Tmax
and Tmin, and their availability of future projection for SSP
1-2.6, SSP 2-4.5 and SSP 5-8.5.
The Kling-Gupta efficiency (KGE) [4] metrics were used toevaluate the association between gridded dataset (CRU) and
GCMs and to select an ensemble of GCMs based on their past
performance.

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KGE range between 1 to -∞, where 1 indicates a perfectassociation and can be calculated from equation (1). KGE
metrics is a combination of combines Pearson's correlation(r), the ratio of spatial variability and the normalized
difference between the gridded dataset (CRU) and each GCM
model.
𝑲𝑮𝑬 = 𝟏 − √(𝒓 − 𝟏)𝟐 + (

𝟐
𝝈𝑮𝑪𝑴
𝟐
⁄𝝁𝒓𝒆𝒇
𝝁𝑮𝑪𝑴
− 𝟏) + ( 𝝈
− 𝟏)
𝒓𝒆𝒇
𝝁𝒓𝒆𝒇
⁄𝝁𝒓𝒆𝒇

where μGCM and μref are the mean, and σGCM and σref are thestandard deviation for GCM and CRU data, respectively.
After the selection of high ranked GCMs based on KGE
values, the ensemble of CMIP6-GCMs rainfall andtemperature was bias corrected using quantile mapping (QM)
bias correction approach. Bias corrected GCMs werecompared to that of their reference period (1990-2015) for
different SSP scenarios, and three future periods (2020-2044),(2045-2069) and (2075-2099) to assess the changes in
Afghanistan future climate in desert and mountainous
regions separately.

Fig. 3. Spatial patterns of changes in rainfall (%)

3 Results and discussion
The performances of CMIP6 GCMs based on KGE metricto reproduce the annual rainfall, Tmax and Tmin are shownin (figure 2). The figure revealed that based on combinationof the rank of all variables using rating metric (RM) equation,
FIO-ESM-2-0, ACCESS-CM2 and MPI-ESM1-2-HR has
higher KGEs values between all models for all three variables.

Fig. 3. Changes in Tmax (°C) for three futures and three
scenarios in mountainous and desert region.

4 Conclusions
The statistical metric has been conducted in this study toevaluate the performance of CMIP6 GCMs in simulating
historical climate. Besides, the MMEs were used to project
the future climate for different scenarios. The study revealed
a higher increase in rainfall and a significantly large rise intemperature for SSP scenarios.

Fig. 2. KGE value for Tmax, Tmin and rainfall.
A multi-model mean ensemble (MME) was formed fromthe three models with highest KGE. Using the MME, thechange in rainfall and temperature were calculated andpresented spatially for three futures (near future 2020-2044,
mid future 2045-2067 and far future 2075-2099). comparedto the base period (1990 - 2014) for the SSP1-2.6, SSP2-4.5
and SSP5-8.5 emission scenarios.
It is projected that for both Tmax and Tmin (figure 3) thelowest change will be in SSP1-2.6, near future and thehighest change is projected in SSP5-8.5 and far future. It’s
also predicted that future temperature changes inmountainous region for all SSPs and time periods is higher
than desert region of the country.
On the other hand, the annual rainfall change (figure.4) was
projected to have a positive in the range of (2 to 30 %) andthe maximum changes is projected to the southwest ofAfghanistan.

17

Reference[1] Taylor KE, Balaji V, Hankin S, Juckes M, Lawrence B,
Pascoe S. 2011. CMIP5 data reference syntax (DRS) andcontrolled vocabularies. San Francisco Bay Area, CA, USA.
[2] Aich, V.; Akhundzadah, N.A.; Knuerr, A.; Khoshbeen,
A.J.; Hattermann, F.; Paeth, H.; Scanlon, A.; Paton, E.N.
Climate Change in Afghanistan Deduced from Reanalysis
and Coordinated Regional Climate Downscaling Experiment.
[3] Sediqi, M.N.; Shiru, M.S.; Nashwan, M.S.; Ali, R.; Abubaker, S.; Wang, X.; Ahmed, K.; Shahid, S.; Asaduzzaman,
M.; Manawi, S.M.A. Spatio-Temporal Pattern in the Changes
in Availability and Sustainability of Water Re-sources in
Afghanistan. Sustainability 2019, 11, 5836.
[4] H.V. Gupta, H. Kling, K.K. Yilmaz, G.F. Martinez. 2009.
Decomposition of the mean squared error and NSE
performance criteria: implications for improvinghydrological modelling.

The 9th International Symposium on Water Environment Systems

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Tohoku University‐‐‐‐‐ with Perspective of Global Safety

Global-scale analysis of crop response pattern to different
drought timescales○ Vempi Satriya Adi HENDRAWAN1,* , Daisuke KOMORI1
1

Graduate School of Environmental Studies, Tohoku University, Sendai Miyagi 980-8579, Japan*
E-mail: vempi@dc.tohoku.ac.jp

Abstract
Drought is one of the extreme climate events lead by water deficit causing subsequent severe impacts. Different
precipitation deficits over time can induce different responses to crops. Here, we identified the response pattern ofcrop yield anomaly to a different time scale of meteorological drought based on past events on a global scale.
Standardized Precipitation Index based on ensemble precipitation dataset was used to identify drought episodes andseverity from 1981 to2016. The crop yield anomaly was estimated by detrending the gridded global dataset of crop
yields for major crops (maize, rice, soybean, and wheat) in 0.5-degree resolution. The result indicates that crop yield
loss is generally more sensitive to medium (5-8 months) to long (9-12 months) drought timescales globally,
compared to short timescale (1-4 months). Various determinants might control the different spatial of crop response.
This study contributes to an ongoing effort to assess crop vulnerability and possible mitigation and adaptation
against climate change based on past understanding.
Keywords: agriculture, drought, SPI, timescale, yield
1 Introduction
IPCC (2013) reported that global warming would result inclimate extremes inducing more frequent and severe natural
disasters. Drought has contributed to some of the world's
most severe famines (e.g. a severe drought in India affecting
300 million people in 2002). Agriculture is the most affected
sector by drought in developing countries, absorbing about
80% of all direct impacts (FAO, 2017). Therefore,
understanding drought and its impact are vital points towards
the rising incidence of weather extremes and its negative
impacts on agriculture.
The nature of drought impact on crops depends on how
drought is defined (i.e., timescale, duration, and severity)(Mckee et al., 1993) and the characteristic of crop resistance(Daryanto et al., 2016). Numerous previous studies haveassessed drought impact to crop by using multiple droughttimescales (Peña-Gallardo et al., 2019). Drought timescale
can be referred to as the length of time (e.g., months) during
which the drought event develops (Hayes, 2001).
This study assesses crop sensitivity based on different
drought timescales. This study aims to understand the global
pattern of crop response to different drought timescales. This
study contributes to existing drought-related studies for
agricultural systems to understand how different droughttimescales are associated with crop yield anomalies.

2 Materials and methods
The different drought timescale was modelled by amultiscalar meteorological drought index (i.e., SPI) with 1 –12-month timescales based on the global gridded
precipitation datasets. All analysis was done for each major
crop (maize, rice, soybean, and wheat) in 0.5° grid resolution
during 1981 – 2016 (36 years).
1.1 Materials
Datasets used in this study are shown in Table 1. The
primary input dataset in this study is the global precipitation
datasets for the drought model and crop yield data forassessing drought risk on crops.

18

Table 1 Dataset used in this study
Name
Data
Use
Drought
Precipitation
Drought
Index (SPI) from ensemble
model
historical global
datasetExposure
Crop
Planting andmodel
calendarharvesting date(Day of Year)The global
Crop yield (t/ha) Risk
dataset ofmodel
historicalyield(GDHY)

References(Hendrawan
et al., 2021)(Sacks etal., 2010)(Iizumi &Sakai,
2020; Kim
et al., 2019)

1.2 Methods
SPI was calculated by transforming monthly accumulated
precipitation (i.e., within 1 – 12-month) to standardized value(mean 0 standard deviations 1) based on the specificdistribution (i.e., gamma distribution) (Guttman, 1998).
Drought Index (DI) was then calculated based on theensemble mean of several SPI data, obtained from theensemble mean of several datasets (GPCC, CRU, PRECL,
UDEL, CPC, MSWEP, MERRA-2, ERA-5, JRA-55). Then,
Eq. 1 was used to convert monthly SPI to annual drought
index based on harvesting month obtained from Sacks et al.
(2010) dataset. To see the detailed method, refer toHendrawan et al. (2021).

𝐷𝐼 ,𝑆𝑃𝐼­𝑛 ,
𝑛𝑢𝑙𝑙

𝑆𝑃𝐼
𝑆𝑃𝐼

0,
0,

(1)
where 𝑆𝑃𝐼Ǧ𝑛 , is the SPI of 𝑛 -month precipitation
accumulation in harvested month 𝑗 in year 𝑡. For example,
is calculated using precipitation sum within
𝑆𝑃𝐼Ǧ3 ,
3-month: June, July, and August in 2015.

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We assessed the relationship between each 12-timescales
DI and crop yield anomaly estimated by detrending the
gridded global dataset of crop yields for major crops (maize,
rice, soybean, and wheat) for the four crops types using thePearson correlation. Thus, we obtained 12 different
correlations in each grid independently for each crop andobtained a DI timescale in which crop yield anomaly shows
the highest correlation (Hendrawan et al., 2021; PeñaGallardo et al., 2019).

3 Results and discussion
The result shows that medium timescale shows a stronger
correlation for maize and soybean by around 24% and 31%of the total global crop area, respectively, followed by longand short timescale. Meanwhile, for wheat, long-timescaleshows the highest global proportion by around 27%. In thecase of rice, the dominant response is shown in the shorttimescale for around 17% global crop area. Medium
responses to drought in maize and soybean are profound,while in contrast, wheat indicates a longer response to
drought, and rice is more sensitive to short drought timescale
despite its less share of global cropland (Fig. 1).

Figure 2 Area proportion of each different response
timescale to drought (short, medium, and long) indifferent climatic regions based on Köppen-Geiger
climate classification.

Conclusion
This study reveals that crop yield loss is generally moresensitive to medium (5-8 months) to long (9-12 months)
drought timescales globally, compared to short timescale (14 months). Various determinants might control the different
spatial of crop response which is essential for further
consideration.

Selected references

Figure 1 Drought time-scales (short, medium, and long)at which the most negative correlation between DI andcrop yield anomaly is obtained.
Considering the different climatic regions that may govern
the response of crop yield to drought, we summarized theresults by categorizing cropland into the main classes(tropical, arid, temperate, cold, and polar) and the sub-types
based on precipitation types (rainforest, monsoon, dry
savannah, wet savannah, steppe, desert, dry summer, dry
winter, without dry season, ice cap, and tundra) (Fig. 2).
Results show that crop response to drought varies dependingon the crop types among different climatic regions. For
example, in the case of maize, medium response timescale
become dominant for arid, cold, and temperate, followed bya long and short response. However, for the tropical region,
the short response has more control in maize. Regarding theclassification based on the sub-types, medium response
timescale still dominates in all regions followed by a long andshort response, except in savannah and wet region dominatedby the short response. In dry summer, monsoon, andrainforest extended response slightly higher than short andmedium timescale response.

19

Daryanto, S., Wang, L., & Jacinthe, P. A. (2016). Global synthesis of drought
effects on maize and wheat production. PLoS ONE, 11(5), 1–15.
FAO. (2017). The Impact of disasters and crises on agriculture and Food
Security.
Guttman, N. B. (1998). Comparing the palmer drought index and thestandardized precipitation index. Journal of the American Water
Resources Association, 34(1), 113–121.
Hayes, M. (2001). Revisiting the SPI : Clarifying the Process Revisiting the
SPI : Clarifying the Process. Drought Network News (1994-2001), 2000,
18–20.
Hendrawan, V. S. A., Kim, W., Touge, Y., Ke, S., & Komori, D. (2021). A
global-scale relationship between a multiscalar drought index andagricultural yield anomaly based on multiple precipitation data.
Manuscript submitted for publication.
Iizumi, T., & Sakai, T. (2020). The global dataset of historical yields for major
crops 1981–2016. Scientific Data, 7(1), 1–7.
IPCC Working Group 1, IPCC, 2013: Climate Change 2013: The PhysicalScience Basis. Contribution of Working Group I to the Fifth Assessment
Report of the Intergovernmental Panel on Climate Change. Ipcc,
AR5(May 2016), 1535.
Kim, W., Iizumi, T., & Nishimori, M. (2019). Global patterns of crop
production losses associated with droughts from 1983 to 2009. Journalof Applied Meteorology and Climatology, 58(6), 1233–1244.
Mckee, T., Doesken, N., & Kleist, J. (1993). The relationship of drought
frequency and duration to time scales. Proceedings of the 8th Conference
on Applied Climatology, 17(22), 179–183.
Peña-Gallardo, M., Vicente-Serrano, S. M., Quiring, S., Svoboda, M.,
Hannaford, J., Tomas-Burguera, M., Martín-Hernández, N., DomínguezCastro, F., & El Kenawy, A. (2019). Response of crop yield to different
time-scales of drought in the United States: Spatio-temporal patterns andclimatic and environmental drivers. Agricultural and Forest Meteorology,
264, 40–55.
Sacks, W. J., Deryng, D., Foley, J. A., & Ramankutty, N. (2010). Crop
planting dates: An analysis of global patterns. Global Ecology and
Biogeography, 19(5), 607–620.

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Evaluate the dynamic change of burn-ability by observing
the fuel moisture content in Japan○ Qin HUANG1*, Yoshiya TOUGE1
1Department of Environmental Engineering, Environmental University, Miyagi 980-8579, Japan.
*

E-mail: huang.qin.p5@dc.tohoku.ac.jp.

Abstract
In recent years, big wildfire events are increasing. It is considered that the warming temperature caused by theclimate change makes the dryness enhanced. Therefore, dryness is essential for evaluation of the wildfire. The
measurement of dead fuel moisture content is a significant variable in determining fire danger since it is highly
related to fire ignition and spread potential, and slight changes in moisture content can cause significant differencesin fire behavior and effectiveness. From 21st February to 15th March 2021, a wildfire broke out in Ashikaga City,
Tochigi Prefecture, Japan. Since the spread of the wildfire was affected by dry weather, to investigate the moisturestatus of the forest fuel, two field investigations were carried out. The Ashikaga wildfire observation results showedthat the fuel moisture was below 10%, which is meaningful for evaluating burn-ability. The overall trend showed
that, as the temperature increase and relative humidity decrease, the moisture content rise. It can be considered thatthe difference between the two species was greatly influenced by relative humidity. The main consideration wasthat the amount of radiation affected the evaporation rate of different densities. It is required to analyze the effectof condensation and evaporation on fuel moisture based on meteorological factors.
Keywords: dryness; wildfire; burn- ability; fuel moisture.
1 Introduction
Forests are a major component of the Earth's ecosystem anda fundamental resource on which human life depends. There
have been several extreme fire incidents in the past two years.
IPCC pointed out that under certain geographical conditions,
there is a strong connection between climate change andwildfires. As the climate gradually becomes dry, we need
quantitative and physical method to evaluate dryness.
Combustibles, fire sources, and meteorological conditions
are the primary factors affecting forest fire risk prediction [1].
Combustibles are the material basis for wildfires, they are theprimary carrier for forest fire risk prediction research [2]. The
occurrence and development of forest fires depend to a large
extent on the fuel moisture content (FMC) and their duration[3,4]. Various meteorological factors directly or indirectly
affect the changes in the moisture content of combustibles,
which in turn affect the difficulty of combustibles on fire, thatis, the size of the fire hazard. Studies on FMC dynamics canbe divided into different time scales such as quarterly
changes, daily changes, and hourly changes. However, few
surveys are conducted on FMC during the fire period(indicating extremely dry weather). when a drought occurs,
it is very likely that a fire will occur. The study of the
dynamic changes of the fuel's moisture content is very
indicative.
In Japan, wildfires are seasonal and regional. Due to Japan's
humid climate, there are more small-scale fires. Japan has
fewer wildfires than other countries, and the area burned is
not large. However, because of the complex impact of fires
on the ecosystem, wildfires capable of causing large-scaleburns pose a greater threat to Japan than typhoon disturbance.
From 21st February to 15th March 2021, a wildfire broke out
in Ashikaga City, Tochigi Prefecture, Japan. This area islocated at the intersection of mountains and plains and is oneof the driest areas in Japan. Since the spread of the wildfire
was affected by dry weather, in order to investigate the FMC

20

status of the forest fuel in this case, two field surveys werecarried out.
The primary aim of this research is to determine themoisture content of forest surface fuel in Japan's driest region
during the dry season, as well as to track intraday dynamicchanges in FMC and conduct joint analyses withmeteorological factors.

2 Materials and methods
2.1 Field sites
When sampling sites were chosen, mixed forests were
avoided.
In the first investigation, samples were taken at threelocations in Ashikaga City (Tochigi Prefecture) and Kiryu
City (Gunma Prefecture). In Ashikaga City, surface dead fuelfrom broadleaf and cedar forests was collected, while in
Kiryu City, surface dead fuel from cedar forest was used. The
sampling sites.
The second investigation's sampling sites were in Ashikaga
City, and gathered surface fuel from cedar forest as well as
dense and loose areas in broadleaf forest. During the period,
continued to collect samples at the site where we collected
the broadleaf in Ashikaga City last time.
2.2 Sampling
All sampling days were rain-free. Dead fuel samples werecollected from dispersed locations within study sites. In
particular, intensive sampling of “easy to collect fuels” wasavoided. The sample was the dead leaves of thecorresponding tree species. Each sample was made up fromthree subsamples. In the second investigation, throughout thetime of this intensive sampling run, samples were collected
at 4-h intervals from 6am to 10pm (10pm only collect cedar).
The samples were sealed in sealed bag for transport back to
the laboratory. The field weight of samples was determined
as soon as practical following collection. After back to thelaboratory, oven-dry weights were obtained after drying

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samples to constant weight at 60 ℃. Due to the large numberof samples collected during the second investigation, thesamples were processed on the same day using a moisture
analyzer (HE73, Mettler-Toledo, Switzerland).

3 Results and discussion
The FMC of the sample is low in first observation.
Especially the FMC of the broadleaf measured in Ashikaga
is as low as 7.6%. The value is meaningful for the descriptionof dryness condition. The value will play a great role inevaluating burn-ability.
The FMC results and meteorological data obtained from thesecond investigation are shown in Fig.1.The overall trend
showed that, as the temperature increase and relative
humidity decrease, the FMC increase. The highest
temperature was at 3 p.m. every day, after which thetemperature began to decrease and the relative humidity
began to rise, with the maximum humidity around 6 am.

(a)

(b)

that the difference in FMC between the two fuels was greatly
influenced by relative humidity. Particle density is anotherphysical factor that influences fuel moisture content. In
general, higher density particles (e.g., oak) absorb or losemoisture more slowly than lower density fuel particles.
The downward trend of FMC shows that the rate of decline
in loose areas was much greater than that in dense areas.
Indeed, canopy shading reduces incoming solar radiation andwind flow in denser stands. According to some studies,
moisture loss from understorey fuels is greatly accelerated inless dense canopies. The main consideration was thedifference in the amount of radiation. Fuel that is in direct
sunlight will not only change the microclimate of the air
immediately surrounding the fuel but can also increase thefuel temperature that can reach up to 70℃ when in direct
sunlight. At 2pm, the value of FMC in the loose site wasmuch lower than that in the dense site. When condensation
began, the adsorption rate of broad leaves in loose site wasmuch higher than that in dense site. Due to the fact that thecapacity of fuel particles to absorb moisture is primarily
determined by the pressure difference between the inside andoutside, it was determined that the FMC was much smaller
than the EMC at this time, resulting in a greater pressure
gradient. And the FMC of two sites were nearly identical at
6 am. It can be shown that even though the variation in theprevious day was significant, the final adsorption process
remained unaffected. It was discovered that condensation
could return FMC to an equilibrium state. This shelter effecthas been incorporated into some fuel moisture models by
incorporating variables such as the leaf area index (LAI) or
stand density, which change dynamically with the seasonsand vary depending on the forest species.

4 Conclusions

Fig.1. The time series of three sites of fuel moisture
content (FMC) in the second investigation (a). Time
series of meteorological observations (b).
FMC is primarily subject to change due to sorption
processes. The gain and loss of moisture through vapor
exchange occurs when the vapor pressure of the fuel surface
differs from the surrounding air. This time, the dynamicchange of FMC was mainly considered from two aspects ofevaporation and condensation. FMC began to rise after two
o'clock in the afternoon, indicating that condensation began
to take effect between two and six o'clock in the afternoon.
Furthermore, the FMC was almost the same in the earlymornings of March 19th and 20th, when the temperature
difference was large and the relative humidity was almost thesame. Given that relative humidity had a greater influence on
FMC during the adsorption process, condensation played asignificant role. The overall FMC is higher in the earlymornings of March 18th and 19th, when the humidity ishigher.
When comparing cedar and broadleaf, the figure shows thatthe time when the FMC differs the most was around 6 a.m.,and the relative humidity at this time was also the highest ina day. When the relative humidity was at its lowest, the gap
in FMC was nearly the smallest. Because adsorption was
primarily affected by condensation at night, it was assumed

21

The FMC results obtained in the first investigation are allless than 10%. The second investigation results showed thateven in dry periods, FMC would vary greatly withmeteorological factors such as temperature and humidity
throughout the day. In the adsorption process, the relative
humidity had a greater influence on FMC, and thecondensation took a major role. The difference between
different species was also considered to be affected byrelative humidity. For forests of different densities, FMC
varied greatly. At 2 pm, the FMC value of the loose site wasmuch lower than that of the dense site. However, even though
the previous day's changes were great, the final adsorption
process was still unaffected. It was considered thatcondensation could recover FMC to an equilibrium state.

Reference[1] K. Anderson, D. L. Martell, M. D. Flannigan, and D.
Wang, Modeling of Fire Occurrence in the Boreal Forest
Region of Canada, Springer, New York, NY, 2000, pp. 357–
367.
[2] S. Matthews, Effect of drying temperature on fuelmoisture content measurements, Int. J. Wildl. Fire, vol. 19,
no. 6, pp. 800–802, 2010.
[3] R. C. Rothermel, How to predict the spread and intensityof forest and range fires., US Dep. Agric. For. Serv. Gen.
Tech. Rep., no. INT-143, 1983.
[4] A. G. and A. McArthur, Fire Behaviour in Eucalypt
Forests. Forestry and Timber Bureau Canberra, 1967.

The 9th International Symposium on Water Environment Systems

GP-RSS & SyDe

(Nov. 25th ~ 26th , 2021)

Tohoku University----- with Perspective of Global Safety

Changes in exposed population to heavy rainfall disasters associatedwith population decline in Japan○ Hayata YANAGIHARA1*, So KAZAMA1 & Seiki KAWAGOE2

1Department of Civil Engineering, Graduate School of Engineering, Tohoku University, Miyagi 980-8579, Japan.

Faculty of Symbiotic Systems Science, Fukushima University, Fukushima 960-1296, Japan.
*
E-mail: yanagihara.hayata.r1@dc.tohoku.ac.jp

2

Abstract
This study evaluated the changes in the exposed population to river flooding, inland flooding, and slope failurefrom 2015 to 2100 with population changes by shared socioeconomic pathways (SSPs). The exposed population
to river and inland flooding was defined as the population living in the area where inundation of 45cm or more(above the floor level of general houses). The exposed population to slope failure was defined as the population
living in the area where the probability of slope failure exceeds 80%. Although there were differences in
population distribution among the SSPs, such as urban concentration and decentralization, the magnitude relationof the total exposed population to the three disasters by SSPs was the same as the magnitude relation of the total
population by SSPs in 2100. The SSPs with the largest number of prefectures with the increase in the ratio of the
exposed population to population were estimated to be SSP4 to river flooding, SSP1, SSP2, and SSP5 to inland
flooding, SSP4 to slope failure, and SSP4 and SSP5 to the three disasters.
Keywords: river flooding; inland flooding; slope failure; shared socioeconomic pathways; disaster risk.
1 Introduction

2.2 Inundation depth data of inland flooding

In recent years, record-breaking rainfall has happened
every year, causing river flooding, inland flooding, andsediment disaster. There are concerns that the damage
caused by river flooding, inland flooding, and sedimentdisaster will increase due to climate change. Therefore,
further disaster management measures based on
quantitatively evaluating the disaster risk are required.
Many previous studies estimated the disaster risk using theexposed population (e.g., Ward et al., 2013[1]). Matsunaka etal. (2021)[2] estimated the exposed population to riverflooding and sediment disaster in two population migration
scenarios, one with more concentrated population to thethree major metropolitan areas and one with more dispersed
population to local areas. However, although sharedsocioeconomic pathways (SSPs) were developed, there are
no studies of changes in the exposed population withpopulation change by SSPs in Japan. This study evaluatedthe changes in the exposed population to river flooding,inland flooding, and slope failure from 2015 to 2100 withpopulation changes by SSPs.

As hazard data of inland flooding, this study used theinundation depth data of inland flooding throughout Japan
under the poor drainage condition computed by Yanagihara
et al. (2020)[6] using a two-dimensional unsteady flow
model (Tezuka et al., 2014[4]). This inundation depth dataassume that precipitation with a return period of 5 years candrain. The inundation depth data under the poor drainage
condition was used because actual inland flooding is often
accompanied by poor drainage. The spatial resolution of theinundation depth data is the fifth-order mesh. The
inundation depth data of inland flooding with return periodsof 5, 10, 30, 50, 100, and 200 years were used.

2 Datasets
2.1 Inundation depth data of river flooding
As hazard data of river flooding, this study used theinundation depth data of river flooding throughout Japan
computed by Yamamoto et al. (2021)[3] using a
two-dimensional unsteady flow model (Tezuka et al.,
2014[4]). The spatial resolution of the inundation depth datais the fifth-order mesh (approximately 250m×250m). The
inundation depth data of river flooding with return periodsof 30, 50, 100, and 200 years were used. The inundation
depth data reflects the capacity of flood control facilities ineach water system and river section utilizing the method of
Tanaka et al. (2019)[5].

22

2.3 Probability data of slope failure
As hazard data of slope failure, this study used theprobability data of slope failure throughout Japan computed
by Kawagoe et al. (2010)[7]. The spatial resolution of theprobability data is the third-order mesh. The probability dataof slope failure with return periods of 5, 10, 30, 50, 100, and
200 years were used.

2.4 Population data
As the reference population data, this study used the
population data of the third-order mesh based on thenational census in 2015 (Statics Bureau of Japan, 2017[8]).
As the population data in 2100, this study used the
population data by SSPs developed by the National Institutefor Environmental Studies[9]. The image of the population
distributions by SSPs is as follows: SSP1: compact +network; SSP2: maintenance of the status quo; SSP3: blightand slums; SSP4: concentration in urban centers and declineof suburbs; SSP5: concentration in metropolitan areas.

3 Method for estimating the exposed population
The exposed population to river and inland flooding was
defined as the population living in the area where

The 9th International Symposium on Water Environment Systems

GP-RSS & SyDe

(Nov. 25th ~ 26th , 2021)

Tohoku University

inundation of 45cm or more (above the floor level ofgeneral houses). The exposed population to slope failure
was defined as the population living in the area where theprobability of slope failure exceeds 80%. The hazard data
used to calculate the future exposed population did notconsider changes due to climate change. The annual
expected exposed population (AEEP) was computed using
Eq.1.
n(1/mi - 1/mi+1 )(xmi + xmi+1 )
E= �
(1)
2
i=1

100
AEEP decline rate[%]----- with Perspective of Global Safety

80

River flooding
Inland flooding
Slope failure
Population decline rate

60
40
20
0

SSP1

SSP2

SSP3

SSP4

SSP5

where E is the AEEP, n is the number of return
periods, mi is the return period, xmi is the exposed
population with a return period of mi.

Fig. 1. The AEEP decline rate by SSPs from 2015 to2100 in Japan

4 Results and discussion

Table 1 The number of prefectures with the increasein the ratio of the AEEP to population

4.1 Changes in the exposed population withpopulation changes in Japan
The AEEP in 2015 was estimated to be 0.66 million
people/year to river flooding, 0.83 million people/year toinland flooding, and 0.74 million people/year to slope
failure. The total AEEP to the three disasters in 2100 was
estimated to be 1.2 million people/year in SSP1, 0.99
million people/year in SSP2, 0.63 million people/year in
SSP3, 0.78 million people/year in SSP4, and 1.3 million
people/year in SSP5. Although there were differences in
population distribution among SSPs, such as urban
concentration and decentralization, the magnitude relationof the total AEEP to the three disasters by SSPs was thesame as the magnitude relation of the total population by
SSPs. Fig.1 shows the AEEP decline rate by SSPs from2015 to 2100 in Japan. For comparison, Fig.1 also shows
the population decline rate. Like the population decline rate,
the AEEP decline rates to river flooding, inland flooding,and slope failure were the largest in SSP3, followed by
SSP4, SSP2, SSP1, and SSP5.

4.2 Changes in the ratio of the exposed population
to population by prefecture
When the ratio of the AEEP to population increases, the
AEEP decline rate is lower than the population decline rate.
The number of prefectures with the increase in the ratio of
the AEEP to population was counted for each SSPs to riverflooding, inland flooding, and slope failure. The SSPs withthe largest number of prefectures with the increase in theratio of the AEEP to population were estimated to be SSP4
to river flooding, SSP1, SSP2, and SSP5 to inland flooding,
SSP4 to slope failure, and SSP4 and SSP5 to the threedisasters.

5 Conclusions
This study estimated the changes in the exposed
population to heavy rainfall disasters with population
change by SSPs. As a result, the SSPs with the largest
number of prefectures with the increase in the ratio of the
AEEP to population were SSP4 to river flooding, SSP1,
SSP2, and SSP5 to inland flooding, SSP4 to slope failure,and SSP4 and SSP5 to the three disasters.

23

River
flooding
Inlandflooding
Slopefailure
Total

SSP1

SSP2

SSP3

SSP4

SSP5

26

25

24

27

26

21

21

20

17

21

1

1

3

5

2

48

47

47

49

49

Reference[1] Ward, P.J. et al., Assessing flood risk at the global
scale: model setup, results, and sensitivity, Environmental
Research Letters, Vol.8, No.4 (2013), 040019.
[2] Matsunaka et al., Analysis of future disaster risk basedon population exposure to disasters, Journal of the City
Planning Institute of Japan, Vol.56, No.1 (2021), pp.73-84(in Japanese).
[3] Yamamoto, T. et al., Evaluation of flood damage
reduction throughout Japan from adaptation measures taken
under a range of emissions mitigation scenarios, Climatic
Change, Vol.165 (2021), Article: 60.
[4] Tezuka, S. et al., Estimation of the effects of climatechange on flood-triggered economic losses in Japan,
International Journal of Disaster Risk Reduction, Vol.9(2014), pp.58-67.

[5] Tanaka, Y. et al., Assessment of the risk of flood andstorm surge with flood control facilities, Journal of Japan
Society of Civil Engineers, Ser.B1 (Hydraulic Engineering),
Vol.75, No.2 (2019), pp.I_109-I_114 (in Japanese).
[6] Yanagihara, H. et al., Estimation of the risk of inland
flood based on extreme precipitation data considering
climate change in Japan, Journal of Japan Society of Civil
Engineers, Ser.B1 (Hydraulic Engineering), Vol.76, No.2
(2020), pp.I_85-I_90 (in Japanese).
[7] Kawagoe, S. et al., Probabilistic modeling of rainfall
induced landslide hazard assessment, Hydrology and Earth
System Sciences, Vol.14 (2010), pp.1047-1061.
[8]
Statics
BureauofJapan,
e-Stat,https://www.e-stat.go.jp/gis/statmap-search?page=1&type=1&toukeiCode=00200521 (2017).
[9] NIES, Results of Environment Research andTechnology
Development
Fund2-1805,https://adaptation-platform.nies.go.jp/socioeconomic/population.html (2021).

The 9th International Symposium on Water Environment Systems

GP-RSS & SyDe

(Nov. 25th ~ 26th , 2021)

Tohoku University----- with Perspective of Global Safety

Assessment of long-term operation performance in mesophilicanaerobic co-digestion of lipid and Food Waste○ Chen WANG1*, Yuanyuan REN1, Yu QIN1,2 & Yu-You Li1,2
1

Department of Civil and Environmental Engineering, Tohoku University, Miyagi 980-8579, Japan.
Department of Frontier Science for Advanced Environment, Tohoku University, Miyagi 980-8579, Japan.
*E-mail: wang.chen.q6@dc.tohoku.ac.jp.

2

Abstract
In this study, long-term operation performance of mesophilic anaerobic co-digestion system of lipid and foodwastes was investigated. The experiment run in a semi-continues mesophilic CSTR reactor with the HRT of 30 days.
It included 6 operating phases, and lipid/TS ratio of each phase was from 10% to 60%. With the increase of thelipid/TS ratio, the biogas production and the proportion of methane gradually increased, and the maximum biogas
production could reach 2.43L/L/d, the proportion of methane could account for up to 66.95%. The removal
efficiency of TS, VS and COD was as high as about 80%, and the removal efficiency of carbohydrate and lipid
could reach 90%. When the ratio of lipid/TS reached 60%, the system broke down, which indicated that the system
could operate stably below the lipid/TS ratio of 50%. The results of this experiment could provide a constructive
basis for the establishment of a stable, low-cost anaerobic co-digestion system of lipid and food waste.
Keywords: Mesophilic anaerobic co-digestion; Food waste; Lipid; CSTR.
1 Introduction
With the increase of the world's population and theadvancement of agricultural processing technology, foodwaste (FW), including food loss is increasing year by year.
At present, 13 billion tons of food are discarded every year in
the world[1], which is equivalent to one-third of foodproduction. A survey shows that by 2025, the production offood waste will increase by 30% compared to 2020[2].
Similarly, as people's dietary structure changes, the world's
production and consumption of edible oil are also increasing
year by year, which has led to an increase in the amount ofedible oil waste. In view of this situation, the disposal of foodand oil waste has become an important topic.
Compared with traditional landfilling, burning and othertreatment methods, anaerobic digestion has shown a strong
advantage in the treatment of FW and lipid[3]. It degrades thewaste while generating usable green gas energy.
In addition, the physiochemical characteristics of FW andedible oil are very suitable for use as raw materials foranaerobic digestion. Anaerobic digestion is a process inwhich organic matter and water are degraded into methane
under the effect of microorganisms. For FW, more than 90%
of it is composed of organic matter, and its moisture content
is also around 70%-90%. And the theoretical methane
conversion rate of lipid is as high as 94.8%. The anaerobic
fermentation system combining FW and lipid is expected toachieve higher methane production and conversion rate while
reducing total operating costs.

2 Materials and methods
2.1 Substrate and inoculum
The FW used in this experiment was made in the laboratory,
according to the survey about the ingredients and proportionof Japanese food waste, and then stored in the refrigerator at
4℃. The lipid used in the experiment was prepared bymixing several kinds of oil according to the edible oil
consumption survey. The anaerobic sludge was collectedfrom an anaerobic reactor treating sewage sludge.

24

2.2 Anaerobic co-digestion experimentThis semi-continuous long-term experiment was carried out
in a continuous stirred tank reactor (CSTR) with an effective
volume of 12L. The operating temperature of the reactor was
37℃, and the hydraulic residence time (HRT) of the reactor
was constant at 30 days. The detail operation conditions wereshown in Table 1.
Table 1 Experimental parameters of 6 phases.
Ⅰ

Phase
HRT
Substr-ate
Lipid/
TS
ratio
TSloading
rate
OLR

Day
s
%(
TS)
%
gTS/L
/d
gCOD
/L/d

Ⅱ

Ⅲ

Ⅳ

Ⅴ

Ⅵ

30

30

30

30

30

30

10

10

10

10

10

10

10

20

30

40

50

60

3.3
3

3.3
3

3.3
3

3.3
3

3.3
3

3.3
3

4.7
1

5.5
5

5.7
9

6.21

6.3
9

7.0
1

3 Results and discussion
3.1 Biogas production
The rate of biogas production rate is the most important
indicator to evaluate the performance of an anaerobic
digestion system. The detail results were shown in the Figure
1 and Figure 2.
When the Lipid/TS ratio was 10%, the biogas production
rate was 2.74L/L/d, and the methane production rate was
1.64L/L/d. When the Lipid/TS ratio reached 50%, the biogas
production rate was 3.63L/L/d, an increase of 32.48%. The
methane production rate was 2.43L/L/d, an increase of
48.17%. This results showed that when the Lipid/TS ratio
was less than 50%, the co-digestion of lipid and FW could
increase the biogas production rate and methane production
rate, and the entire anaerobic system had a better
performance. When the Lipid/TS ratio reached 60%, as theThe 9th International Symposium on Water Environment Systems

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(Nov. 25th ~ 26th , 2021)

Tohoku University

Phase Ⅰ

Phase Ⅱ

CO2
CH4
N2

4

Phase Ⅳ

Phase Ⅲ

Phase Ⅵ

Phase Ⅴ

100

BiogasMethane

80

3

60

2

40

1

20

0
560

0
0

40

80

120

160

200

240

280

320

360

400

440

480

Gas Composition (%)

Gas Production Rate (L/L/d)

5520

Operation Time (d)Fig. 1. The gas production rate
At the same time, the proportion of methane in the biogas
produced in the anaerobic reactor also increased obviously.
As shown in the Figure 2(b), during the operation withlipid/TS ratio of 50% or less, the proportion of carbon dioxide
dropped from about 40% at the beginning to about 33%,
while the content of methane rose from about 60% at the
beginning to about 67%.

3

2

1

BiogasMethane

80

30

40

50

10

60

20

30

40

50

Phase Ⅴ

Phase Ⅵ

pH

pH

5
10000

Alkalinity-6.5
Alkalinity-4.8

7500
5000
2500
0
3000

2000

1000

120

160

200

240

280

320

Operation Time (d)

10

20

30

40

50

Lipid content (g/L)

360

400

440

480

520

For mesophilic anaerobic co-digestion of food waste andlipid, the system could be operated successfully in the case of
50% Lipid/TS ratio, from the perspective of system
performance and stability. When the concentration oflipid/TS ratio reached 50%, the removal efficiency of lipid
could reach 90%, biogas production rate of 3.63L/L/d andmethane production rate of 2.43L/L/d can be achieved at
OLR of 6.39 g-COD/L/d.

[1] 農林水産省, 食品ロスの現状を知る, aff (あふ),2020 年 10 月号.
[2] Yuanyuan Ren, Miao Yu, Chuanfu Wu, Qunhui Wang,
Ming Gao, Qiqi Huang, Yu Liu, A comprehensive review onfood waste anaerobic digestion: Researchupdates andtendencies, Bioresourece Technology, 247 (2018) 1069-1076.
[3]M.F.M.A.Zamri,SaifulHasmady, Afifi Akhiar, Fazril
Ideris, A.H. Shamsuddin, M. Mofijur, I. M. Rizwanul Fattah,
T.M.I.Mahlia, A comprehensive review on anaerobic
digestion of organic fraction of municipal solid waste,
Renewable and Sustainable Energy Reviews, 137 (2021)
110637.

MAD-4.8
MAD-6.5

8000
6000
4000
2000
0
3000
2000
1000
0

0
80

50

Reference

7
6

TAN (mg/L) Alkalinity (mg-CaCO3/L)

TAN (mg/L)

Alkalinity (mg-CaCO3/L)

6

40

40

4 Conclusions

8

0

30

9

7

5
10000

TS
VS
COD

70

Lipid content (g/L)

Phase Ⅳ

Phase Ⅲ

20

75

It shows that this anaerobic co-digestion system can achieve
an ideal degradation effect of organic matter.

60

3.2 Sludge characteristics
In an anaerobic digestion system, pH, alkalinity and totalammonia nitrogen are usually indicators of the stability,
while these three indicators also influence each other. During
the long-term operation, the characteristics of the sludge wereshown in the Figure 3.
Phase Ⅱ

Carbohydrate
Protein
Lipid

80

20

Fig. 2. Gas production rate in each phase ((a) Gas
production; (b) Gas composition))

Phase Ⅰ

20

85

Fig. 4. Organic removal efficiency in each operation
phase

40

Lipid content (g/L)

840

Lipid content (g/L)

0

20

80

10

60

0
10

90

100

0

N2
CH4
CO2

4

Gas Composition (%)

Gas Production Rate (L/L/d)100

were relatively stable, which showed strong buffering
capacity of the system. With the lipid/TS ratio increasing to50%, alkalinity had dropped from 6130 mg-CaCO3/L to 3350
mg-CaCO3/L. And it can be seen that there were slightfluctuations around 7.5 in pH. The reason for the decrease
was that the total ammonia nitrogen as the buffering materials
began to decrease. After continuing to increase the ratio of
lipid/TS to 60%, the alkalinity was reduced to 2180 mgCaCO3/L, the pH was only 5.99, and the system wascompletely acidified.
3.3 Organic removal efficiency
The organic removal efficiency represented the metabolic
capacity of the system, and generally the more organic matter
was degraded, the higher the methane production would be.
Through experimental determination, it could be obtainedthat when the lipid/TS ratio was less than 50%, the reactor
could be operated stably, the degradation rate of TS, VS and
COD has been stable at about 80%, and the degradation rateof carbohydrates and lipid could reach about 90%.
Removal efficiency (%)

entire anaerobic digestion system broke down, the biogas
production rate and methane production rate dropt sharply,
becoming 0.86L/L/d and 0.38L/L/d, a decrease of 68.61%
and 76.83%. To obtain higher gas production rate while
maintaining the stable operation of the system, it could beroughly inferred that the optimal Lipid/TS ratio was 50% or
less.

Removal efficiency (%)----- with Perspective of Global Safety

10

20

30

40

50

60

Lipid content (g/L)

Fig. 3. Sludge characteristics ((a) During long-term
operation; (b) In each phase)
It could be seen from the figure that in the first four phases,
when the lipid/TS ratio was lower than 40%, the pH,
alkalinity, and total ammonia nitrogen content of the system

25

The 9th International Symposium on Water Environment Systems

GP-RSS & SyDe

(Nov. 25th ~ 26th , 2021)

Tohoku University----- with Perspective of Global Safety

Influence of ammonia concentration on the treatment performance ofpilot-scale one-stage PN/Anammox process○ Zibin LUO1*, Chao Rong2, Tianjie Wang1, Yan Guo1, Yu Qin1 & Yu-You Li1,2
1

Department of Civil and Environmental Engineering, Tohoku University, Graduate School ofEngineering, Miyagi 980-8579, Japan2
Department of Frontier Science for Advanced Environment, Graduate School of Environmental Studies,
Tohoku University, Miyagi 980-8579, Japan.
*E-mail: luo.zibin.q1@dc.tohoku.ac.jp.

Abstract
A pilot-scale novel wastewater treatment system combining an anaerobic membrane bioreactor (AnMBR) and aone-stage partial nitrification-anammox (PN/A) reactor was set up to verify the application of this brand new systemon real wastewater. The biofilm-based PN/A reactor was started up successfully and quickly in the first year of
running. However, anammox biofilm, one of the critical points in the system, did not proceed well enough as thestudies before. This study focuses on biofilm formation and reactor performance in dealing with wastewater ofdifferent ammonia concentrations after biofilm is formed. Through 164-days cultivation, biofilm was obviously
observed. With a stable nitrogen loading rate (NLR) of 0.3 g-N/L/d and decreasing influent ammonia concentrationfrom 5000 mg-N/L to 100 mg-N/L, the nitrogen removal efficiency dropped from 94.8% to 74.1%. The results
confirm that the system has the great potential to be widely applied in wastewater with different nitrogenconcentrations.
Keywords: Partial nitrification; Anammox; Biofilm; Municipal wastewater.
1 Introduction
The anaerobic ammonia oxidation (anammox), whereammonium could be combined with nitrite to generate
nitrogen, was a great discovery in recent years. For the reason
that the traditional nitrification/denitrification process has
been blamed for the disadvantage of being too energyintensive, this brand new technology is expected to be used
as an alternative to conventional denitrification for thetreatment of nitrogen in wastewater. Since the anammox
reaction has been found, a number of researchers are working
on basic research related to anammox and trying to get thetechnology into practical application.
Up to now, the anammox-based research has proceeded intofull scale, and a large number of full-scale implementationsof the one-stage nitrification/anammox process have been
conducted. However, seldom of them are primarily related tothe treatment of low-strength municipal wastewater inmainstream[1].
According to the Environment Bureau of Aichi Prefecture
data, 46% of the total nitrogen released by human activities
comes from household water. Applying this energy-saving
anammox process as a mainstream process in the nitrogen
treatment of domestic water is necessary from a sustainable
development perspective.
In this study, a pilot-scale PNA reactor was started up withan anaerobic membrane bioreactor (AnMBR) to verify thefeasibility of this brand-new system in treating wastewater ofdifferent nitrogen concentrations in the mainstream, which
can provide a reference for subsequent practical studies.

2 Materials and methods
2.1 Reactor Setup and Operation
The moving bed biofilm reactor (MBBR) possesses aworking volume of 1.67 m3, equipped with a stirrer, a pH

26

sensor, and an NH4+-N sensor. Hollow cylinder carriers,
made of hydrophobic polypropylene resin, were added into
the reactor until the filling rate of 15%. Air would be pumped
intermittently into the bottom of the reactor to supply theoxygen, which could be regulated by a rotameter attached.
Artificial influent was transferred by a peristaltic pump,while an impeller pump provided the effluent of AnMBR.
Mixed liquid from the PN/A reactor would flow into a 1.92
m3 radial-flow sedimentation tank, and the collected sludge
in the bottom was refluxed into the PNA reactor through an
impeller pump. The operation temperature was set at around23 degrees centigrade. The activated sludge containing
ammonia-oxidizing bacteria (AOB) and anammox seedsludge were inoculated in the reactor and supplied withsynthetic wastewater for proliferation. In the start-up stage,
nitrite-oxidating bacteria (NOB) that remained in the sludge
were inhibited. DO concentration and pH in the effluent wereregularly measured using a DO meter (HORIBA HC-200NH,
Japan) and a portal pH meter (HORIBA D-71, Japan),respectively.
The operation condition is shown in Table 1.
Table 1 Operation Conditions
Stage

Ⅰ

Ⅱ

Ⅲ

Ⅳ

Ⅴ

Duration (day) 1-164 165-180 181-214 215-236 237-264
Influent
ammonia30-440 5000
concentration+(mg-NH4 -N/L)
HRT (Days)

0.110.87

NLR(g-N/L/d)

0.2-0.5

MLVSS (mg/L) 1766

16.70

1000

500

100

3.30

1.67

0.33

1876

2179

0.3
2471

2361

The 9th International Symposium on Water Environment Systems

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Tohoku University----- with Perspective of Global Safety

2.2 Sampling and analytical methods
All of the samples of influent and effluent were analyzed
after being filtrated through Millipore filter units with 0.45
μm pore size. The NH4+-N, NO2−-N, and NO3−-N
concentration was measured by capillary electrophoresis(Agilent 7100, Agilent Technologies, USA).

3 Results and discussion

This study is divided into five stages, containing thebiofilm-forming stage and the experiment stages. In Stage Ⅰ,
several strategies were adopted for the growth of anammox
bacteria. As shown in Fig. 1, reactor performances were
unstable. The nitrogen removal efficiencies were quite
different while treating wastewater of 30-440 mg-N/L due tothe sparse and thin biofilm and the impact from the actual
sewage. However, the maximum removal efficiency of
84.2% can be achieved when the influent concentration is
440 mg-N/L. More importantly, the anammox biofilm, themain target of this stage, has clearly formed as Fig. 2.
In order to further understand the effect of influent nitrogenconcentration on the PN/A reactor performance, the reactor
was maintained at a nitrogen loading rate of 0.3 g-N/L/d, andthe influent ammonium concentration was gradually reduced
from 5000 mg-N/L in Stage Ⅱ to 100 mg-N/L in Stage Ⅴ. As
with the results of many studies, the anammox process wasvery effective in treating wastewater with high ammonium
concentrations. When the reactor was fed with 5000 mg-N/L
sewage in Stage Ⅱ, a 94.8% nitrogen removal was achieved.
Once the influent nitrogen concentration dropped to 1000
mg-N/L in Stage Ⅲ, the nitrogen removal efficiency
decreased to 88.5%. With a further halving of the influent
ammonium concentration to 500 mg-N/L in Stage Ⅳ, aremoval rate of 84% could still be achieved. Finally, in stage
Ⅴ, when the influent ammonium concentration became 100
mg-N/L, relatively low compared with stage Ⅱ, the reactor
performance became unstable, and nitrogen removal
efficiency declined to 76.1%. From the result above, it wasevident that as the influent NH4+-N concentration got lower,
the nitrogen removal efficiencies of the reactor were withvarying degrees of decline. Moreover, the trend line fit
revealed that the ammonium concentration might belogarithmically or power functionally related to the nitrogen
removal efficiency in this case. Meanwhile, the anammox
biofilm in Stage V became denser and thicker compared withthe former stage.
After all, in this pilot plant study, it is confirmed that thebiofilm-based one-stage PN/Anammox process showed an
excellent performance with a wide range of concentrations of
nitrogen wastewater.

4 Conclusions(1) In a pilot-scale PN/A reactor, anammox bacteria can beproliferated using real wastewater, and anammox biofilms
have been successfully formed on the hollow cylinderhydrophobic polypropylene resin carriers.
(2) At the same nitrogen loading rate, the nitrogen removal
efficiency of the PN/A reactor decreases to varying degrees
as the influent ammonium concentration decreases and theactual wastewater ratio increases. However, the results ofstudies at the pilot-scale show that the biofilm-based onestage PN/Anammox process has great potential to treat awide range of concentrations of ammonia nitrogenwastewater.

Fig. 1. Reactor performance

A

B

Reference[1] Rong Chen, Using Partial Nitrification and Anammox toRemove Nitrogen from Low-Strength Wastewater by Coimmobilizing Biofilm inside a Moving Bed Bioreactor, ACS
Sustainable Chemistry & Engineering (2019) 1353-1361.

Fig. 2. Biofilm on (A) Day 1 and (B) Day 102

27

The 9th International Symposium on Water Environment Systems----- with Perspective of Global Safety(Nov. 25th ~ 26th , 2021)

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Development of a BrISH for environmental microorganisms○ Kampachiro URASAKI1*, Yu-You LI 1 & Kengo KUBOTA2
1

Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University,
Miyagi 980-8579, Japan.
2
Department of Frontier Sciences for Advanced Environment, Graduate School of Environmental Studies, Tohoku
University, Miyagi 980-8579, Japan.
*
E-mail: kampachiro.urasaki.p1@dc.tohoku.ac.jp

Abstract
Fluorescence in situ hybridization is a convenient tool for understanding microbial community because it canvisualize microorganisms at single cell resolution. FISH has a lot of variants that uses the heavy element instead of
the fluorophore for the X-ray detection. X-ray based techniques can detect with high resolution; therefore, have atechnical potential for the single cell detection. In this study, we attempted to develop a novel bromine labelingmethod, “BrISH.” BrISH employs TSA (tyramide signal amplification) reaction to enhance the intensity of thelabeled element. Two candidates of the tyramide-Br compound (tyramide-Br-1, C10H12O2NBr; tyramide-Br-2,
C7H6O2NBr) were synthesized, nevertheless, tyramide-Br-1 (C10H12O2NBr) yield was low and another tyramide
compound added Cl was obtained. Tyramide-Br-2 (C7H6O2NBr) was not obtained. BrISH using tyramide-Br-1 wasapplied to the pure cultures however Br signal wasn’t obtained so far.
Keywords: CARD-ISH; Bromine; X-rays detection; Scanning electron microscope.
1 Introduction
FISH (fluorescence in situ hybridization) is widely used invarious fields because it can detect microorganisms at singlecell resolution without cell cultivation and DNA/RNA
extraction. FISH is an attractive tool for understanding
microbial community structure because it can detect target
microorganisms phylogenetically. In recent years, detection
using X-ray-based techniques, e.g., SEM (scanning electron
microscopy), are becoming mainstream due to their highresolution. For X-rays detection, labeling the microbial cellswith heavy elements is necessary. Gold (Au) is commonlyused as a labeling element for the X-ray detection [1]. For
multicolor staining, a novel labeling method that uses heavy
elements other than Au is promised. In this study, bromine(Br) was focused on as the cell labeling element. In order tolabel cells with high density Br, TSA (tyramide signal
amplification) reaction was employed. TSA reaction is theperoxidase-catalyzed reaction to bind the tyramide
compounds with the aromatic amino acids in the cell tissue.
The reaction was employed highly sensitive FISH method(TSA-FISH), ELISA and etc. In this study, a novel Brlabeling method employing TSA reaction, named “BrISH,”
was attempted to develop.

2 Materials and methods
2.1 Sample preparation
The strains used in this study were Comamonas testosteroni
and Escherichia coli. Both strains were cultivated in LB
medium at 37˚C with agitation. During exponentially growthphase, these cells were fixed in a 4% paraformaldehyde
solution in phosphate buffered saline (PBS; 150 mM NaCl,
20 mM PO43- [pH7.4]) for 12 h at 4oC, and stored inethanol/PBS solution at -20˚C.

28
28

2.2 Tyramide synthesis
First, a synthesize reaction of tyramide compounds wasinvestigated. Two candidates of tyramide-Br compounds
were prepared which were tyramide-Br-1 (C10H12O2NBr,
MW 258) and tyramide-Br-2 (C7H6O2NBr, MW 216).
Tyramide compounds were synthesized in accordance withthe previous report with some modifications [2]. TyramideBr-1 was synthesized from tyramine-HCl and 2bromoisobutanoic acid NHS ester, and tyramide-Br-2 wassynthesized from tyramine-HCl and bromoacetic acid NHS
ester. NHS esters were dissolved in DMF (10 mg/ml) toobtain the stock solution A. Tyramine-HCl was dissolved in
DMF containing TEA (10 μl/ml) to obtain the stock solution
B. Then the stock solution A was added in 1.1 times
equimolar amounts to the stock solution B. The mixture of
the stock solution A and B was incubated for two hours in thedark with mild stirring. Obtained compounds were analyzed
by GC-TOF/MS (JEOL, JMS-T100GCV).
2.3 BrISH
The scheme of BrISH was shown in Fig.1. First, cell wall
treatment was performed using lysozyme solution (10mg/ml). In-situ hybridization with BET42a-HRP (5’-GCCTT
CCCAC TTCGT TT-3’) was performed as described
previously [3]. After in-situ hybridization, TSA reaction was

The 9th International Symposium on Water Environment Systems----- with Perspective of Global Safety(Nov. 25th ~ 26th , 2021)

carried out using the working buffer (10% dextran sulfate and0.0015 % [v/v] H2O2 0.1% [w/v] blocking reagent in PBS)
containing 20 μg/ml of tyramide-Br-1 compound for 15 minat room temperature. Then, the samples were equilibrated in
0.05% [v/v] PBSX for 15 min at room temperature. For
microscopic observation, digital photograph, and EDX
measurement, scanning electron microscope (JEOL, JSM7100F) was used.

3 Results and discussion
3.1 Analysis of the synthesized tyramides
Fig.2(A) shows the TOF/MS spectrum analyzing theobtained tyramide-Br-1 solution. The low intensity oftyramide-Br-1 was detected (m/z 257). The highest signal(m/z 213) was estimated “C10H12O2NCl.” It was speculated
that Cl in tyramine-HCl (C8H11NO・HCl) was replaced withtyramide-Br-1’s Br among the synthesis. Fig.2(B) shows the
TOF/MS spectrum analyzing the obtained tyramide-Br-2
solution; however, tyramide-Br-2 was not detected. The
highest peak is estimated “C12H16O2NBr” (m/z 285).
Tyramide-Br-2 was failed to synthesize; therefore tyramideBr-1 was used for BrISH.

3.2 BrISH
Fig.3 shows the C.testosteroni by BrISH of (A) secondary
electron image and (B) EDX measurement by scanningelectron microscope (SEM). For EDX measurement, Br peak
(1s; 1.60 keV, 2s; 1.78 keV) was not observed from the target
microorganism (C. testosteroni). Only C peak (1s; 0.28 keV)and O peak (1s; 0.54 keV) were observed that were from thecell’s organic matter. Br was not detected from the nontarget
microorganism (E. coli, data not shown). Cl peak (1s; 2.82
keV) wasn’t observed thus “C10H12O2NCl” didn’t deposit to
the cell tissue. Those results indicated that synthesizedcompounds didn’t have the function of the tyramide
compounds.

4 Conclusions
We attempt to develop the novel phylogenetically specific
Br labeling method, “BrISH.” Tyramide-Br was synthesizedfrom 2-bromoisobutanoic acid NHS ester and tyramide-HCl,however sufficient yield was not obtained. BrISH wasapplied to the pure cultures and detected by SEM, but any Br
signals were not obtained so far.

Reference[1] Schmidt H, Eickhorst T, Mussmann M. Gold-FISH: a
new approach for the in situ detection of single microbial
cells combining fluorescence and scanning electron
microscopy. Syst Appl Microbiol. 35(8) (2012):518-25.
[2] Hopman AH, Ramaekers FC, Speel EJ. Rapid synthesisof biotin-, digoxigenin-, trinitrophenyl-, and fluorochromelabeled tyramides and their application for In situ
hybridization using CARD amplification. J Histochem
Cytochem. 46(6) (1998):771-7.
[3] Kubota K, Imachi H, Kawakami S, Nakamura K, Harada
H, Ohashi A. Evaluation of enzymatic cell treatments forapplication of CARD-FISH to methanogens. J Microbiol
Methods. 72(1) (2008):54-9.

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29

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The 9th International Symposium on Water Environment Systems

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Methane fermentation performance of swine wastewater treatment by apilot-scale self-agitation anaerobic baffled reactor○ Junhao SHEN1, Yunzhi QIAN1,Yan GUO1, Fuqiang CHEN1,Yu-You LI2*
1

Dept. of Frontier Sciences for Advanced Environment, Tohoku University, Sendai, 980-8579, Japan.
Dept. of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University,
Sendai 980-8579, Japan.
*
E-mail: shen.junhao.q2@dc.tohoku.ac.jp
gyokuyu.ri.a5@tohoku.ac.jp

2

Abstract
In the context of the intensification of pig production and consequent higher animal densities, the environmental
effects have to be considered. Swine Wastewater (SW), as the main direct environmental impact pig production,
can be removed by biological treatment, which is called methane fermentation. In this research, SA-ABR(Self-Agitation Anaerobic Baffled Reactor) is used in the treatment of SW to save energy as the goal. The
performance, in term of gas production, organic removal, and the stability of the system in practical applications
were investigated during 400 days by changing the hydraulic retention time (HRT) and organic loading rate (HRT)from 60 to 7.5 days and from 0.18 to 7.16 g/L/d. SW which had TCOD, proteins and carbohydrates of 22.4, 6.34
and 1.48g/L, respectively, was used as substrate. COD removal efficiency reaches a maximum of 65% when theorganic load on HRT 10 days is 1.14g/L/d, and COD removal efficiency is maintained at 50% or more until theorganic load on HRT 10 days is 1.85 g/L/d, but after the OLR exceeded 2, it was going to drop more andmore.The biogas production was about 100 L / day, and a maximum of 544.2 L / d was recorded when the organic
load was 4.8g/L/d.
Keywords: Swine Wastewater; Methane Fermentation; Self-Agitation Anaerobic Baffled Reactor (SA-ABR).
1 Introduction
Recent years, in the context of the intensification of pig
production and consequent higher animal densities, theenvironmental effects have to be considered. Global issue
such as greenhouse gas emission from livestock production
are becoming internationally recognized. Swine wastewater(SW), as the main direct environmental impact pig
production, can release the production of combustibles
through bio-digestion which can help to make optimum useof the natural resources involved in the production cycle.
(FAO, 2021).
A common treatment process in SW is ananaerobic-aerobic treatment system. The processing
capacity of this process is low depending on the volume ofthe processing equipment and is expensive in terms ofinvestment, maintenance and operation. Therefore, we arekeenly aware of the need to improve the efficiency ofremoving SW and to find a treatment process that can beapplied to the recovery of resources. On another hand,anaerobic digestion (AD) has presented high effectivenessin the elimination of biodegradable pollutants from complex
agro-industrial effluents, as well as bioenergy production
through biogas (G. Lourinho,2020).
Various of anaerobic bioreactor were developed for
anaerobic digestion, such as up-flow anaerobic sludge
blanket (UASB), continuously stirred tank reactor (CSTR),
anaerobic membrane bioreactor (AnMBR) and baffled
reactor. The first anaerobic baffled reactor (ABR) was
developed by Bachmann (1983). Then, many researchers
have been working on baffled reactor and found its several
advantages. ABR has faster granulation process (HutnÏan,M. et al., 1999), higher microbial diversity in every chamber,

30

good resilience to hydraulic and organic shock loads,
prevent the sludge wash-out (Tanikawa, D., 2017 andMotteran et al., 2013), high resistance in environmental
parameters such as pH and alkalinity (Rongrong et al.,2011; Zhong and Yang, 2012), simple design low cost for
construction and operating (Tanikawa, D., 2017; Ji et al.,2009). Moreover, it is lauded for its simple design and the
low construction and operating costs (Ji et al., 2009).
With the advantages of the ABR, Previous researchersdeveloped a new ABR called self-agitation anaerobic
baffled reactor (SA-ABR). The SA-ABR has been
investigated and the result show that SA-ABR iscomparable in digestion performance to the completely
stirred tank reactor (CSTR) (Kobayashi and Li, 2011). In
addition, subsequent experiments were carried out on alaboratory scale with actual fish processing wastewater as
the substrate. The experimental results showed that
SA-ABR showed good processing performance in thetreatment of fish processing wastewater (Eli, 2020). In
another study by Qiao, a higher methanogenic performance
was achieved by the SA-ABR than the CSTR in treating
swine wastewater. In that study, at an HRT of 1 day, thespecific methane yield of the SA-ABR was 0.43 L/g, while
the CSTR failed to produce biogas due to the sludge
washout, and stable biogas production was achieved at ashort HRT of 0.5 days for the SA-ABR (Qiao et al., 2018).
Therefore, based on previous studies, in this study, we
designed a pilot-scale SA-ABR system for anaerobic
fermentation of swine wastewater and urine. The purpose ofthis research is to investigate the performance of SA-ABR
in methane fermentation of SW in term of COD conversion;
biogas production and the stability of SA-ABR.

The 9th International Symposium on Water Environment Systems

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efficiency, the optimal operating condition was OLR
1.75±0.25g/L/d in HRT of 10 days.

2 Materials and methods
2.1 Reactor design and operation
The reactor design is shown on Fig.1 with working volume
1000 L (total volume 1050 L), setting temperature 35±1℃.
The seed sludge was taken from anaerobic wastewater
treatment Jnex Waste recycling factory. The reactor is set
up in the Za-O pig farm, and samples are taken twice aweek and taken back to the laboratory for measurement andanalysis.

Fig.1 SA-ABR system Design

2.2 Analysis
Analyses of pH, alkalinity, COD, protein, carbohydrate,
lipid, NH4+, TS, VS, MLSS, MLVSS were performed
according to the Japan standard methods (JSWA, 1997).
VFA was determined by gas chromatography(Agilent-6890). Biogas composition was measured by a gas
chromatograph (SHIMADZU GC8A).

3 Results and discussion
3.1 Substrate profile
Characteristics of swine wastewater, such as pH, TAN isdetermined with the average 7.78, 2.967g/L. On the other
hand, the averages of alkalinity, protein, carbohydrate, TS,
VS, SS, VSS were 12.26g/L, 6.34g/L, 1.48g/L, 24.7g/L,
12.48g/L, 13.82g/L and 7.49g/L. In addition, the fluctuationof COD is relatively large, between 8.0g/L to 56.3g/L andthe average is 22.4g/L.

3.2 Performance and stability of fermentation
process
In general, the performance of SA-ABR in treatment ofswine wastewater was good. Organic loading rate (OLR)
increased from 0.18 g/L/d to 7.16g/L/d with the decrease of
Hydraulic Retention Time (HRT). COD removal efficiency
reaches a maximum of 65% when the organic load on HRT
10 days is 1.14g/L/d, and COD removal efficiency ismaintained at 50% or more until the organic load on HRT
10 days is 1.85 g/L/d, but after the OLR exceeded 2, it wasgoing to drop more and more. And with regard to biogas
production, the amount of biogas produced was about
100L/day, and a maximum of 544.2L/d was recorded when
the organic load was 4.8 g/L/d. To look for optimal
operating conditions, calculated COD balance, the result
showed when OLR was 1.90g/L/d, the COD balancereached over 90% and the methane conversion efficiency
exceeded 20%.
About the stability of system, when HRT was 15days with
OLR of 0.5±0.05g/L/d, the performance of system was very
good that can be applied to various conditions, such as low
temperature, extremely high concentration of COD. But if
take consideration such as biogas production, COD removal

31

Fig.2 SA-ABR Performance in Swine Wastewater
Fermentation

4 Conclusions
The content of components such as the content of organic
matter in swine wastewater was extremely unstable, which
influenced the research. But even if in this situation, theSA-ABR showed satisfying stability. Biogas production
recorded a maximum of 544.2L/d with an OLR of 4.8g
COD/L/d on the HRT of 10 days. However, it is stillnecessary for advanced studies of SA-ABR for COD
removal efficiency and higher methane conversion
efficiency.

Reference[1] Eli Hendrik Sanjaya, Mesophilic methane fermentation
performance and ammonia inhibition of fish processing
wastewater treatment using a self-agitated anaerobic baffled
reactor, Bioresource Technology313 (2020) 123644.
[2] G. Lourinho et al., Recent advances on anaerobic
digestion of swine wastewater, International Journal ofEnvironmental Science and Technology volume 17,
pages4917–4938 (2020).
[3] Qiao et al., Continuous anaerobic treatment of swine
wastewater by using self-agitation anaerobic baffled reactor,
Nongye Gongcheng XuebaoTransactions Chin. Soc. Agric.
Eng. 34, 210–215.

The 9th International Symposium on Water Environment Systems

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Enhancement Effect of Two Novel Pretreatment Methods on Anaerobic
Digestion of Waste Activated Sludge with Thermophilic AnMBR○ Shitong ZHOU1*, Guangze GUO1, Yemei LI2,3, Yu-You LI1,2
1

Department of Frontier Science for Advanced Environment, Graduate School of Environment Studies,
Tohoku University,6-6-06 Aoba, Aramaki-Aza, Sendai, Miyagi 980-8579, Japan.
2Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku
University,6-6-06 Aoba, Aramaki-Aza, Sendai, Miyagi 980-8579, Japan.
3
Material Cycles Division, National Institute for Environmental Studies, Tsukuba 305-8506, Japan*
E-mail: zhou.shitong.q2@dc.tohoku.ac.jp.

Abstract
Two novel integrated pretreatment methods called venturi tube combined with steam injection (VT-SI) andinflow heating steam injector (IHSI) were firstly applied to increase the sludge solubility of waste activated sludge(WAS). Both methods innovatively combined hydrodynamic cavitation (HC) and steam. All the untreated sludge
and pretreated sludge were digested in a thermophilic anaerobic membrane bioreactor (ThAnMBR) respectively
under the high solid condition with TS =30 and 40 g/L for a long term. Both VT-SI and IHSI proved effective insludge solubility enhancement, with COD disintegration degree (DD) of 11.2% and 11.0% respectively. Besides,
biogas yield increased by 5.4% and 7.0%, and methane conversion efficiency increased by 6.9% and 9.0%
through VT-SI and IHSI pretreatment, respectively. In addition, the ThAnMBR was operated stably for a longterm under the condition that TS was 30 g/L with the average flux of 6 L/m2/h (LMH). However, when the TScontinued increased to 40 g/L, the filtration performance showed a great reduction. Membrane cleaning was
conducted and membrane resistance of each foulant layer was calculated. And cake layer was considered as thebiggest contributor to membrane fouling.
Keywords: Pretreatment; ThAnMBR; Waste activated sludge; Hydrodynamic cavitation; Membrane
Performance
1 Introduction
During the municipal wastewater treatment, a large
amount of WAS is produced. Anaerobic digestion (AD) has
been widely used for WAS treatment. However, microbial
flocs can be discharged with the effluent, resulting in bad
effluent quality and low methane conversion efficiency.
AnMBR is an emerging treatment process to solve thisproblem with several merits. Combining the membrane
filtration technology, AnMBR realizes the complete
separation of HRT and SRT, thus effectively maintaining
the microorganism in the reactor, reducing the sludge
discharge, guaranteeing excellent effluent quality, andimproving the organic conversion efficiency.
Another problem lies in AD of WAS is known as theslow hydrolysis rate due to the recalcitrant substances andcomplex structure. To increase the biodegradability,
pretreatment has been proposed accordingly. There arevarious pretreatment methods, which can be classified asthermal hydrolysis, mechanical pretreatment, chemical
pretreatment, and biological pretreatment. Nowadays,
mechanical pretreatment has attracted more and moreinterest because it is energy-saving, convenient, and is easyof operation with good enhancement performance as well.
The principle of hydrodynamic cavitation (HC) has
commonly applied in mechanical pretreatment, which takes
advantage of the local pressure drop resulted from thechange of cross section. During the HC process, cavitation
bubbles produce, grow and finally implosive break torelease huge kinetic energy and heat near the local area. In
this way, it disrupts the sludge structure, increases solubility
and accomplishes homogenization.

32

In this study, the enhancement effect of two novel
pretreatment methods on the AD of WAS in a ThAnMBR
was first investigated, especially the sludge solubility,
biogas production and organic conversion efficiency. In
addition, the feasibility of stable operation of AnMBR underhigh solid condition for a long term was also explored.

2 Materials and methods
2.1 Substrate and Pretreatment methods
The WAS was collected from S municipal wastewater
treatment plant in Japan. Then part of WAS was pretreatedby VT-SI and IHSI, respectively. In VT-SI, pre-heated
WAS was added to pass through a venturi tube which had athroat with narrowed diameter. In venturi throat, pressure
dramatically decreased due to the increase of velocity,
leading to the production of cavities. In the downstream
area, the pressure recovered and caused the cavitation
bubbles breaking. At the same time, steam was injected in a
speed of sound to promote the cavitation (Fig.1a).
As for IHSI, it also took advantage of HC and had anarrowed cross section as well, but with a different
application method of steam. The steam was input to mix
with sludge so that it realized simultaneous cavitation
promotion and sludge heating. The temperature of outflow
WAS was 70 ℃ while that of inflow was 30 ℃. Due toadjustment of the configuration of steam injector, IHSI
could achieve great mixture effect (Fig.1b).
2.2 Experimental Device and Operation Conditions
The ThAnMBR system used in this study was external
submerged AnMBR composited of one continuous stirredtank reactor (CSTR) of 13 L and one membrane unit of 2 L(Fig.1c). The membrane was hollow fiber membrane with

The 9th International Symposium on Water Environment Systems

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pore size of 0.1 μm and effective membrane area of 0.1 m2,
the material of which was polytetrafluoroethylene (PTFE).
There were five stages in the whole operation period,
with the HRT kept as 15 days. In the first three stages, threedifferent types of sludge were fed as substrate, which wereuntreated WAS, pretreated WAS by VT-SI and pretreated
WAS by IHSI, respectively. And the total solid (TS)concentration of bulk sludge in reactor was kept at 30 g/L.
In the later two stages, the TS was increased to 40 g/L, anduntreated WAS and pretreated sludge by IHSI were used as
substrate respectively.

Fig. 1. The schematic diagram of the pretreatment
methods and experimental device. a) VT-SI; b) IHSI; c)
ThAnMBR

3 Results and discussion
3.1 Sludge Solubility
Since most of anaerobic microorganisms only ingest
soluble organics, converting large-size organic substances
into small ones, namely increasing sludge solubility willlead to biodegradability improvement. The suspended solids(SS) and volatile suspended solids (VSS) concentration
decreased while soluble substances going up. Disintegration
degree (DD) is commonly used to evaluate the solubility
enhancement performance. A modified DD was used in thisexperiment because the concentrations of total organic
substances were detected not the same in different stages,
which was calculated in the following equation (1).
𝑴𝒐𝒅𝒊𝒇𝒊𝒆𝒅 𝑫𝑫(%) =𝑺𝒐𝒍𝒖𝒃𝒍𝒆𝒙,𝒊 𝑺𝒐𝒍𝒖𝒃𝒍𝒆𝟎,𝒊−
𝑻𝒐𝒕𝒂𝒍𝒙,𝒊
𝑻𝒐𝒕𝒂𝒍𝟎,𝒊𝑺𝒐𝒍𝒖𝒃𝒍𝒆𝟎,𝒊𝟏−

× 𝟏𝟎𝟎%

significant, which was because thermophilic AD posed
higher hydrolysis rate and better disintegration efficiency
itself compared with mesophilic AD. Thus, theenhancement effect seemed to be weakened accordingly.
Table 1 The biogas yield and methane conversion
efficiency in each stage
Items
Biogas yield
Biogascomposition

CH4
CO2
H2S

Methane conversion
efficiency

Unit

Stage 1

Stage 2

Stage 3

Stage 4

Stage 5

L/d
%
%
ppm
L-CH4/g-TS
L-CH4/g-VS
L-CH4/g-COD

13.6
65.0
33.6
527
0.354
0.510
0.249

13.8
63.3
34.4
588
0.361
0.488
0.254

12.9
63.1
34.3
500
0.297
0.413
0.233

13.9
64.5
33.8
769
0.355
0.468
0.255

13.2
63.6
34.7
667
0.316
0.409
0.242

3.3 Organic Removal and COD Balance
Due to membrane rejection, ThAnMBR successfully
realized high removal efficiency with excellent effluent
quality. The removal efficiency of COD, carbohydrates andproteins were all above 92%. Besides, material flow
analysis was also conducted by comparing the COD mass insystem input (substrate) and output (digested sludge,
permeate and biogas). And the results showed nearly half of
the COD remained in the digested sludge with 42%-47%
COD converted into methane, indicating the great energy
recovery potential of digested sludge.
3.4 Membrane Performance and Membrane Fouling
Membrane fouling is an important issue in AnMBR
system. It was discovered that when filtration mode was 1
min filtration and 1 min relaxation with the average flux
was 6 L/m2/h (LMH), membrane could work stably under
the high solid condition of TS 30 g/L (Fig.2). However,when the TS concentration continuously increased to 40 g/L
in stage 4 and 5, there was a great reduction in filtration
performance. The filtration mode could not be maintained
as that in first three stages and had to be adjusted into 1.6
LMH, indicating solid concentration was an important
constraint in AnMBR application. In addition, membranecleaning as well as clean water filtration test wereconducted to calculated membrane resistance of eachfoulant layer. The results showed that cake layer was thelargest contributor to membrane fouling, which accounted
for nearly half of the resistance.

(1)

𝑻𝒐𝒕𝒂𝒍𝟎,𝒊The results showed DD (%) of COD, carbohydrates andproteins were 11.7%, 3.48%, 11.2% respectively after
VT-SI, while that of IHSI were 10.9%, 7.39%, and 11.0%,
respectively. Both pretreatment methods proved effective inincreasing sludge solubility.
3.2 Biogas Production
These three types of sludge were fed as substrate in eachstage and biogas yield, and biogas composition as well as
methane conversion efficiency were analyzed andcalculated (Tab 1). In general biogas composition is rather
stable in each stage. Methane took up 63.1%-65.0%, whilecarbon dioxide accounted for 33.6%-34.7%. As for biogas
yield, it increased from 12.9 L/d to 13.6 L/d and 13.8 L/dafter VT-SI and IHSI pretreatment, respectively. When it
comes to methane conversion efficiency, it increased from
0.233 L-CH4/g-COD to 0.249 and 0.254 L-CH4/g-COD
after VT-SI and IHSI pretreatment, improving by 6.9% and9.0%, respectively. The improvement effect was not that33

Fig. 2. Membrane filtration performance in ThAnMBR

4 Conclusions

VT-SI and IHSI greatly improved the sludge solubility,with the DD of COD at 11.2% and 11.0%, separately.
VT-SI and IHSI also enhanced the biogas yield andmethane conversion efficiency.
ThAnMBR operated stably in long term under highsolid condition of TS=30 g/L with the average flux of
6 LMH. But filtration performance greatly reduced
when TS increased to 40 g/L.

Reference[1] Mancuso, G., Langone, M., & Andreottola, G. (2020). A
critical review of the current technologies in wastewater
treatment plants by using hydrodynamic cavitation process:principles and applications. Journal of Environmental
Health Science and Engineering, 18(1), 311–333.

The 9th International Symposium on Water Environment Systems

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Applications of Solar Photovoltaics and Offshore Wind Power
towards Carbon Neutrality in Coastline Cities
Hongxing Yang
Department of Building Environment and Energy Engineering,
The Hong Kong Polytechnic University, Hong Kong, China
E-mail: hong-xing.yang@polyu.edu.hk

Abstract
Renewable energy applications are playing an important role for achieving the carbon neutral targets
in the world. Solar photovoltaic power generation and offshore wind power generation are the main
renewable energy resources for most coastline cities, especially in Hong Kong and the Greater Bay
Area of China. This presentation will focus on our research and development of solar photovoltaic
applications, especially building-integrated solar photovoltaics (BIPV), and offshore wind power
production. The world development trends of these two main renewable energy resources are
introduced first and our research efforts are then presented. In Hong Kong, the Feed-in-Tariff policy
has greatly promoted the BIPV power generation in the territories, but less development in wind
power. It is estimated that the potential annual power generation from these two renewable energy
resources are about 30% of local annual power demand in Hong Kong. In Chinese mainland, BIPV
is a hot topic nowadays due to the pressures to realize carbon neutrality in 2060. Our research projects
in solar photovoltaic façade, wake model development of wind farms and hybrid solar-wind power
generation will be briefly introduced. The local policy towards renewable energy applications will be
discussed. A new development project in Hong Kong will be used as a sample project to highlightthe importance of solar photovoltaic and offshore wind power generations for achieving carbon
neutrality in Hong Kong by the year 2050.

34

The 9th International Symposium on Water Environment Systems

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(Nov. 25th ~ 26th , 2021)

Tohoku University----- with Perspective of Global Safety

Exploring Microbiome Assembly and Antibiotic Resistome in
Wastewater Treatment Plants
Feng Ju 1,2
Environmental Microbiome and Biotechnology Laboratory (EMBLab), School of Engineering, Westlake
University, Hangzhou 310012, China; 2 Institute of Advanced Technology, Westlake Institute for Advanced
Study, Hangzhou 310024, China.
*
E-mail: jufeng@westlake.edu.cn
1

Abstract
Microbiome, which encompasses microbial communities (i.e., microbiota) and their ‘theatre of activity’, plays acentral role in the success of biological wastewater treatment plants (WWTPs). Our and other researches havefully acknowledged that WWTPs microbiome not only contains diverse beneficial microbes that convert andremove various wastewater pollutants or produce biomethane, but also harbors a proportion of detrimental
microbes and genes responsible for common operational problems (e.g., bulking and foaming) and/or hygienic
issues (human pathogens and antibiotic resistance). More importantly, new progress has also been achieved toresolve the patterns and processes underlying microbiome assembly and antibiotic resistome in WWTPs,
providing a theoretical basis for targeted microbiome-based control and regulation of process functioning.
Keywords: Wastewater Treatment Plant; Activated sludge; Anaerobic digestion; Microbiome; Resistome.

Activated sludge (AS) and anaerobic digestion (AD) are themost popular bioreactors in municipal WWTPs worldwide
with microbes as the key driver to their success in
wastewater de-contamination and sludge resourcization.
However, they frequently suffer from operational problems
such as sludge bulking and foaming [1]. Worse still, in
contrast to their contribution in environmental protection,municipal WWTPs are increasingly criticized as a hotspot
for the release of antibiotic resistant genes (ARGs) andbacteria (or pathogens) into the environment [2]. Because of
the importance of microbiome for the bioreactor functioning,
it is therefore crucial to investigate on the microbiome
structure and function, and link them to environmental (i.e.,
wastewater and operational) parameters and bioreactor
performance, which should inform on the management
strategies and engineering measures for the targeted
microbiome control to optimize WWTPs operation.

and biotic interactions [1-2]. In one WWTP with seasonallyoccurring foaming events, AS community shows limited
seasonal succession over 5 years. Biotic interactions are
revealed as important drivers of microbiota assemblage [1],whereas sludge retention time (SRT) and inorganic nitrogen,partially explain phylogenetic and quantitative variances ofcommunity patterns (Fig. 1). Moreover, antibiotic resistome(i.e., the collection of all ARGs) greatly varies throughout
WWTPs (Fig. 2), and its composition strongly correlatewith bacterial composition. Although no strong drivers of
resistome composition could be identified among thechemical stressors analyzed, the sub-inhibitory level ofmacrolide antibiotics in wastewater appears to select for
macrolide and vancomycin resistance genes and induce theirexpression. Notably, pathogenic and indigenous denitrifying
bacteria are found as transcriptionally active and key
multi-antibiotic-resistant players, and a small proportion of
persistent ARGs traverse WWTPs and show upregulated
expression in the secondary effluent [3].

2 Materials and methods

4 Conclusions

16S rRNA gene amplicon sequencing was used to profile
microbial community diversity, composition, and temporal
dynamics in full-scale WWTPs or lab-scale bioreactors.
Microbial interactions and the MEP nexus between
microbiota (M), environment parameters (E), and process
performance (P) were explored by co-occurrence networkand multi-variates analyses [1]. Moreover, quantitative
meta-omics (i.e., metagenome and metatranscriptome) wereco-used to quantify ARGs and ARG transcripts in 12
WWTPs [2], achieving a systematic view of the fate, in-situ
expression, and influential factors of ARGs of over 20classes of antibiotics throughout WWTP compartments: i)clarified influent, ii) denitrification stage, iii) nitrification
stage, and iv) secondary effluent.

Multiple deterministic processes (e.g., habitat filtering andbiotic interactions) co-drives microbiome assembly anddynamics in WWTPs, where antibiotic resistome is shapedby bacterial composition, genetic exchange, and upregulated
expression in the effluent microbiomes.

1 Introduction

3 Results and discussion
The results showed WWTP microbiome is non-randomly
assembled by taxonomic relatedness and driven by multiple
deterministic processes, e.g., habitat filtering, immigration,

35

Reference[1] Ju F and Zhang T*. 2015. Bacterial assembly andtemporal dynamics in activated sludge of a full-scalemunicipal wastewater treatment plant, ISME J. 9: 683-695[2] Ju F, Helmut Bergmann* et al. 2019. Wastewater
treatment plant resistomes are shaped by bacterial
composition, genetic exchange and up-regulated expression
in the effluent. ISME J. 13 (2): 346-360[3] Yuan L, Ju F* et al., 2021. Pathogenic and Indigenous
Denitrifying Bacteria are Transcriptionally Active and Key
Multi-Antibiotic-Resistant Players in Wastewater Treatment
Plants. Environ. Sci. Technol. 55 (15): 10862-10874

The 9th International Symposium on Water Environment Systems

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Fig. 1. Bacteria-bacteria and bacteria-environment co-occurrence network reveals distinct niches of
foaming-thrived bacteria versus nitrogen-removing bacteria [1]. An edge represents a statisticallysignificant and strong correlation between a bacterial OTU, and a wastewater or an environmental parameter.

Fig. 2. Key hypotheses about processes affecting the resistome (resistance genes of microbiome) during
passage of a WWTP. Conventional WWTPs consist (a) of primary and secondary treatment compartmentswith contrasting environmental conditions including (b) changing concentrations of stressors (e.g., antibiotics
and metals) that may act as drivers on microbial biomass (c), community assembly (d) and resistome (e) [2].

36The 9th International Symposium on Water Environment Systems

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(Nov. 25th ~ 26th , 2021)

Tohoku University----- with Perspective of Global Safety

Diversity and genomic information of Patescibacteriain activated sludge○ Shuka KAGEMASA1*, Kyohei KURODA2 , Ryosuke NAKAI2, Yu-You Li1, 3,
Kengo KUBOTA1, 3
1

Department of Civil and Environmental Engineering, Tohoku University, Miyagi 980-8579, Japan.
Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST),
Hokkaido 062-8517, Japan.
3
Department of Frontier Sciences for Advanced Environment, Tohoku University, Miyagi 980-8579, Japan*
E-mail: shuka.kagemasa.t2@dc.tohoku.ac.jp
2

Abstract
Uncultured microorganisms make it difficult to understand the mechanisms of biological wastewater treatment
processes. The candidate division, Patescibacteria, is always present in sludge treating wastewater (~10%), but
their roles remain unknown. The purpose of this study is to reveal the diversity and obtain genomic information ofPatescibacteria in activated sludge treating sewage for understanding their ecophysiology and roles in treatment
processes. Very small cell sizes characterize Patescibacteria. In this study, microorganisms were fractionated bysize for the enrichment of Patescibacteria, and metagenomic analysis was conducted using the size-fractionatedsample. The size fractionation enriched Patescibacteria (Saccharimonadia, Parcubacteria, Gracilibacteria,
Microgenomatia, and ABY1). The richness of Patescibacteria species detected by size fractionation of activatedsludge also increased. In addition, we successfully obtained metagenome-assembled genomes of Patescibacteria
and were able to infer metabolic pathways from the genomic information. This study deepened our understandingof Patescibacteria ecophysiological characteristics in activated sludge treating sewage.
Keywords: Patescibacteria; Filtration fractionation; Metagenomic analysis; Metabolic pathways;
Activated sludge.
0

1 Introduction
Bacteria belonging to the superphylum Patescibacteria isuniversally found in sludge treating wastewater.
Patescibacteria is part of a large bacterial phylogenetic groupcalled candidate phyla radiation (CPR), a group of uncultured
bacteria at the phylum level [1]. Patescibacteria have beeninferred to contribute to wastewater treatment [2, 3].
However, when we analyze Patescibacteria bymetagenomics analysis, there is often not enoughPatescibacteria to construct MAGs (metagenome-assembled
genomes) for functional analysis in sludge. In this study, we
focused on the size fractionation of samples as a method ofPatescibacteria enrichment. Patescibacteria is characterized
by small cell size (about 0.2 µm in diameter) [4] and small
genome size (about 1 Mbp) [5]. By size-fractionation ofsludge treating wastewater, Patescibacteria is enriched, andtheir diversity in sludge treating wastewater was clarified. In
addition, we attempted to obtain genomic information ofPatescibacteria by metagenomic analysis.

2 Materials and methods
2.1 Sample and sample treatment
Activated sludge in the reaction tank of a sewage treatment
plant was centrifuged, and the supernatant was sizefractionated in the order of filter pore sizes of 0.45 µm, 0.22
µm, and 0.1 µm (Stericup, Merck Millipore). Filters withpore sizes of 0.22 µm and 0.1 µm were collected as
fractionation samples (referred to as 0.45-0.22 µm fraction
and 0.22-0.1 µm fraction).

2.2 Microbial community structure analysis
PCR amplification used the 341F-806R-mix primer set, and

37

20

40

60

80

100

Sludge0.45-0.22 µm
fraction
0.22-0.1 µm
fraction
Woesearchaeia
Anaerolineae
ABY1
Parcubacteria
Alphaproteobacteria
Spirochaetia

Actinobacteria
Campylobacteria
Berkelbacteria
Saccharimonadia
Deltaproteobacteria
Mollicutes

Bacteroidia
Bacilli
Gracilibacteria
WS6 (Dojkabacteria)
Gammaproteobacteria
Others (< 1%)

Ignavibacteria
Clostridia
Microgenomatia
WWE3
Leptospirae

Fig.1 Microbial community structure analysis
result of the size-fractionated activated sludge(%, the gray area indicates Patescibacteria)sequencing was performed using MiSeq (Illumina, Inc.). The
sequence data were analyzed using QIIMETM (database:silva132) after removing a single read. Assigned as "None"and "No blast hit" operational taxonomic units (OTUs) were
excluded from the analysis. They randomly selected 7,000
reads that were subjected to microbial community structure
analysis. The coverage was 96.4~98.3%. The beta diversity
and alpha diversity for Patescibacteria was calculated using
QIIMETM.

2.3 Metagenomic analysis
Metagenomic analysis was performed using 0.45-0.22 µm
fractions. Library preparation was performed using the
Nextera XT DNA Library Preparation Kit (Illumina, Inc.)and sequenced using MiSeq. The sequencing data werebinned (MetaBAT2, MaxBin2, vamb, MyCC) to obtaingenomic bins, and the bins were quality-checked by CheckM(CPR maker gene) and phylogenetically classified (GTDBtk ver. 1.5.1).

The 9th International Symposium on Water Environment Systems

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(Nov. 25th ~ 26th , 2021)

Tohoku University----- with Perspective of Global Safety
Table 2
Relative abundance (%)
Microbial community
structure analysis(Sludge)
Metagenomic analysis
Number of Bin*2
Completeness(%, Min ~ Max)
Contaminations(%, Min ~ Max)
Genome size(%, Min ~ Max)

Genomic information of Patescibacteria recovered in the 0.45-0.22 µm fraction
Saccharimonadia

Gracilibacteria

Paceibacteria*1

Microgenomatia

ABY1

50.1 (3.5)

9.4 (2.1)

10.6 (0.2)

2.2 (0.03)

0.8 (0.07)

49.0
7

1.6
1

41.0
13

1.3
1

5.9
2

73.6 (55.2~84.3)

76.7

66.3 (52.6~83.8)

58.5

85.8 (84.5~87.1)

2.2 (0~6.3)

1.9

2.5 (0~6.9)

0.2

1.0 (0~2.0)

1.09

0.70 (0.39~0.91)

0.76

0.94 (0.93~0.94)

0.92 (0.46~1.32)* Parcubacteria in the silva132 database. * Bin with completeness ≥50% and contamination ≤10%.
1

2

3 Results and discussion
3.1 Microbial community structure analysis
The results of microbial community structure analysis areshown in Figure 1. In the unfractionated activated sludge,
Proteobacteria and Bacteroidia were dominant in thesamples, while Patescibacteria is dominant in the sizefractionated samples. The relative abundance ofPatescibacteria in the samples was 69.9% in the 0.45-0.22µm fraction and 51.1% in the 0.22-0.1 µm fraction, compared
to 5.8% in the activated sludge. Saccharimonadia,
Gracilibacteria, Parcubacteria, Microgenomatia, and ABY1
were detected in more than 1% of the size-fractionatedsamples. In particular, Saccharimonadia was the mostdominant Patescibacteria in activated sludge, accounting for59.7~68.1% of the Patescibacteria detected regardless of
size fractionation or fraction size. Saccharimonadia andGracilibacteria had a higher percentage in the 0.45-0.22 µm
fraction than in the 0.22-0.1 µm fraction, and Parcubacteria,
Microgenomatia, and ABY1 had a higher percentage in the0.22-0.1 µm fraction than in the 0.45-0.22 µm fraction. This
result indicates that by changing the pore size of the filter,
different Patescibacteria can be enriched.
The number of OTUs of Patescibacteria was significantly
increased by size fractionation of activated sludge. A total of
388 OTUs of Patescibacteria were detected in all samples,but only 46 OTUs were detected in activated sludge, andabout 88% of total OTUs were detected only in sizefractionated samples. About 70% of the OTUs detected in
activated sludge were also detected in the size-fractionatedsamples. These results suggest that Patescibacteria can beenriched by size-fractionation of activated sludge and that
there may be a greater variety of Patescibacteria thanpreviously thought.

3.2 Metagenomic analysis
As a result of metagenomic analysis, we obtained 25 bins
with completeness ≥50% and contamination ≤10%, of which
24 bins were Patescibacteria. In addition to
Saccharimonadia, we obtained the genomes of several other
Patescibacteria (Table 1). We obtained multiple bins for
Paceibacteria, Saccharimonadia, and ABY1 whitch differedat the family level. As for the completeness of Bin, 14 bins
were ≥70%~90% and 11 bins ≥50% ~ 70%. 21 bins were≤5% (4 bins of them 0%), and 4 bins were 5% ~ ≤10%.
Although the completeness values varied, we were able toobtain genomes with low contamination.

38

The predicted genome size of Patescibacteria for which wewere able to obtain genome information was around 1 Mbp,
and some species, such as Saccharimonadia with 0.46 Mbp(completeness:
69.8%,
contamination:
0%)
andPaceibacteria with 0.39 Mbp (completeness: 55.3%,
contamination: 0%), which may have a minimal genome size.
We obtained eighteen 16S rRNA gene sequences(Paceibacteria, Saccharimonadia, ABY1, Gracilibacteria,
Microgenomatia) from 15 bins of the total of 24 bins ofPatescibacteria. These 16S rRNA gene sequences and OTUs
(by amplicon analysis) with high relative abundance within
the phylogenetic group belong to Patescibacteria werehighly identified. We obtained genomes close to the major
species in the phylogenetic group belonging toPatescibacteria detected in the 0.45-0.22 µm fraction.
Patescibacteria, for which we could obtain genomic
information, lacked genes involved in metabolic pathways
such as glycolysis and were consistent with the report [5].
These characteristics suggest that they are dependent on othermicroorganisms for metabolic resources.

4 Conclusions
By size-fractionating the activated sludge and applying it to
the analysis, it was shown that a wide variety ofPatescibacteria existed in the activated sludge and that it waspossible to obtain their genomic information. The enrichment
and analysis techniques of Patescibacteria established in thisstudy are expected to deepen our understanding of thecontribution of Patescibacteria to the degradation of organic
compounds and the material cycle and conversion processes
in wastewater treatment.

Reference[1] Castelle, J.C. et al., Major New Microbial Groups Expand
Diversity and Alter our Understanding of the Tree of Life Cell,
172 (6) (2018) 1181-1197.
[2] Kindaichi, T. et al., Phylogenetic diversity and ecophysiology ofCandidate phylum Saccharibacteria in activated sludge, FEMS
Microbiology Ecology 92 (6) (2016).
[3] Kuroda, K. et al., Patterns of uncultured bacteria phyla indifferent wastewater treatment sludges, Journal of japan societyof civil engineers G (Environment), 70 (3) (2014) 42-52 (inJapanese).
[4] Beam, P. J. et al., Ancestral absence of electron transport chainsin Patescibacteria and DPANN, Frontiers in Microbiology(2020).
[5] Brown, C.T. et al., Unusual biology across a group comprisingmore than 15% of domain Bacteria, Nature 523 (2015) 208–211.

The 9th International Symposium on Water Environment Systems(Nov. 25th ~ 26th , 2021)----- with Perspective of Global Safety

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Tohoku University

Sewage concentration for detecting public health biomarkers in
wastewater○ Luhur Akbar DEVIANTO1*, Yifan ZHU1 & Daisuke SANO1,2
1

Department of Frontier Sciences for Advanced Environment, Tohoku University, Miyagi 980-8579, Japan.
2
Department of Civil and Environmental Engineering, Tohoku University, Miyagi 980-8579, Japan.
*
E-mail: luhur.akbar.devianto.r1@dc.tohoku.ac.jp

Abstract
Sewage, mixture of water from domestic activity and possibly run-off water, is not only containing pollutants but
also including biomarkers that would be useful as public health surveillance tool. One of the potential biomarkers
is human immunoglobulin A (IgA). Biomarkers from urine and fecal samples have a broad range of concentrationfrom ng/mL to mg/mL, but those biomarkers will be diluted in the wastewater. In this research we employed 4
different methods: filtration-ultrafiltration, filtration, ammonium sulphate precipitation, and polyethylene glycol
6000 precipitation. The human IgA in concentrated samples was detected using commercial human IgA enzymelinked immunosorbent assay (ELISA) kit and western blotting. The highest recovery of human IgA (22.7%) was
achieved by filtration-ultrafiltration using 0.22 µm PVDF membrane with Amicon® Ultra 15K centrifugation filter
with 100kDa molecular weight cut-off (MWCO). Also, the detection of human IgA from real wastewater wasachieved by using Amicon® Ultra 15K with 30kDa MWCO that was confirmed by western blotting.
Keywords: biomarkers; ultrafiltration; IgA; precipitation; sewage concentration.
1 Introduction

2 Materials and methods

Sewage contains nutrients (nitrogen and phosphorus),organic matter, and pathogens and includes biomarkers,
which are biological molecules that could be found in blood,
saliva, urine, and feces. Recently in wastewater-based
epidemiology (WBE), we can monitor health indicators andpopulation behavior by using biomarkers in wastewater [1].
Biomarkers in wastewater were used as a non-invasive
diagnosis of respiratory diseases [2], infectious diseases [3],and other diseases analyzed from serum or blood. One of thepotential biomarkers that we can detect from sewage is
Immunoglobulin A (IgA). IgA has functions ranging fromprotection against enteric pathogens to maintaining hostcommensal symbiosis. Through adsorption and agglutination
to the mucosal surface, IgA prevents pathogens' penetration[4]. Furthermore, IgA also contributes to intestinal
homeostasis by inhibiting virulence or promoting symbiosis
among bacteria and shaping microbiota composition [5].
However, the quantification of human IgA in sewage
samples is challenging. Protein biomarkers concentration
varies from mg/mL to ng/mL in urine samples that possibly
is diluted into hundred-fold dilution in wastewater [6]. The
concentration method to improve human IgA detectability
from wastewater is very important. In the previous study , theviral particle of severe acute respiratory syndrome
coronavirus 2 (SARS-CoV-2) was able to be detected fromstool and sewage [7]. The presence of the viral particle wasconfirmed by the detection of specific viral RNA sequences
by qPCR. Several pretreatment methods such filtration precipitation, centrifugation - ultrafiltration, centrifugation precipitation in order to concentrate virus particles have been
applied to improve detection [7,8]. Fortunately, similar
methods were utilized for the protein purification andconcentration [9]. In this research, we conduct preliminary
research for the detection of potential public healthbiomarkers from sewage by employing various concentration
methods.

Sewage concentration was done by employing filtration,
adsorption,andprecipitation
processes.
Severalconfigurations methods (A-D) were applied as dual-stage offiltration-ultrafiltration by using PVDF membrane with thepore size of 0.22 µm (Merck) followed with Amicon® Ultra
15K centrifugation filter and the molecular weight cut-off(MWCO) of 100kDa (Merck Millipore Ltd), filtration by
PVDF membrane (0.22 µm) followed with purification by
PIERCE Protein L Magnetic Beads (ThermoFisher),ammonium sulphate, ((NH4)2SO4) precipitation (Kanto
Chemical Co.Inc.), and polyethylene glycol (PEG 6000)
precipitation (FUJIFILM Wako Pure Chemical Corp.). The
best outcome of the concentration method will be used forhuman IgA recovery from an actual wastewater sample.
IgA concentration was initially using wastewater spiked
with 30 µg of IgA (the final concentration 2 ng/mL) fromhuman serum (Cat# I4038-5MG Sigma-Aldrich). Methods A
and B began with filtrating 15 mL samples with PVDF
membrane (0.22 µm). For method A, the supernatant wasconcentrated using Amicon® by centrifugation at 5000 x g for
30 min at 4°C in a bucket rotor. For method B, 50 µL (0.50mg) of Pierce Protein L Magnetic Beads were washed by 150µL Binding/washing buffer (Tris-buffered saline) in 1.5 mL
microcentrifuge tube than by magnetic stand to discard thesupernatant. The sample was diluted ten folds before
incubation with magnetic beads for 1 hour at room
temperature (RT). After the incubation, supernatant wasremoved, followed by 500 µL binding/wash buffer. IgA wasrecovered by adding 100 µL elution buffer (Pierce IgG
elution buffer, pH 2) that was mixed and incubated for 10 min
in RT. Neutralization was done by adding 15 µL
neutralization buffer (1 M Tris, pH 8.5).
Chemical precipitation for methods C and D were done by
precipitation by (NH4)2SO4 and PEG 6000, respectively. A
twenty-five-milliliter sample was spiked with 30 µg IgA (thefinal concentration 1.2 ng/mL). For method C, two-step(NH4)2SO4 precipitation was done. After slow dilution of39

The 9th International Symposium on Water Environment Systems(Nov. 25th ~ 26th , 2021)----- with Perspective of Global Safety

GP-RSS & SyDe
Tohoku University

12.5 mL 30% (NH4)2SO4, incubation was done for 6 hours at
4°C. The solution free of low soluble protein was collected
after centrifugation at 4000 x g for 30 min at 4°C. Further
precipitation was done by adding 12.5 mL 50% (NH4)2SO4
with overnight incubation. After centrifugation at 4000 x g
for 30 min at 4°C, precipitated proteins were resuspended
with 500 µL phosphate buffer saline (PBS). For the method
D, 25 mL sample was stirred with 2 g PEG 6000 and 0.575 g
NaCl and incubated for 16 hours at 4°C. The measurement ofconcentrated IgA in the samples was done by enzyme-linked
immunosorbent assay (ELISA) using human IgA ELISA kit(Invitrogen) by following the manufacturers’ instructions.
Human IgA in wastewater was also detected by Western blot
using iBind Flex western device according to the
manufacturers’ instructions (Thermo Fisher Scientific) after
SDS-PAGE (BioRad) for 30 min at 180 V using MiniPROTEAN TGX 4-20% polyacrylamide precast-gels(BioRad) and protein transfer using Trans-Blot Turbotransfer system with a 0.2 µm PVDF membrane (BioRad).

method A gave the highest concentration recovery, 22.7%,
with a concentration of 454.3 ng/mL. In contrast, therecovery method by chemical precipitation had a tiny
recovery ratio of less than 3% for PEG 6000 precipitation.
While, precipitation by (NH4)2SO4 was under the detection
limit. The further step of human IgA detection fromwastewater were confirmed by western blotting.
Concentrated wastewater by using Amicon® Ultra 15K 30
kDa MWCO results in detecting human IgA from wastewater
as indicated in Figure 1.

3 Results and discussion

Reference

Human IgA ranges from 10-15% of a humanimmunoglobulin and is abundant in serum, nasal mucus,
saliva, breast milk, and intestinal fluids [10]. Human serum
IgA is the second most abundant human Ig after IgG. It is theprevailing Ig in external secretion as mucosal surfaces. In
human adults, IgA was estimated to be produced andselectively secreted by the gastrointestinal tract as in thesmall intestine and urine as up to 5,000 mg/day and 3 mg/day
respectively, with a half-life 4 to 6 days [4,11].
Table 1. Concentration and recovery ratio
No
Concentration
Concentration
methods(ng/mL)1
Method A
454.3
2
Method B
226.0
3
Method C
4
Method D
56.7

RecoveryRatio (%)
22.7
11.3
2.8

a
b
Figure 1. Western blot analysis of human IgA in sewage
using Amicon® Ultra 15K: a). 100kDa MWCO; b). 30kDa
MWCO.
Note: 1 = human IgA 100 µg/ml; 2 = human IgA 10 µg/ml; 3 =human IgA 1 µg/ml; s = negative control; a = raw wastewater; b= supernatant of PVDF membrane (0.22 µm) filtration; c =concentrated b sample with Amicon 100 kDa.

The concentration method is an essential step for thedetection of human IgA from a wastewater sample. Fromvarious physical and chemical methods shown in Table 1,40

4 Conclusions
In this study, concentration method which results highest
recovery ratio was done by physical separation by
combination of PVDF membrane 0.22 µm followed with
Amicon® Ultra 15K 100kDa MWCO with recovery ratio
22.7%. The human IgA was successfully detected from real
wastewater by using Amicon® Ultra 15K with 30kDa
MWCO that was confirmed by western blotting.
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S C, Kaserzon S L, Mackie R, O’Malley E, Crosbie N D,
Thomas K V. and Mueller J F 2018 Wastewater-based
epidemiology biomarkers: Past, present and future TrAC Trends Anal. Chem. 105 453–69[2] Dobler C C 2019 Biomarkers in respiratory diseases
Breathe 15 265–6[3] Jain K K 2017 Biomarkers of Infectious Diseases The
Handbook of Biomarkers (New York, NY: Springer NewYork) pp 219–38[4] de Sousa-Pereira P and Woof J M 2019 IgA: Structure,
Function, and Developability Antibodies 8 57
[5] Sterlin D, Fadlallah J, Adams O, Fieschi C, Parizot C,
Dorgham K, Rajkumar A, Autaa G, El-Kafsi H, Charuel J L,
Juste C, Jönsson F, Candela T, Wardemann H, Aubry A,
Capito C, Brisson H, Tresallet C, Cummings R D, Larsen M,
Yssel H, von Gunten S and Gorochov G 2020 Human IgAbinds a diverse array of commensal bacteria J. Exp. Med. 217[6] Rice J and Kasprzyk-Hordern B 2019 A new paradigm
in public health assessment: Water fingerprinting for protein
markers of public health using mass spectrometry TrAC Trends Anal. Chem. 119 115621[7] Foladori P, Cutrupi F, Segata N, Manara S, Pinto F,
Malpei F, Bruni L and La Rosa G 2020 SARS-CoV-2 fromfaeces to wastewater treatment: What do we know? A review
Sci. Total Environ. 743 140444[8] Lu D, Huang Z, Luo J, Zhang X and Sha S 2020 Primaryconcentration – The critical step in implementing thewastewater based epidemiology for the COVID-19
pandemic: A mini-review Sci. Total Environ. 747 141245[9] Goldring J P D 2019 Concentrating Proteins by Salt,
Polyethylene Glycol, Solvent, SDS Precipitation, ThreePhase Partitioning, Dialysis, Centrifugation, Ultrafiltration,
Lyophilization,
Affinity
Chromatography,
Immunoprecipitation or Increased Temperature for Protein
Isolati Electrophoretic Separation of Proteins: Methods andProtocols ed B T Kurien and R H Scofield (New York, NY:
Springer New York) pp 41–59[10] Wang P 2021 Significance of IgA antibody testing forearly detection of SARS-CoV-2 J. Med. Virol. 93 1888–9[11] Mestecky J, Russell M W, Jackson S and Brown T A
1986 The human IgA system: a reassessment Clin. Immunol.
Immunopathol. 40 105–44

The 9th International Symposium on Water Environment Systems

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Tohoku University----- with Perspective of Global Safety

Influence of temperature on treatment performance of municipal
wastewater by a pilot-scale Anaerobic Membrane Bioreactor (AnMBR)○ Tianjie WANG1*, Chao RONG1, Zibin LUO1, Yan GUO1, Yu QIN1 & Yu-You LI1
1

Laboratory of Environmental Protection Engineering, Department of Civil and Environmental
Engineering, Graduate School of Engineering, Tohoku University, 6-6-06 Aza-Aoba, Aramaki, Aoba
Ward, Sendai, Miyagi 980-8579, Japan.
*
E-mail: wang.tianjie.s3@dc.tohoku.ac.jp

Abstract
The operation performance of a pilot-scale submerged anaerobic membrane bioreactor (AnMBR) treating realmunicipal wastewater with an effective volume of 5.0 m3 was investigated at variable temperatures of 25℃, 20℃,
and 17℃. This demonstration plant realized stable organic pollutant removal rates at the HRT of 8h under the abovementioned temperatures, obtaining excellent effluent quality with the COD removal efficiency of over 89% andBOD5 removal over 91%. Biogas was recovered efficiently from municipal wastewater with a biogas production of
0.062-0.084 L L-1 raw wastewater, and the methane content was 75%-80% in the biogas. Stable operation at 25℃
was confirmed under HRT 8h conditions, and no rapid TMP change appeared even when the operating temperature
was lowered to 20℃. Although the temperature was further lowered to 17℃, it became clear that the membrane
filtration pressure increased sharply, and membrane fouling was likely to be severe.
Keywords: anaerobic digestion; AnMBR; municipal wastewater; membrane fouling.
1 Introduction
The conventional activated sludge (CAS) process and its
derivatives are the most common municipal wastewater
treatment and have been widely implemented worldwide.
Despite the reliable effluent quality, the CAS process
consumes a significant quantity of energy for supplying
oxygen and generates a large amount of excessive sludge. In
contrast, more sustainable and low-carbon anaerobic
treatments have been widely applied to the treatment ofindustrial wastewater and biomass for decades and showfeatures such as high biogas energy recovery and low
biomass production. There has been increasing interest inanaerobic digestion (AD) process research on municipal
wastewater treatment to reduce sludge yield and recoverbiogas as energy in recent years.
Anaerobic digested sludge is usually the mostmethanogenic under mesophilic (35℃) or thermophilic(55℃) conditions for effective treatment of high-strength
wastewater or solid waste. The need for energy consumption
for heating is essential for the AD process. As a result, themethanogenic activity of anaerobic sludge is significantly
limited by the environmental temperature of temperateregions.
On the other hand, due to its low COD concentration, it isconsidered that the methanogenic activity with limited
relative low-temperature environmental conditions is still
sufficient for the efficient treatment of municipal wastewaterby the anaerobic digestion process. However, except for thelimitation of methanogenic activity due to low-temperature
conditions, there are problems such as a decrease in biogas
recovery rate due to an increase in gas solubility and anincrease in sludge yield due to insufficient decomposition ofsuspended solids (SS). The solution is awaited.
Therefore, with the rapid development of membrane
technology in recent years, the anaerobic membrane
separation method (AnMBR) has also gained a reputation asa particularly excellent sewage treatment technology

41

compared to conventional anaerobic treatment processes.
Anaerobic digested sludge and inflow SS are entirelycollected by the membrane module, ensuring a long SRT forbiomass growth and achieving the same treated water quality
as biogas generation and advanced treatment.
A demonstration plant using a pilot-scale AnMBR was
conducted to investigate real municipal wastewater'sanaerobic wastewater treatment performance. As a result of
long-term continuous experiments with the HRT 8-48h at
psychrophilic conditions (17-25℃), the COD and BOD5
removal efficiency reached 89% and 91%, respectively.
Biogas was recovered efficiently from municipal wastewaterwith a biogas production of 0.062-0.084 L L-1 raw
wastewater, and the methane content was 75%-80% in the
biogas.

Fig. 1. Schematic of Pilot AnMBR.

2 Materials and methods
The Schematic diagram of the AnMBR system is shown in
Fig.1. The influent of the AnMBR was pumped from the gritchamber effluent of a full-scale municipal treatment plant to
the raw wastewater tank. A drum screen treated the raw
wastewater to remove impurities. The effective volume of
AnMBR was 5 m3, the liquid level was maintained at theheight of 1910 mm, and both the raw wastewater tank and
AnMBR were kept at specific temperatures by a constantwater bath system. The membrane module consisted of 12

The 9th International Symposium on Water Environment Systems

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hollow fiber membrane elements, with a total membrane areaof 72 m2 (6 m2 for each element). The hollow-fiber membrane
is made of polyvinylidene fluoride (PVDF) and has a pore
diameter of 0.4 μm and an outer diameter of 2.8 mm. The
membrane filtration operation was 5 minutes per cycle (4minutes for filtration, 1 minute for relaxation). The
membrane maintenance method was the online back-wash
applying sodium hypochlorite (NaClO) solution and citratesolution.

3 Results and discussion
Fig.2 shows the diurnal changes in COD and BOD
concentrations and removal rates during the operation period.
In long-term continuous operation, the COD and BOD
removal rates remained high at 85% and 90%, respectively,
except for the unstable periods of 48h and 70h of HRT at an
operating temperature of 25℃. In some cases, the COD
removal rate was over 90%, and the BOD removal rate wasover 95%.
It was found that lowering the temperature from 25℃ to
20℃ and then to 17℃ during the stabilized operating period(HRT 8h) did not affect the anaerobic MBR or treated water
quality.

Table 1 Operating conditions for each RUN.
RUN
HRT (h)Temperature (℃)
24
I
48
70
12
II
24
25℃
III
8
IV
24
V
12
8
25℃
8
VI
20℃
12
20℃
VII
8
17℃
The inlfuence of temperature changes on the amount of
biogas generated was also significantly observed from theoperating results of the stabilized HRT 8h. At HRT 8h, thebiogas generations at 25℃, 20℃, and 17℃ were 1260.5
NL/d, 1165.1 NL/d, and 933.4 NL/d, respectively.
Biogas generation rates in stabilized AnMBR at HRT 8h
were 0.084 NL/L (0.084 NL biogas generated from 1 L of
raw water), 0.078 NL/L, 0.062 NL/L, respectively, from
25℃ to 17℃.
The conversion rates of the removed COD to methane gas
were 0.172 N L/g COD, 0.171 NL/g COD, and 0.133 NL/g
COD, respectively, from 25 ° C to 17 ° C.

Fig. 3. Biogas production and content.

4 Conclusions
Fig. 2. Long-term performance of Pilot AnMBR.
The operation of AnMBR is divided into 7 RUNs according
to the operating conditions, as shown in Table 1.
Fig.3 shows the diurnal changes in the amount andcomposition of biogas generated from AnMBR during theentire operating period.
The stabilized methane gas content in the whole periodalways reached 75%, and a high value of about 80% was also
obtained. RUN I started operation at HRT 24h, and therecovery of methane gas content was slow, but in RUN II, III,VI, and VII, the recovery of methane gas content by resuming
operation under the condition of HRT 12h or 8h was within
one week. It was over 75%. It was found that the temperature
lowering operation from 25℃ to 20℃ and then to 17℃ had
no effect on the biogas composition.

421) The performence at HRT 8h at water temperatures of
25℃, 20℃, and 17℃ were stable, and the volume of raw
wastewater treated was 15 m3. In addition, the COD of treatedwater was below 50 mg/L, the removal rate was over 89%,
the BOD was below 15 mg/L, and the removal rate was over91%.
2) The amounts of biogas generated at water temperaturesof 25℃, 20℃, and 17℃ were 0.084 NL/L, 0.078 NL/L, and0.062NL/L, respectively. The methane content in thegenerated biogas was stable at about 78%. In the stable stateof 20℃, biogas production decreased by about 8% comparedto the condition of 25℃. At 17℃ stable condition, biogas
production decreased by 20% and 26%, respectively,
compared to the 20℃ and 25℃ conditions.

The 9th International Symposium on Water Environment Systems

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(Nov. 25th ~ 26th , 2021)

Tohoku University----- with Perspective of Global Safety

Treating high-strength swine wastewater with AnMBR: Energy recovery
efficiency and membrane fouing behaviors○Yu Li1, Gaojun Wang1,2, Guohao Liu1, Rong Chen1,2,*
1Key Lab of Environmental Engineering (Shaanxi province), School of Environmental and Municipal

Engineering, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR
China.
2
International S&T Cooperation Center for Urban Alternative Water Resources Development, Key
Laboratory of Northwest Water Resource, Environment and Ecology (Ministry of Education), Xi'an
University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China.
Abstract
In this study, a lab-scale anaerobic membrane bioreactor (AnMBR) feeding with swine wastewater was operated
over 190 days with increasing organic loading rate (OLR) gradually. The results showed that a stable COD
removal rate higher than 97.0 % was achieved at high OLR of 20.5 g COD/L/d, during which the methane
production rate maintained 0.23 L/L-reactor/d. Further increasing of OLR to 26 g COD/L/d declined the COD
remove rate 92.1%, which resulted in a lower methane yield of 0.15 L/L-reactor/d simultaneously. What’s more,
the shortening of HRT aggravates membrane fouling. The filtration experiment results covered that cake layer
resistance accounted for 98% of the total resistance, and the organic pollutants in cake layer were SMP and T-EPS
with concentrations of 37.4 mg/gVS and 50.3 mg/gVS, respectively. Microbial community analysis uncoveredthat although the varied OLR altered microbial diversity, Methanothrix, Methanobrevibacter and Methanoculleus
were always the dominant methanogens, which seemed responsible for the excellent methane yield. According,
Our study confirmed that AnMBR was a promising technology for treating high-strength swine wastewater, which
can not only guarantee the efficient pollution removal performance, but also achieve considerable energy recovery
efficiency.
Keywords: Swine wastewater; Anaerobic membrane bioreactor; Energy recovery; Membrane fouling;
Microbial community.

1 Introduction
The world's largest consumer of pork, China breeds morethan 500 million pigs a year. Consequently, the industry
produces a tremendous amount of swine wastewater. swine
manure is a valuable soil regulator that nourishes crop
production, but mismanagement and overuse can adversely
affect the environment [1-2]. However, this waste also
represents a valuable source for renewable energy
production in the form of biogas. Biogas is produced during
the anaerobic degradation of organic matter and can be used
to replace fossil fuel in the production of heating/cooling,
electricity, and transport fuel. In contrast to traditional
biological process, the complete separation of hydraulicretention time (HRT) and solid retention time (SRT) can beachieved in AnMBR so that a high microbial activity can be
maintained. However, so far, there are few studies on thetreatment of swine wastewater by AnMBR.
Anaerobic digestion treatment is a complex biochemical
process, and is usually affected by various environmental
parameters such as types of wastewaters, chemical
constitutes, operational conditions, microbial activity,
organic loading rate (OLR) and HRT [3]. Among thesefactors, HRT is a crucial parameter governing anaerobic treatment process for its significant effects on OLR, microbial
diversity/activity and methane-conversion rate. Longer HRT
is beneficial to the removal of pollutants whereas thiscauses larger reactor volume and higher capital cost. In
different studies, the effect of HRT on the operational
performance might vary greatly, probably resulting from thediscrepancies in operational parameters, feed characteristics,
biomass characteristics and reactor configuration.

43

Therefore, the purposes of this study were to: (ⅰ)
comprehensively study the stability and long-term
performance of AnMBR treatment of swine wastewater,
especially pollutant removal and methane recovery; (ii)
Analysis of the influence of high concentration of sludge on
membrane fouling; (iii) To explore the response of
microbial community under different HRT. To achievethese ends, a lab-scale AnMBR treating swine wastewater
has been in operation for over 190 days. Different
physicochemicalparameters,
includingwastewater
protein/polysaccharide, organic matter removal and biogas
production, were investigated to evaluate the stability andlong-term performance of the process. Key factors affecting
membrane fouling were identified by detecting anaerobic
biomass properties such as extracellular polymer content
and filtration experiments. In addition, 16S rRNA genesequencing was used to explore the evolution of microbialcommunity structure over time.

2 Materials and methods
A lab-scale AnMBR , with an effective working volume of
2.5 L, was constructed for treating swine wastewater. The
membrane module is PVDF flat membrane with an effective
area of 0.0312 m2 and a nominal pore size of 0.1 µm. The
operational temperature was maintained at 37 ± 1℃ by athermostat water bath. Both the influent and effluent
processes were controlled by rate-adjustable peristaltic
pumps. All the pumps were controlled by digital timer toadjust the HRT in each stage. The pH was measured by pH
meter. The COD, Polysaccharide, protein, total solids (TS)and volatile solids (VS) were measured according to theStandard Method [4]. Biogas composition was monitored by

The 9th International Symposium on Water Environment Systems

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(Nov. 25th ~ 26th , 2021)

Tohoku University----- with Perspective of Global Safety
a gas chromatography equipped with a thermal conductivity
detector. Three types of EPS in anaerobic granular sludge
were extracted in accordance with the heating extraction
protocols. Other methods of analysis are omitted here.

3 Results and discussion
The time course of OLR, biogas composition, biogas
composition, TS, VS and TMP during the long-term
operation is shown in Fig. 1. With the shortening of HRT,
the OLR increases gradually, and when the OLR is
20.5±1.53 g-COD/L-reactor/d, the biogas production rate of
AnMBR reaches 0.23±0.02 L/L-reactor/d. However, when
the organic load is increased to 27 g-COD/L-reactor/d, it
can be seen from the figure that the biogas production
decreases obviously. At this time, the effluent COD ofAnMBR system also increased by nearly two times, and the
COD removal rate also decreased significantly. The relevant
data of effluent quality was omitted in this abstract. In thewhole process, the biogas gas composition is always stable,
and the methane and carbon dioxide gas composition isabout 75.1% and 24.6% respectively.

As shown in Fig. 1e. The shortening of HRT significantly
increases the fouling rate of membrane, so the operation
performance of membrane must be improved by reducing
sludge concentration and scour frequency. It is obvious
from Fig. 1d. that the running time of membrane increases
significantly with the decrease of sludge concentration.
More membrane fouling characterization is omitted here.
To track the evolution of microorganisms within the
AnMBR system, microbial community structure wasanalyzed by 16S rRNA high-throughput pyrosequencing
during the whole process. The specific development of
microbial structure with HRT shortening is omitted here.

Fig. 2.Variation of methane production andmethanogenic activity with substrate concentration.

4 Conclusions
This study demonstrated the great potential of AnMBR forswine wastewater treatment and methane recovery. The
comprehensive results showed that under the condition of
20.05 g-COD/L/d and HRT of 2 d, the performance of
AnMBR was the most stable with the average COD
removal of 97.0 ± 0.05%, and methane production rate was
0.23 ± 0.02 L/L-reactor/d with methane content of about
64%. In the treatment of high strength swine wastewater,
the formation of cake layer is the main cause of membranehole blockage. Cake layer formation can be effectively
alleviated by reasonably increasing scouring frequency anddecreasing sludge concentration. Micrrobial community
structure showed that the suitable HRT could regulate themicrobial diversity, promote the proliferation of bacterias
and accelerate the biodegradation of swine wastewater;

Reference

Fig. 1. Time course of OLR, biogas production rate,biogas composition, TS, VS and TMP.
On the 181th day, a methanogenic activity test with adifferent OLR was performed at 37 °C, and the results areshown in Fig. 2. As can be seen from the figure, with theincrease of OLR, the methanogenic activity of sludge
decreased significantly, which may be mainly due toexcessive VFA generation inhibiting methanogenic
activity. The results show that in AnMBR system, when the
OLR is about 20 g-COD/L/d, the fermentation of swine
wastewater is the most favorable.

44[1] Benyamin Khoshnevisan, Na Duan, Panagiotis Tsapekos,
Mukesh Kumar Awasthi, Zhidan Liu, Ali Mohammadi, Irini
Angelidaki, et al. A critical review on livestock manurebiorefinery technologies: Sustainability, challenges, andfuture perspectives. Renewable and Sustainable Energy
Reviews 2021;135: 1364-0321.
[2] Mengmeng Jiang, Maria Westerholm, Wei Qiao, Simon
M. Wandera, Renjie Dong. High rate anaerobic digestion ofswine wastewater in an anaerobic membrane bioreactor.
Energy 2020;193: 0360-5442.
[3] Maaz, M., Yasin, M., Aslam, M., Kumar, G., Atabani,
A.E., Idrees, M., Anjum, F., Jamil, F., Ahmad, R., Khan,
A.L., Lesage, G., Heran, M., Kim, J., 2019. Anaerobic
membrane bioreactors for wastewater treatment: novel
configurations, fouling control and energy considerations.
Bioresour. Technol. 283, 358–372.
[4] APHA, 1998. Standard Methods for the Examination of
Water and Wastewater, twentieth ed. A.P.H. Association,
Washington, DC, USA.

The 8th International Symposium on Water Environment Systems

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(Nov. 25th ~ 26th , 2021)

Tohoku University----- with Perspective of Global Safety

Mitigation of membrane fouling in a thermophilic hybrid AnMBR
treating food waste○ Mengmeng JIANG1, Min LIN1, Wei QIAO1*, Renjie DONG1
1

College of Engineering, China Agricultural University, Beijing 100083, China*
E-mail: qiaowei@cau.edu.cn; wayqiao@sina.cn

Abstract
A hybrid anaerobic membrane bioreactor (Hy-AnMBR) was developed by incorporating polyurethane sponge
carriers to mitigate membrane fouling and compared with a control AnMBR (Con-AnMBR) without carries underthermophilic condition (50±1) °C. The results showed that the TS, VS and operation time are essential parameters
influencing membrane filtration. MLSS in the Hy-AnMBR was 20% lower than the Con-AnMBR, resulting in
improved filtration performance. The scanning electron microscope (SEM) photograph shows the membrane pores
could be observed on the Hy-AnMBR surface, which indicated that the cake layer pollution of Hy-AnMBR wasless than Con-AnMBR. Adding sponge carriers mitigate 3.3%-9% pore-blocking analyzed by confocal laser
scanning microscopy (CLSM).
Keywords: AnMBR; thermophilic anaerobic digestion; membrane fouling; sponge carriers.
1 Introduction
Anaerobic membrane bioreactor (AnMBR) is a promisingtechnology that combined anaerobic digestion and membrane
filtration technology, which has successfully been used totreat kinds of wastes. However, membrane fouling is one of
the main obstacles to the development and application of
AnMBR technology. The biomass concentration including
mixed liquor suspended solids (MLSS), total solid (TS), andEPS has been concluded by some reports to harm membrane
fouling in membrane bioreactors. As a result, lower sludge
concentration in AnMBR is beneficial to membrane filtration
performance, thus reducing membrane fouling.
Hybrid AnMBR by carrier addition can further retain
microorganisms and decrease the biomass concentration in
the bulk sludge, thereby improving membrane filtration
performance, even improving the organic matter removal rate,
which is a technology worth looking forward to. In this study,
a hybrid-AnMBR (Hy-AnMBR) with polyurethane sponge
carrier was investigated and compared with a control
AnMBR (Con-AnMBR). Based on our latest report (Jiang etal., 2021), this study focuses on membrane foulingcharacteristics. The filtration performance and MLSS
concentration in the bulk sludge were compared between thetwo systems, the fouled membrane surface and membranepore morphology were investigated to evaluate themembrane anti-pollution performance after introducing
carriers.

in Table 1, and the architecture of hybrid AnMBR was given
in Fig. 1.
Table1 Characteristics of food wastewater and inoculum
TS

g/L

Food
waste
(n=18)
80.0±4.0VSg/L

68.4±4.2

43.1±0.0

MLSS

g/L

41.4±7.956.5±0.4

MLVSS

g/L

39.1±7.6

22.9±0.1

TCOD

g/L

111.0±4.6

49.3±1.3

SCOD

g/L

63.3±7.5

10.4±1.3

NH4+-Nmg/L

272±551034±11VFA

mg/L

2078±1091180±35

Parametersunit

62.7±0.0

The hollow fiber membranes used in this study were madeof polytetrafluoroethylene (PTFE) with a mean pore size of
0.1~0.2 μm and an effective filtration area of 0.1m2(Sumitomo Electric, Japan). The AnMBR system consists ofa CSTR and a separated membrane chamber. Two systems
were operated during this study: parallel operated during thestartup period which was HRT 20 days; biofilm carrier wasadded in one CSTR bottom unit as the HRT was shortened to
15 days. The polyurethane biofilm carrier cube has a side
length of 1 cm and a porosity of 98%. The filling volume of
the biofilm carrier was around 3 L. The biogas recirculation
pump has a sparging rate of 7 L/min. The filtration mode of
the two AnMBR was 4 min on and 1 min off.

2 Materials and methods
Buffer bag

Permeate TMP
pumpsensor

Water vapor Biogas recirculation
condensation
pump

Gas
bag

Water vapor
condensation

TMP sensor
P

Feed inM

Permeate

LiquidSludgeP
Biofilm carriers

CSTR unit

membrane unit

System 1
AnMBR 1#: 1~30 d
SRT: 100 d
Flux:8.1±0.3 L/m2/h

Control AnMBR:
31~75 d
SRT: 50 d
Flux:8.0±0.4 L/m2/h

H

Heating water

System 2
AnMBR 2# : 1~30 d
SRT: 100 d
Flux:8.1±0.4 L/m2/h

EmbeddedcarrierHybrid AnMBR :31~75 d
SRT: 50 d
Flux:8.0±0.5 L/m2/h

Fig. 1. Concept of the hybrid AnMBR

45

P

H2S removal

Biogas recirculation

The food waste used in this study was taken from a fullscale industrial project located in Jiangsu province. The foodwaste was produced after sorting, crushing, pulping, andsolid-liquid-oil separation, then the liquid phase wascollected and used. Trace elements were added with aconcentration of Fe: 100 mg/L, Co: 1 mg/L and Ni: 1 mg/L
before feeding. The inoculum was taken from a mesophilic
sewage sludge digester and was diluted twice before use. The
inoculum was kept at 50 ºС before being fed with thesubstrate to get acclimated to the thermophilic temperature.
The characteristics of food waste and inoculum were given

Inoculum (n=2)

The 8th International Symposium on Water Environment Systems

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Tohoku University----- with Perspective of Global Safety

3 Results and discussion
Membrane filtration performance: In this study, thecontinuously TMP, Flux, MLSS and viscosity deviation were
given in Fig. 2. The TMP and flux of both the two systems
were almost the same before day 30, the MLSS and viscosity
in the reactors showed not much difference. However, an
increasing profile of TMP in both the Con-AnMBR and HyAnMBR after 30 days of operation was observed. From day
30 to day 50, the TMP of Con-AnMBR rapidly increased
with a rate of 0.994 kPa/d (Fig. 2a). On the other hand, theadjustment of flux can be achieved to some extent in HyAnMBR but is difficult to sustain at a higher value in ConAnMBR. The growth of TMP is relatively slow, with anincreasing rate of 0.375 kPa/d (Fig. 2a). MLSS and viscosity
showed a similar increasing trend after introduced carriers
but were different in the two systems (Fig. 6c & d). Afterembedding the carriers, the MLSS in the Hy-AnMBR was
20% lower than the Con-AnMBR. In addition, the viscosity
which typically used to characterize the rheologicalproperties of sludge increased from 64 mPa·s to 96 mPa·s in
AnMBR, and from 56 mPa·s to 60 mPa·s in hybrid AnMBR.
Principal component analysis was conducted among somepossible factors shown in Fig. 2 (e & f). It can be concluded
that in both the Con-AnMBR and Hy-AnMBR, thepermeability showed a negative correlation with permeability,
but the TS, VS and operation time are essential parametersthat
influencethemembrane
filtration.
HRT 20 d

30

HRT 15 d, embedded carrier(b)8

y=0.994t-30.06
R2=0.9829

Flux (L/m2/h)

TMP (kPa)

24
18

HRT 15 d, embedded carrier

HRT 20 d

9

(a )

AnMBR
Hybrid AnMBR

12

7

AnMBR
Hybrid AnMBR

6

y=0.375t-8.20
R2=0.9781

6

5
0

15

30
45
Duration (days)

50

60

0

75

15

30

45
Duration (days)

60

75

(d)

(c)

100
Viscosity (mPa·s)

MLSS (g/L)

45

AnMBR
Hybrid AnMBR

40

80

Food waste is a substance with high protein andpolysaccharide content belonging to biomacromolecules.
Even if they are well decomposed in a high-solid AnMBR
system, part of them may inevitably remain in the mixed
liquid. The organic biomacromolecules block the membranepores or form the cake layer and gel layer during long-term
membrane filtration, leading to irreversible fouling.

Fig.3 SEM images and physical appearance of themembrane module after fouling and cleaning

The dyeing area of protein, α-polysaccharide and βpolysaccharide through confocal laser scanning microscopy(CLSM) analysis are concluded in Table 2. The staining areaof Hy-AnMBR is smaller than that of Con-AnMBR. Amongthem, the stained areas of protein, α-polysaccharide and βpolysaccharide accounted for (59.1±10.1) %, (47.9±4.3) %and (60.3±7.0) % of the total area respectively, which is 3.3%,
9% and 6.6% lower than that in Con-AnMBR, respectively.
The main pollutants of Hy-AnMBR membrane pores areprotein and β-polysaccharide.
Table 2 Ratio of dyeing area to sample area of CLSM
fluorescent staining results

AnMBR
Hybrid AnMBR

60

Percentage of clogging surface of membrane (%)

35

Proteinαpolysaccharides

β-polysaccharides

62.4±10.4

56.9±7.566.9±2.959.1±10.1

47.9±4.3

60.3±7.0

40
30

0

15

30
45
Duration (days)

60

0

75

4

30
45
Duration (days)

60

75

Control
AnMBR
Hybrid
AnMBR

4
(e)

(f)

Flux
Viscosity
Time
TS
VS

0

TMP

Permeability

TS
0

-2

-4

-4
-2

0
PC 1 (94.47%)

2

4

Time
VS
TMP

4 Conclusions

Permeability-2-4ViscosityFlux2
PC 2 (19.44%)

2
PC 2 (2.58%)

15

-4

-2

0

2

4

PC 1 (62.37%)

Fig. 2. Membrane filtration performance of the two systems

The SEM images and physical appearance of themembranes after fouling and cleaning are shown in Fig. 3. It
can be seen from the photograph of the membrane surface
that with upward hydraulic shear, the filamentous materials
were entangled with the membrane fibers, especially in the
Con-AnMBR. Observed by the SEM photograph, the fouled
Con-AnMBR membrane surface was also covered with an
obvious cake layer, the membrane pores were severely
blocked and not visible after fouling, which increase filtration
resistance and may be one of the main reasons for the
reduction of membrane filtration performance. On themembrane surface of Hy-AnMBR, although there are somepollutants on the surface, the membrane pores were still clear.

46

The Hy-AnMBR through adding biofilm carriers caneffectively mitigate and delay the formation of membrane
fouling by decreasing sludge concentration in the reactor.
The cake formation and pore-blocking were therefore largely
alleviated. The affecting factors identified by PCA analysis
proved the advantages of the hybrid AnMBR for alleviating
membrane fouling formation.

5 Acknowledgement
This work was partially supported by National Science
Foundation of China (51778616).

Reference[1] M. Jiang, Z. Wu, J. Yao, S.M. Wandera, D.E. Algapani, R. Dong,
W. Qiao. Enhancing the performance of thermophilic anaerobic
digestion of food waste by introducing a hybrid anaerobic membranebioreactor, Bioresource Technology, 341 (2021) 125861.

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Elucidating fouling charactization in a high solid anaerobic membranebioreactor treating OFMSW leachate○Zhiyue WU1, Junqiang YAO1 , Wei QIAO1*,Renjie DONG1
1

College of Engineering, China Agricultural University, 17 Qing hua East Road, Beijing 100083, China.
*
E-mail: qiaowei@cau.edu.cn; wayqiao@sina.cn.

AbstractLong-term scaling formation in a high solid anaerobic membrane bioreactor (AnMBR) has been a major
challenge in treating the leachate from the municipal solid waste (MSW). In this study, the role of inorganic
precipitation were evaluated. The chemical analysis exhibited that the mass balance and distribution of inorganic
caions in the system, and inorganic mineral were identified by the XRD. Considerable results showed that calcite
was the dominant inorganic precipitation, besides, the content of inorganic ash is more than 70% in bulk suldge,
and it was higher on membrane surface. Moreover, around 17.4 mg Ca/cm2, 1.3 mg-P/cm2 and 0.4 mg-Mg/cm2
were detected residual on the membrane surface. It is reasonable to assume that inorganic particles based on
calcium carbonate scour the membrane surface and form a hard skeleton layer. Membrane permeability could be
easily recovery with chemical cleaning, especially, and the precipitation layer retained until after 2% citric acidcleaning.
Keywords: Anaerobic membrane bioreactor, inorganic precipitation, OFMSW leachate , high solid, membranescaling.
1 Introduction
The amount of municipal solid waste (MSW) in China has
increased rapidly in the past three decades due to urban
expansion. And more than 55% of MSW bas been
incinerate in big cities, before buring, 0.1-0.3 ton leachate
per ton waste was produced during the storage period[1].
Usually, in a combination of physical, chemical andbiological methods, used to treat MSW leachate, anaerobic
digester treatment has been demonstrated to be the mostuseful technology. However, the biggest challenges for AD
process is low efficiency due to the loss of slow-growing
methane microorganisms. Anaerobic membrane bioreactors(AnMBR) as a novel and efficient biotechnology caneffectively retain key microorganisms inside the reactor bydirect membrane rejection.
In fact, the effect of the presence of inorganic ions in thefeed on the AnMBR system is very complex. Admittedly,
inorganic elements are necessary for the growth of
methanogens[2], however, high concentration of inorganic
ions in influent results in some problems, like membranescaling. To date, most of the previous studies focused onmembrane fouling due to organic matter. In this study, weinvestigated the fouling charactization in a high solid
anaerobic membrane bioreactor treating OFMSW leachate.

2 Materials and methods
Briefly, a flat sheet membrane (Kubota, Japan) with thetotal area of 0.116 m2 and an average pore size of 0.2 µm
was immersed in the bioreactor, and operated at 37± 1°C,
which running at a constant average flux of 6 L/MH. During
the operation, trans-membrane pressure (TMP) wasmonitored with a pressure sensor and tracked TMP trend by
a online recorder, as shown in Fig. 1. As the influent, theleachate of OFMSW contained: total chemical oxygen
demand (TCOD) 57±4 g/L, ammonium nitrogen (NH4+-N)

47

860±120 mg/L, calcium (Ca) 2350±540 mg/L, magnesium(Mg) 708±304 mg/L and total phosphorus (TP) 94±5 mg/L.
(a)

(b)

Biogas circulating pump

Biogasbuffer
bag

Water
seal
tank

H2 S
removalunit

2

Gas meter
1

TMP
meter

Permeate
bump

TMP
meter

Feedingbump

OnlinerecorderPermeatebump

M

Biogasbump

Permeate

Substrate tank
(4℃)

37 ℃

4℃

Sludgesampling

AnMBR
Coolingbath

Coolingbath

Substrate tank (4℃)

Heatingbath

AnMBR (37℃)

Fig. 1. Photograph(a) and schematic diagram(b) of the
AnMBR.
The calcium and magnesium concentration were measured
by an Atomic Absorption Spectrophotometer after acidizing
treatment. A Loss on Ignition test is performed to determine
the inorganic content of foulant on loose cake layer andprecipitation layer.
Carry out a cleaning mode to analyze the membrane
resistance distribution and the characteristics of pollutants.
As the following three core steps: (1) Gas washing；(2)NaClO cleaning；(3) Citric acid cleaning.

3 Results and discussion
In the high-solid AnMBR, the membrane operation
performance at continuous flux of 6 LMH was evaluated,
and the results were shown in Fig 2. Variation curves of
instantaneous Max-TMP and Min-TMP were obtained
shown in Fig. 2a. After 61 days running, Max-TMP was
remained at a low level and increased by only 1.1kpa, when
Min-TMP did not show an increasing trend. Reversible
fouling caused by cake layer and resulted in the Max-TMP
increased gradually, and the stability of Min-TMP reveals
that irreversible fouling was not obvious.
Permeability was calculated as a ratio of the average flux
and TMP in order to evaluate changes in membrane
filtration performance. It was observed that membrane

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permeability was gradually decline by 2.7% within 44 days,
while the TS in bluk sludge was increased from 3% to 5%.
(a)17.4 mg-Ca

61th day sludge
1.3 mg-P
Ca15(PO4)2(SiO4)6

Cake
PDF-72-1937

0.4 mg-Mg

1.6
0

10

20

30

40

50

PDF-50-0905

60

1.4

Ca Mg P (g/L) Concentration (g/L)

PDF-19-0768

60

(c)

60 0

10

TS

VS

VS/TS

20

30

40

50

60 50

40

40

20

30

0

12

20

20

(d)

80

Ca

Mg

10

20

10

20

P

30

40

50

60

30

40

50

60

30

40

50

60

4
0

40
2q
2 θdegreedegree50

MgSiO3

60

Ca

C

P

1 cm2
O

Mg

Si

0
10

20

Duration Time (d)Duration time (d)Fig. 2. Evolution of the membrane performance during
the operation time with different concentration of TS
and inorganic ions.
Additionally, a submerged membrane permeability wasdecreased significantly with an increase TS, especially after
more than 4%. A similar result was shown until after 44days with a 15.5% reduction. It was suggested that a better
membrane filtration performance was obtained in a TS
below 5%.The AnMBR rejected calcium, phosphorus andmagnesium reach to 94.4±5.3%, 84.5±7.8% and 73.1±6.8%,
respectively. And about 63%, 61%, 46% were rejected in
the reactor, when the 4%, 23%, 11% embedded in permeate,
and 33%, 16%, 43% discharge with sludge, respectively.
Table 1 The concentration of Ca, Mg and TP in feed,bulk sludge and permeate.
Parameter

30

Fig. 3 XRD analysis and Ca, P, Mg distribution on
membrane.
organic matter and 73.3%~76.1% inorganic matter, andabout 6% organic foulant was detained in precipitation layer.
As the inorganic foulants accumulated on the membranesurface with flux decline, inorganic-organic interaction
became stronger.

VS/TS (%)

Permeability(L/m2·h/kPa)

CaCO3

(b)

0

TP
(mg/L)(b)(b)

49th day sludge

-4

1.2
80

Mg
(mg/L)

1st day sludge
23th day sludge

Min-TMP

Max-TMP

-5

-3
1.8

Ca
(mg/L)

Ca15(PO4)2(SiO4)6

CaCO3

Intensity
Intensity

TMP
(kPa)

-6

MgSiO3

SiO2

(a)

Item

1st day

23th day

49th day61st day

Feed
PermeateBulk
sludgeFeed
PermeateBulk
sludgeFeed
PermeateBulk
sludge

2050
189

1620
65

2942
114

2450
59

834

3056

8878

11892

689
331

810
259

1010
177

797
246

110

210

651

1180

58
10

91.6
5

93
6.6

87
18

490

856

923

521

Table 2 LOI resulst for foulant from the loose cake layer
and precipitation layer.
Item
Loss onIgnition/%
Organic
Content/%
InorganicContent/%

Loose cake layerTop
Middle Bottom

Precipitation layerTop
Middle Bottom

26.7

25.1

23.9

6.2

6.1

5.9

26.7

25.1

23.9

6.2

6.1

5.9

73.3

74.9

76.1

93.8

93.9

94.1

4 Conclusions
This study focuses on the fouling charactization ofleachate with high calcium concentration in HS-AnMBR
system. The results show that AnMBR was a practicabletechnology for the treatment of OFMSW leachate rich in
calcium. A significant accumulation of inorganic
precipitation at high alkalinity was observed due to theaccumulation of calcium carbonate precipitation. During theoperation, membrane fouling may not be a challenge since it
can work long-term before cleaning due to the calcite
precipitate layer with a hard skeleton on the membranesurface. Moreover, phosphorus was partially anaerobicallyremoved in AnMBR benefit by the precipitation.

5 Acknowledgement
This work was partially supported by National Science
Foundation of China (51778616).

Based on the XRD analysis, calcite was the dominant
inorganic precipitation, and a complex precipitatecontaining calcium and phosphorus was found by analyzinga software, and its molecular formula was Ca15(PO4)2(SiO4)6,
merely it was a small amount.
Fig.3 shows the concentrations distribution of the
inorganic elements on membrane detected in the solution ofwater cleaning, NaClO cleaning and citric acid cleaning.
There are no obvious P and Mg characteristic peaks in the
cake layer, but they are obtained 1.3 mg-P/cm2 and 0.4
mg-Mg/cm2 remain on surface of membrane by chemical
analysis.
The results from LOI (Table 2) shown that the loose cakelayer on the membrane surface consisted of 23.9%~26.7%

48

Reference[1] Zhou L, Zhuang WQ, Ye B, et al. Inorganic
characteristics of cake layer in A/O MBR for anaerobicallydigested leachate from municipal solid waste incineration
plant with MAP pretreatment. Chem Eng J.
2017;327:71-78.
[2] Tian L, Chen XD, Yang QP, Chen JC, Shi L, Li Q.

Effect of calcium ions on the evolution of biofouling by
Bacillus subtilis in plate heat exchangers simulating theheat pump system used with treated sewage in the 2008
Olympic Village. Colloids Surfaces B Biointerfaces.
2012;94:309-316.

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Effective enrichment of anammox granules for high-loading landfill
leachate treatment: Research progress○ Jinghuan LUO* & Jianyong LIU
School of Environmental and Chemical Engineering, Shanghai University, 333 Nanchen Road, Shanghai
200444, China.
*E-mail: jhuanluo@shu.edu.cn.

Abstract
Anammox is an autotrophic nitrogen removal process and sludge granulation has been an effective approach toachieve abundant slow-growing anammox bacteria in the reactor, while the ﬂoatation and wash-out of anammox
granules was usually occurred in particular at high loading rates. Our research demonstrates that anammox
granules could be effectively enriched with hydroxyapatite (HAP), granular activated carbon (GAC) or calcium
carbonate (CaCO3) as the inner core, thus achieving a satisfactory biomass retention. Anammox granules could bealso quickly cultured from anaerobic digestion (AD) granules by the layered inoculation. The mature anammox
granules were then successfully employed to treat landfill leachate for advanced nitrogen removal.
Keywords: anammox; granulation; biomass retention; landfill leachate; nitrogen removal.

2 Results and discussion

Fig. 1. Effective enrichment of anammox-HAP granules.

49

Layered inoculation for fast
start-up of anammox reactor

Activity of anaerobic digestion
granular sludge
100

100

12

8

P

NRR

TNre

8

60

6
40
4

No cell lysis phase,20
one day lag phase,
NLR=11 kg N/m3 d (day 42).

2
0

0
0

5

10

15

20

25

30

35

P

40

80
NLR

6

Day 11

TNre
60

4

40

2

20

0

0
0

10

20

30

40

50

60

70

80

90

Time (d)Time (d)

Day 1

NRR

Removal efficiency (%)

80
NLR

NLR and NRR (kg·N/m3·d)

10

Removal efficiency (%)

Compared with conventional nitrification-denitrification
process, anammox requires no external organics and muchless aeration demand, and also largely reduces waste sludge
production and carbon dioxide emission [1]. As an
environmentally-friendly technique, it has been drawing
much attention worldwide to treat ammonium-richwastewaters [1]. Nonetheless, there are also some
limitations in anammox operation, one of which is the slow
growing rate (e.g., 0.21 d-1) and the low biomass yield (e.g.,
0.071 mol C/mol NH4+) [2] for anammox bacteria with adoubling times reported at 4~15 days [3]. In order toachieve abundant anammox bacteria, sludge granulation has
been demonstrated as one of the most effective approaches[1]. However, the granules ﬂoatation and wash-out fromanammox reactors has been a notorious issue in particular athigh loading rates [4], which easily causes sludge loss andprocess deterioration.
To ensure an efficient biomass retention for theslow-growing anammox bacteria, our research wasdedicated to enriching anammox granules with HAP, GAC
or CaCO3 as the inner core and culturing anammox granules
from AD granules. The mature anammox granules werethen employed to treat landfill leachate for advanced
nitrogen removal.

Under a high NLR and an efficient mass transfer,anammox-HAP granules were successfully enriched with acell yield of 0.23 g VSS/g NH4+-N. The biomass wasincreased from 732 g to 6,577 g and anammox bacteria
jumped from 18.6% to 82.8% after 140 days of operation.

NLR and NRR (kg·N/m3·d)

1 Introduction

Day 40(Adsorption, interception, domestication)

Day 1

Day 38

Day 75

Day 90Fig. 2. Anammox granules cultured from AD granules
by layered inoculation.
Anammox granules were cultured from AD granules by
their layered inoculation in R1 reactor with both cell lysis
phase and lag phase being shortened. The maximum NLR
and NRR were 11 kg N/m3/d and 9.9 kg N/m3/d on day 42,
respectively. The domesticated AD granules on the upper
layer were later transferred to R2 reactor to investigate theiranammox activity. AD granules in R1 did perform
anammox activity and could be cultured into anammox
granules. Adsorption, interception and domestication allcontributed to anammox biomass in AD sludge bed in R1,
thus accelerating the start-up of the reactor.

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Fig. 3. GAC promoting re-granulation of
anammox-HAP granules at low phosphateconcentration.
A reactor inoculated with mature anammox-HAP
granules and fed with low phosphate (5 mg P/L) was addedwith GAC to maintain sludge granulation andnitrogen-removing stability. At influent total nitrogen >800
mg/L and NLR ~9.8 kg/m3/d, a satisfactory nitrogen
removal of around 88% was maintained during 140 days ofoperation. Insufficient phosphate supplement resulted in asludge bulking, with suspended solid and sludge density
decreased whereas sludge water content and expansion ratio
increased due to HAP loss. Nevertheless, the sludge
re-granulation was found at the later stage as the proportionof granules in 2.8~3.35 mm went up to 37.4% after large
granules disintegrated into small pieces at the initial stage.
The settling velocity was finally ranging from 129.8 to
182.2 m/h. In addition, Candidatus Brocadia was increased
from 2.1% to 20.1% and dominated in the microbialcommunity. These findings suggest GAC was able topromote re-granulation of anammox-HAP granules at low
phosphate concentration, which avoids sludge ﬂotation andwidens their application as an inoculum.

Fig. 5. Anammox granules for advanced nitrogen
removal from landfill leachate.
A stable advanced nitrogen removal from mature landfill
leachate was achieved by anammox granules with refractoryorganics used to further reduce anammox by-product nitrate.
Soluble microbial products, polycarboxylic acid and fulvic
acid were found to be removed, and the unsaturatedfunctional groups such as carboxyl, hydroxyl and carbonylon aromatic compounds were transformed into aliphatic
ones. In addition to anammox bacteria, microbial groups todegrade macromolecules and refractory organics were also
detected in anammox granules.

3 Conclusions
Anammox granules were effectively enriched with HAP,GAC or CaCO3 as the inner core, thus avoiding sludge
floatation or wash-out and achieving satisfactory biomass
retention. Anammox granules could be also cultured fromAD granules by the layered inoculation strategy. The mature
anammox granules were successfully employed to treat
landfill leachate for advanced nitrogen removal.

References

Fig. 4. Effective enrichment of anammox-CaCO3
granules.
Anammox-CaCO3 granules were successfully enrichedwith an anammox abundance above 80%. Compared tosevere sludge floatation and wash-out of anammox granules
in the control reactor, anammox-CaCO3 granules were wellsettled even under a high NLR up to 36 kg N/m3/d. A
satisfactory biomass retention was thus achieved.

50[1] Lackner et al. Full-scale partial nitritation/anammox
experiences - An application survey. Water Research 2014;55: 292-303.
[2] Lotti et al. Physiological and kinetic characterization ofa suspended cell anammox culture. Water Research 2014;
60: 1-14.
[3] van der Star et al. The membrane bioreactor: A novel
tool to grow anammox bacteria as free cells. Biotechnology
and Bioengineering 2008; 101: 286-294.
[4] Chen et al. Floatation of flocculent and granular sludge
in a high-loaded anammox reactor. Bioresource Technology
2014; 169: 409-415.

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Biochar enhances partial denitrification/anammox by sustaining highrates of nitrate to nitrite reduction
Ziwen Jia1*, Jingwei Fu1 & Qian Li1,2,3

Key Lab of Environmental Engineering, Shaanxi Province, Xi’an University of Architecture andTechnology, No.13 Yanta Road, Xi’an 710055, PR China.
2
Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku
University, 6-6-06 Aza-Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8579, Japan.
3
Corresponding Author: Qian Li, 81933758@qq.com.
*
E-mail: jiaziwen005008@163.com.

1

Abstract
To examine the mechanism by which biochar enhances the reduction of nitrate to nitrite, and its effect on thepartial-denitrification anammox (PD/A) process, the adsorption kinetics, nitrogen degradation characterization,
microbial community succession, and electron transfer properties of wastewater treatment systems with andwithout biochar added were determined. Biochar enhanced the total nitrogen (TN) removal of the system, likely
via increases in the nitrate reduction rates, which resulted in an overall TN removal rate increase of about 10%.
This TN removal enhancement by sawdust biochar pyrolyzed at 300°C was attributed mainly to the strong
electron donating capacity of biochar (EDC = 2.64 mmole-g-1)
rather than its adsorption performance. The reduction functionalgroups on the surface of the biochar allowed additional electrons toparticipate in the reduction of nitrate. The electron utilization of thebiochar experiments (BC) reached 1.56 mmole-L-1, which was
twice that of the control experiments (CT). Eventually, analysis of
the nitrogen transfer pathway of the PD/A process showed thatwhen sufficient substrate was available, the anammox anddenitrification reactions simultaneously removed nitrogen. Whenthe nitrite supply was insufficient, the anammox reaction
outcompeted the denitrification reaction for the regenerated nitrite.
These results revealed the metabolic pathways involved in nitrogen
removal and the mechanism by which electron donation isfacilitated by biochar.
Keywords: anammox; partial-denitrification; nitrate; biochar; electron donor.

1 Introduction

Anaerobic ammonia oxidation (anammox) has recently
been identified as an effective and sustainable biologicalwastewater treatment method capable of high-efficiency andlow-energy nitrogen removal from ammonia-containing
wastewater[1-3]. However, as one of the final metabolic
products, anammox effluent retains 11% nitrate, which is a
key factor limiting the nitrogen removal efficiency of thismethod[4-6].
To further remove the nitrate from the anammox effluent,systems that add extra carbon sources as electron donors for
denitrification are commonly utilized[7,8], but they arecomplex and costly. Recently, denitrifying bacteria havebeen found coexisting with anammox bacteria (AnAOB) in
anammox reactors such as the UASB. With thiscombination of bacteria within a single system, the nitrate
generated by anammox can be reduced to nitrite and rapidly
consumed by AnAOB, which is referred to as the partial
denitrification/anammox (PD/A) process. However, even if
nitrate can be removed by the in situ triggering of PD/A,
controlling the carbon sources still presents an important
challenge. Common carbon sources, such as organic matter,
sulfur compounds, hydrogen, etc., all affect the reaction
activity to a certain extent. Therefore, an alternative electron

51
51

donor which is cost effective and easy to control is needed
to enhance nitrate removal in anammox systems.
Biochar has an electron donating/accepting capacity andcan facilitate rapid electron transfer[9-13]. Furthermore,biochar is a cost-effective and environmentally friendly
material relative to other commercial redox media[14,15].
Previous studies concluded that biochar prepared at low
temperatures has a strong nitrogen removal ability due to its
specific characteristics. Nevertheless, the effect of biocharon the metabolic pathways of nitrogen removal in an
anammox system and the competition between AnAOB anddenitrifying bacteria remain unclear.
In this study, batch tests were conducted to characterize
the role of biochar in enhancing PD/A by facilitating theefficient reduction of nitrate to nitrite. Furthermore, theadsorption kinetics, nitrogen degradation characterization,
microbial community succession, and electron transfer
properties were analyzed to elucidate the effects of biochar
on competition between AnAOB and denitrifying bacteria
for a common electron acceptor (NO2-), revealing themetabolic pathway of nitrogen removal and the mechanism
by which biochar facilitates electron donations.

2 Materials and methods
Laboratory batch adsorption experiments were performedin serum bottles with working volumes of 100 mL. 50 mL

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Tohoku University----- with Perspective of Global Safetyof nutrient solution and 1 g of biochar were added into theserum bottles, and 50 ml of deionized water was added toobtain a working volume of 100 ml. There were threegroups in total and two parallel replicates in each group.
Each of the three groups had nutrient solutions consisting of:
0.47 g/L (NH4)2SO4, 0.49 g/L NaNO2, and 1.44 g/L KNO3.
The seed sludge used in this study was collected from astable operating UASB anammox reactor in the laboratory.
Batch tests were performed in serum bottles with working
volumes of 100 mL. Biochar 1 g, seed sludge 25 mL, andnutrient solution 50 mL were added into serum bottles andthen deionized water (25 mL) was added to obtain a 100 mL
working volume. All batch tests were performed in athermostatic shaker with the shaking speed and temperature
controlled at 120 rpm and 35°C, respectively.

3 Results and discussion
3.1 Effects of biochar on nitrogen removal
Batch adsorption experiments were conducted to assess theoverall aqueous NH4+, NO2-, and NO3- sorption ability ofbiochar. As illustrated in Figure 1(a), the biochar rapidly
adsorbed NH4+ for the first 4 h. However, the biochar did
not adsorb NO2- and NO3-, which may have been related to
the negative charge on the biochar surface, which can only
be associated with cation exchange in the adsorption
solution[16,17]. Quasi-first-order and quasi-second-order
dynamics equations were used to fit the experimental data
and the results are shown in Figure 1(b). The
quasi-second-order kinetic equation better described theadsorption process of NH4+ by biochar.
Although biochar has a certain capacity to adsorb NH4+,
biological nitrogen removal still dominated the overall
nitrogen removal of the reaction. As shown in Figure 1(d),when the substrate was ammonium and nitrite (Group A),
the total nitrogen removal rate of the BC was 97.4% over 45
hours, while that of the control was only 87.3%.
Furthermore, during the reaction, the cumulative N2
production of the BC was higher than that of the control
group [Fig. 1(c)]. It can be seen from the change in the three
nitrogen contents at the end of the reaction that nitrate was
the main reason that the nitrogen removal efficiency wassignificantly different between the biochar group andcontrol group. The nitrate concentration of the biochar
group was much lower than that of the control group.
Therefore, it was concluded that biochar improved theefficiency of anammox nitrogen removal and dinitrogenproduction by promoting the degradation of nitrate.
Furthermore, the N2O released by the denitrification
reaction was detected during the reaction. As shown in
Figure 1(c), at the initial stage of the reaction, the N2O
concentration of the biochar group was higher than that of
the control group. The BC had a 95% reduction in N2O
within 12 h, while the N2O in the CT only decreased by
73%, indicating that the biochar group had higher N2O
production and degradation capabilities. Therefore, theaddition of biochar promoted the denitrification process,and also improved the activity of N2O reductase, thus
reducing the risk of N2O spillover.

Figure 1. (a) Adsorption of NH4+, NO2-, and NO3- bybiochar; (b) adsorption kinetics of NH4+ by biochar; (c)change in N2 and N2O during the reaction; and (d)change in total nitrogen during the reaction in Group A.
3.2 Effect of biochar on electron the transport system
The results showed that [Fig. 2(c)], during the stage of
rapid ammonium decline (stage 1), electron transfer in BC
reached 0.89 mmole-L-1, nearly 3 times that of CT, and theelectrons were mainly utilized for denitritation. In thesecond stage, due to the lack of suitable substrates, thereaction rates of denitritation and partial denitrification
gradually declined and the quantity of electrons consumed
also decreased. From the third stage, the nitrite substrate
was depleted and the remaining nitrate was partiallyreduced. The amount of electrons consumed for partial
denitrification in BC reached 0.23 mmole-L-1, twice that of
CT. Denitritation consumes almost no electrons, which wasevident in the above results, suggesting that when the nitrite
supply was limited, the anammox reaction outcompeted thedenitritation reaction for nitrite. At the end of the reaction,
the total electron transfer in BC was 1.56 mmole-L-1, twice
as much as that of CT. In the first two stages, the electron
consumption by denitritation NO2- →N2) accounted for 85%
of the total electron consumption, while in the latter twostages partial denitrification (NO3- → NO2-) accounted for
94% of the total electron consumption. This corresponded to
the reaction rates of denitritation and partial denitrification
shown in Figure 2(a). In conclusion, the addition of biochar
affected the reduction rate of nitrate and nitrite by altering
electron transfer. During the reaction period, INT initiallyexhibited an increasing trend, and then decreasing [Fig.
2(b)], which was mainly related to the change in substrateavailability. In addition, the INT value of BC was always
higher than the control, indicating that the addition ofbiochar improved the electron transport efficiency of thesystem, which may explain the rapid decrease in nitrate inBC.

Figure 2. (a) Reaction rates of partial denitrification anddenitritation in the biochar and control groups; (b)changes in electron transfer activity (INT) at different
stages in the biochar and control groups; and (c) the52
52

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amounts of electrons consumed by denitritation andpartial denitrification during the reaction in the biochar
and control groups.
3.3 Impact of electrochemical properties of biochar onelectron transfer
The EDC and EAC of biochar were 2.64 and 0.79
mmole-g-1, respectively, indicating that biochar was a redox
mediator that tended to supply electrons [Fig. 3(a)]. FTIR
analysis was carried out to characterize the functional sitesof the biochar. As shown in Figure 3(b), sawdust biochar
pyrolyzed at 300°C contains a large number ofoxygen-containing functional groups, among whichelectron-donating groups (C-O) account for a relatively
large amount. These results indicated that the presence of
reducing groups in biochar prepared at 300°C provides
plenty of electron sources for the reduction of nitrite andnitrate. Among them, phenolic hydroxyl (-OH) and ether(C-O-C) were the strong and weak electron-donating groups,
respectively, which were the main electron-donating
functional groups that were the source of the reducing
ability of biochar[18, 19].

Figure 3. (a) The slopes of the linear regressions ofcurrent versus biochar dosage correspond to theelectron accepting capacity (EAC) and electron donating
capacity (EDC). (b) FTIR spectrum of biochar.

4 Conclusions
This study demonstrated that as an additive ， theoxygen-containing functional groups on the surface ofbiochar have higher electron donating ability. During thereaction, biochar acts as an electron pool, continuously
providing electrons for the reduction of nitrate. The
reduction of nitrate is accompanied by the progress of theentire reaction. Under the action of denitrification, it issynchronized with the anammox reaction to achieve
nitrogen removal. In the case of insufficient nitrite in thesystem and restricted anammox reaction, priority is given toproviding secondary nitrite for the anammox reaction, sothat the nitrogen removal efficiency of the system issignificantly improved.

Reference[1] Wang, X., et al., Characteristics and mechanism of
anammox granular sludge with different granule size in highload and low rising velocity sewage treatment. Bioresour
Technol, 2020. 312: p. 123608.
[2] Zhang, J., et al., Start-up and bacterial communities ofsingle-stage nitrogen removal using anammox and partial
nitritation (SNAP) for treatment of high strength ammonia
wastewater. Bioresour Technol, 2014. 169: p. 652-657.
[3] an der Star, W.R., et al., Startup of reactors for anoxic
ammonium oxidation: experiences from the first full-scale

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anammox reactor in Rotterdam. Water Res, 2007. 41(18): p.
4149-63.
[4] Wang, T., et al., Efficient nitrogen removal in separate
coupled-system of anammox and sulfur autotrophic
denitrification with a nitrification side-branch undersubstrate fluctuation. Sci Total Environ, 2019. 696: p.
133929.
[5]Lackner,
S.,
et
al.,
Full-scalepartialnitritation/anammox experiences--an application survey.
Water Res, 2014. 55: p. 292-303.
[6] Winkler, M.K., et al., Segregation of biomass in cyclic
anaerobic/aerobic granular sludge allows the enrichment ofanaerobic ammonium oxidizing bacteria at low
temperatures. Environ Sci Technol, 2011. 45(17): p. 7330-7.
[7] Zheng, Z., et al., Enhanced nitrogen removal of thesimultaneouspartialnitrification,
anammoxanddenitrification (SNAD) biofilm reactor for treating
mainstream wastewater under low dissolved oxygen (DO)concentration. Bioresour Technol, 2019. 283: p. 213-220.
[8] Wang, D., et al., Roles and correlations of functional
bacteria and genes in the start-up of simultaneous anammox
and denitrification system for enhanced nitrogen removal.
Sci Total Environ, 2019. 655: p. 1355-1363.
[9] Wu, Z., et al., Highly efficient nitrate removal in aheterotrophic denitrification system amended with
redox-active biochar: A molecular and electrochemicalmechanism. Bioresour Technol, 2019. 275: p. 297-306.
[10] Zhang, M., et al., Evaluating biochar and its
modifications for the removal of ammonium, nitrate, andphosphate in water. Water Res, 2020. 186: p. 116303.
[11] Sathishkumar, K., Y. Li, and E. Sanganyado,
Electrochemical behavior of biochar and its effects on
microbial nitrate reduction: Role of extracellular polymeric
substances in extracellular electron transfer. Chemical
Engineering Journal, 2020. 395.
[12] Kappler, A., et al., Biochar as an Electron Shuttle
between Bacteria and Fe(III) Minerals. Environmental
Science & Technology Letters, 2014. 1(8): p. 339-344.
[13] Oh, S.Y., et al., Microbial reduction of nitrate in thepresence of zero-valent iron and biochar. Bioresour Technol,
2016. 200: p. 891-6.
[14] Ye, S., et al., The effects of activated biochar addition
on remediation efficiency of co-composting withcontaminated wetland soil. Resources, Conservation andRecycling, 2019. 140: p. 278-285.
[15] Saquing, J.M., Y.-H. Yu, and P.C. Chiu,
Wood-Derived Black Carbon (Biochar) as a Microbial
Electron Donor and Acceptor. Environmental Science &Technology Letters, 2016. 3(2): p. 62-66.
[16] Tan, Z., et al., Mechanism of negative surface charge
formation on biochar and its effect on the fixation of soil Cd.
J Hazard Mater, 2020. 384: p. 121370.
[17] Yao, Y., et al., Effect of biochar amendment on
sorption and leaching of nitrate, ammonium, and phosphatein a sandy soil. Chemosphere, 2012. 89(11): p. 1467-71.
[18] Li, S., et al., Quantifying the contributions of surface
area and redox-active moieties to electron exchange
capacities of biochar. J Hazard Mater, 2020. 394: p. 122541.
[19] Wu, S., et al., Redox-Active Oxygen-Containing
Functional Groups in Activated Carbon Facilitate Microbial
Reduction of Ferrihydrite. Environ Sci Technol, 2017.
51(17): p. 9709-9717.

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Enhancing phosphorus recovery from sewage sludge using
anaerobic-based processes: Current status and perspectives
Bohan Yu a, Xiangmin Xiao b, Jianwei Wang b, Meng Hong b, Chao Deng b, Yu-You Li c, Jianyong
Liu a,*
aSchool of Environmental and Chemical Engineering, Shanghai University, 333 Nanchen Road, Shanghai
200444, Chinab

Cangzhou Water Supply and Drainage Group Company Limited, 15 West Jiuhe Road, Canghzou, Hebei
Province 061001, Chinac

Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University,
6-6-06 Aza, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan
Email: liujianyong@shu.edu.cn

Abstract
Anaerobic-based processes are green and sustainable technologies for phosphorus (P) recovery from sewage
sludges economically and are promising in practical application. However, the P release efficiency is always notsatisfied. In this paper, the P release mechanisms (regarding to different P species) from sewage sludge using
anaerobic-based processes are systematically summarized. The obstacles of P release and the updated
achievements of enhancing P release from sewage sludges are analyzed and discussed. It can be concluded thatdifferent P species can release from sewage sludge via different anaerobic-based processes. Extracellularpolymeric substances and excessive metal ions are the two main limiting factors to P release. Acid fermentation
and anaerobic fermentation with sulfate reduction could be two promising ways, with P release efficiencies of up
to 64% and 63%. Based on the summarization and discussion, perspectives on practical application of P recovery
from sewage sludge using anaerobic-based processes are proposed.
Keywords: phosphorus recovery; sewage sludge; anaerobic-based process; acid fermentation; sulfate reduction.
1 Introduction
Phosphorus (P), a necessary and irreplaceable resource for
global food production, which is geographicallyconcentrated and nonrenewable, is going to be depleted in
100-200 years. As well known, anaerobic fermentation (AF)is a traditional and widely used technology for sewage
sludge treatment economically, with carbon source orbioenergy recovery and sludge amount reduction.
Meanwhile, anaerobic microorganisms play a crucial role in
P release from natural media, e.g., soil and sediment. Thus,
using anaerobic-based processes to recover P from sewage
sludge is highly feasible.
However, the release efficiency of P is not satisfied, which
is an obstacle to practical application. The problems are
summarized. First of all, extracellular polymeric substances(EPSs) and cell structures in waste activated sludge (WAS)
reduce the mass transfer efficiency and thus organic P (OP)release is limited. Secondly, several limiting factors that
influence release of inorganic P (IP) are found, includingexcessive metal ions in sewage sludge, solubility difference
and aging process of IP species. Thirdly, high P
concentration in sludge is a common obstacle to all P
species release.
In this review article, the P release mechanisms (regarding
to different P species) from sewage sludge using
anaerobic-based processes are systematically summarized.
The obstacles of improving P release efficiency fromsewage sludge using anaerobic-based processes areanalyzed with solutions proposed. The state-of-the-art

54

achievements of enhancing P release from sewage sludge
are discussed and compared. Based on the abovesummarization and discussion, two items of perspectives are
put forward, which advance the insights of improving the
economic feasibility of P recovery and necessity of acomprehensive assessment of wastewater treatment & P
recovery.

2. Release of different P species from sewage
sludge via anaerobic-based processes
Anaerobic release of OP from WAS commonly relies on
the microbial hydrolysis stage, and could be identified as
two steps. At first, the anaerobic decomposing bacteria(fermenting bacteria), e.g., proteolytic bacteria, lipolytic
bacteria, starch decomposing bacteria, and cellulose
decomposing bacteria, makes sludge disintegrate bysecreting extracellular hydrolytic enzymes. In the second
step, the intracellular components are massively leachedafter the first step; the intracellular di-ester P likedeoxyribonucleic acid and ribonucleic acid are further usedby microbial metabolism.
Poly-phosphate accumulating organisms play a key role in
the release of poly-P in WAS (Fig. 1). Under anaerobic
conditions, PAOs get energy from breaking poly-P chains.
The obtained energy is used to uptake volatile fatty acids(VFAs) and synthetize polyhydroxyalkanoates throughtricarboxylic acid cycle. When the anaerobic duration isshort, poly-P is released into liquid phase positively by
PAOs under anaerobic conditions, so it can be consideredthat there is no obstacle to release poly-P under anaerobic
condition.

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When the anaerobic duration is long, it is observed that all
poly-P was hydrolyzed to ortho-phosphate after 12 days ofAF, which indicated a cell lysis happened
There are three main pathways of IP release underanaerobic condition. Microbial acidogenic process is an
important anaerobic process with system acidified; apartfrom acid-dissolving, sulfide is found as a novel way torelease Fe–P under neutral conditions with generation of
FeS; moreover, dissimilated iron reduction bacteria cause
reduction of ferric phosphate to ferrous phosphate. Taking
the release pathways of all P species into consideration, it isclear that anaerobic-based processes are capable ofaccommodating all P species release.

3. Obstacles to P release via anaerobic-based
processes
OP release is usually insufficient due to poor mass transfer
efficiency between intracellular OP and bacteria, which isalso regarded as rate-limiting step of acidogenic process.
For obstacles to IP release, excessive metal elements andaging structure of IP are main problems. The metal ions inthickened WAS are highly-concentrated about 3~50 foldthan that in WAS without thickening, whereas the total P isonly about 2~3 fold. The highly-concentrated metal ions
may be attributed from sludge dewatering agents. As foraging structure, when phosphate is combined (removed) by
ferric salts, the generated Fe–P can be further identified as
innersphere complex, outersphere complex, and surface
precipitation, according to the combination way betweenhydrous iron oxides and PO43-; normally, innersphere andoutersphere complex is easier to release than surface
precipitation complex. Ca–P is proved to easily form
granular Ca–P, which is an aging structure of Ca–P. Besides,
the complex and strong structure of Al–P is also a barrier in
P release. Toor et al also found that most of the phosphatebound with Al was innersphere complex through ligand
exchange; under acid conditions, the phosphate bound with
Al was mainly outersphere complex due to highly
protonated surface, which can adsorb phosphate efficiently[1].
High concentration of sludge P (usually >500 mg/L) is
found as a serious inhibiting factor of P release. It can beinferred that when the equilibrium concentration of liquid
phosphate is high, the metal ions are more likely to combine
phosphate, and the adsorbed metal ions in sludge floc may
also capture P to form IP precipitates.

4. Enhancing
fermentationP

releasevia

anaerobic

Pretreatments at WAS can mitigate the low mass transfer
efficiency. At the aspect of P release, the significance ofpretreatments should be release of cellular P (OP andpoly-P) into liquid phase and improve mass transfer
efficiency of sludge. As a conclusion, acid/alkali andhydrothermal treatment are more efficient to release cellular
P than the other pretreatment by comparing the residual
content of OP and poly-P in solid phase after pretreatment
and disintegration efficiency.
For enhancing IP release from sewage sludge via
anaerobic fermentation, acid fermentation and anaerobic
fermentation with sulfate reduction are two promising ways
for future application. As shown in Fig. 3, it is assumed touse biological + Fe for P removal, the properties of WAS
can be summarized as followed: 19-35 g/L total suspended

55

solid, 10-30 g/L total chemical oxygen demand, 300-500
mg P/L total P, Fe/P=0.3-1.5. The P species and fractions
are quoted from the previous study [2], in which thefractions of Fe–P, Ca–P, OP, and poly-P are 5-24% of TP,
2-11% of TP, 10-30% of TP, and 30-80% of TP,
respectively. The total P release efficiency of each step was
calculated by summarizing the efficiencies from literatures
and the previous studies. In acid fermentation, Fe–P isreduced to Fe2+–P by dissimilated iron reduction, thendissolved by low pH. The increase of Fe–P fraction(33-50%TP) after acid fermentation is attributed toconversion of released OP and poly-P to Fe–P. After thepost acid extraction (pH=3-4), almost all of Fe2+–P isreleased, and the total release efficiency reaches up to 90%
of TP. In AF with sulfate reduction, Fe–P is substantiallyreleased under neutral condition, and Fe/P in WAS greatly
influences the release efficiency (19-63% of TP). After
extracting Ca–P by post acid extraction, the total release
efficiency reaches up to 79% of TP. After P recovery, aconcentrated VFAs stream can be obtained, and thus carbon
source and biogas production are two options for carbon
recovery. For the reason that that both acid fermentation andsulfate reduction may cause decrease of methane production.
Methanogenic process should be carried out in anotherreactor.

Fig. 1. Enhancing P release from sewage sludge by acidfermentation and AF with sulfate reduction for practicalapplication.

5. Conclusion and perspectives
Anaerobic-based processes can accommodate all P species
release, especially AF technology. EPSs and excessive
metal ions in sludge are two main limiting factors of P
release, and medium P concentration (<500 mg P/L) is
preferable for anaerobic P release. Acid fermentation andAF with sulfate reduction could be two promising ways,
with P release efficiency up to 64% and 63%. With
simultaneous recovery of carbon and P, anaerobic-based
processes are economically feasible for application.
Comprehensive life cycle assessment is required forsynthetically evaluating the wastewater treatment and P
recovery process, as well as its environmental and humanhealth impact.

Reference[1]Toor, U.A., H. Shin, and D.-J. Kim, Mechanistic insights into nature ofcomplexation between aluminum and phosphates in polyaluminum chloride
treated sludge for sustainable phosphorus recovery. Journal of Industrial
and Engineering Chemistry, 2019. 71: p. 425-434.
[2].Yu, B., et al., Species, fractions, and characterization of phosphorus insewage sludge: A critical review from the perspective of recovery. Sci Total
Environ, 2021. 786: p. 147437.

The 9th International Symposium on Water Environment Systems

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Tohoku University----- with Perspective of Global Safety

Mainstream nitrogen removal by a one-stage partial nitritation-anammox
reactor with HAP syntrophic granules after an AnMBR○ Gaoxuefeng FENG1*, Yujie CHEN1 & Yu-You LI1, 2
1

Department of Civil and Environmental Engineering, Tohoku University, Miyagi 980-8579, Japan.
Department of Frontier Science for Advanced Environment, Tohoku University, Miyagi 980-8579, Japan.
*
E-mail: feng.gaoxuefeng.q1@dc.tohoku.ac.jp

2

Abstract
The anaerobic ammonium oxidation (anammox) process has attracted attention because of its advantages over traditional
biological nitrogen removal processes. Although the anammox process for the treatment of high nitrogen concentration
wastewater has been widely used worldwide, the treatment of mainstream wastewater is mainly carried out at laboratory
scales, and the full scale application is limited. A one-stage partial nitritation-anammox (PN/A) reactor with hydroxyapatite(HAP) syntrophic granules was setup to treat the mainstream wastewater after an AnMBR. In this study, the nitrite-oxidizing
bacteria (NOB) was successfully suppressed by the free ammonia (FA) treatment and low dissolved oxygen (DO), thenitrogen removal rate (NRR) of 0.35 kg·N·m3·d-1 with 79% nitrogen removal was achieved in a one-stage PN/A reactor inmainstream wastewater treatment and the feasibility of operating a one-stage PN/A reactor in mainstream wastewater
treatment was demonstrated in this study.

Keywords: anammox; PN/A; mainstream; HAP

1 Introduction
Wastewater treatment mainly includes physical, chemicaland biological methods. Generally speaking, biologicalmethods rely on the metabolic capacity of microorganisms,
and are lower in cost compared with physical and chemical
methods. Elements such as nitrogen and phosphorus canlead to eutrophication which can affect the quality of water
for daily life and production.
Many
sewagetreatment
plantsuse
thenitrification-denitrification process for nitrogen removal,
which requires a large amount of aeration and the supply oforganic carbon. The anammox process was discovered to be
an advanced technology for nitrogen removal which cansignificantly reduce energy consumption and sludge
production compared to the nitrification-denitrification
process[1].
Although the anammox process for the treatment of highnitrogen concentration wastewater has been widely usedworldwide, the treatment of mainstream wastewater ismainly carried out at laboratory scales, and the full scale
application is limited[2]. Due to the high C/N ratio ofmainstream wastewater, a high C/N ratio will cause a large
amount of heterotrophic bacteria in the sludge resulting in
the inhibition of ammonium-oxidizing bacteria (AOB) andreduce the nitrogen removal rate. However, due to the low
concentration of ammonium nitrogen in the influent, theconcentration of FA is low, making the suppression of NOB
which is a major challenge in mainstream PN/A process
more difficult. Low DO and FA treatment is widely used tosuppress NOB[3].
The addition of calcium and proper pH can generate HAP
crystals, which are effective conditions for improving thesludge settleability of the anammox process and the PN/A
process[4]. HAP particles have the quality of small particles
and good sedimentation. Using HAP as a sludge carrier is agood means to stabilize the operation of the reactor.
In this study, a one-stage partial nitritation-anammox
reactor was setup to evaluate the nitrogen removal

56

performance of the one-stage PN/A reactor with HAP
syntrophic granules in mainstream wastewater treatment.
The NOB suppression and the stable operation of PN/A
reactor in mainstream wastewater treatment was studied.

2 Materials and methods
2.1 Reactor setup and operation
The one-stage partial nitritation-anammox system wascomprised of a air-lifting reactor (effective vlume:2L), a
substrate tank, two pumps and a water bath heater, as shownin Fig.1. Influent was pumped by a peristaltic pump. An air
pump with a dispenser which was fixed to the bottom wasused to oxygenate and stir the mixed liquid. The flow rate iscontrolled by the flow meter. The operation temperature is
kept at 25°C by a water bath heater.

Fig. 1. Reactor configuration.
As shown in Table 1, the whole experiment was divided
into 3 parts.
1) Phase 1 (0-10d): Using artificial mainstream
wastewater, the influent nitrogen concentration

The 9th International Symposium on Water Environment Systems

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Tohoku University

(b)

DO
AR

0.5

120
100
80

0.6

0.4

DO(L·min-1)

140

0.5

0.3

0.4
0.2

0.3

0.1

0.2

60
40

0.1

20

0.0
0

20

40

60

80

100

120

140

160

0

20

40

60

Time(d)30

NH+4-Neff

9.2

(c)

100

120

140

160

(d)

pHinf
pHeff

9.0

NO-2-Neff

8.8

NO-3-Neff

20

80

Time(d)

8.6
8.4
8.2

10

8.0
7.8
7.6

0

7.4
0

20

40

60

80

100

120

140

160

0

20

40

60

Time(d)

80

100

120

140

160

Time(d)
1.0

(e)

0.4

40

0.2

20

NRE
NRR

MLVSS(g/L)

NRE(%)

0.6

60

(f)

7
0.8

80

NRR(kg·N·m3·d-1)

100Phase 373-153
36
2
0.35
79
5.8
55

6
5
4
3

0.0

0

2
0

20

40

60

80

100

120

140

160

0

20

40

60

80

100

120

140

(g)

50
40
30
20
10
0
0

20

40

60

80

100

Time(d)The influent and effluent samples which were filteredthrough 0.45μm filters were measured daily to know theexact situation of the reactor. Ammonium, nitrite and nitrate
were analyzed by capillary electrophoresis (Agilent 7100).
The mixed liquor volatile suspended solid (MLVSS) andmixed liquor suspended solid (MLSS) were analyzed
according to APHA standard methods.

120

140

160

COD removal efficiency(%)

100

2.2 Analysis method160

Time(d)Time(d)ΔNO3- -N/ΔN(%)

Table 1. Experimental condition.
PeriodPhase 1
Phase 2
Time(d)0-10
11-72
NH4+-N(mg·L-1)
178-6042
HRT(h)
5-3
3
NRR(kg·N·m3·d-1)
0.56
0.26
NRE(%)
80.9
77.1
MLVSS(g·L-1)
4.2
3.6
Ca(mg·L-1)
25

0.8
0.7

160

AR(L·min-1)

(a)

180

pH

3)

200

NH4+-Ninf(mg·L-1)

2)

gradually decreased from 178 mg·L-1 to 60 mg·L-1
and the HRT was adjusted from 5h to 3h. Phase 1
served as the start up period.
Phase 2 (11-72d): Using the real mainstream
wastewater after an AnMBR instead of the artificial
mainstream wastewater. Adding calcium to generate
HAP as a carrier of sludge.
Phase 3 (73-153d): Adjust the HRT from 3h to 2h.
Increase the calcium concentration of the influent
from 25 mg·L-1 to 55 mg·L-1.

Nitrogen(mg·L-1)----- with Perspective of Global Safety

(h)

80
60
40
20
0
0

20

40

60

80

100

120

140

160

Time(d)Fig. 2. The operation performance of the one-stage PN/A
reactor at mainstream conditions ((a) the influent
nitrogen concentration, (b) DO and AR, (c) the effluent
nitrogen concentration of ammonium, nitrite and nitrite,(d) pH, (e) NRE and NRR, (f) MLSS, (g) ΔNO3--N/ΔN,(h) COD removal rate).

4 Conclusions
3 Results and discussion
The nitrogen removal performance during the wholeexperiment is shown in Table 1 and Fig. 2. The influent
nitrogen concentration decreased from 178 mg·L-1 to 36
mg·L-1. The average NRR reached 0.33 kg·N·m3·d-1 and thenitrogen removal efficiency (NRE) reached 78.1%.
The average ΔNO3--N/ΔN was 11% and during every
period of the experiment, the average ΔNO3--N/ΔN was
under 12%. In the end of the period 2, the ΔNO3--N/ΔN wasover 20% and the maximum reached 49%. It means that the
NOB appeared in the sludge which seriously affected theremoval efficiency of nitrogen. At the begging of period 3,
the HRT was adjusted from 3h to 2h, ammonium
bicarbonate were putted into the reactor every day, and theinfluent pH was increased by sodium hydroxide from 7.9 to
8.7, thereby the FA concentration was increased to inhibit
the activity of NOB, the DO concentration was under 0.05
mg·L-1 through the whole experiment to suppress the NOB,
and stop adding ammonium bicarbonate after a few days.
The NOB was successfully inhibited, proving that inhibiting
NOB through FA and low DO is a successful strategy.
ΔNO3--N/ΔN was below 12% for most time of the phase 3
which indicates that DNB consumed part of NO3- andenhance the nitrogen removal rate of this system.

57(1) The use of FA treatment and low DO is an effective
way to stably suppress NOB.
(2) A stable operation with the nitrogen removal efficiencyof 79% and nitrogen removal rate of 0.35kg·N·m3·d-1 wasachieved in a one-stage PN/A reactor in mainstream
wastewater treatment.

Reference[1] TRINH, Hoang Phuc, et al. Recent Development of theMainstream Anammox Processes: Challenges andOpportunities. JournalofEnvironmental
ChemicalEngineering, 2021, 105583.
[2] CHEN, Yujie, et al. High nitrogen removal
performance of anaerobically treated fish processing
wastewater by one-stage partial nitritation and anammox
process with hydroxyapatite (HAP)-based syntrophic
granules and granule structure. Bioresource Technology,
2021, 338: 125526.
[3] WANG, Zhiyao, et al. Unravelling adaptation of
nitrite-oxidizing bacteria in mainstream PN/A process:Mechanisms and counter-strategies. Water Research, 2021,
200: 117239.
[4] GUO, Yan, et al. Achieving superior nitrogen removal
performance in low-strength ammonium wastewater
treatment by cultivating concentrated, highly dispersive, andeasily settleable granule sludge in a one-stage partial
nitritation/anammox-HAP reactor. Water Research, 2021,
200: 117217.