2nd International Symposium on Water
Environment Systems---with Perspective of Global Safety(January 30-31，2015)


Dept. of Civil and Environmental Engineering
Graduate School of Engineering
Tohoku University

Sponsors
http://www.g-safety.tohoku.ac.jp/
Tohoku University, Main Administration Office
Organization for Leading Graduate School Programof Tohoku University, Sendai, Miyagi 980-8578, Japan

http://www.eng.tohoku.ac.jp/
Tohoku University, Graduate School of Engineering,Sendai, Miyagi 980-8579, JapanORGANIZERSDr. So Kazama(Professor，Tohoku University)

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

Dr. Daisuke Komori (Associate Professor，Tohoku University)

STUDENT SECRETARIESDC Student, Yanlong ZHANG
E-mail: zhangyl@epl1.civil.tohoku.ac.jp
MC student, Toshiki SUGO
E-mail: sogo@epl1.civil.tohoku.ac.jp
MC student, Yizhe ZHENG
E-mail: Zhengyz@epl1.civil.tohoku.ac.jp

PARTICIPANTS
Tohoku university

JAPAN

Name

Identity

AdrianaP.D.

adriana@epl1.civil.tohoku.ac.jp

Yanlong ZHANG

Student

Zhangyl@epl1.civil.tohoku.ac.jp

Xueqing LU

Student

luxq@epl1.civil.tohoku.ac.jp

Yuan LIU

Student

liuyuan@epl1.civil.tohoku.ac.jp

Toshiki SUGO

Student

sugo@epl1.civil.tohoku.ac.jp

Yu QIN

Student

qinyu@epl1.civil.tohoku.ac.jp

Haiyuan MA

Student

mahy@epl1.civil.tohoku.ac.jp

Yizhe ZHENG

Student

Zhengyz@epl1.civil.tohoku.ac.jp

Xi'an university of architecture and Technology
Name
Identity
Dangcong PENG
Professor
Yun HAN
Yongmei ZHANG
Jialing TANG

Associate Professor
Student
Student

Southeast university

E-mailCHINA
E-maildcpeng@xauat.edu.cn
hanyun@xauat.edu.cn
zym58625@163.com
921221788@qq.com

CHINA

Name

Identity

E-mailHailiang SONG

Associate Professor

songhailiang@seu.edu.cn

Feng HONG

Assistant Professor

hong4796@seu.edu.cn

Yuli YANG

Student

230149398@seu.edu.cn

Xizi LONG

Student

230149343@seu.edu.cn

PARTICIPANTS
Beijing Normal university
Name
Baolin SU

Identity
Professor

CHINA
E-mailsubl@bnu.edu.cn

Universiti Teknologi Malaysia
Name
Fadhil
Nickholas Anting Anak Guntor

Identity
Associate Professor
Student

MALAYSIA
E-mailmfadhil@utm.mynickholasanting@gmail.com

Sultan Qaboos University
Name
Luminda GUNAWARDHANA

Identity
Assistant Professor

OMAN
E-mailluminda@squ.edu.om

INDIA

Indian Institute of Technology Hyderabad

Name

Identity

Basudev Biswal

Assistant Professor

E-mailbasudev@iith.ac.inAccess to Aobayama Campus
School of Engineering
Sendai Station andAobayama Campus
map

Sendai Station Map

Buses leave the bus terminal at the JR
Sendai Station (bus stop No. 9) every 30
minutes for the 20-minutes trip to the"Kogakubu-chuo" bus stop in front of the
School of Engineering.
Buses Numbers
S710-715, 719, 750, or 757

VenueAobayama campus, Tohoku University
Meeting Room-A (105) of civil engineering and architecture. (Morning)
Complex building, Room 101. (Afternoon)
Aobayama Campus Map

Meeting Room-A (Room105)

Complex building (Room101)

Program
January 30, 2015
Lab Visit
10:00~11:00
Meeting at the Meeting Room-A (Room105) of civil engineering andarchitecture.
Place: Laboratory building of civil and environmental engineering.
Session I, Poster exhibition and free discussion
11:00~12:00
Place: Meeting Room-A (Room105) of civil engineering and architecture.
" Operation performance of upflow anaerobic sludge blanket (UASB) reactor
treating starch wastewater "Xueqing LU (Tohoku University)"Reaction evolution to one-stage anammox in a partial nitritation reactor"
Yuan LIU (Tohoku University)"Effect of Substrate Concentration on the Operation Performance ofAnammox Process in a UASB Reactor "Haiyuan MA(Tohoku University)"Current state of knowledge of antibiotics in the environment: a global approach"
Adriana(Tohoku University)"Phase Separation by Hyper-thermophilic Temperature in Anaerobic Digestion ofWaste Activated Sludge"
Yu QIN (Tohoku university, Japan)

ILunch
12:00~13:00
Place: The main cafeteria in Aobayama Campus

Organizer Opening address (Prof. Yu-You Li, Tohoku University)
13:00~13:10
Place: Complex building Room No.101

Memorial Photo
13:10~13:20
Place: Complex building Room No.101II13:30~16:00

Session II, Special lecture

13:30 – 14:00"River Discharge Variations Attributed to Extreme Rainfall in Oman"
Dr. Luminda Gunawardhana (Sultan Quboos University, Oman)

14:00 – 14:30"A field-scale observation method for non-point source pollution of paddy fields"
Dr. Baolin SU (Beijing Normal University, China)

14:30 – 15:00"Algae as Energy Securing, Supplement Reserve and Formulating Carbon
Sequestration for Waste Management from Palm Oil Mill Effluent (POME)"
Dr. Fadhil (Universiti Teknologi Malaysia, Malaysia)

15:00-15:30"Enhancement of Biogas Productivity through Bio-pretreatment of Crop residue
during Anaerobic Digestion"
Dr. Feng HONG (Dongnan University, China)

15:30-16:00"Geomorphological recession flow model for estimation of drainable storage"
Dr. Basudev Biswal (Indian Institute of Technology Hyderabad, India)

16:00~16:15

Coffee breakIII16:15~18:15

Session III, Presentations by students

Place: Complex building Room No.101"Preparation and evaluation of fermentation liquid of food waste as a carbon
16:15~16:30

source for denitrification"
Yongmei ZHANG (Xi'an university of architecture and Technology, China)"Nitrogen removal enhancement in A/O-MBR with fermentation liquid of

16:30~16:45

food waste (FLFW) as external carbon"
Jialing TANG (Xi'an university of architecture and Technology, China)

16:45~17:00"Structure Optimization of Constructed Wetland Coupled Microbial Fuel
Cell for Organism Removal"
Xizi LONG (Dongnan University, China)

17:00~17:15"Analysis of enhanced nitrogen removal in MBR with new biological carriers
addition by real-time PCR"
Yuli YANG (Dongnan University, China)

17:15~17:30"Effect of oysters on size-fractionated marine phytoplankton communities in
Shizugawa bay"
Yizhe ZHENG (Tohoku university, Japan)

17:30~17:45"Evaluation of new sewage treatment system using anaerobic membranebioreactor"
Sugo TOSHIKI (Tohoku university, Japan)

17:45~18:00"Study of the start-up and inhibition process of Anammox reaction in UASB
Reactor"
Yanlong ZHANG (Tohoku university, Japan)

18:00~18:15

18:15~18:25"Innovation of cool-pavement technology from waste tile"
Nickholas Anting (Universiti Teknologi Malaysia, Malaysia)

Closing speechIVJanuary 31, 2015 Fieldwork
Minami-Gamo Sewage Treatment Plant
Tsunami was hitting Sewage Facilities

Effect on the wall of pump station

VSession I
Poster exhibition and free
discussion

1

2

2nd International Symposium on Water Environment Systems-------with Perspective of Global Safetythst(January30 -31 ，2015)

G-Safety
TOHOKU UNIVERSITY

Operation performance of upflow anaerobic sludge blanket (UASB) reactor treating
starch wastewater○Xueqin Lu1, Guangyin Zhen2, Adriana Ledezma Estrada1, Yu-You Li1*
1
2

Department of Civil and Environmental Engineering,Tohoku University,Sendai,Miyagi 980-8579, Japan
National Institute for Environmental Studies, Onogawa 16-2, Tsukuba, Ibaraki 305-0053, Japan*E-mail: yyli@epl1.civil.tohoku.ac.jp

AbstractLong-term performance of a lab-scale UASB reactor treating starch wastewater was investigated under different
hydraulic retention times (HRT). Successful start-up could be achieved after 15 days’ operation. The optimal HRT was
6 h with organic loading rate (OLR) 4 g COD/L•d at COD concentration 1000 mg/L, attaining 81.1–98.7% total COD
removal with methane production rate of 0.33 L CH4/g CODremoved. Specific methane activity tests demonstrated thatmethane formation via H2-CO2 and acetate were the principal degradation pathways. Vertical characterizations revealed
that main reactions including starch hydrolysis, acidification and methanogenesis occurred at the lower part of reactor(“main reaction zone”); comparatively, at the up converting acetate into methane predominated (“substrate-shortagezone”). Further reducing HRT to 3 h caused volatile fatty acids accumulation, sludge floating and performance
deterioration.
Keywords: UASB, starch wastewater, granule sludge, Specific methane activity

1. Introduction
Starch, composed of repeating D-glucopyranosyl units,
are largely used in human and animal nutrition, or as virginmaterials for a wide range of industrial products. The
increased adopts of starch inevitably lead to the productionof massive starch wastewater. One such type of wastewater,
with COD 25 g/L and low pH 3.8–5.2, for instance, washarvested from about 250 existing small-scale plants by the
starch extraction process which was discharged to water
bodies without any treatment. The limited knowledge

achieved until now yet cannot definitely answer whether
UASB proceeds smoothly during the long-term operation if
starch is added solely.

Therefore, in this study, a lab-scale UASB reactor has
been constructed and operated for more than 200 days tocomprehensively evaluate the long-term performance of
UASB in treating starch wastewater. The effects of OLR on
the overall stability were examined by varying HRT (from24 to 3 h) to optimize the operating condition. Besides, thepossible changes of water qualities (i.e. pH, ORP, COD,
acetate, etc.) and granule characteristics along the height
were detected, hoping to map the core degradation
dynamics occurred in the interior of UASB.

Fig. 1 Schematic diagram of the UASB reactor system.

3. Results and discussion
3.1 Roles of OLR on biogas production and COD removal

The results showed that the performance of UASB systemstrongly depended on OLR applied (Fig. 2). As presented inFig. 2a, biogas production rate showed a closely positive
correlation with OLR, and increased linearly with OLR (R =0.9846, p < 0.01), agreeing well with the investigations ofParthiban et al. (2007) on anaerobic tapered fluidized bed
reactor fed with starch wastewater. On the other hand,methane content in biogas reached a maximum, up to 78% at
4 g COD/L•d (i.e. HRT 6 h) and then dropped down with thefurther increasing of OLR. Meanwhile, with the OLR
increasing from 1 to 8 g COD/L•d, TCOD and SCOD
removal also declined to some extents, possibly owing tohigher upflow velocity (Vup) which reduced the contact time
between granules and targets present in wastewater in
addition to smashing and resultantly higher washout of
sludge granules.

2. Materials and Methods
The schematic diagram of the UASB reactor is depicted
in (Fig. 1). The set-up designed herein consists of a starch
wastewater feed tank, a temperature control unit, UASB
main body, a wet gas flow meter and a desulfidation unit.
The operational temperature was kept constant at 35 ± 1 ◦Cusing a heated water bath.
The synthetic wastewater was composed of (mg/L): 1000
CODstarch, 2000-2700 NaHCO3, 850 NH4Cl, 750 KCl, 250
K2HPO4, 100 KH2PO4, 125 MgCl2•6H2O, 4.2 NiCl2•6H2O,
4.2 CoCl2•6H2O, 15 CaCl2•2H2O and 42 FeCl•4H2O.

Lab of Urban and Regional Environmental Systems

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2nd International Symposium on Water Environment Systemsthst(January30 -31 ，2015)-------with Perspective of Global Safety

2.0

4= 0.9586,= 0.0025
0.01
RR= 0.9846,
p =p3.55
x 10-4 <<0.01

3

1.5

(a)

2

1.0

1

0.5

0

CH4 content (%)

Biogascomposition (%)

80
60

CH4
CO2
H2S

40
20

SCOD removal (%) TCOD removal (%)

01000

3.3 Characterization of granular sludge in the UASB

The granular sludges, after 104 days of operating, werecollected from different positions of UASB by SEM analysis.
The granules from the up and middle mainly comprised ofrod-shaped archaebacterial (Fig. 4b-c); the cells closely
associated with or entrapped within sludge matrix, forming acompact and intact micro-structure.For the granules from thebottom, not only rod-shaped archaebacterial also coccishaped archaea prevailed on the surface or interior of
granules (Fig. 4d).

(b)
R2 = 0.9300
R2 = 0.5679

TCOD
SCOD

800
600
400
200
0
100
80
60
40

TCOD
SCOD

20
0
0

1

2

3
4
5
6
OLR (g COD/L/d)

7

8

9

80
60
40

(a)

Recovery stage
Stable20
0100

TOHOKU UNIVERSITY

but exhibited the poor decomposition capability to starch(0.188–0.199 g CODCH4/g VSS•d). In this sense, the cogrowth of starch- and acetate-utilizing microbes at thebottom were predominant while the unique microorganisms
feeding on acetate grew in abundance at the up. The dynamic
distribution of key populations in the reactor did not only
increase the resistance of microbes against the external stress,
but also improved the overall operating stability.

0.0
100

100

COD removal (%) CODeffluent (mg/L)

Recovery stage
StableRegr

Biogas production
rate(L/L/d)

Biogas production
rate (L/L/d)Hence, taking into account efficient bioenergy recovery
and continuous stability of the system, the optimum OLR in
the present study should be 4 g COD/L•d, i.e. HRT 6 h.
Furthermore, the relationship between OLR and UASB
performance in stable and recovery stages were compared(i.e. at HRT of 24, 12 and 6 h), and the results aregraphically reported in Fig. 2b. Biogas production and COD
removal were less stable and efficient in recovery stage incomparison with the stable stage at the same OLR
conditions. In this situation, biogas production gave a very
poor correlation with OLR (R2 = 0.5679), in sharp contrast
with the perfect linear increment under stable operations (R2= 0.9300).

G-Safety

80
60
40
Recovery stage
Stable

20
0
100
80
60
40

Recovery stage
Stable

20
0
0.5

1.0

1.5

2.0
2.5
3.0
OLR (g COD/L/d)

3.5

4.0

4.5

Fig. 2. Effect of OLR on UASB performance under normal andrecovery phase.

3.2 Possible biodegradation mechanisms of starch in UASB

Specific methanogenic activity test was conducted to indepth understand the decomposition mechanisms of starch.
The tests with H2-CO2 and four volatile fatty acids (i.e.
formate, acetate, propionate and butyrate) revealed thatmethane formation via H2-CO2 and acetate were theprincipal degradation pathways.

Fig. 4 Starch fermentation dynamics and principal mechanismsof sludge floating in the interior of UASB (a); SEM images of
granules collected from (b) up; (c) middle; and (d) bottom.

UASB height (cm)(a) 120

Starch indicated by SCOD at the bottom was the highest(Fig. 3a); and it was gradually metabolized, attenuated along
the upflow direction (i.e. from the bottom to up) and nearly
diminished at the up. Likewise, acetic acid derived fromstarch exhibited a similar variation, peaking at the bottom
and there was extremely low residual acetic acid detected at
the up. From the experimental data, it can be speculated thatthe reactions taking place between the bottom and middle in
UASB were the hydrolysis of starch, accompanied by theformation of acetate (i.e. acidification) and concurrent
utilization (i.e. methanogenesis); therefore, the zone could becalled the “main reaction zone”. Comparatively, thanks to theefficient degradation of starch previously, converting acetate
into methane (i.e. methanogenesis) at the up predominated(i.e. “substrate-shortage zone”) (Fig. 4a).

100
80
60
40
20
0

(b)

0.30
0.25
0.20
0.15
0.10
0.05
0.00

StarchUp

Middle Bottom

SMA(g COD CH4/g VSS d)

SMA(g COD CH4/g VSS d)

6.8 7.2 7.6 8.0 -350 -280 -2100 200 400 6000 20 40 60 80
pH
ORP (mV)
SCOD (mg/L) Acetic acid (mg/L)
0.4

Acetate

0.3
0.2
0.1
0.0
Up

Middle Bottom

Fig. 3. (a) Variations of pH, ORP, SCOD, and acetic acid along
the height of UASB; (b) SMA of granular sludges sampledfrom the up, middle and bottom.

Vertical characterizations (Fig. 3) indicated that main
reactions including starch hydrolysis, acidification andmethanogenesis occurred at the lower part of reactor (“mainreaction zone”); while at the up converting acetate intomethane predominated (“substrate-shortage zone”).
Bottom-granules could efficiently utilize both starch andacetic acid for methane recovery, with SMA value of 0.247,
and 0.211 g CODCH4/g VSS•d, respectively; the granularsludges from the middle and up, in contrast, were capableof decomposing acetate (0.277–0.288 g CODCH4/g VSS•d),

4. Conclusions(1) UASB showed good performance for treating starch
wastewater. The optimal HRT was 6 h with OLR 4 g
COD/L•d, gaining 81.1–98.7% COD removal and 0.33 L
CH4/g CODremoved methane yield.
(2) Methane production via H2-CO2 and acetate were theprincipal starch fermentation pathways, which occurred at
the lower part of reactor while at the up converting acetate
into methane predominated.

Lab of Urban and Regional Environmental Systems

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2nd International Symposium on Water Environment Systems-------with Perspective of Global SafetythG-Safetyst(January30 -31 ，2015)

TOHOKU UNIVERSITY

Reaction evolution to one-stage anammox in a partial nitritation reactor○Yuan LIU1, Jiayuan1 JI, Toshimasa HOJO2, Yu-You LI1,2*
1

Graduate School of Environmental Studies, Tohoku University, Sendai 980-8579, Japan
2
Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan*E-mail: yyli@epl1.civil.tohoku.ac.jp

Abstract
This study investigated partial nitritation achievement and maintenance in a CSTR reactor. The reactor was operated
at temperature range of 25~33℃ and pH between 8.0-8.5. Under the comprehensive effect of DO limitation, nitrite
accumulation and partial nitritation was achieved successfully. The effect of variation of DO concentration in the reactor
on the efficiency of NH4+-N conversion to NO2--N and ratio of NO2--N/NH4+-N in the effluent was evaluated. Results
showed that when DO concentration was kept as 0.13mg/L or AR was set as 1.60L/min, the optimum NO2--N/NH4+-N
ratio can be achieved and long-term maintained. Subsequently, by adjusting AR, the one-stage anammox was achieved
and the maximum nitrogen removal rate was gained when AR was kept as 1.50L/min.
Keywords: partial nitritation, one-stage anammox, low C/N, biological nitrogen removal

50~60%% of partial nitritation maintenance. When it comesto one-stage process, both groups of bacteria need to be in
the right redox environment, which can be achieved bycarefully controlling the bulk oxygen concentration.
The goal of this research were to (i) establish a robust
method to rapidly partial nitritation achievement and longterm maintenance; (ii) autotrophic N removal from NH4+ in
an aerated lab-scale reactor.

1. Introduction
Anammox, the most innovative process discovered in theearly 1990s, converts NH4+ and NO2- to N2 with the absenceof oxygen and organic carbon sources has arisen great
expectations regarding elimination of N high-loaded
wastewaters containing low biodegradable organic carbon
to nitrogen (C/N) ratio. In brief, anammox process consistsof (1) partial nitritation (PN) in which 57% of NH4+ wasoxidized in to NO2- and (2) anammox (A) by which theadditional NH4+ and produced NO2- in (1) process were
removed as N2 and a small amount of nitrate. Two different
strategies are used for anammox establishing: NO2- can beeither produced in a separate aerated reactor andsubsequently be fed into an anoxic anammox reactor named
as two-stage PN/A or accumulated in the same reactor withanammox process that is one-stage PN/A.
Over the last decade, the cumulative nitrogen loadincreased almost 60-fold, indicating that from an economic
perspective, the anammox-based processes are becoming
increasingly widespread. Recently many technologies havebeen developed and studied for their applicability to the
PN/A concept and several have made it into full-scale. It
was predicted that by 2014 100 full-scale installations will
be in operation worldwide. More than 50% of all PN/A
installations in application are sequencing batch reactors,
88% of all plants being operated as single-stage systems,
and 75% for side-stream treatment of municipal
wastewater.
With respect to two-stage PN-anammox process, there
are two requirements needed to be met in this system: (1)the nitrite accumulation rate (η=NO2--N/NOx--N× 100%,
where NOx--N=NO2--N+NO3--N) should be high sincenitrate is not the direct substrate of anammox; (2) nitrite
and ammonium should be at an approximate equimlar ratio(NH4+-N/NO2--N = 1:1.32). And it is a significant researchissue that exploring a practical operation for long-term of

2. Materials and Methods
2.1 Experiment configuration and operation conditions

As shown in Fig.1, the partial nitritation was carried out ina lab-scale continuous stirred-tank reactor (CSTR), which ismade of a transparent PVC plastic rectangular reactor withworking volume of 8 liters and settling zone volume of
2L.The temperature in the reactor were set and keep in therange of 25~33℃ by a heater with temperature adjuster set in
the reaction zone. Dissolved oxygen (DO) concentration was
controlled in low concentration, and adjusted to a series ofconcentrations in order to obtain the optimum results. The
hydraulic retention time (HRT) was kept as 12 h, nitrogen
Air
Influent

HeaterEffluent

Reactionzone : 8L
M

Settlingzone : 2L

Pump
Substrate tank
AeratorFig. 1 Schematic diagram of partial nitritation reactor

Lab of Urban and Regional Environmental Systems

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2nd International Symposium on Water Environment Systems

G-Safetyst(January30 -31 ，2015)

DO (mg/L)

loading rate in the operation period was 0.5kgNH4+-N/m3/d.
2.2 Synthetic wastewater and seed sludge

During the whole operation period, the reaction was
feeding with synthetic wastewater and trace element shownin Table 1, in which the NH4+-N concentration was 250
mg/L. pH in the substrate was adjusted in a range of
8.0~8.5 by adding of buffer agents consist of NaHCO3,
KH2PO4 and K2HPO4. The seed sludge was obtained from S
Municipal wastewater treatment plant and was cultivatedby full-and-draw technique before transferring it into thereactor. The initial mixed liquor suspended solid (MLSS)
concentration of the reactor was set at 2000 mg/L.

TOHOKU UNIVERSITY

PhaseⅠ
Partial nitritation

0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00

PhaseⅡ
One-stage partial nitritation/Anammox

2.5
2.0
1.5
1.0
0.5

AR (L/min)-------with Perspective of Global Safety

th

0.0
0

50

100

150

200

250

300

350

400

450

500

N concentration (mg-N/L)

300.0
250.0

NH4-N in
NH4-N out
NO2-N out
NO3-N out

200.0
150.0
100.0
50.0
0.0

2.3 Methodology

0

50

100

150

200

0

50

100

150

200

250

300

350

400

450

500

250

300

350

400

450

500

100.0

The MLSS were determined according to the Standard
Methods (APHA, 2002). Ammonium, nitrite and nitrateconcentrations were detected by capillary electrophoresis ofAgilent 7100 (M. Vilas-Cruz, 1994). DO concentration and
pH were measured by a portable DO and pH meter.

NRR (%)

80.0
60.0
40.0
20.0
0.0

Time (day)Fig. 2 Changes of DO concentration, AR, nitrogenconcentrations and NRR in the reactor

3. Results and Discussion
3.1. Establish of long-term partial nitritation

The exploration of method to long-term partial nitritaion
was conducted during Phase I. The changes of DO
concentration, AR, nitrogen concentrations in the reactor
during the operation period are shown in Fig.2. As Do
concentration was controlled as lower than 0.8mg/L since
the first day, which was favor to ammonia oxidizing
bacteria (AOB) compare to nitrite oxidizing bacteria (NOB),
majority of ammonia was oxidized into NO2--N. When DO
concentration was further decreased gradually, the AOB
activity was restricted and the ratio of NO2--N/NH4+-N (asshown in Fig.3) also decreased correspondingly. By
adjusting the DO concentration and aeration rate (AR) in
the reactor, the relationship between DO, AR and NO2-N/NH4+-N ratio showed that when DO concentration was
kept as 0.13mg/L or AR was set as 1.60L/min, the optimum
NO2--N/NH4+-N ratio can be achieved and long-term
maintained, which met the requirement of anammox
reaction.

PhaseⅠ
Partial nitritation

PhaseⅡ
One-stage partial nitritation/Anammox

NO2-N/NH4-N

6.0
5.0
4.0
3.0
2.0
1.0
0.0

NO3-N/NH4-N

0.7

0

50

100

150

0

50

100

150

200

250

200

250

300

350

400

450

500

300

350

400

450

500

0.6
0.5
0.4
0.3

0.2
0.1
0

-

Time (day)

+

-

+

Fig. 3 Variations of NO2 -N/NH4 -N and NO3 -N/NH4 -N

during the operation periodremoval during this period was caused by typical one-stage
anammox process. The higher nitrogen removal (over 65%)
was maintained for about 50 days until increasing highconcentration of nitrate production was found in the reaction
and the NRR began to go down. The reason for thisphenomenon can be attributed to the failure of anammox
bacteria to compete NO2--N for substrate with NOB. As aresult the concentration of ammonia was also increased andled to much worse nitrogen removal rate. Afterwards, eventhough AR was increased to 2.0L/min and ammonia
concentration deceased, the concentration of nitratecontinued increasing, which caused much lower NRR of
47%.

3.2. Reaction evolution to one-stage anammox

As shown in Fig.2, during day 242~day 264 in Phase I, aslight amount of nitrogen removal was achieved with thenitrogen removal rate (NRR) as about 13%. However, as
shown in Fig.3 the ratio of NO3--N/NH4+-N showed that thenitrate production during this period was a little lower thantheoretical value by anammox reaction. In order to promote
anammox reaction rate, AR was gradually decreased inPhase II (day 265~day310), with the result that NRR
increased to 25% while a great mount of ammonia was still
remained in the reactor. Subsequently, as a result of AR
was increased into 1.50L/min, nitrogen removal was
correspondingly enhanced up. During this period, theconcentration of NH4+-N decreased slowly and it camethrough about 50 days before the NRR achieved the
maximum 88.8%. In addition, the ratio of NO3--N/NH4+-N
in Fig.3 showed that the nitrate production during thisperiod was at the same level to theoretical value by
anammox reaction, which can be deduced that nitrogen

4. Conclusions(1) Under this experiment condition, when DO
concentration was kept as 0.13mg/L or AR was set as
1.60L/min, the optimum NO2--N/NH4+-N ratio can beachieved and long-term maintained.
(2) By adjusting AR, the one-stage anammox was achieved
and the maximum nitrogen removal rate was gained
when AR was kept as 150L/min.

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Effect of Substrate Concentration on the Operation Performance ofAnammox Process in a UASB Reactor○Haiyuan MA1, Shilong HE1, Yuyou LI1*
Department of Civil and Environmental Engineering, Tohoku University, Japan*E-mail: yyli@epl1.civil.tohoku.ac.jp

Abstract
This study investigate the effect of substrate concentration on the operation performance of Anammox process in a
UASB reactor. The TN concentration was raised from 300mg/L, to 450mg/L and finally to 700mg/L. Under the conditionof TN 300mg/L(nitrogen loading rate of 2.4kgN・d-1・m-3) and 450mg/L(nitrogen loading rate of 3.6kgN・d-1・m-3), the removal efficiency
of TN reached 85.5% and 84.4%, respectively. When TN was raised up to 700mg/L, the average removal efficiency for TN dropped to 66.4%.
The reason for removal efficiency decline is considered to be FA and FNA inhibition.

Keyword: Anammox, UASB, substrate concentration, FA, FNA

Table 1 the operation condition in each period

1. Introduction
In order to prevent the eutrophication of water environment,
it’s very important to remove nitrogen form waste water.
Anaerobic ammonium oxidation (Anammox) is now a very
attractive denitrogenation technique because it reduces theaeration cost and the need for carbon resource compared withthe old process. In our research, continuous experiment was
operated in a UASB reactor and the total nitrogenconcentration was increased during three stage. The effect of
substrate concentration on the operation performance ofAnammox process in a UASB reactor was studied.

periodI

II

III

operation time(d)1-76

77-111

112-219

HRT(h)

3

3

3

TN(mgN・L-1)

300

450

700

NLR(kgN・d-1・m-3)

2.4

3.6

5.6

2.2 Analytical method
The water quality of input and output was measured every twodays. The NO2--N and NO3--N were measured with the Agilent 7100

2. Materials and methods

capillary electrophoresis system. The NH4+ was measured according
to the standard methods (APHA, 2005). pH was measured with a pH
meter and the nitrogen gas produce rate was measured with a gas
holder everyday. The FA (free ammonia) and FNA (free nitrite acid)was calculated according to the formula below.

2.1 Reactors and procedure
The reactor used in this research was shown in Fig.1. The
effective volume of the reactor is 5L, and the temperature of thereactor was maintained in 33±1℃ by waterjacket. The inoculate
sludge in this research is the granular sludge cultivated in our lab.
The input synthesis substrate contains (NH4)2SO4 and NaNO2, andthe mole ratio of NH4+:NO2- is 1:1.32. The condition of each period

FA =

17
[NH4+ − N] × 10pH
× [6344/(273+T)]
14 e+ 10pH

FNA =

46
[NO−
2 − N]
× [−2300/(273+T)]
14 e
× 10pHis shown in Table 1.

The activity test was conducted with the sludge taken from13cm, 33cm, 53cm height and cultivated in a 33℃ thermostatic
water bath oscillator. The ongoing change of gas produce volume
and the water quality were measured.

3. Result and discussion
3.1 Performance of continuous experiment
The ongoing change of gas produce rate, nitrogen removal
ratio and nitrogen component is shown in Fig.1. In this research,
the total nitrogen (TN) concentration was raised up from300mg/L to 450mg/L and finally to 700mg/L under the HRT of
3h. Under the TN concentration of 300mg/L and 450mg/L, theremoval ratio of NH4+-N is over 95%, and the TN removal ratio is85.5% and 84.4%, respectively. Nevertheless, when TN is raised up
Fig. 1 the schematic of experiment

7

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International Symposium on Water Environment-------with Perspective of Global Safety
TN=300mg/L TN=450mg/L

nitrogen gas produce rate(mL・L-1・d-1)

5000

Systems(January30 -31 ，2015)thst

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TN=700mg/L
nitrogen gas produce rate
theoretical produce rate

4500
4000
3500
3000
2500
2000
1500
1000
500
0

nitrogen removal
efficiency(%)

100%

Fig. 3 nitrogen concentration variation according to heightunder inlet TN of 700mg/L

80%
60%
40%

TN

20%

NH4+-N0%nitrogen component
concentration(mgN・L-1)

900

inlet TN

800

NO2-N

NO3-N

NH4-N

700
600
500
400

Fig. 4 specific activity of sludge from each part

300
200
100

0.005

FA

40

outlet FNA concentration(mg/L)

outlet FA concentration (mg/L)

0
50

0.004

FNA

30

0.003

20

0.002

10

0.001

0

0

50

100

150

200

0

Fig. 5 FA and FNA variation according to heightTime(day)Fig. 2 ongoing change of continuous experimentis 700mg/L. The variation of FA and FNA according to height in thiscondition is shown in Fig.5. The FNA was over the inhibition
concentration of 0.007mg/L below the height of 23cm, and the FA
was over the inhibition concentration of 20mg/L. And because thesludge below the height of 23cm held high activity, we consideredthat FNA inhibited the removal efficiency of the whole reactor.

to 700mg/L, the removal of nitrogen came into a very unstable status.
With about 100d continuous operation, the average removal
efficiency is about 66.4%.
3.2 The inhibition of Anammox activity
The microorganism shows a severe variation according to theheight as UASB reactor is an incompletely mixed reactor. The
nitrogen component according to height is shown in Fig.3. The
concentration of NH4+-N and NO2--N declined and the concentrationof NO3--N rose. The result of the sludge activity test in this period isshown in Fig.4. The highest activity reached 0.513 gN・gVSS-1・d1 for the bottom sludge under TN 232mg/L. Nevertheless, when the
TN is higher than 232mg/L, the Anammox activity was inhibited,and showed a dropping toward. The sludge taken from middle partand top part showed the same toward, and reached their highest
activity between TN232-464mg/L. Furthermore, the activity of thesludge taken from middle part and top part only reached 18.4% and11.0% of that of the bottom sludge.
As was shown in Fig.3, under the condition of TN700mg/L, thesludge in the whole reactor is under the TN of 232mg/L and the
Anammox reaction was possibly inhibited. On the other hand, evenlow concentration of FA or FNA will inhibit the Anammox activity.
According to the research result in our lab1), for granular Anammox
sludge, when FNA is higher than 0.007mg/L or FA is higher than
20mg/L, 40% of the activity will be inhibited. From the continuous
experiment, the FA and FNA of outlet water rose notably when TN

4. Summary
In this research, the TN concentration in a UASB Anammox
reactor was raised from 300mg/L, to 450mg/L, and finally to
700mg/L. The following conclusion is obtained.
1) Under the condition of TN 300mg/L and 450mg/L, Anammox
process is operated stably. In the nitrogen loading rate of
2.4kgN・d-1・m-3 and 3.6kgN・d-1・m-3, the NH4+-N removal
efficiency is over 95% and the removal efficiency of TNreached 85.5% and 84.4%, respectively.
2) When TN was raised up to 700mg/L, because of the inhibitionof FA and FNA, the average removal efficiency for TN and
NH4+-N is 66.4% and 78.8%, respectively.
It is very important to keep the inlet TN concentration under
450mg/L to prevent inhibition caused by FA and FNA in the UASB
Anammox process.

References
1)

8

ZHANG Yanlong, NIU Qigui, LI Yuyou, J. JSCE, Ser. G(Environmental Research) Vol.69, No.7, III515-III522, 2013

G-Safety

International Symposium on Water Environment Problem
with Perspective of Global Safety in East Asian Countries， Part II(March 21-22，2014)

TOHOKU UNIVERSITY

Current state of knowledge of antibiotics in the environment: a global approach○Adriana Ledezma Estrada1,2, Lu Xueqin1, Yu-You Li1,
1

2

Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
Escuela Nacional de Ciencias Biologicas del Instittuto Politecnico Nacional. Av. Plande Ayala S/N. Del. Miguel Hidalgo. Mexico City, Mexico*E-mail: adriana@epl1.civil.tohoku.ac.jp

Abstract
Antibiotics first considered as the most important drugs to save lives now are in the list of emerging pollutants
that threat life. This is the result of decades of misuse and overuse that has lead into a big problem of antibiotic
resistance of pathogenic strains. In the last decade, due to the advance in science and the emerging concern on
environmental topics, a deeper analysis of problem has been possible. Nowadays, the effect of the antibiotics in theenvironment is holistically approached. The influences of the economy, culture, biological, genetic and chemical
processes are considered. On the other hand, the global concern has exerted a positive pressure to write stricter lawsthat demand not only a control in its use but its disposal. The result is an active development of new technologies toaddress this problem.
Keywords: antibiotics, antibiotic resistance, antibiotic environmental impact

show a strong decrease in their AC. except for Australia
and New Zealand that increased their AC. The decrease of
AC could be ascribed to the calling for stricter laws tocontrol the self-prescription in almost every country.

1. Introduction
Although the first antibiotic was discovered 80 years
ago it was during the World War II they were intensively
used. In this period different kind of antibiotics werediscovered and its use was diversified. Originally they wererestricted to humans, but soon it was extended toagriculture i.e. live stock and cultivated land.
Initially the regulation was focused only in the toxicity
due to the lack of knowledge about other side effects. It
resulted in their misuse and abuse with significant
consequences. By 1955 the 13% of Staphylococcus
aureus (SA) were resistant to penicillin, in 1988 theresistance increased up to 93%, and nowadays almost
any antibiotic can kill the Multi-Resistant SA (MRSA).
The presence of antibiotics in the environment was
unknown and ignored because of their low concentrationand ignorance on antimicrobial resistance. Today theadvances in science have changed the perception of thisglobal concern leading to stricter laws that consider not
only its use but production and total elimination.
The last is a hot research in wastewater because most of
the antibiotics and the resistant strains are spread in theenvironment by this means.
2. Global trends of antibiotics human consumption
The consumption of antibiotics is influenced by thecountries’ economy. Opposite to developed countries,
developing countries have higher human consumption due
to the low hygiene conditions that promote infectious
diseases. However, for farming the use or abuse is almost
the same. Fig. 1 shows the growth of antibiotics
consumption (AC) of 63 countries (doses per month)during the last decade (2000-2010). Most European
countries have lowered the AC because of strict laws that
limit its use only to absolute necessary cases and the trend
is scaling to the farming sector. Most developed countries

Fig. 2 Growth (decrease) rate of antibiotics consomptuin for
63 countries for the period between the years 2000 and 2010.
Expressed as number of doses per month (Based on Van
Boeckel et al., 2014).

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with Perspective of Global Safety in East Asian Countries， Part II(March 21-22，2014)

TOHOKU UNIVERSITY

amilovora also nown as fire blight.
Nevertheless, a particular concern is water pollution
because it functions as a vector to transport resistantbacteria as well of ARGs to different places. Thus, theresistance is dispersed in big areas through the water
natural flow; reaching also the soil and the air.
Consequently, multi-resistant bacteria are more alike toappear even in pristine places. When the bacterial

3. RESISTANT MECHANISM
Antibiotics are naturally produced by microbes in theenvironment; the purpose of such antimicrobial substances
is to protect them from other microbes that threat their
existence. However, as a response the attacked microbes
switch on genes, known as antibiotic resistant genes(ARGs), that encode for metabolites to protect them likeenzymes which deactivate the antimicrobial substances.
Usually the resistance occurred after the microbes are incontact with the antibiotic whether at low concentrations or
short time of exposure. Then, this resistance could betransferred to other microbes that had not been exposed tothe antibiotic by means of horizontal genetic exchange ofresistant elements. As a result, the antibiotic resistance isspread into other bacteria. For instance, Liu et al. reported
that one bacterium can encode 8 different resistant genes
while exposed to a single kind of antibiotic. This fact could
explain the presences of multi-resistant antibiotic strains.
Also this study confirms the horizontal transfer of thegenetic material.

composition in the soil changes the plants that use to
grow on it change as well. Then, the animals that
depend of such vegetation will may face food scarcity
and eventually some of them will disappear if theycannot adapt. This slow effect is scaled up until reachhumans. Finally, another factor that promotes thedissemination of resistance are migration movementsfrom animal but also from people traveling far from its
original place because they could transmit the local or
natural resistance to far places.

5. STAY OF THE ART:
The advances in analytic chemistry allow to detect and tomeasure antibiotics and other small related molecules in theenvironment, especially in water. Furthermore, genetics
have also advanced and become more accessible thus more
research on the microbial mechanism for the resistance had
been achieved. The result of this knowledge has stressed:
the importance of efficient wastewater treatments (WWT)
to completely remove such kind of pollutants, and thecreation of stricter laws to regulate its use. In the field of
WWT new technology is been developed like theAdvanced Oxidation Processes (AOPs), that completely
oxidize such substances, efficient filtration processes toremove them or effective biological process like membranebioreactors MBRs are tried.
Additionally, this problem is approached through better
regulations and educational campaigns to explain the
problem and create conscience. In Europe this movement isvery strong and is gaining territory around the world. Still,there is so much to do but the solution is on the way.

4. HEALTH IMPACT
Human health has been notably affected by the
antibiotics. The lifespan was elongated and many lives
were saved. However, it is improper use has also brought
negative effects. The most important and best documented
is the antibiotics resistance of pathogenic bacteria, whichconsequences are high mortality from common infections
that can be treated. In the livestock has been notice that
antibiotics put weight on, such effect is believed to boost
human obesity. Fig. 2 compares two farmed chickens, one
in 1950 and the other in 2008.

6. CONCLUSIONS
Antibiotic resistance is an environmental-health problem
recently consider as a significant threat for human health.
Years of indifferences have buildup remarkable problems
difficult to address. However, since it is a global concern
strong actions are taken. To overcome this challenge broadresearch on this topic as well deeper understanding isneeded..
7. References

Fig.2 Comparative weight gain of two chickens, on the left
is without using antibiotics as growth promoters while theright is fed on antibiotics.

The recent cutting edge project of the human gut, haspointed out the important relationship of the microbes in
the gut with the immunological system. A remarkablefinding is that after taking antibiotics people are more
prone to get another infection disease from different
microbe including viruses.
Finally, the last founded antibiotics were synthetic andhighly toxic. Therefore, the pharmaceutical industry since2000 had nearly stopped the research on new antibiotics.

1. Miaomiao Liu, et. al. Abundance and distribution of Macrolide-

Lincosamide-Streptogramin resistance genes in anaerobic-aerobic systemtreating spiramycin production wastewater, Water Research, 63 (2014) 3341
2. Thomas P Van Boeckel, Sumanth Gandra, Ashvin Ashok, Quentin
Caudron,Bryan T Grenfell,
Simon A
Levin,
RamananLaxminarayanGlobal antibiotic consumption 2000 to 2010: an analysis ofnational pharmaceutical sales data. The Lancet. 14 (2014) 742-750
3. Heather K. Allen, et. al. Call of the wild: antibiotic resistance genes innatural environments. Nature Reviews: Microbiology focus on
antimicrobial resistance 8 (2010) 251-259

4. ENVIRONMENTAL IMPACT
The main impact on the environment is the slowly
modification of the ecosystem that alters the trophic net, a
process which eventually will affect human`s wellness. In
agriculture sometimes antibiotics are used to protect thecrops from plagues, like in apple or pear trees from Erwina
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TOHOKU UNIVERSITY

Phase Separation by Hyper-thermophilic Temperaturein Anaerobic Digestion of Waste Activated Sludge○Yu QIN1, Lijie WU 2, A tsu shi H IGASH IMORI 2, Toshimasa HOJO 2, Yu-you LI 2
1

Graduate School of Environmental Studies, Tohoku University, Sendai 980-8579, JAPAN
2
Graduate School of Engineering, Tohoku University, Sendai 980-8579, JAPAN*E-mail: yyli@epl1.civil.tohoku.ac.jp

Abstract

In order to investigate the performance of phase separation by different temperatures as first stage in a temperaturephased anaerobic digestion (TPAD), continuous experiments were conducted combining a thermophilic (55˚C) firststage and a mesophilic (35˚C) second stage, named TM-TPAD, and then combining a hyper-thermophilic (70˚C) firststage and a mesophilic (35˚C) second stage, named HM-TPAD, focusing on the long-term performance, organic
degradation and particle hydrolyzation. The experiments of a single mesophilic (35˚C) anaerobic digestion (MAD) werealso carried out as comparisons. In this study, the HM-TPAD was operated stably in the long run, achieving a volatilesolids (VS) destruction of 51.8%, which was 1.16-fold and 1.39-fold of the values of TM-TPAD and MAD respectively.
It can also be concluded that the higher temperature is set to the first stage, the more efficient organic degradation andparticle hydrolyzation is obtained for WAS digestion. Especially, the acidogenic phase and methanogenic phase wereseparated in the first stage only when it was operated under hyper-thermophilic (70˚C) condition in the hydraulicretention time of 6 days.
Keywords: Anaerobic digestion, Temperature phased anaerobic digestion, Hyper-thermophilic, Waste Activated Sludge

thermophilic conditions have rarely been reported in TPAD.
In this case, this study was proposed to investigate a
TPAD combining hyper-thermophilic (70˚C) and mesophilic(35˚C) conditions (HM-TPAD) focusing on its long-term
performance and organic removal efficiencies. As
comparison, a TPAD combined with thermophilic (55˚C)and mesophilic conditions (TM-TPAD) and a single-phasemesophilic anaerobic digestion (MAD) were also operated.

2. Experimental apparatus
The apparatus were as shown in Fig. 1. The total hydraulicretention time (HRT) for each process was 30 days.
M

WAS

Substrate tank

HEATER

COOLERPPHEATER

M

M

P

Acidogenic Methanogenic
tank
tank
(3L,55/70oC)(12L,35oC)

TPAD
M
M

P

HEATERWAS
COOLER

1. Introduction
Nowadays expensive cost has to be spent on disposing
the sewage sludge from wastewater treatment plants.
Anaerobic digestion can minimize those organic solids andreuse the produced biogas as fuel, which is also an effective
method to ease the urgent problems of shortage of fossil
fuels and global warming. Practically, most of the anaerobic
digesters were set at the mesophilic temperature of 35˚C.
Through the mesophilic anaerobic digestion of sewage
sludge, which consists of primary sludge and waste
activated sludge (WAS), the latter was confirmed slower todegrade. Furthermore, hydrolysis was reported as the ratelimiting step along the methane fermentation.
In the recent decades, hyper-thermophilic condition
attracts great interests in the field of anaerobic digestion ofsolid wastes. Due to the effect of physical denaturationfrom heating and the rapid reaction from the functioning
enzymes, the hyper-thermophilic conditions of 70˚C havebeen reported capable to evaluate the degradation of WAS.
On the other hand, most of the lab-scale hyper-thermophilic
digesters were focused on acidogenesis or hydrogen
fermentation and the methanogenic archaea communities
were reported fragile and unstable under hyperthermophilic conditions. Thus, we connected a mesophilic
digester following the hyper-thermophilic tank, whichguarantees a stable environment for methane fermentation.
Temperature phase anaerobic digestion (TPAD) has also
been extensive studied for its effectiveness on the phaseseparation. By separating the acidogenic phase and themethanogenic phase, each phase provides better condition
for its dominant microbial communities. Whereas,
compared to numerous reports on TPAD applied withthermophilic (55˚C) and mesophilic conditions, hyper-

P
Substrate tankSingle stage
mesophilic tank
(5L,35oC)

Fig.1 the schema of the experimental apparatus

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Methane(%)

Gas
Production(L/L/d)The HM-TPAD were started right after the TM-TPAD by
resetting the temperature in acidogenic tank from 55˚C to
70˚C. The results and discussion were based on the steadystage of each conditions, i.e. after the duration longer than
90 days (3 times of HRT).

3. Results and discussion
The performance of TPAD were as shown in Fig. 2. In
the acidogenic tank of TM-TPAD, gas production rates
were obviously high and methane took about 60% in the
biogas. The pH values around 7.5 and little accumulation ofvolatile fatty acids (VFA) in this tank suggested that themethanogenesis was remained and active in the acidogenic
tank. When the acidogenic tank changed to hyperthermophilic temperature, gas production rate wasrelatively low and methane took only 40% in the biogas.
The sharp decrease of pH until around 6.5 and increase of
VFA concentrations implied that methanogenesis was weakin this tank. However the acidogenic tank performed, themethanogenic tank remained at pH values around 7.5 andno VFA detected. The stable performance of methanogenic
tank ensured the favor environment for methanogenesis andthe safeness of the whole TPAD process.
The organic removal efficiencies in each process arecalculated by the following formula and shown in Fig. 3.

4. Conclusions

1) The TPAD was operated stably in the long run under
TM and HM conditions;Start up

TM conditions

HM conditions

2.0
1.0
0.0
80

60
40

pH

20
8.0
7.0
6.0

VFA
(mg-COD/L)

15000
10000
5000
0

0

50

100

150

200

Operation Day
AcidogenicphasetankMethanogenicphasetank
Acidogenic
Methanogenic

250

Fig. 2 Long-term performance of TPAD

Removal efficiency (%)

80

100
0 3527Single
TM-A
HM-A
HM-M
7 4553
21
20
4334
4352
31
26 TM-M
21 413620
22 3723
1853
14
1425
646
538

60

6 20
14

40
14

20

35

27

18

26

20

36

43
25

22
23 31

53

21
41

5

45

34

53

46

43

52
38

37
23 21

7

0

TS

VS

COD

P-COD Proteins (CH₂O)

Fig. 3 Removal efficiencies in each process
100%

Percentages basedon the input COD

𝑐influent − 𝑐effluent
Removal (%) =× 100%𝑐WAS
The removal efficiencies for each process ranked as HMTPAD > TM-TPAD > MAD, which intimated the tendency
that the higher temperature applied in the acidogenic tank,the more enhancement obtained through the whole process.
The volatile solids (VS) removal of HM-TPAD was 51.8%,
which was 1.16 times and 1.39 times of the values of TMTPAD and MAD, respectively.
Referring to the distributions of organic removal
efficiencies between acidogenic and methanogenic tanks,
the former degraded more than latter in TM-TPAD whileon the contrast acidogenic tank degraded less in HM-TPAD.
Even though the hyper-thermophilic acidogenic tankachieved less removals compared to TM-TPAD, it wassuggested that the higher temperature resulted the proteins,which is the main component of WAS, denatured to be
more degradable in the following methanogenic tank.
In order to grasp the degrading behavior of each process,the COD balances were calculated and shown in Fig. 4.
100% was the total COD values of the substrate WAS.Boththe TM-TPAD and HM-TPAD left less particle COD(solids) than single phase MAD, especially the HM-TPAD
reduced 15% more solids than MAD. The soluble COD,
which mainly contained undegradable components, took up
about 10% of the total COD. The major amounts ofmethane was produced in acidogenic tank of TM-TPAD
while produced in methanogenic tank of HM-TPAD. Only
5% of COD were transformed into methane in acidogenic
tank of HM-TPAD suggested that the phase separation wereachieved, which is considered the reason for higher
degradation ratio for HM-TPAD.

3.0

TOHOKU UNIVERSITY

Re-------with Perspective of Global Safety

th

75%
50%
25%
0%

18%

11%
37%

89%

9%
48%

39%

56%

12%

5%
9%

36%

31%

Input(WAS) Single Phase TM Process HM Process
Particle COD
CH₄(Single)
CH₄(Methanogenic)

Soluble COD
CH₄(Acidogenic)

Fig. 4 COD balance of each process2) The higher temperature is set to the first stage, the more
efficient organic degradation and particle hydrolyzation is
obtained for WAS digestion. HM-TPAD achieved thevolatile solids (VS) destruction of 51.8%, which was 1.16fold and 1.39-fold of the values of TM-TPAD and MAD
respectively;3) The acidogenic phase and methanogenic phase wereseparated in the first stage only when it was operated under
hyper-thermophilic (70˚C) condition in the hydraulicretention time of 6 days.

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Special lecture

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TOHOKU UNIVERSITY

River Discharge Variations Attributed to Extreme Rainfall in Oman
○Luminda GUNAWARDHANA1*, Ghazi AL-RAWAS2, So KAZAMA 3
1,23

Department of Civil and Architectural Engineering, Sultan Qaboos University, Oman
Graduate School of Environmental Studies, Tohoku University, Sendai 980-8579, Japan*E-mail: luminda@squ.edu.om

Abstract

This study investigates how the extreme precipitation and subsequent wadi flow are affected by climate change in anarid catchment area in Oman. A lumped-parameter rainfall-runoff model and 6-member ensembles of General
Circulation Models from the Coupled Model Intercomparison Project Phase 5 (CMIP5) were used to simulate the wadi
flow response to variation in precipitation. Yearly maxima of the daily precipitation and wadi flow for varying return
periods were compared by fitting the Generalized Extreme Value distribution function. The results indicate that extreme
precipitation events consistently increase by the middle of the 21 st century for all return periods (49-52%) but changes
may become more profound by the end of the 21 st century (81-101%). Consequently, the relative change in extreme
wadi flow is greater than twofold for all of the return periods in the late 21 st century compared to the relative changes
that occur in the mid-century period.
Keywords: Climate change, weather generator, frequency analysis, Oman

1. Introduction
An expanded body of evidence, along with the physicalexplanation by Trenberth et al. (2003), supports theconclusion that the global warming driven by both naturaland anthropogenic emissions of greenhouse gases increases
mean global precipitation (Cubash and Meehl, 2001). Karland Trenberth (2003) demonstrated that, as the temperatureand the associated water-holding capacity of theatmosphere increases, the frequency of extreme daily
precipitation increases, even when total precipitation
remains constant. The Fifth Assessment Report (AR5) of
the United Nations Intergovernmental Panel on Climate
Change (IPCC) concluded that further increase inanthropogenic greenhouse gas concentrations will cause
irreversible changes in the climate system on centuries-longtime scales. Based on the projections of three of the four
emission scenarios (Representative Concentration Pathways
commonly known as RCPs) considered in IPCC AR5, therise in the mean global surface air temperature by the end of
the 21st century relative to the pre-industrial period is likely
to exceed 1.5C (Symon, 2013). Consequently, the intensityof extreme precipitation events is expected to increase inmany parts of the world (Kharin et al., 2007)
Arid and semi-arid areas, where conditions of chronic
water stress, catastrophic flooding and prolonged droughtprevail, such as in the Gulf region of the Middle East, areparticularly vulnerable to the impacts of extreme climate
events. Gunasekara et al. (2013) analyzed the combined
impacts of population change and climate change andidentified the Middle East as one of the four regions thatwill be exposed to extremely negative impacts that could
lower fresh water availability by 50% by 2100 compared tothe situation in 2000. In Oman, changes in precipitation andtemperature extremes are already evident and have caused
an accelerated frequency of flooding (Al-Rawas and Valeo,2010). However, a comprehensive analysis to determine thepotential impacts of climate change on precipitation and thewater cycle has not yet been conducted for Oman. This study,
to the best of our knowledge is the first of its kind for Oman.
The results from 19 RCP scenarios embedded in 6 state-ofthe-art global climate models from the Coupled Model
Intercomparison Project Phase 5 (CMIP5) were used tosimulate the present-day extremes in precipitation and wadi
flow and to project their potential changes in the future in the
Al-Khod catchment area in Muscat, the capital city of Oman.

Fig. 1 Study area

2. Study Area
Oman is located in the southeastern corner of the Arabian
Peninsula (Fig. 1). It covers an area of 309,500 km2 andencompasses a diverse range of topography, including
mountain ranges, arid deserts and fertile plains. The climate
varies mainly from semi-arid to hyper-arid. On average, theannual rainfall is less than 100 mm, compared to the global
annual mean of 1123 mm. The Al-Khod catchment
encompasses a total area of greater than 1600 km2. Becauseof the common flash floods that occurred in this wadi, AlKhod dam was built at the downstream end of the catchment
to prevent flooding.
3. Methodology

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2nd International Symposium on Water Environment Systems(January30 -31 ，2015)th-------with Perspective of Global Safety

The Tank Model used in this study to simulate rainfall
runoff process is a lump-parameter model that was firstdeveloped by Sugawara (1995). The ephemeral flows (raindependent flows) that occur in arid areas such as Oman
only endure intense water runoff for short periods; hence,the evapotranspirative effect on wadi flow was neglected
for this extremely short duration of the year.
Predictions of future climate require the generation of aplausible range of greenhouse gas (GHG) emission
scenarios and the simulation of earth system responses tothe corresponding emissions. In this study, we employed 6
GCMs and 4 scenarios, which altogether produced 19
scenarios to evaluate precipitation-driven changes in wadi
flow in the Al-Khod catchment. Based on the data
availability for our study area, the years 1977-2005 wereselected to represent the past climate. Two future periods,
each encompassing 20 years, were also defined: 2040-2059
and 2080-2099. Even though many models included in the
CMIP5 have improved model resolutions, the horizontal
resolutions of GCMs are still modest and generally toocoarse to apply directly to local-scale impact studies. We
used LARS-WG5.5 (Long Ashton Research Station
Weather Generator, version 5.5), a widely used stochastic
weather generator (Semenov and Stratonovitch, 2010), todownscale GCM precipitation records to the local scale.
Moreover, the yearly maxima of the daily precipitation andthe wadi flow were analyzed using the Generalized Extreme
Value (GEV) distribution function.

R95P / PRCPTOT

4. Results and Discussion
The Tank model performance was evaluated using
precipitation and wadi flow events from 1997 to 2011.
Considering the availability of quality data and theephemeral nature of the wadi flow, 17 discrete hydrographs
were selected. The overall model efficiency was estimatedto be reasonably high as indicated by a NSE of 0.79.
We found a significant increase in extreme precipitation
in base period. The contribution from very wet days (R95P)
to the annual precipitation (PRCPTOT) shows steady raise(Fig. 2), even though its trend is significant at 75% only.

st

G-Safety
TOHOKU UNIVERSITY

similar phenomenon occurs for the 2040-2059 time period aswell. When the mean of all the scenarios was considered, theextreme precipitation for the different return periods
consistently increases relative to the estimations for thepresent climate. Notably, these increases are greater for the2080-2099 period compared to the corresponding changes in
the 2040-2059 period. For example, the relative change inthe extreme precipitation for the 20 year return period is 49%
for the 2040-2059 period and increases to 83% for the 20802099 period. On average, the relative increase in themagnitude of extreme precipitation for all the return periods
is 51% (ranging between 49% and 52%) for the 2040-2059
period and 89% (ranging between 81% and 101%) for the2080-2099 period.
A similar effect is also expected for changes in wadi flow.
Figure 3 presents a boxplot of the annual maximum wadi
flows for the various return periods. Similar to the extreme
precipitation, the projected range of the change is smaller forthe small return periods and, as the return period increases,
the projected range of the changes in extreme wadi flow
become substantial. The annual maximum wadi flow
consistently increases in the mid and late century with asignificantly greater increase towards the end of the 21 st
century. For example, when the means of all the scenarios
and return periods were considered, the extreme wadi flow
increases between 18% and 43% for the 2040-2059 period
and between 54% and 84% for the 2080-2099 period acrossall return periods compared to the estimated mean wadi flow
for the present climate. Notably, for all return periods, therelative change in extreme wadi flow is more than twofold
greater in the late 21st century compared to the relativechange in mid-century.

1
0.8
0.6
0.4

Fig. 3 annual maximum wadi flows for the various return
periods for 2080-2099.

0.2
0
1975

5. Conclusions

1985

1995

2005

2015

Fig. 2 Trend of extreme precipitation

Our results of the annual maximum precipitation for thevarious return periods indicate that, for small return periods(e.g., 5 and 10 years), the projected range of the change isrelatively smaller. As the return period increases (e.g., 20
and 50 years), the projected range of the change becomes
relatively large. For example, the projected range between
the maximum and minimum extreme precipitation is 75 mm
for the 5 year return period for 2080-2099 and the range
increases to 218 mm for the 50 year return period. A very

Our results indicate that the magnitude of precipitation
during extreme events will significantly increase by the
middle of the 21st century and become even more intense by
the end of the 21st century.
The ratio between the relative change in wadi flow and therelative change in precipitation is always greater for the latecentury period compared to the mid-century or present
climate periods. Therefore, the increase in intense extreme
precipitation projected in future will likely cause extreme
wadi flows beyond the precipitation and associated wadi
flow response observed for the present climate.

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TOHOKU UNIVERSITY

A field-scale observation method for non-point source pollution of paddy fields○Baolin SU1,*, Ningbo HUANG1, Ruirui LI 2
1
2

College of Water Sciences, Beijing Normal University, Beijing 100875, China
School of Environment, Tsinghua University, Beijing 100084, China*E-mail: subl@bnu.edu.cn

Abstract

This paper proposes a direct method to observe NPS pollution from paddy fields. The evapotranspiration andinfiltration loss hydrographs of paddy fields in different stages of growing season are estimated firstly dependedon observed water-depth, rainfall and irrigation data, and outflow of paddy fields is analyzed through waterbalance approach. Combined with observed surface water quality data, loads of NPS pollution in outflow f rom
the paddy field can be derived. The proposed method can be applied to quantificational observation of NPS
pollution from paddy field in the condition of multi-outlets and dynamic variation of the lowest ridge height
during growing season, which is impossible to conduct field observation by using conventional methods.
Keywords: non-point source pollution, runoff observation, paddy field, evapotranspiration and infiltration loss

1. Introduction
Currently, there are two ways to observe non-point
source pollution which are Runoff Storage Pond method(RSP) and Synchronous Observation (SO) method ofwater quantity and quality. For RSP method, it isnecessary to construct a runoff pond with specificvolume at the outlet of a paddy field, and total generated
runoff and pollutant loads during a rainfall event willconcentrate into the pond, and runoff volume andconcentration can be measured. Although the RSP
method has been applied for many cases, there are some
limitations. Firstly, there are some pre-conditions for
applying RSP method, such as runoff storage ponds withcertain volume, and unchangeable ridge height of uniqueoutlet. In the field observation, these pre-conditions arequite difficult to meet. There is more than one outlet formost paddy fields, and the ridge height of each outlet isvariable due to water management during growing
period. Secondly, if the experimental field is very large,
the big pond volume is needed. But it is very hard,sometimes impossible to find a suitable space toconstruct a big runoff storage pond in the field.
The SO method measures water samples and outflow
volume synchronously at a certain time interval whenoutflow or runoff generates. These data will be used toanalyze runoff hydrograph and runoff quality variation.
However, the SO method also need the experimental
field have only one outlet and cannot consider the ridge
height variation during whole growing season.
In order to solve above problems which conventional
methods cannot be applied to conditions with multiple
outlets and lowest ridge height variation, this paper
proposes a new observation method, which estimates theevapotranspiration (E) and infiltration loss (F) during
different growing periods based on observed water depth
variation of paddy fields, and calculates outflow throughwater balance theory. Then, combined with surface water
quality variation data, non-point source pollution load
exported from paddy field can be estimated.

Fig. 1 Schematics of instrument installation

2. Materials and Methods
2.1. Instrument installation
A pluviograph (rain gage) and a mariograph (waterlevel meter) need to be installed in the experimental field
after paddy transplantation (Figure 1). The pluviographshould be installed on a fixed tripodal platform, and therain barrel should be kept vertically and 70cm high fromthe ground. The mariograph was installed in the paddy
field, and the mariograph probe should be installed atabout 2 cm high above the field bottom to prevent probefrom blocking by mud, and probe installation heightshould be kept unchanged during whole growing season.
2.2 Data collection
In order to observe continuously rainfall and water
depth, pluviograph was set up to record rainfall every 10
minutes, and mariograph was set up to record surface
water depth variation every 30 minutes. Meanwhile,different sampling points were selected in theexperimental field to obtain average water quality ofsurface water at regular intervals. Surface water samples
were collected twice a week in this study for water quality
analysis in the laboratory. Additionally, it was also needed
to investigate the water management practices such as thetime and duration of irrigation and manually drainage.

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2nd International Symposium on Water Environment Systems(January30 -31 ，2015)th-------with Perspective of Global Safety

Table 1 Results of evapotranspiration and infiltration loss rate

Growing
periodTime duration
rangeof (E+F)(mm d1)(2)∆R i > 0，R out,i = ∆R i

7-24

7-27

7-30

8-2

8-5

8-8

8-11

8-14

8-17

8-20

5-7

7-9

9-12

8-10

evapotranspiration andinfiltration loss (mm)50

daily mean water depth

45

daily evapotranspiration and infiltration loss

40

30

125

25
100

20

75

15

50

10

25
0

5
30/5

6/6

13/6

20/6

27/6

4/7

11/7

18/7

25/7 1/8
8/8 15/8
time(day/mon)

22/8

29/8

5/9

12/9

19/9

26/9

3/10 10/10

0Fig. 3 Daily mean water depth, rainfall andevapotranspiration and infiltration loss hydrographs

3.2. Outflow estimation
As shown in the Table 2, the daily outflow from theexperimental paddy field during the whole growing period
can be calculated based on Equation 2.
As we can see from Table 2, there were totally 18 rainfall
events in year 2012, and 11 events generated outflow andformed non-point source pollution. Besides, there were 3
times of rice fields drying processes (18/7, 22/8 and 16/9)
which also caused non-point source pollution.
Table 2 showed that both heavy rainstorm (1 time) andstorm rainfall (2 times) generated outflow. The rainfall ofJune 19th was 25.4mm but no outflow happened because
there were 10 days in dry period before the rainfalls and thefield was short of water. Moreover, there were 4 times ofmoderate rain, and 3 times of them generated outflow.
Table 2 Calculation results of outflow

100

No.

200

2

400

7-21

7-9

35

1

7-18

8-10

precipitation

300

0

6-8

Aug 23~
Oct 14

150

200

100

4-6

175

0

cloudysunnymaturityJun 7~
Jul 17

jointing-booting
Jul 18~Aug 22

200

precipitation
(mm)

300

tilleringwater depth(mm)precipitation(mm)3. Results and Discussion
3.1. Evapotranspiration and infiltration loss
The evapotranspiration and infiltration loss of paddy
fields include surface water evaporation, plant transpirationand infiltration. The rate of water depth drops down stably
and smoothly caused only by the loss of evapotranspirationand infiltration during no-rain, no-irrigation and noartificially drainage periods (Figure 2).
water depth(mm)overcast& rainy
sunny

returninggreen
May 15~Jun 6

225∆R i < 0，R in,i = −∆R i
During raining period, ∆R i > 0 means that there iswater left after the evapotranspiration, infiltration loss
and surface water depth variation. For this portion ofwater, it flows out of the paddy field in the form of
surface outflow. Therefore, the surface outflow can be
estimated as ∆R i . On the other hand, if ∆R i < 0, it meansthat the rainfall is not enough to supplement the changeof water quantity. Therefore, irrigation was assumed
instead of outflow, and the amount of irrigation can be
estimated according to water balance.
The key point of this method is to decide thedecreasing rate of water depth by analyzing water depth
variation process when no outflow occurs. The outflow
volume of non-point source pollution was calculated by
the amount of decreased water volume deducting with
evapotranspiration and infiltration loss (E+F).

400

TOHOKU UNIVERSITY

growing stages and different weather conditions were chosen
to calibrate and estimate the average evapotranspiration andinfiltration loss (E+F) process, which can be used to calculate∆R i in Equation (2). The (E+F) estimates for different
growing stages are shown in Table 1 and Figure 3. Thereinto,
it is assumed that (E+F) are approximately equal to values
with similar weather conditions as cloudy or sunny days
depending on observed rainfall process and linear
interpolations for periods of rainfall, irrigation or artificiallydrainage.

2.3 Data analysis method
The monitored variables related to outflow estimation
include rainfall, evapotranspiration, infiltration loss,
irrigation and water depth variation. For eachdownstream paddy field, the water and nutrients inoutflow will directly flow into surface water system, andthus forms the non-point source pollution. Water balance
equation is shown as following:
P + R in − (E + F) − R out = ∆H
(1)
Where P is daily rainfall (mm), R in is irrigation water
inflow (mm), E is evapotranspiration loss (mm), F isinfiltration loss (mm), R out is water outflow (mm), H isdepth variation (mm).
Normally R in and R out will not happen at the sametime. ∆H can be observed through mariograph thatindicates how P , R in , (E + F) and R out affect water
depth variations. Therefore, the parameter R out can becalculated as following:∆R i = Pi − (Ei + Fi ) − (Hi+1 − Hi )
{

st

3
4

500
8-23

5

time(day/mon)Fig. 2 Schematics of evapotranspiration and infiltration loss analysis

6

When estimating evapotranspiration and infiltration loss,
sudden change periods of water depth should be avoided
such as periods of rainfall, irrigation or artificially drainage.
Thus, steady water depth decreasing periods in each rice7
8

9

Lab of Urban and Regional Environmental Systems

date(d/m)

rainfall
(mm)

31/5
1/6
2/6
3/6
8/6
9/6
19/6
21/6
24/6
25/6
26/6
28/6
29/6
5/7
7/7
8/7
9/7
10/7
14/7
15/7
16/7

1.5
1.9
0.2
4.7
2.1
3.5
25.4
2.3
10.8
23.7
8.8
9.9
6.1
11.3
1.4
1.3
23.7
13.2
0.0
0.0
0.0

Water
depth
(mm)
55.1
47.4
46.9
51.9
40.2
91.5
115.6
127.0
125.7
154.3
142.5
128.2
131.8
79.7
75.2
69.5
84.1
73.2
47.4
37.4
23.8

(E+F)
(mm)
9.2
9.3
4.9
4.7
6.9
7.2
6.2
6.5
6.2
6.2
6.9
6.3
6.2
8.3
7.2
7.0
6.3
7.0
7.4
7.5
7.7

Inflow(mm)

Outflow(mm)

Remarks

6.9
9.7

irrigation

56.2
7.7

irrigation

3.0
24.1

29.3
12.2
10.0

20.3

28.2
7.5
2.6
6.1
9.8

irrigation
irrigation
drainagedrainage

irrigation
drainagedrainage

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2nd International Symposium on Water Environment Systems-------with Perspective of Global Safety

No.

10

11
12
13
14
15
16
17
18
19
20
21

date(d/m)

rainfall
(mm)

21/7
22/7
23/7
24/7
25/7
27/7
28/7
29/7
30/7
31/7
1/8
8/8
11/8
12/8
13/8
20/8
21/8
1/9
2/9
6/9
7/9
11/9
12/9
15/9
16/9
25/9
9/10

179.6
16.3
0.0
0.0
1.3
55.9
11.1
0.0
22.4
32.1
17.3
5.4
3.9
17.2
1.1
0.0
0.0
23.5
79.2
2.0
0.3
8.0
1.5
0.0
0.0
7.9
3.1

Water
depth
(mm)
130.3
177.1
129.1
88.6
67.8
44.9
143.7
109.7
90.3
113.1
114.0
66.9
55.9
74.0
69.7
38.3
25.2
55.4
169.3
99.7
96.9
77.6
73.8
57.6
41.5
20.4
2.0

(E+F)
(mm)
9.2
9.1
10.3
10.6
10.9
9.2
9.0
10.3
9.6
9.5
9.6
9.0
9.7
9.1
9.7
10.7
10.7
7.6
7.5
7.4
7.3
8.0
8.0
8.4
8.5
8.0
3.3

Inflow
(mm)

52.1
10.0

23.9
4.3
98.0
2.6

(January30 -31 ，2015)th

Outflow(mm)

Remarks

123.6
55.2
30.1
10.3
14.3

overflow

36.2
9.1

irrigation
drainage
irrigation

21.7
20.9

drainage
irrigation
drainage
irrigation

12.3
2.4
12.9

drainage

108.4
4.3
3.7
3.4
7.7
23.7

irrigation
drainage
irrigation
drainagest

G-Safety
TOHOKU UNIVERSITY(2) Through observing the variation of water depth, andrecording rainfall and paddy field water management
practices, the evapotranspiration and infiltration loss
(E+F) can be determined for different paddy growing
stages. Then the runoff outflow process can be estimatedby applying water balance approach.
(3) The proposed runoff observation method is moreeasily operable in observation of NPS pollution frompaddy fields, especially in the condition when a paddy
field has multi-outlets of outflow and lowest ridge heights
varies through whole growing seasons which conventional
observation methods fail to apply.

drainagedrainage

3.3. Event Mean Concentration Calculation
Event Mean Concentration (EMC) is an average or“flow-weighted”
pollutantconcentration
thatis“representative” concentration for agricultural runoff from aparticular land use. The EMC can be calculated as the total
pollutant load from paddy filed outflow divided by the total
outflow volume caused by a particular rainfall event and its
values vary greatly between land uses and rainfall events.
In this study, Equation (3) is used to calculate EMC:tt
EMC = M/V = ∫0 Ct Qt dt / ∫0 Q t dt = ∑ Ct Qt ∆t / ∑ Qt ∆t (3)Where M is total pollutant load of outflow runoff, V is
total runoff volume, t is time, Ct is the concentration ofpollutants at time t, Q t is runoff flow rate at time t, and ∆t issampling time interval.
According to Equation (3), we can calculate the EMCs ofexperimental paddy field for each rainfall event with
outflow generation (Table 3).
Table 3 EMCs of target paddy plot during growing period
Date
25/6
26/6
29/6
9/7
10/7
14/7
15/7
16/7
21/7
22/7
23/7
24/7
25/7
28/7
29/7
31/7
1/8
20/8
21/8
2/9
7/9
11/9
12/9
15/9
16/9
total

Outflow
(mm)
29.28
12.20
10.00
28.20
7.50
2.56
6.05
9.78
123.60
55.17
30.09
10.26
14.29
36.20
9.07
21.68
20.89
2.42
12.87
108.42
4.30
3.70
3.40
7.67
23.69

Concentration (mg/L)
NO3-N
1.85
1.84
1.8
0.96
0.97
1.22
1.25
1.28
0.99
1.05
1.1
1.16
1.22
1.39
1.34
1.25
1.2
2.74
2.86
2.49
3.18
3.12
3.1
3.87
4.12

NH4-N
4.42
4.45
4.25
3.86
3.7
4.87
4.64
4.42
4.25
4.08
3.9
3.73
3.56
3.04
3.07
3.13
3.16
3.74
3.79
2.49
3.24
3.48
3.54
3.71
3.77

Outflowed pollutant
mass (mg/m2)
NO3-N
54.17
22.46
17.99
27.07
7.28
3.12
7.56
12.52
122.36
57.93
33.10
11.90
17.44
50.32
12.15
27.10
25.07
6.63
36.80
269.97
13.67
11.54
10.54
29.70
97.60
985.98NH4-N
129.4254.31
42.49
108.85
27.75
12.46
28.05
43.22
525.30225.11117.3538.27
50.88
110.06
27.83
67.85
66.01
9.05
48.76
269.97
13.93
12.88
12.04
28.47
89.31
2159.60

EMC(mg/L)
NO3-N

NH4-N

1.85

4.43

1.80

4.25

0.96

3.83

1.26

8.47

1.04

5.25

1.38

3.05

1.23

3.14

2.84

3.78

2.49
3.15

2.49
3.35

3.11

3.51

4.06

3.76

1.66

3.64

4. Conclusions(1) It is found that the decrease rate of water depth
caused by evapotranspiration and infiltration loss isstable and well-regulated, and has close relations tometeorological condition and rice growing stages. Thus,
the evapotranspiration and infiltration loss in different
growing stages and meteorological conditions can befound out by variation of surface water depth, which is
the most important step in this proposed method.
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G-Safety
TOHOKU UNIVERSITY

Algae as Energy Securing, Supplement Reserve and Formulating Carbon Sequestration
for Waste Management from Palm Oil Mill Effluent (POME)○Fadhil
Institute of Environmental Water Resources and Management (IPASA) c/o (WATER RESEARCH ALLIANCE)
Department of Environmental Engineering, Faculty of Civil Engineering, Universiti Teknologi Malaysia, 81310 SkudaiJohore, Malaysia*E-mail: mfadhil@utm.my

Executive Summary
Algae are defined as any organisms which are plant-likeand perform photosynthesis. Based on their morphology
and size, algae are typically subdivided into two major
categories—macroalgae and microalgae. Microalgae aremicroscopic organisms that grow in salt or fresh water.
The three most important classes of microalgae in termsof abundance are the diatoms (Bacillariophyceae), thegreen algae (Chlorophyceae), and the golden algae(Chrysophyceae). Growing algae on wastewater streams
have a number of benefits. It will offset additional costs
for nutrient removal from wastewater streams, and thecosts associated with nutrient and water supplies foralgae growth will be greatly reduced or eliminated. If it
is grown in wastewater like palm oil mill effluent(POME) and can produce higher amount of lipid, which
has higher application as energy raw materials. The
macrophytes are considered as one type of algae species
that are present in aquatic environment and have theability to remove inorganic nutrients, toxic metals, andorganic constituents. It is also widely accepted that theuse of macrophytes (or weeds) in wastewater treatment
is a cost effective and environment-friendly approach.
Such type of species has received considerable interest
as a potential feedstock and depending on the species
and cultivation conditions; they can produce usefulquantities of polysaccharides (sugars) and triglycerides(fats). Water hyacinth (Eichhornia crassipes), anothertype of algal species is also widely accepted inwastewater treatment as cost effective and environmentfriendly approach to serve as bio-fertilizer and has
potential role as carbon dioxide sink. The emission ofgreenhouse gases from industries such as the palm oil
mill industry contribute to nearly 72% of the totallyemitted greenhouse gases to be as carbon dioxide (CO2),
18% Methane and 9% Nitrous oxide (NOx) andtherefore are considered as one of the most importantcauses of global warming. The CO2 is also inevitably
created by burning fuels like e.g. oil, natural gas, diesel,organic-diesel, petrol, organic-petrol, and ethanol. The
good news is that researchers have found the way of
estimating the by product management as a measure ofcarbon sequestration for determining the carbon uptake
and storage, which aid in restoring the security of feedstock and to serve as continuous supply for ecobalancing the cycle of providing materials and obtaining
the ratio of by-product.

Theory and scientific basic to the project
The world seems to be raising its energy needs owing to
an expanding population and people desire for higher
living standards. Diversification bio fuel sources havebecome an important energy issue in recent times. Amongthe various resources, algal biomass had received muchattention in the recent years due to its relatively highgrowth rate, its vast potential to reduce greenhouse gas(GHG) emissions and climate change, and their ability tostore high amounts of lipids and carbohydrates. Theseversatile organisms can also be used for the production of
bio fuel. Water hyacinth is low in lignin content (10%),high amount of cellulose (25%) and hemicellulose (35%),
these show the promises of converting fermentable sugar
into bioethanol which can be achieved during
fermentation process and distillation mechanisms.
Furthermore, in providing partial substitution of fossil
fuels, biomass combustion has the potential to be carbon
dioxide (CO2) neutral compared to the burning of fossil
fuels alone will contribute towards the “greenhouse”
effect. This project aims to explore the opportunities forenergy and bio-conversion products, encompassing micro
and macro algae as good alternative sustainable waste
management practice. For a quick understanding, about
1.8 tons of CO2 are removed from the atmosphere foreach ton of dry algae biomass produced. Furthermore,algae crops do not compete with human food crops, andcan be grown year-round under the right conditions.

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TOHOKU UNIVERSITY

Enhancement of Biogas Productivity through Bio-pretreatment of Crop residue during
Anaerobic Digestion○Feng HONG, Fei HUANG, Chuqiao WANG, Xianning LI
School of Energy and Environment, Southeast University, Nanjing, 210096, PR China *E-mail:hong4796@seu.edu.cn

Abstract

The rice straw bio-pretreatment of aerobic composting with fermented liquor was investigated in order toincrease biogas productivity in mesophilic anaerobic digestion. The biological hydrolysis effect was verified byexperimental result that the lignin removal efficiency and biogas productivity increased 30.2% and 33.8%
respectively in aerobic composting with raw fermented liquor, comparing to the sterilized fermented liquor.
Four pretreatment factors (temperature, moisture content, size, time) were selected to evaluate its influence onhydrolysis and biogas productivity. The results indicated that the optimum operational conditions were 40 ℃ of
temperature, 70% of moisture content, 5-10mm of size, and 3d of time, the biogas productivity could reach to262 N-ml/g-TS,substrate which was 52.2% higher than that of un-pretreated crop residue.
Keywords: aerobic composting, rice straw, fermented liquor, BMP test, biogas productivity

1. Introduction
In China, the amount of crop residue generated wasestimated at 650 million ton per year, comprising about
16.0% of total MSW. The crop residue belong to lingocellulosic substrate comprising cellulose, hemi-celluloses,
and lignin. The crop residue was usually disposed byuncontrolled incineration in many farmlands for rapid
minimizing and collection of potash fertilizer. Thisfrequently caused air pollution of PM2.5, traffic accident
and forest fire.
Village-scale energy center that converting crop
residue to biogas has several advantages, such as low
cost of feedstock collection and storage, local utilizationof generated energy and process residue. Anaerobic
digestion (AD) of crop residue has attracting attention
for this energy center, owing to security of operation,
low demand for labor, local utilization of fermented
residue as fertilizer.
The biogas production efficiency is only about 20-30%
with CODcr base in traditional mesophilic AD, which islargely lower than that of food waste and livestock.
Generally, hydrolysis is the rate-limiting step in AD ofcrop residue, due to its lingo-cellulosic complex
structure, which inhibits biodegradability and biogas
productivity of substrate. The bio-pretreatment of
aerobic composting is one of pretreatment that could
promote the dissociation of lingo-cellulosic complex
structure and promote biogas productivity in AD.
The aim of this study is to investigate the effect ofaerobic composting on biogas productivity of crop
residue in AD, to determine the optimum operational
conditions such as temperature, moisture contents, size
and time.
2. Materials and Methods
2.1. Substrate and inoculums

The air-dried rice straw with moisture contents of 8-9%
was used as substrate, its TS content is 91%, including
86.7% of VS.
Inoculums used in this study was AD fermented liquor,
which was collected from 5-L mesophilic AD reactor ofrice straw. The MLVSS content concentration of
fermented liquor was 20,000mg/L.

2.2 Aerobic composting pretreatment
The aerobic composting pretreatment was performed in
duplicates, 60g rice straw and 53g inoculums were mixedin 1-L grass beaker. The moisture contents of inoculated
substrate was about 50%, and then tap water was added toadjust moisture content of 60%, 70%, 80%, 90%
respectively for different test Runs. The glass beakers
were covered with plastic film which was cut several
holes for aerobic condition, and then were placed inthermostat with temperature of 20℃, 30℃, 35℃, 40℃,
45℃for different test Runs. The substrate were taken out
and mixed for aerobic condition every 8 hours among thepretreating period.
2.3 BMP test
Mesophilic (37 ℃ ) BMP tests were performed toinvestigate the pretreated rice straw biogas yield. The 5gTS of pretreated substrates were added with 200ml
inoculum in a 250-ml glass bottle. Each bottle was flushedwith N2 for 2min to replace the oxygen gas, and thencovered with rubber stopper, placed in shaking water bathat 37℃ with 130rpm. During the BMP test period, thebiogas volume was measured using water replacement
method.
3. Results and Discussion
3.1. The effect of biological hydrolysis during
pretreatment
The rice straw pretreatment of aerobic composting was
performed by three Runs, raw fermented liquor used as
inoculum in Run 1, sterilized fermented liquor used as

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inoculum in Run 2. The Run 3 was the blanket test without
pretreating, only performed in BMP test. As shown in Fig.1,
the removal efficiency of cellulose, hemi-cellulose, lignin
after pretreatment in Run 1 was higher than that of Run 2,
the lignin removal efficiency increased 30.2% withcomparison of R1 and Run2.
The daily biogas yield of Run1 had been always greaterthan that of Run 2 and 3, the cumulative biogas yield after
24 days in Run 1 reached to 239.4 N-ml/g-TS,substrate, whichwas 33.8% higher than that of Run 2.
After 3days aerobic composting in Run 1, white hairymaterials appeared in the substrate, was thought as fungus.
According to above test result, the biological hydrolysis
effect of aerobic composting was confirmed.

stG-Safety
TOHOKU UNIVERSITY

Photo of R1 after
pretreatment

3.2. The optimum pretreatment conditions
The operational factors (temperature, moisture, size,time) of aerobic composting were selected to investigate
its influence on performance of pretreatment by theindex of organic content (cellulose, hemi-cellulose,lignin) removal efficiency after pretreatment and biogas
productivity in mesophilic BMP test. Fig.2 showed thetest result of 4 operational factors (temperature, moisture,size, time) from upper to bottom about organic content
removal efficiency and biogas productivity.
The lignin removal efficiency increase withtemperature increasing, cellulose and hemi-cellulose
removal efficiency was lowest under condition of 40℃.
The biogas yield and producing constant was highest
under condition of 40 ℃ , 245N-ml/g-TS,substrate and0.0434d-1 respectively.
The cellulose removal efficiency of 70% and 80%
moisture test were significantly lower than that of othertests, was about 4.0-8.0%. The biogas yield undermoisture contents condition of 70-80% was higher thanthat of other tests, 245-248N-ml/g-TS,substrate.
About the influence of chopped size, the removal
efficiency of cellulose, hemi-cellulose, lignin was nearlysame, the biogas yield increased with chopped size,
about in the range of 245-262 N-ml/g-TS,substrate.
The removal efficiency of cellulose, hemi-cellulose,lignin increased with the prolonging of pretreatment time.
At the pretreatment condition of 2 days, the biogas yieldreached to top value, was about 245 N-ml/g-TS,substrate.
The above results indicated that the optimum
operational conditions were 40℃ of temperature, 70% ofmoisture content, 5-10mm of size, and 3d of time.

R1: Pretreatment of raw fermented liquor as inoculum
R2: Pretreatment of sterilized fermented liquor as inoculum
R3: Un-pretreatment

Fig.1. Performance of pretreatment of aerobic
composting

4. Conclusions(1) The biogas yield of rice straw could be improved
after pretreatment of aerobic composting.
(2) The biological hydrolysis effect of aerobic
composting was confirmed by the addition of raw
fermented liquor.
(3) The optimum operational conditions of aerobic
composting were 40℃ of temperature, 70% of moisture
content, 5-10mm of size, and 3d of time.

Fig.2. The influence of operational factors on organic
materials removal efficiency and biogas productivity
in BMP test
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TOHOKU UNIVERSITY

Geomorphological recession flow model for estimation of drainable storage
Basudev Biswal1,*, Marco Marani2 and D. Nagesh Kumar3
Department of Civil Engineering, Indian Institute of Technology Hyderabad, Hyderabad, India
2
Department of Civil and Environmental Engineering, Duke University, Durham, USA
3
Department of Civil Engineering, Indian Institute of Science, Bangalore, India*Email: basudev@iith.ac.in

1

Abstract
The hydrologic response of watersheds is a result of the interplay between three dominant controls: climate,landscape and vegetation. The response of a basin to rainfall events has been shown to be linked to the basic
structural organizations of its channel networks. This has led to development of hydrologic response model basedon channel network morphology for various practical applications. This talk will particularly discuss about
geomorphological recession flow model and the issue of ‘drainable’ storage estimation. Drainable storage caneasily be computed for a rainfall-runoff event by taking the area under the 'complete' recession flow curve (i.e. adischarge vs. time curve where discharge continuously decreases till it approaches zero). But a major challenge inthis regard is that recession curves are rarely 'complete' due to short inter-storm time intervals. Therefore, it isessential to analyze and model recession flows meaningfully. Here Brutsaert and Nieber method is adopted forrecession analysis which expresses time derivative of discharge dQ/dt as a power law function of 𝑄: −𝑑𝑄/𝑑𝑡 =𝑘𝑄 𝛼 . However, the problem with dQ/dt-Q analysis is that it is not suitable for late recession flows. Traditional
studies often compute 𝛼 considering early recession flows and assume that its value is constant for the whole
recession event. But this approach gives unrealistic results when 𝛼 ≥ 2, a common case. The issue is addressed
here by using geomorphological recession flow model that exploits the dynamics of active drainage networks.
According to the model, 𝛼 is close to 2 for early recession flows and 0 for late recession flows. A simple
expression for drainable storage is then derived, which is a function of 𝑘 and basin area. Using 121 complete
recession curves from 27 USGS basins it is showed that predicted drainable storage matches well with observed
drainable storage, indicating that the model can also reliably estimate drainable storage for 'incomplete' recession
events to address many challenges related to water resources.
show that 𝑑𝑄/𝑑𝑡-Q curves from different eventsare very different from one another (quantified interms of 𝑘), meaning that recession flow curves
need to be analyzed individually. Recent studies
have shown that recession flow curve properties ofa basin can be modelled by considering its channel
network morphology.

1. Introduction
River networks exhibit remarkable morphologicaland structural similarities, which can be expressed
quantitatively through traditional and fractal
geometry. One important question thereupon is
how the spatial organization of river networks isreflected in the hydrologic response to rainfall
inputs. Several studies in the past have discussed
about
the
relationshipbetweenbasin
geomorphology
andhydrologic
response,
particularly during flood periods. Here weparticularly
discuss
about
how
basin
geomorphology controls recession or drought
flows.

At any point of time, 𝑄 can be expressed as a
product of flow generation per unit length (𝑞) andtotal length of the channel network contributing
flow 𝐺(𝑡): 𝑄 = 𝑞 ⋅ 𝐺(𝑡). If we assume that 𝑞 andthe rate at which the channel network shrinks indownstream direction (𝑐) are constant, we will findthat −𝑑𝑄/𝑑𝑡 = 𝑞𝑐 ⋅ 𝑁(𝑡) . That means 𝑁(𝑙) =𝜌𝐺(𝑙)𝛼 , where 𝑙 = 𝑐 ⋅ 𝑡 and 𝜌 = 𝑘𝑞𝛼−1 /𝑐 . It is
generally found that the value of 𝛼 obtained byconsidering channel network is quite close to thatof obtained by considering real recession curves.
That means we can model recession flows by
considering the geomorphological recession flow
model for various practical purposes. In the next
section we will discuss about how thegeomorphological recession flow model for model
can be used to estimate drainable storage.

1.1. Recession flow analysis and modelling
A systematic recession flow analysis arguably
began with the work by Brutsaert and Nieber, who
expressed 𝑑𝑄/𝑑𝑡 as a function of 𝑄 ( 𝑄 being
discharge at the basin outlet at time 𝑡). They foundthat 𝑑𝑄/𝑑𝑡 typically exhibits a power law
relationship with 𝑄 during recession periods:−𝑑𝑄/𝑑𝑡 = 𝑘𝑄 𝛼 . In generally practice theparameters 𝛼 and 𝑘 for a basin are obtained byconsidering ( 𝑑𝑄/𝑑𝑡 , Q) data points from allrecession events together. However, recent studies
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should be noted that 𝑘 can be computed using a
few days of recession flow data only. Finally, themodel’s performance is evaluated done byconsidering 121 complete recession events, forwhich the values of 𝑘 were obtained byconsidering early recession flows only. It was
found that modelled drainable storage matches
well with observed drainable storage (𝑅 2 = 0.96,
see Fig. 1).

2. Estimation of drainable storage
Storage of water within a river basin is often
estimated by analyzing recession flow curves as it
cannot be instantly estimated with the aid ofavailable technologies. For example, GRACE(Gravity Recovery and Climate Experiment)
satellites can measure storage fluctuation, butcannot measure absolute storage. In this study, we
particularly discuss about drainable storage (𝑆𝐷)or the part of basin storage that turns into streams
flows. If a recession event is sufficiently long suchthat discharge approaches zero in the end (i.e. therecession event is ‘complete’), drainable storage
can be computed simply by integrating dischargeover time. However, in most real scenarios
recession events are ‘incomplete.’ Therefore, arecession flow model must be used to construct a
pseudo-complete recession curve to computedrainable storage. In earlier times it was assumed
that the value of 𝛼 for a basin is constantthroughout a recession event. However, thisassumption would suggest that drainable storage isinfinite when 𝛼 ≥ 2 , which is a common case.
That means 𝛼 cannot remain constant throughout arecession event. The geomorphological recession
flow model suggests that for natural basins ingeneral 𝛼 is 2 for early recession flows and 0 forlate recession flows. Therefore, it can be seen thatdrainable storage-discharge curves exhibit two
distinct relationships distinguished from one
another by a sharp transition. This behavior is very
well captured by the geomorphological recession
flow model. After following suitable mathematicalprocedures a simple mathematical equation for
initial drainable storage (drainable storage at the
beginning of a recession event) is obtained: 𝑆𝐷0 =0.5/𝑘 ⋅ [1 + ln(𝐴)] , where 𝐴 is basin area. It

Fig. 1. Modelled drainable storage vs. observed
drainable storage.

3. Conclusions
Recession flows can be modelled by considering
the morphology of channel networks. The
geomorphological recession flow model predicts
the value of exponent 𝛼 quite well. It is also foundthat the model very well mimics the scalingtransition in drainable storage-discharge curves.
Finally, the ability of the model in estimating
drainable storage indicates that it can be used tocompute drainable storage for incomplete
recession events to solve many practical problems
related to water resources management.

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Session III
Presentations by students

25

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2nd International Symposium on Water Environment Systems-------with Perspective of Global Safety(January30 -31 ，2015)thst

TOHOKU UNIVERSITY

Preparation and evaluation of fermentation liquid of food waste as a carbon
source for denitrification○Yongmei ZHANG1, Xiaochang WANG1*, Zhe CHENG 1, Yu-You LI 2,Jialing TANG1
1

Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi’an University ofArchitecture and Technology, Xi’an 710055, P.R. China
2

Graduate School of Environmental Studies, Tohoku University, 6-6-06 Aza-Aoba, Aramaki, Aoba-ku,

Sendai, Miyagi 980-8579, Japan

Abstract*E-mail: xcwang@xauat.edu.cn

The anaerobic fermentation of food waste with different temperature and initial substrate concentration werestudied when considering total amount of organic acids production, and then the carbonaceous mixture was
evaluated as an alternative carbon source for denitrification performance using batch nitrate utilization rate tests(NURs) under different initial COD/N ratios. The denitrification kinetics parameters depended on initial COD/N
ratios such that the maximum rate value of 14.11mgN/gVSS.h with COD/N ratio of 10, however, the maximum
potential value of 0.299gN/gCOD with COD/N ratio of 2. The obvious linear relationships between values ofnitrogen reduction and COD consumption were obtained, and the maximum readily biodegradable fraction in
FLFW was obtained for ratio of 6.
Keywords: Food waste, anaerobic fermentation, carbon source, denitrification performance, COD/N ratio

1. Introduction
The process of anaerobic digestion consists of four
steps: hydrolysis, acidogensis, acetogenesis andmethanogenesis, and the fermentation production in thefirst two steps is viable alternative carbon source for
denitrification process due to the effluent rich indissolved organic matter composed of organic acids,
primarily acetate, propionic and lactic acid. The
temperature and initial substrate concentration affect theamount and types of each fermentation production, andselecting a suitable operation condition is also crucial toenhance organic acids production. The optimum organic
acids production were studied in previous reports,
however, there were few reasearchs on the denitrification
effects of these complex mixture as an alternative carbon
source.
In this study, firstly selection of optimum conditionsof anaerobic fermentation was determined and then the
denitrification characteristic of fermentation liquid(FLFW) was evaluated with nitrate utilzation tests(NURs) as an alternative carbon source.
2. Materials and Methods
2.1 Fermentation material and inoculums
The fermentation material was taken from a student
restaurant. In each collection, bones and insert material(paper and plastic) were discarded, only the fermentablematerial was preserved. After selecting the waste, it was
firstly heated treatment through enough boiled waterwith the aim of greatly avoiding the inhibition fromwaste oil, and then was crushed and homogenized in a
blender to ensure the particle size less than 5mm.
Anaerobic activated sludge from Xi’an Siyuan
wastewater treatment, whose operation mode isanaerobic-anoxia-aerobic activated sludge reactor andcontinuously run for 2 years, was used as the inoculums,
after natural sedimentation for one day.

2.2 Experimental procedures
The anaerobic digestion experiments were conductedin a single-stage reactor with a working volume of 10L.
The operation conditions were shown in Table 1.
Table 1 Operation conditions for Run1-Run6
Parameters

R1

R2

R3

R4

R5

R6

Temperature

35℃

55℃

25℃

25℃

25℃

25℃

11%

11%

11%

9%

13%

15%

Substrate
concentration

The sealed conical flask reactors (1L) were used in thebatch experiments to investigate the effects of COD/N
ratios on denitrification performance when using FLFW
as carbon source. Various quantities FLWF and NaNO3
solutions were added into the reactors with synthetic
wastewater, giving the initial COD/ NO3-N of 2, 4, 6, 8
and 10, respectively. All the reactors were placed on
stirring plates in constant temperature incubator at 25±
1℃. The initial pH values in all batch experiments were
adjusted to 7.5±0.2 using 0.5M NaOH and 0.5M HCl
solution.

3. Results and Discussion
3.1. Selection of optimum fermentation condition
Fig.1 shows that carbohydrate degradation was
extreme due to operation conditions, but the protein
degradation was generally reached at 20±2% except forwhen temperature was at 55 ℃ .Apparently, thecarbohydrate and protein degradation at high temperature
were significantly lower than other conditions, whichwere because that higher temperature inhibited activity of

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th

15
10
5
0

R1

R2

R3

R4

R5

b

25
20
15
10
5
0

R6

R1

c
Acidogenesis rate (%)

Hydrolysis rate (%)

R3

R4

R5

R6

40

30

R1

R2

R3

R4

R5

R6

40

xs

ss

10

4

2

R1

R2

R3

R4

R5

R6

50
40

xs

30 ss

COD/N=4

200
150

20

100

10

50

0

300

COD/N=6

200

100

10

Endogenous materials

50

300

20

30

0

xs Endogenous materials

ss

30

Endogenous materials 60

20

6

40

90

TN
NOX-N

400

COD/N=8

50

NO3-N

30

8

120

COD
NO2-N

COD/N=2

50

d

50

20

R2

10

60

0

COD/N=10

50

500
400

40
30

xs

ss

20

Endogenous materials

300
200

10

100

0
0

50

100

150

200

250

300

Time (min)

40
200

30

xs

ss

Endogenous materials

100

10
0

0
0

50

100

150

200

250

300

Time (min)Fig.2 Variation of TN, NO2--N, NO3--N, NOX--N and
COD with the electron donor of FLFW.
60

50

COD/N=2

VDN,SS = -0.4809x + 48.24
R² = 0.999

40

NO3-N+0.6NO2-N (mg/L)

NO3-N+0.6NO2-N (mg/L)

60

VDN,XS = -0.2127x + 42.3
R² = 0.9907
VDN,endo= -0.0679x + 29.501
R² = 0.9563

30
20
10

0

50

100

150

200

250

VDN,SS = -0.5211x + 46.375
R² = 0.9944

40
30

VDN,SS = -0.2839x + 39.663
R² = 0.9867

20

VDN,endo= -0.0748x + 22.69
R² = 0.9695

10

COD/N=6

VDN,SS = -0.5346x + 46.757
R² = 0.9918

40
30

VDN,XS = -0.2884x + 32.282
R² = 0.9574
VDN,endo= -0.0248x + 5.9755
R² = 0.84

20
10
0

0

50

100

150

200

250

300

Time (min)

60

50

50

100

150

200

250

300

Time (min)60

NO3 -N+0.6NO2 -N (mg/L)

50

0

300

Time (min)60

NO3-N+0.6NO2-N (mg/L)

COD/N=450

0

0

NO3 -N+0.6NO2 -N (mg/L)

Fig.1 Effect of operation conditions on fermentation
parameters.
3.2. Evaluation denitrification performance of FLFW
as carbon source
Fig.2 illustrates the transformation of NO 3-N, NO2N and COD in denitrification process using FLFW as
carbon and electron sources under different COD/N
ratios. Incomplete denitrification process occurs whencarbon is limiting and is characterized by large fractionsof residual nitrate and slight nitrite accumulation at theend of the process when COD/N ratios were 2 and 4. At
ratios up to 6 and 8, complete denitrification (nitrogen in
effluent less than 1mg/L) were obtained, which indicatedthat denitrification was limited by carbon amount rather
than carbon availability. With respect to residual COD in
the effluent, values lower than 30mg/L with ratios of 2, 4
and 6, while increased concentration with ratios of 8 and
10 were obtained in the treated effluent after 4.5h
reaction. In view of results obtained, so the optimum
COD/N ratio (where both COD and N concentrations
reached minimum in the effluent) for FLFW is 6.
Three linear phases of NOx-N reduction occur
simultaneously during the process of denitrification(Fig.3). The maximum denitrification rates are obtainedin the first 80 or 100 minutes of reaction, with values
ranging between 11.65 and 14.11mg/gVSS .h, depending

20

50

VDN,SS = -0.5712x + 47.514
R² = 0.9958

40

COD/N=830

VDN,XS = -0.2551x + 28.968
R² = 0.9413
VDN,endo = -0.0278x + 6.1255
R² = 0.5884

20

10
0

0

50

100

150

200

250

300

Time (min)COD/N=10
VDN,SS = -0.6089x + 47.822
R² = 0.9933

40

30
20

VDN,XS = -0.2306x + 23.547
R² = 0.8811
VDN,endo = 1
R² = 0

10

0
0

50

100

150

200

250

300

Time (min)Fig.3 NOX-N profiles for different COD/N ratios
when using FLFW as carbon source.

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COD concentration (mg/L)

20

30

4. Conclusions(1) Temperature (25℃) and substrate concentration (13%)
were selected as optimum operation condition foranaerobic fermentation of food wastes.
(2)The optimum COD/N ratio was 6 for free values of
COD and nitrogen in effluent when batch NURs were
performed.
(3)The maximum denitrification rate and maximum
denitrification potential reached with ratios of 10 and 2,
respectively.
(4) The readily biodegradable fraction of FLFW was
58.35%.

Nitrogen concentration (mg/L)a25

on the COD/N ratio employed. The denitrification
potential ranged between 0.133 and 0.299gN/gCOD.
There was a negative relationship between pDN and
COD/N ratio, where the greatest pDN was more than twiceof the lowest value.
The readily biodegradable fractions (SS) were calculated
by pDN, and the slowly biodegradable fraction (X S) was
calculated from the measured SS and the known total
COD added. And the maximum fraction of S S was 58.35%
with COD/N ratio of 6.

Nitrogen concentration (mg/L)

30

Removal efficiency of protein (%)

Removal efficiency of carbohydrate (%)

acidification bacterial. The obvious negative relationshipbetween initial substrate concentration and removal
efficiencies of carbohydrate was found in this study.
Hydrolysis phase during solid wastes degradation canbe considered as limiting step because wastes are often
particulate material. The hydrolysis rate seems to be only
related with temperature, and a higher hydrolysis and alower acidogenesis of food waste at a higher temperature
were observed. Acetate and lactic acid are prevalentorganic acids under all conditions. Taken together,basing on the views of acidogenesis rate and totalorganic acids amounts, the fermentation liquid at
optimum condition R5 (25℃ and 13% of substrateconcentration) was selected as alternative carbon source
to evaluate its denitrification performance.

TOHOKU UNIVERSITY

COD concentration (mg/L)-------with Perspective of Global SafetystG-Safety

2ndInternational Symposium on Water Environment Systems-------with Perspective of Global Safety(January30 -31 ，2015)thst

TOHOKU UNIVERSITY

Nitrogen removal enhancement in A/O-MBR with fermentation liquid of food waste (FLFW)
as external carbon
Jialing Tang, Xiaochang Wang*(School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi’an
710055, China)*E-mail: tangjialing88@126.com

Abstract

Fermentation liquid of food waste (FLFW) was applied as external carbon to enhance N removal in A/OMBR. Results showed that FLFW characterizes high denitrification potential and can be regarded as readi ly
degradable carbon. The denitrification was enhanced after adding FLFW in pilot A/O-MBR, and high N
removal was achieved (above 65%). Moreover, FLFW did not cause serious membrane fouling, and the fouling
can be effectively controlled by chemical clean.
Keywords: Fermentation liquid of food waste (FLFW), A/O-MBR, nitrogen removal, membrane fouling1.

one was 8h. The membrane surface area was 0.5m2 andIntroduction
Nutrient pollution caused by excess nitrogen andphosphate discharge has been hotly discussed and studied inrecent years. The commonly applied nitrogen removal
pathwaywasachievedthroughnitrification

and

10m2 respectively. Pore sizes of the hollow fiber
membrane were 0.2μm. Recycle rate of the two MBR
were both 2. Glucose, Sodium Acetate and FLFW wereapplied as carbon sources in lab-scale A/O-MBR. COD

denitrification to reduce ammonia into nitrogen gas withand TN in influent were 300-350mg/L and 25-35mg/L.

organic matter as electron donor. Low organic matters in

2.2 Analysis methods

wastewater always restrict nitrogen removal for low energy

The N compounds and COD were measured every day

for substrate transport and biomass produce. So in practice,according to APHA. The TMP was recorded by on-line

external carbon was always added to increase the C/N inmeters. Membrane fibers were cut from the membrane

influent and enhance nitrogen removal. Glucose or acetate

frame before and after the chemical clean to survey thewas used for wastewater treatment, but the cost was too

effect of chemical clean on membrane fouling control.

high for full-scale plants. In this background, to find

AFM was applied to observe the surface of membrane.

economic and environment-friendly external carbon is

EEM of the Dissolved Organic Matters (DOM) in influent,

always the object for researchers.

supernatant and effluent were got to analyze theFood wastes contain high organic matters and are easily

membrane fouling. EPS were extracted and analyzed todegradable which was suitable to be chosen as external

explain the membrane fouling.

carbon source. So in this study, food waste fermentation3.

liquid was added into A/O-MBR as external carbon to
improve nitrogen removal. Nitrogen removal characters and3.1. Denitrification potential of FLFW

membrane fouling were the main concerns in this study.

2.

Results and Discussion

Materials and Methods

2.1. A/O-MBR
A lab and pilot-scale A/O-MBR were involved to
study the characters and nitrogen removal efficiencies inthis research. The lab-scale one was 37.5L, while thepilot one was 8m3. MLSS and in two reactors were both
3000-4000mg/L. HRT in lab one was 17h and in pilot
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operation conditions. The fouling rate (FR) was a little higher
after adding FLFW (from 158Pa/d to 198Pa/d), and thelonger HRT can slow down the FR. Chemical clean caneffectively decrease membrane fouling.

Fig. 1 Denitrification rate and COD utilization rate of FLFWThe specific denitrification rates (SDNR) of the threeexternal carbons were shown in figure 1. It can be seen that
the SDNR of FLFW was very close to Sodium Acetate(SA), but higher than that of glucose. The results
demonstrated

that

the

FLFW

characterizes

Fig. 3 Variation of TMP, Resistance of pilot A/O-MBR

highdenitrification capacity and could be regarded as readily
degradable carbon source. The COD utilization efficiencyof these three carbon sources were the same to that of
SDNR, which also meant that the FLFW owns the highdenitrification potential.

3.2. N removal in pilot MBR

Fig. 4 AFM images of membrane before and after chemical clean

It can be seen in figure 2 that after adding FLFW, theFrom figure 4, it can be seen that the surface of membrane

denitrification was enhanced and the TN in effluent

before and after chemical clean. It can be seen that the poresdecreased sharply. The TN removal efficiencies increasedon the surface was blocked by sludge or other compounds,

from 30% to 65%. In addition, the higher the COD was inwhile after chemical clean, the pores could be seen clearly.

influent, the lower the TN was in effluent. And the TN

That is why the TMP decreased sharply after chemical clean.

removal also was influenced by HRT. The longer HRT

But some pores were still fouled, which was the reason why

caused the higher TN removal.

the resistance (R) cannot decrease to the former stage (figure
3).

4.

Conclusions

FLFW was utilized as external carbon to enhance N

5.

removal in A/O-MBR. The results demonstrated that, sametosodiumacetate,

the

FLFW

characterizes

highdenitrification potential and COD utilization, can be regarded
as readily degradable carbon source. And the pilot MBR
achieved high N removal after adding FLFW. The membrane
Fig. 2 TN removal in pilot A/O-MBR

3.3. Membrane fouling
It can be seen in figure 3, the TMP increased slowly

fouling increased slightly, but can be effectively controlled
by chemical clean.

before and after FLFW addition, which demonstrated that
the FLFW did not cause serious membrane fouling in our
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Structure Optimization of Constructed Wetland Coupled Microbial Fuel Cell for Organism
Removal○Xizi LONG1*, Xianning LI1, Hailiang SONG1, Feng HONG1 , Wenli XIANG1
School of Energy and Environment, Southeast University, Nanjing 210096, China*E-mail: 230149343@seu.edu.cn

1

Abstract

Constructed wetland was employed to generate electricity due to the different potentials between aerobiczone (high position) and anaerobic zone (low position). The experiment for optimizing the condition usedcurrent (density), power density and internal resistance as parameters to characterize the performance ofelectricity generation. Resulting from changing the spacing between the anode and cathode, 20cm spacing
exhibited the best performance (94.9% COD removal rate, 0.149W/m 3 Power density, 339.8Ω internal
resistance). In brief, the optimal operation contributed to achieving practical implementation.
Keywords: constructed wetland, microbial fuel cell, spacing, structure optimization

1. Introduction
Microbial fuel cells (MFCs) function as a promising
new energy technology for electricity generation inparallel to acquire benefits for the environment, whichmake use of domestic sewage, effluent of industry,leachate, sediment and rhizodeposits as biodegradable
substrates. A large number of investigations have been
devoted to exploit the MFCs construction in nature
successfully, thus a difference of potential between theanode (positive) and the cathode (negative).
Apparently, constructed wetland owns places withdifferent redox potential either conversing organic
matters to electrons by exoelectrogens or acting as
cathode with high level of dissolved oxygen, whichindicates the feasibility to assemble constructed wetland
into some kinds of MFC and has been improved toenhance the degradation of dye in wastewater in somecases.
This work aimed to explore the structure ofconstructed wetland coupled microbial fuel cell
(CWMFC) to obtain the optimized the space between
two electrodes.
2. Materials and Methods
2.1. Constructed wetland coupled microbial fuelcell fabrication
CWMFC was integrated with a vertical organic glass
pipe, as shown in Fig.1. Both of two electrodes consistedof granular activated carbon. Stainless steel mesh current
collector buried in the electrode was linked withinsulated titanium wire to external circuit whichconnected to potentiostat. The total volume of theinstallation was 35.3L with total efficient volume of
12.4L compared to anode of 7L and 2.1L of efficientFig. 1 Experiment installation

volume. To culture microorganisms, condensed
anaerobic slurry (20g/L mixed liquid suspended solids)
was added into CWMFC and the synthetic wastewater
was transported by a peristaltic pump. The hydraulicretention time was reckoned 48h and the installation had aflow of 6.36 mL/min.The components of wastewater are
as follows:
Glucose 200mg/L, KNO3 252.5mg/L, K2HPO4·3H2O
26.32mg/L, NaHCO3 336mg/L, NaCl 330mg/L and 10
mL micronutrients.

2.2 Experimental procedures
The anode located in10cm, 20cm, 30cm and 40cm
position far from the cathode (Fig.2) respectively to
explore the factors of different distances between the twoelectrodes.

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Fig. 4 The polarization curves and the power density-current
density curves

3. Results and Discussion
The evolution of voltages of different spacing between
two electrodes during the experiment was shown(Fig.3).The voltages of 20cm were recorded in the orderof 560mV throughout the experiment, while 30cm
resulted in 520mV. However, the 10cm, 40cm justapproximately reached 440mV, 420mV respectively.

Fig. 5 COD removal efficiency of 4 kinds of electrode spacing

Fig. 3 The evolution of voltages of difference electrode spacing

Fig.4 portrayed polarization profiles and power
density profiles. The maximum open circuit voltage,
741mV, was achieved at 20cm spacing which obtained
the maximum current density of 0.486A/m 3and the
maximum power density of 0.198 W/m 3 with about 400
Ω external resistance. The internal resistance(R int) was
reckoned to be 385.8 Ω (Rint,10cm),339.8 Ω(Rint,20cm),
367.68Ω(Rint,30cm) and 406.32 Ω(Rint,40cm) by linear
part of polarization curves(the external resistance varied
between 100−1000Ω).
When feeding on the same synthetic wastewater, thecathode potential was determined primarily by the
dissolved oxygen, after all, the reactions occurring in the
MFC determined the electrodes potential. On thecontrary, the anaerobic condition conformed to theexoelectrogens as the efficient catalyst which suggested
that the electricity producing was closely related to thelevel of DO.
The COD removal efficiency of 4 kinds of electrodespacing against reactor height was shown in Fig.5 with
1000Ω external resistance at continuous flow. The 20cm

spacing achieved the minimum effluent COD
concentration of 11mg/L, thus the maximum COD
removal efficiency of 94% and features of electricity(power density 0.149 W/m 3, coulombic efficiency
0.313%). According to the curves, a huge drop of COD
concentration exactly in each anode compartment wasobserved which demonstrated the excellent oxidation
efficiency of the anode based on the granular activatedcarbon anode material with huge specific surface area forbiomass adsorption. MFC with higher current generation
also facilitated the terminal COD removal.

4. Conclusion
In this constructed wetland coupled microbial fuel Cellsystem, optimal spacing (20cm) between two electrodes
can enhance the process of electricity generation andorganism removal.

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Analysis of enhanced nitrogen removal in MBR with new biological carriers addition by realtime PCR○Yuli YANG1, Hailiang SONG2, Xiaoli YANG1*
School of Civil Engineering, Southeast University, Nanjing, 210096, PR China
School of Energy and Environment, Southeast University, Nanjing, 210096, PR China*E-mail: yangxiaoli@seu.edu.cn
1

2

Abstract
The effect of new biological carriers’ addition on nitrogen removal and denitrifying microbial flora and functional
enzymes by real-time PCR were investigated in six submerged membrane bioreactor. The mean density of AOB, NOB,
amoA, nirS gene obtained by real-time PCR was 106/mL, 108/mL, 105/mL and 1019/mL, respectively. Carbon source andDO had a great effect on TN removal. The mean TN removal rate in MBR with modified carriers addition reached to
40.69%, which was higher than the control MBR (13.72%). Modified biological carriers were proved to be effective inenhancing nitrogen removal with easy operation.
Key words: MBR; biological carrier; real-time PCR; enhanced nitrogen removal; microbial flora; functional enzyme

1.

Introduction

One of the major drawbacks of MBR was lack ofcarbon sources and insufficiency of total nitrogen removal.
It was necessary that a new MBR should be introduced toenhance nitrogen removal.
Anewsubmerged
hybrid biological carrier MBR was constructed toenhance nitrogen removal by adding a certain amount ofagricultural wastes. As nitrification and denitrification
were biological processes, understanding the ecology of
microorganisms involved may ultimately lead to theimprovement of nitrogen removal. Real-time PCR was
helpful to solve environmental engineering problem as a
powerful approach and had allowed studies of bacterial
community populations in response to varying
environmental conditions. This constitutes significant
progress for microbial ecology studies as it had been
estimated that only a minor proportion (about 1%) of
naturally occurring microorganisms have been isolated inpure culture experiments.
This study investigated the effect of DO concentration,
the carrier types and the carbon source properties on theremoval of nitrogen in MBR. Comparative research was
conducted in order to reveal the mechanism of enhanced
nitrogen removal with new type of biological carriers’
addition. And real-time PCR was used to reveal thechanges of these microbial floras and functional enzymes.

2. Materials and Methods
2.1. Experimental facilities
There were six parallel operation MBRs in thisexperiment,
which werecylindricalwiththedischargeable capacity of 10L. The operation conditionsof different MBR were shown in Table 1.
Synthetic wastewater was adopted in this experiment.
COD, NH4+-N, TP of influent water was controlled at
200mg/L, 40mg/L and 5mg/L, respectively. The
modified of biological carriers was to soak them in 2%
Sodium hydroxide for 24h.

Table 1 Reactor operation parameters
Reactor

Filler and carbon source

DO (mg/L)

1#

liquidcarbon source（ethanol）

3

2#
3#
4#
5#
6#

PVC carrier（polyhedral
hollow sphere PVC）
blank（no extra carbon
source and carrier）
low DO（no extra carbon
source and carrier）
unmodified carrier（unmodified straw）
modified carrier（modified
straw）

3
3
1.5
3
3

2.2 Experimental procedures
DNA isolation from the mixed sludge in MBR was
performed by using Ezup® column Soil Genomic DNA
exaction kit. For PCR purposes, the DNA concentration
was measured spectrophotometrically. PCR amplificationof 16S rRNA genes, amoA, nirS genes was performed in a
total volume of 25μl in an Applied Biosystems 2720
Thermocycler. Table 2 shows PCR primers in this study.
Table 2 Primer sets included in PCR assay
Target gene
Nucleotide sequence (5′–3′)
16S rRNA AOBGGAGRAAAGCAGGGGATCGGGAGGAAAGTAGGGGATCGCTAGCYTTGYAGTTTCAAACGC
16S rRNA NOB
CCTGCTTTCAGTTGCTACCG
GTTTGCAGCGCTTTGTACCGCTAAAACTCAAAGGAATTGA
amoA
GGGGTTTCTACTGGTGGT
CCCCTCKGSAAAGCCTTCTTCnirSGTSAACGTSAAGGARACSGGGASTTCGGRTGSGTCTTGAThe annealing temperature of AOB, NOB, amoA, nirS
was 55°C, 50°C, 65°C, 57°C. Amplification of quantitative
PCR products was carried out with an ABI Step One Plusby using SYBR green as the detection system. The template

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copy number was determined from CT values by using astandard curve.

3.1. Nitrogen removal
The removal of NH4+-N was irrespective of theoperating conditions and achieved a high removal.
However, TN removal rate varied a lot with the removal
rate in the order of adding liquid carbon MBR > low DO
condition > adding modified carriers MBR, and the orderof nitrate nitrogen was just the opposite (table 3). Whenusing carbon source of modified carrier, the amount of
nitrite nitrogen was less. The TN removal rate was higher.
The difficulty of carbon source utilization had great effecton nitrate nitrogen, which indicated that carbon source
have great impact on denitrification. Adding modified
carriers MBR not only could form micro environment, butalso could provide the carbon source. So it improved
nitrogen removal effectively in consideration of theeconomic situation.
Table 3 Nitrogen removal in the 6 reactors. All the values are given
as mean (n=18).
NH4+remTN removal
NO3oval rate/%
rate/%/(mg/L)
PVC
96
30
27
low DO
98.4
44.49
21.31
liquid carbon
95.01
49.48
18.33
blank
96.61
13.72
33.03
unmodified
carriers
97.37
32.69
25.75
modifiedcarriers
98.65
40.69
23.18

3.2. Quantification of 16S rRNA, amoA, nirS genes
The mean density of AOB, NOB, amoA, nirS gene insix reactor obtained by real-time PCR is 106/mL, 108/mL,
105/mL and 1019/mL, respectively (table 4). The densityof ammonia oxidizing bacteria of adding unmodified
biological carriers MBR were obviously more than theother reactors,
butthedensityofammonia monooxygenase was the lowest. There was nocorrelation between ammonia oxidizing bacteria andammonia monooxygenase,which
indicatedthatammonia monooxygenase activity was not only byammonia oxidizing bacteria, but also existed otherbacteria of ammonia oxidation function. Because the highremoval rate of ammonia nitrogen, ammonia oxidation
was not the limiting factor for nitrogen removal. The
density of nitrite oxidizing bacteria of low DO condition
was obviously lowest, and nitrate nitrogen was relatively
low. It can be supposed that DO was in favor of nitrite
oxidizing bacteria’s growth and low DO could realize
short-cut nitrification. The highest nitrate concentration
was achieved when no carbon source was added. This
proved that nitrite oxidizing bacteria was autotrophic
bacteria. The density of nirS of adding liquid carbon MBR
and adding modified carriers MBR was obviously highest,
followed by low DO condition and adding PVC carriers
MBR. Adding liquid carbon MBR and low DO
condition’s nitrate nitrogen rather low, which indicatedthat carbon source and low DO are beneficial for
denitrification, which suggested that denitrification inMBR
washeterotrophic
anaerobic
process.

UNIVERSITY

Denitrification in MBR with modified carriers addition was
also perfect because of its abundant microorganisms andavailable carbon source carriers. There was a significant
correlation between TN removal and density of nirS (table5), which indicated that denitrification in MBR was the key
process for nitrogen removal. Therefore, TN removal ofadding modified carriers MBR was also perfect.
Table 4 The density of 16S rRNA, amoA, nirS genes (number/mL).
All the values are given as mean (n=10).
AOB

NOB

amoA

nirS

PVC

5.00E+06

3.00E+08

22505

1.00E+19

low DOliquidcarbonblank

3.00E+06

2.00E+0832522

2.00E+19

7.00E+06

3.00E+08

37273

1.00E+20

7.00E+06

3.00E+08

21112

9.00E+18

unmodified
carriers

1.00E+07

3.00E+08

18527

8.00E+18

modifiedcarriers

6.00E+06

3.00E+08

43073

1.00E+20

Table 5 The relationship between TN removal and nirS gens (n=10).
TN removal rate and nirS gens
The reactor typerp
PVC carrier-0.948**0
low DO-0.837**0.01
liquid carbon source-0.959**0blank-0.745*0.034
unmodified carriers-0.959**0.057
modified carriers-0.931**0.001
r is the correlation coefficient; p is the Pearson's correlation coefficient;** Significant correlation at the 0.05 leve; * Significant correlation at the0.01 leve.

3. Conclusions(1) The mean density of AOB, NOB, amoA, nirS gene in
MBR obtained by real-time PCR is 106/mL, 108/mL,
105/mL and 1019/mL, respectively.
(2) Carbon source and DO had a great effect on TN removal.
Modified carriers were effective in improving nitrogen
removal of MBR.

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Effect of oysters on size-fractionated marine phytoplankton communities in Shizugawa bay○Yizhe ZHENG1, Kyohei Hayashi 2, Takashi Sakamaki 3, Osamu Nishimura 4＊
1,2,3,4

Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan*E-mail: osamura@eco.civil.tohoku.ac.jp

Abstract

Knowing phytoplankton community compositions which can be predicted best by the size distribution is urgent as ittightly links with ecosystem functions; for instance, the nutrient cycling. Responses of phytoplankton community
compositions to eutrophication and global warming effects are well researched while responses to aquaculture are rarely
investigated. In this study, mesocosm experiments were conducted in situ and suspended organic particles were sizefractionated. Both Fatty Acids and Stable Isotope ratio were analyzed to study the oyster effect on marine phytoplankton
community compositions and their ecological funcitons. The results showed that oysters have significant effects onphytoplankton communities such as the diatom, the green algae and the dinoflagellate in in some size-fractionated water
samples.

Keywords: Oyster, Phytoplankton community compositions, Mesocosm, Fatty acids, Stable Isotope ratio

1. Introduction
The community composition of phytoplankton is crucial
for ecosystem functions such as nutrient cycling. It can bepredicted accurately by its size distribution. Responses ofphytoplankton community composition in size distribution
to the eutrophication and global warming effects were wellresearched while responses to the aquaculture have beenrarely investigated. However, many aquaculture species suchas oysters show size-preferences which means they will
choose the food resources inside limited sizes (Dupuy 2000).
The size-preferences effect might cause shift in thephytoplankton size distribution which may in turn affect theirecological functions (Sandra 2011).
The experiment occurred in Shizugawa bay (Fig. 1) which
is an area affected by tsunami because it has more need tofocus on the environmental sustainability of oyster farming
after the huge damage.

mesocosm (Fig. 2) system in triplicate was biomanipulated by
the oyster species, Crassostrea gigas, while another was nottreated by oyster as control. After 22h, suspended organic
particles in the water sample at all mesocosms werefractionated in size by 2μm membrane filter, 20 and 75μm
sieve respectively, which finally filtered into the GF/F filter.
Fatty acids (FAs) and stable isotope ratio (δ13C andδ15N)of suspended organic particles were analyzed.

Fig. 2 Image of the mesocosm

Fig. 1 Study area

2. Methodology
Mesocosm experiments were conducted in situ in
Shizugawa bay near the suspended oyster farming area. One

3. Results
The POC was mainly consisted of 2~20μm and 20~75μm particles(Fig. 3). Oysters had no significant effect on sizefractionated POC; however, significant decrease was observed
on both the specific FAs concentration(Fig. 4) and theirratios(Fig. 5) of diatom/terrestrial plant, green algae/
terrestrial plant and dinoflagellate /terrestrial plant after size
fractionation. Specifically, specific FAs concentration of
diatom in in 2~20μm and 20~75μm, green algae in 20~75
μ m and dinoflagellate in 2~20 μ m were significantly
decreased by oysters. The ratios of diatom/terrestrial plant in
2~20 μ m and 20~75μ m, green algae/ terrestrial plant in
20~75μm, dinoflagellate/ terrestrial plant in 2~20μm werealso significantly decreased by oysters..

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4. Discussion

Without oyster

With oyster

POC (mg•L-1)

0.4
0.3
0.2
0.1
0
0.7~2μm 2~20μm 20~75μm >75μm
Fig. 3. Comparison between Without oyster (white bar) andWith oyster (dark bar) for POC concentrations (expressedas mg•L-1; Mean±SD, n=3) in each size-fractionated water
sample.
0.6

Diatom1

Green algae

0.4•

FAs (μg

000.7~2μm 2~20μm 20~75μm >75μm

1Dinoflagellate

0.5

0.7~2μm 2~20μm 20~75μm >75μm
420Terrestrialμg•L-1

L—1)

0.5
0.2

0.7~2μm 2~20μm 20~75μm >75μm

Fig. 4. Comparison between Without oyster (white bar) andWith oyster (dark bar) for specific FAs concentrations(expressed as μg•L-1; Mean±SD, n=3) in each sizefractionated water sample.

FAs concentration ratio

1

Diatom/Terrestrial
Without oyster

With oyster

01

5. Conclusions
Oysters showed significant effect on phytoplankton
communities such as diatom, green algae and dinoflagellate insome size-fractionated water samples. Oysters have selective
predation on phytoplankton with different size while 2~75μm
size were mainly preyed on. They also have selective predation
on organic matters with different origins while the specific FAs
concentration ratios significantly decreased. The farming ofoysters probably shifts the size distribution of marine
phytoplankton, which may further affect the ecological functionsof marine ecosystem.

References

00.7~2μm 2~20μm 20~75μm >75μm

Although oysters had no significant effects on sizefractionated POC which represent for the quantity ofphytoplankton communities, they showed significant effects on
the specific FAs concentration ration which represent for thequality of phytoplankton communities. The results of decreasein each ration indicate that oysters have selective predation onorganic matters with different origins. Oysters mainly preyed on
diatom in both 2~20μm and 20~75μm size while the green
algae and the dinoflagellate were mainly preyed in 20~75μm
and 2~20μm size respectively. This may indicate that oysters
showed different size-preferences in different phytoplankton
species. In addition, the community composition ofphytoplankton in both size distribution and species number
might be affected by the predation of oysters.

Dupuy, C., Pastoureaud, A., Ryckaert, M., Sauriau, P.G.,
Montanié, H., (2000). Impact of the oyster Crassostrea gigas on
the microbial community in Atlantic coastal ponds near La
Rochelle. Aquat. Microb. Ecol. 22, 227–242.
Sandra E. Shumway (2011). Shellfish Aquaculture and theEnvironment,

Green algae/Terrestrial

0.5

00.7~2μm 2~20μm 20~75μm >75μm

10.7~2μm 2~20μm 20~75μm >75μm
10Dinoflagellate/Terrestrial
0.5

Bacteria/Terrestrial

5000.7~2μm 2~20μm 20~75μm >75μm

0.7~2μm 2~20μm 20~75μm >75μm

Fig. 5. Comparison between Without oyster (white bar) andWith oyster (dark bar) for specific FAs ratio in each sizefractionated water sample.

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Evaluation of new sewage treatment system using anaerobic membrane bioreactor○Toshiki Sugo1 , Ryoya Watanabe2 , Yu-You Li1,3
1,2

Graduate School of Environmental Studies, Tohoku University, Sendai 980-8579, Japan
Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan*E-mail: yyli@epl1.civil.tohoku.ac.jp

3

Abstract

Possibility of phosphorus removal was evaluated by adding flocculants (FeCl3) in Submerged Anaerobic Membrane
Bioreactor(SAMBR). Two ways of experiments were conducted. One is flocculation test for membrane permeate waterto evaluate possibility of post-stage processing. And 80% of phosphorus was removed by adding flocculants of molar
ratio 1.5. In another experiment, flocculants were directory added to the reaction tank. As a result, COD removal rate andmethane production was increased. Progress of membrane fouling was changed by density. But in spite of having added
enough flocculants , T-P removal rate was only up to 25%.
Keywords : anaerobic, membrane, flocculation, SAMBR, sewage

holder and measured everyday. The temperature in the reaction
tank was set on 25 degrees Celsius by the water jacket which I
attached outside. Ferric chloride was used for flocculant.

1. Introduction
Recently the sewerage treatment method of the energy-saving
and low carbon emission model came to be demanded. In thisstudy, sewage treatment of laboratory scale was carried out by
SAMBR which is space - saving and energy - generate system.
Then flocculants were added SAMBR system to evaluate
phosphorus removal and effect for SAMBR system. At first,
flocculation test for the permeate was carried out to evaluate poststage processing. After that, Consecutive experiments by adding
flocculants to reaction tank was carried out to evaluate phosphorus
removal, membrane fouling, gas production and water quality.

2.2. Experimental condition
As shown in table 1, artificial sewage was used in thisexperiment.
CODcr was adjusted to 500mg/L. Before adding flocculant in thereactor, control system was operated with gradually shortening
HRT(HRT 24 → 8 h). Then FeCl3 was added to permeate andphosphorus removal rate was measured to evaluate the possibilityof post - stage processing. After that, flocculants ware added to thereactor at HRT 8 h. The injection of the flocculant was carried out
with a pump．

2. Materials and Methods
2. 1. Experimental facilities
As shown in Fig.1, SAMBR reactor with 6L working volume
was used in the experiment. The reactor had a submerged
membrane which was made by in the reactor. The materials of
the membrane are polyethylene chloride. And the membranesurface area is 0.116㎡. An aperture diameter of the membrane is
0.2μm. Pump were used for influent and effluent water. And
HRT was controlled by timer. The gas which was generated byreactor was diffused from bottom of reactor to reduce membrane
fouling and circulate sludge. And the gas was collected by a gas

Table.1 Artificial sewage property

2.3. Analytical method
COD, BOD, T-P and T-N of influent and permeate water wereanalyzed regularly. In the mixture in the reaction tank, SS and
VSS were analyzed. COD was analyzed according to APHA
Standard Method. BOD, SS, VSS, T-N and T-P were analyzed
according to 下水試験方法（1989）
3. Results and Discussion
3.1. Flocculation test for permeate of SAMBRResult of flocculation test was shown in Fig. 2. FeCl3 were addedby changing molar ratio of iron for phosphate - phosphorus. As
shown in Fig. 2, as molar ratio rises, the removal of phosphorus
increased. In molar rario 1.5, 80% of phosphorus were removed(4.48→ 1.0 mg-P/L). From this result, It was found that
phosphorus can be removed enough in post-treatment.

Fig.1 Schematic diagram of SAMBRLab of Urban and Regional Environmental Systems
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Fig. 2 Flocculation test for permeate of SAMBR

3.2. Direct addition to the SAMBR(a) Membrane pressure, (b) COD, (c) BOD, (d) T-P, areshown in Fig. 3. Treatment performance is shown in table. 2.
From Fig. (a), it’s found that membrane pressure increase
speed increased by adding low concentration of FeCl3 (molar ratio
1.0〜1.5), but it decreased by adding high concentration of FeCl3(molar ratio 2.0〜2.5).
From Fig. (b) and Table. 2, the COD removal rate rose (97%→98.5％) by adding FeCl3. This is because a particle size in thereactor became big by adding flocculant. Effluent of BOD wasalways less than 20 mg/L. As a result of having calculated the
COD mass balance, COD was converted into methane effectively
in comparison with before addition.
From Fig. (d), in spite of having added enough flocculant, only
up to 25% of phosphorus were removed. By measuring Fe of
effluent, it was found that 75% of Fe were flowed out. From this,most Fe may not react with phosphorus. According to the water
quality test method of Ministry of Land, Infrastructure andTransport1), it says “under the anaerobic condition at the bottom of
the lake, a part of formed iron phosphate elutes”. Combined withthis study, it is found difficult to remove phosphorus by directory
adding FeCl3 to the reactor.

Fig. 3 (a) Membrane pressure (b) COD (c) BOD (d) T-P
Table. 2 Treatment perfprmance

4. Conclusion
・At low molar ratio(1.0〜1.5), membrane fouling is reduced.
But, at high molar ratio(2.0〜2.5), that turns worse.
・COD removal rate is increased from 97 % → 98.5 % byadding FeCl. From COD mass balance, It was found that adding
FeCl increase methane production.
・In spite of having added enough flocculant, only up to 25% of
phosphorus were removed by adding directory to the reactor. ・But, from flocculation test for permeate of SAMBR, phosphorus
was removed enough (4.48 → 1.0mg/L) by adding 1.5 molar
ratio FeCl3.

Table.3 Removal rate of phosphorus< Reference >1) The water quality test method : Ministry of Land,
Infrastructure and Transport

Fig. 3 COD mass balance
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st

Study of the start-up and inhibition process of Anammox reaction in UASB Reactor○Yanlong ZHANG1, Shilong HE2, Haiyuan MA 1, Qigui NIU 1,Yu-You LI1,3*
1

Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
School of Environment Science and Spatial Informatics, CUMT, Xuzhou, 221116, China
3
Graduate School of Environmental Studies, Tohoku University, Sendai 980-8579, Japan*E-mail: yyli@epl1.civil.tohoku.ac.jp

2

Abstract

The Anammox system was started up with 2L of activated sludge and 3L of anaerobic digestion sludge in a
UASB reactor. After 140 days enrichment, the Anammox system was successfully started up. The ammonium
removal efficiency reached to near 99.5%.Substrate concentration shock, nutrient salt shock and nitrogen loading
shock were also investigated in the experiment. The results indicated that the Anammox process was very
sensitive to the change of operational conditions, and the recovery process took 2~3 months long time. The
reaction ratio of consumed nitrite to ammonium (R S ) and produced nitrate to consumed ammonium (R P ) were alsostudied in long-term experiment and short-term experiment.
Keywords: Anammox, inhibition, recovery, free ammonium (FA), free nitrite acid (FNA), reaction ratio

1. Introduction
As an innovative and sustainable biotechnology for
nitrogen removal with the advantage of low-cost and low
sludge production ， anaerobic ammonium oxidation(Anammox) process has been increasingly valued in thewastewater treatment with low carbon to nitrogen (C/N)
ratios. In this process, Planctomycete type bacteria
combine ammonium and nitrite to generate nitrogen gas
under anaerobic condition without organic carbon source.
Eq. (1) describes the nitrogen removal reaction by
Anammox process.
NH4+ + 1.32NO2- + 0.066HCO3- + 0.13H+ → 1.02N2 +0.26NO3- + 0.066CH2O0.5N0.15 + 2.03H2O ·············(1)The reaction characteristics of Anammox process
results in 60% reduction of energy consumption as well as
90% reduction of CO2 emission that minimize the carbon
footprint in wastewater treatment plant. However,challenges in fast start-up and steady operation of
Anammox system limited its application andindustrialization. The long doubling time (10d~14d) andlow cell yield (0.11gVSSg -1NH4+-N) of Anammox
bacteria results in a quite long startup period of Anammox
reactor. Both substrates can exert inhibitory effects on
Anammox process, high substrate concentration caneasily cause the decrease of Anammox activity and theloss of the stable operation.
The aim of this study focused on the evaluation of thestart-up process in UASB reactor. Substrate inhibition andrecovery process was also studied in the experiment.
2. Materials and Methods
2.1. Experimental facilities
As shown in Fig.1, UASB reactor with 5L working
volume was used in the experiment. The reactor had aheight-diameter ratio of 8:1 and made with strong
plexiglass. Water jacket was used to control thetemperature in the range of 33±1℃. The reactor wascovered with light-weight shading fabric to avoid thegrowth of photosynthetic microorganism which would

Fig. 1 Experimental setup

produce oxygen. Influent pumps were controlled by timer(on 1min, off 1min) to intermittently provide substrate into
the reactor. Gas production was measured with homemade
Gas-holder.

2.2 Experimental procedures
3L of nitrification sludge and 2L of anaerobic digestion
sludge were inoculated into the reactor. Effluent pH wascontrolled in the range of 7.6~8.5.The reactor was fed withsynthetic wastewater, the initial HRT was set at 24 hours.
NLR increased gradually by changing HRT at a constant
substrate concentration of 210mg-N/L, and finally reached
to 1.68 g/L/d. Then, the influent TN concentration was
doubled without change of NLR. After the TN removal
efficiency decreased to 40%, the influent TN concentration
was returned to the initial level of 210mg-N/L to study theeffects of substrate shock. Nutrient salt shock and overloading shock were also investigated. When the Anammox
reaction was totally recovered, TN concentration wasincreased to 1250mg/L to raise the NLR to 10g/L/d.
3. Results and Discussion
3.1. Start-up phase
As shown in Fig.2, N2 gas production rate and TN removal
efficiency began to increase from 100d. Gas component
analysis indicated that over 98% of the produced gas was N2.

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Ⅰ

Ⅲ

Ⅱ

Ⅳ

Ⅵ

Ⅴ

NLR and NRR(ｇN/L/d)4.50 inhibition is restorable. Recovery took a long time(3) The4.00
around40 days.
3.50
3.00
2.50

NLR
NRR

2.00
1.50
1.00
0.50
0.00

9.00

8.50
pH

The theoretical N2 gas production was basically consistent
with the measurement value that confirmed the Anammox
reaction. Accompany with the occurrence of Anammox
activity, pH also increased due to the consumption of HCO3which was provided as inorganic carbon source and buffer
agent. It took around 40 days to achieve the highest
ammonium removal efficiency which around 99% andmaintain stable.
Accompany with the change of HRT, gas production
maintained stable growth. Anammox bacteria further
enriched in the reactor. Fig.3 shows the successfully enriched
Anammox granular with an average diameter of 1-2mm.

8.00

7.50
N2 Gas production rate
(L/L/d)

3.50

3.00

Theoretical gas production
Gas production rate

2.50

2.00
1.50

1.00
0.50
0.00

Effluent concentration(mg/L)

Fig. 3 Enriched Anammox granular sludge

3.2. Inhibition and recovery phase
After doubling the TN concentration at 327d, pH
increased to 9.0. Then, 2 times of buffer was added inorder to decrease the pH to the optimum range (Fig.2,
phase II). Gas production rate and TN removal efficiency
rapidly decreased to 420mL/L/d and 40% respectively. As
a result, effluent NH 4+-N and NO2--N reached to 100 mg/L
and 120 mg/L respectively. The average results obtained
from previous studies to evaluate the effects of substrateon Anammox process are presented on the basis of theFree Ammonia (FA) and Free Nitrite Acid (FNA)
concentration, due to the fact that FA and FNA are
considered to be the true inhibitor compounds. In thisstudy, FA increased to 20 mg/L, FNA decreased during
the first 10 days and then increased rapidly to 7μg/L due
to the change of pH and NO2- concentration (Fig.4, phase
II). Similar results were observed in the experiments ofnutrient salt shock and overloading shock (Fig.4, phase IV,phase VII). The concentration of FA and FNA were
obviously related to the stability of Anammox reactor.
To evaluate the ability of the recovered Anammox
system, influent TN concentration was increased to500mg/L gradually at a constant HRT of 3h,correspondingly, the NLR increased to 4.0g/L/d. The
nitrogen removal efficiency decreased with the change ofinfluent TN concentration but soon recovered to previous
level, the results that indicated that the nitrogen removal
potential of the Anammox system was further improved.

140

NH4+-N
NH4-N

120

NO2--N
NO2-N

100

NO3--N
NO3-N

80
60
40

TN removal efficency(g/L/d)

20
0
100
90
80
70
60
50
40
30
20
10
0

0

100

200

300

400

500

600

700

800

900

Operation time (days)

Fig. 2. Time course of Anammox reaction during continuous
operation
Ⅰ

Ⅱ

Ⅲ

Ⅳ

Ⅴ

Ⅵ

4. Conclusions(1) Anammox system was successfully started up in 140
days from a mixture of nitrification sludge and anaerobic
digestion sludge. TN removal efficiency reached to 90%.
(2) The system was sensitive to the substrate shock,nutrient salt shock and overloading shock. FA, FNA and
pH were the factors that affecting the stability of
Anammox system.

90
80

70

20

60

15

FA

10

TN removal
efficiency

50
40
30
20

5

10

0

0

9

100

8

90

7

80

70

6
5

4

FNA

60

TN removal efficiency

50
40

3

30

2

20

1
0

TN removal efficency (%)

100

25

TN removal efficency (%)

FNA concentration (μg/L)

FA concentration (mg/L)

30

10
0

50

100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900

0Operation time (days)

Fig.4. Effects of FA and FNA on reactor performance during
different operational stage

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stInnovation of cool-pavement technology from waste tile
○Nickholas Anting
Universiti Teknologi Malaysia
E-mail: nickholasanting@gmail.com

PRODUCT INFORMATION
Product Summary
The typical paving materials used today are mostly
dark in color and solid, which predominantly absorb
and retain more solar heat than reflect it. This ordinary
type of construction pavement material is one of the
major the contributors to the urban heat island (UHI)
occurrence. If the solar radiation is directly exposed tothe materials, it will cause higher elevation in groundtemperature. Large amount of heat that is stored intypical pavement may contribute to the heat storage
and will affect the surrounding ambient temperatureand can cause a simultaneous heat stroke. Although
the measure of heat stroke is nearly rare recorded in
the country, a future data prediction seems to happen
due to urbanization warnings. In order to reducing theurban heat islands, some modification to the existing
pavement should be conducted in order to increase thesolar reflectance on the surface of the pavement. These
strategies can reduce the amount of heat to be absorbed
and decline any heat stored by the ordinary pavement.
The solar radiation will be reflected by the special
anti-store surface material on the top of the surface
pavement layer. After the thermal heat being reflected,
the pavement will remain at its ambient temperature,thus allowing more convenience to the surrounding
temperature.
This study is focusing on the new material for coolpavement, which is a resin based asphalt surface
coating, with special reflective aggregate from wastematerial. The materials is originally from wasted tiles
mix together with sand to improve its physicalproperties. Different kind of tiles are mixed together
to achieve the higher solar reflectivity, which reduce
the surface temperature of the asphalt surface.
Preliminary development result shown that thecomposite surface coating materials able to reduce thesurface temperature of asphalt surface about 4.4 °C
during peak solar intensity. New improvement of thecoating material has found that the developed coating
material able to reduce the surface temperature of thepavement about 10 °C during peak solar intensity,with surface reflectance more than 0.50. Based on thisdata, the developed material has a good potential to be
used as cool-pavement material, thus reducing theeffect of urban heat island.
Product Features and Pictures

CIP-Tech Coating is a new materials innovation which
is originally from wasted tiles. It is the combination of
three types of selected tiles in the form of aggregate,
which are Full Body Porcelain (FBP White Colour),
Monoporosa and Porcelain Glaze. The combination ofthese tiles aggregate are attached together as surface
coating materials by using epoxy.
This product able to increase the surface reflectivity ofasphalt surface from 10% - 15% into 50% - 55%, whichmean that the surface temperature can be reduce up to
20 °C. CIP-Tech Coating is suitable to be applied atasphalt parking lot and pedestrian walk.

CIP-Tech Coating Model

Application of CIP-Tech Coating at Actual Parking Lot

MATERIALS INGREDIENT AND PROPERTIES
CIP-Tech Coating is made from the combination of
two types of wasted tiles, with the specific proportion
as mentioned below:

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By considering 50% of losses, add 50% to be
included in the design. Then,

Tiles aggregate after crushing

MANUFACTURING PROCESS
1. Materials Collection
This activity involve with the selection of thematerials from the supplier company that able tomeet our materials requirement needs.
Lorry for transportation of the materials is need totransport the materials from the materials supplier tomanufacturer.

3. Sieving ProcessThis is perform in order to obtain the size ofaggregate between 1.0 mm to 2.0 mm.
Collect the sieved aggregate and put into gunny sackseparately.

Raw materials (unused wasted tiles)

2. Crushing the Materials
The materials collected from tiles manufacturer
crushed by using crusher into a form of aggregate.
Different types of tiles should crushed separately.

Crusher Machine

4. Washing ProcessThis process is important to remove the dust andimpurities.
Use clean water.
Immerse the materials into clean water for 24 hours
period.
……..

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