\documentclass[10pt]{article}

\usepackage{fullpage}
\usepackage{setspace}
\usepackage{parskip}
\usepackage{titlesec}
\usepackage[section]{placeins}
\usepackage{xcolor}
\usepackage{breakcites}
\usepackage{lineno}
\usepackage{hyphenat}





\PassOptionsToPackage{hyphens}{url}
\usepackage[colorlinks = true,
            linkcolor = blue,
            urlcolor  = blue,
            citecolor = blue,
            anchorcolor = blue]{hyperref}
\usepackage{etoolbox}
\makeatletter
\patchcmd\@combinedblfloats{\box\@outputbox}{\unvbox\@outputbox}{}{%
  \errmessage{\noexpand\@combinedblfloats could not be patched}%
}%
\makeatother


\usepackage{natbib}




\renewenvironment{abstract}
  {{\bfseries\noindent{\abstractname}\par\nobreak}\footnotesize}
  {\bigskip}

\titlespacing{\section}{0pt}{*3}{*1}
\titlespacing{\subsection}{0pt}{*2}{*0.5}
\titlespacing{\subsubsection}{0pt}{*1.5}{0pt}


\usepackage{authblk}


\usepackage{graphicx}
\usepackage[space]{grffile}
\usepackage{latexsym}
\usepackage{textcomp}
\usepackage{longtable}
\usepackage{tabulary}
\usepackage{booktabs,array,multirow}
\usepackage{amsfonts,amsmath,amssymb}
\providecommand\citet{\cite}
\providecommand\citep{\cite}
\providecommand\citealt{\cite}
% You can conditionalize code for latexml or normal latex using this.
\newif\iflatexml\latexmlfalse
\providecommand{\tightlist}{\setlength{\itemsep}{0pt}\setlength{\parskip}{0pt}}%

\AtBeginDocument{\DeclareGraphicsExtensions{.pdf,.PDF,.eps,.EPS,.png,.PNG,.tif,.TIF,.jpg,.JPG,.jpeg,.JPEG}}

\usepackage[utf8]{inputenc}
\usepackage[english]{babel}



\usepackage{float}








\begin{document}

\title{BIOELECTRICITY GENERATION AND REMEDIATION OF CONTAMINATED INTERTIDAL
ZONE OF YAMAGUCHI BAY, JAPAN}



\author[1]{M Azizul MOQSUD}%
\author[2]{Victor Khong}%
\affil[1]{Yamaguchi University Japan}%
\affil[2]{Cornell University}%


\vspace{-1em}



  
  \date{May 07, 2024}


\begingroup
\let\center\flushleft
\let\endcenter\endflushleft
\maketitle
\endgroup





\selectlanguage{english}
\begin{abstract}
In this study, to generate bioelectricity to power the monitoring
sensors and to improve sediment simultaneously is discussed in Yamaguchi
bay located in the south part of the Honshu island, Japan through
sediment microbial fuel cell (SMFC). To supply energy to the
geoenvironmental monitoring sensors is a serious problem, as traditional
batteries and solar cells are often inconvenient due to the limitations
of recharging and weather conditions, respectively. Four different
sediments were used in the laboratory to generate bioelectricity and to
improve sulfide contamination simultaneously by SMFCs. The acid volatile
sulfide (AVS) was determined to check the improvement of the
geo-environment of the sediments as it was the main source of
contamination in the intertidal zone (tidal flat). Various factors which
affected the voltage generation have been studied. Voltage values showed
almost twice when two anodes were used instead of a single anode. Higher
temperature showed the higher voltage due to increased activity of the
bacteria in the higher temperature. AVS values reduced quickly when the
closed circuit was used. All the marine sediments showed the decreasing
trend of AVS value with time and reached at the 0.2 mg/g-dry mud
indicating the geoenvironmental improvement of the marine sediments
within 14 days . Field test showed the higher value of voltage comparing
to the laboratory test by using the similar sized SMFCs.%
\end{abstract}%



\sloppy


\textbf{Bioelectricity generation and remediation of contaminated
intertidal zone of Yamaguchi Bay, Japan}

M. Azizul Moqsud\textsuperscript{1} and Victor Khong\textsuperscript{2}

\textsuperscript{1}Department of Civil and Environmental Engineering

Yamaguchi University, Japan. University of California Berkeley, USA

\textsuperscript{2}Department of Civil Engineering, Cornell University,
USA

Corresponding author:

M. Azizul Moqsud

Department of Civil and Environmental Engineering,

University of California, Berkeley, USA

Emai: azizul@yamaguchi-u.ac.jp, azizul@berkeley.edu

Phone: 81-9020858547

Department of Civil and Environmental Engineering

Yamaguchi University, Ube city, Japan

\textbf{Bioelectricity generation and remediation of contaminated
intertidal zone of Yamaguchi Bay, Japan}

ABSTRACT:

In this study, to generatebioelectricity to power the monitoring sensors
and to improve sediment simultaneously is discussed in Yamaguchi bay
located in south part of the Honshu island, Japan through sediment
microbial fuel cell (SMFC). To supply energy to the geoenvironmental
monitoring sensors is a serious problem, as traditional batteries and
solar cells are often inconvenient due to the limitations of recharging
and weather condition, respectively. Four different sediments were used
in the laboratory to generate bioelectricity and to improve sulfide
contamination simultaneously by SMFCs. The acid volatile sulfide (AVS)
was determined to check the improvement of the geo-environment of the
sediments as it was the main source of contamination in the intertidal
zone (tidal flat). Various factors which affected the voltage generation
have been studied. Volatge values showed almost twice when two anodes
were used instead of a single anode. Higher temperature showed the
higher voltage due to increased activity of the bacteria in the higher
temperature. AVS values reduced quickly when the closed circuit was
used. All the marine sediments showed the decreasing trend of AVS value
with time and reached at the 0.2 mg/g-dry mud indicating the
geoenvironmental improvement of the marine sediments within 14 days .
Field test showed the higher value of voltage comparing to the
laboratory test by using the similar sized SMFCs.

\textbf{Keywords:} AVS, bioelectricity, geoenvironment, marine sediment,
SMFC

\textbf{1. INTRODUCTION}

We need green energy which could be a sustainable source for the power
supply to the environmental monitoring sensors such as temperature
sensors in the remote intertidal zone (tidal flats) in Japan and other
places. Depletion of energy reserves, global warming and the concern of
environmental pollution are inspiring the search for new environment
friendly and sustainable energy production methods all over the world.
Renewable bio-energy is viewed as one of the ways to alleviate fuel
needs of the future and to overcome the crisis of global warming.

Microbial Fuel Cell (MFC) is the bio-electrochemical device that
converts microbial reducing power into electrical energy which is a
green and safe source of bioelectricity (Logan \& Regan, 2006; Hong et
al., 2009; Moqsud 2020). They use the existing substrates from renewable
sources and convert them into harmless by-products with simultaneous
production of bioelectricity (Habermann W. \& Pommer, E.H., 1991). In
this way, bioelectricity production employing MFC has generated
considerable interest in both basic and applied research in recent
years. Moqsud et al., (2014) tried to get bioelectricity from various
organic wastes and also living plants by using MFC technology.

SMFCs are being considered for use as a potential power source for
aquatic water quality sensors such as pH, temperature, and dissolved
oxygen sensors (Moqsud 2020; Moqsud et al., 2017). SMFC can be a
potential source of remediation of this problem. The geo-bacteria (which
live in soil) break the organics in the soil and consequently generate
the bioelectricity. Abbas et al., (2017) found that SMFCs could be a
source of sustainable energy and heavy metal remediation. To change the
batteries from the environmental monitoring sensors of this contaminated
tidal flat is a serious problem and often the solar system is not
working due to the bad weather or other reasons.

The major objective of this study is to generate bioelectricity from a
contaminated sediment while improving its geoenvironmental condition in
the laboratory experiment and to compare it through field experiment of
SMFCs.

2. METHODS AND MATERIALS

2.1 SAMPLE COLLECTION

Four samples were collected for this experiment from Yamaguchi bay at
depths of 0-20 cm from tidal flat and the river areas during the ebb
tide. A ponar dredge sediment sampler was used to collect the samples.
Sample 1, 2 and 3 were collected near the intertidal zone of Yamaguchi
bay (33.93 N, 131.22 E), Ube city. Sample 4 was collected from the river
near that tidal flat area (33.93 N, 131.22 E) to compare the marine
sediments SMFCs and the river sediment SMFCs. The samples were collected
middle of May, the average ambient temperature is around
25\textsuperscript{0}C. The geoenvironmental condition of the Yamaguchi
bay tidal flat area is not good due to the various human activities. The
smell of the sediment was unpleasant and there is very small signs of
benthos in the sediment. The AVS value is more than suitable range in
different parts of the Yamaguchi bay and hence caused the declination of
catch of shell and decrease of the horseshoe crab has been observed
(Moqsud et al., 2017). This is a serious ecological problem and the
researchers are trying to solve this problem.

Table 1 summerises the basic physico-chemical properties of the four
sediments. From the grain size analysis of the four sediments, it was
observed that all the three sea sediments showed the similar trend,
however, the river sediment showed a different trend and the particle
size is larger than the sea sediments. It was seen that the loss on
ignition (LOI) which is the indicator of organic content was relatively
lower in sea sediments (sample 1, 2, 3) 12\% than in the river sediment
14\% (sample 4). The AVS value was also higher in the case of marine
sediments (more than safe limit , 0.2 mg/g-dry mud). Anaerobic bacteria
(sulfate reducing bacteria) reliably to generate AVS by converting the
sulfate to sulfide and is one of the major indicators for the
geoenvironmental condition (Rickard \& Morse, 2005). In this study, the
AVS value will be taken as a key indicator of the geo-environmental
condition improvement. According to the Japanese fisheries research
association, the safe value for AVS is 0.2 mg/g dry mud for the benthos
living in the mud.

2.2 Laboratory Experiments

Figure 1 illustrates the schematic diagram of SMFC in the laboratory
experiment. One liter glass beaker was used in the laboratory as a
single chamber SMFC without a separator. The sediment sample was placed
in the cell. Same size (100 cm \textsuperscript{2}) of carbon fiber
(Toray Corp. Tokyo, Japan) was used for both the anode and cathode
materials (Moqsud 2020; Moqsud et al., 2014). The anode was placed
inside the sediment and the cathode was placed on the top of the surface
(Moqsud et al., 2013; Omine, 2009). Both of the electrodes were
connected to a fixed external resistance (100 ) and measured the data
by using a multimeter (UNI LCD Multimeter, USA). The external resistance
was fixed at 100  by assessing the polarization curve with different
resistors and also by comparing open circuit voltage (OCV) (Moqsud et
al., 2017). The polarization curve was drawn by following other
literature (Logan nad Regan 2006). The laboratory investigation was
conducted at a constant room temperature of 25\textsuperscript{0} C. AVS
was measured by following the GASTEC method.

2.3 Field Test

The field test was carried out in Ube city Yamaguchi bay tidal flat area
(33.93 N, 131.22 E) (near the Sample 3) from where the sediment samples
were collected for the laboratory experiments and it was considered that
the basic physicochemical properties of the marin sediments were similar
both in the laboratory and field experiments. The similar size of
laboratory SMFC was set up in the tidal flat area in where the water
inundates during the high tide and exposed to atmosphere during the low
tide. The cathode was set up on the surface of the tidal flat sediment
and the anode was set up inside the sediment (5 cm below). The same
carbon fiber (Toray company, Japan) was used with the same surface area
100 cm\textsuperscript{2} which was used during the laboratory
experiment. The voltage was measured in the field and the AVS was
calculated in each week by following the same method of the laboratory
experiment. To check the AVS variation both from laboratory and field
test, the samples were collected from the anode area.

\textbf{Statistical analysis}

For statistical significant testing, \emph{p} (probability value) less
than or equal to 0.05 was used.

\textbf{4. RESULTS AND DISCUSSIONS}

\textbf{4.1 Variation of current with time}

Figure 2 illustrates that the variation of voltage with duration in the
laboratory experiment. It is seen that all the three marine sediments
showed the higher value of voltage than the river sediments. Sample 3
showed the peak voltage and reached at around 300mV after 1 week. Sample
1 and sample 2 showed the similar trend of voltage generation with
sample 3. The initial rate of voltage generation was higher as the
bacteria got ample of food during the early stage of laboratory
experiments. After reaching at the peak the voltage generation reduced
and almost constant for another 2 weeks. However, voltage generation was
always lower in the case of river sediment. Though the organic content
of the river sediment was little bit higher than the marin sediment, the
grain size of river sediment was larger and consequently affect the
voltage generation. The peak voltage generation in river sediment was
140 mV which was 60\% lower than the sea sediments. The high electrical
conductive saline water of sea could be another reason for the higher
value of voltage in the sea sediment (Song and Jiang, 2018). The
external resistance used in this particular research was 100  both in
the lab and the field. So, the peak power output from one cell is around
28 mW/m\textsuperscript{2} . Wang et al., 2014 showed that the voltage
generation can be great influenced by the organic content present in the
sediment. However, our results showed that the power generation was
always higher in the sea sediment instead of river sediment. The
particle size and the salinity affected the results more significantly
than the organic content of the sediment.

\textbf{4.2 Variation of anode number and generation of voltage}

Figure 3 illustrates the effects of the anode number in the SMFC in the
laboratory experiments. It was observed that the amount of voltage
increased twice when the anode number was twice. The peak reached up to
250 mV when double anode (2 anodes) were used. The electron acceptor
areas were increased by increasing the number of the anode, as a result,
the peak value was also showed higher when double anode was used instead
of a single anode. The number of anode has an influence on generation of
bacteria-induced electricity which was revealed by this experiment. The
bacteria also closely attached with the anode materials to transfer the
electrons from the sediment by making biofilm on the surface of the
anode materials. Again, the surface area of the anodes had a greater
influence on the bioelectricity generation. Moqsud 2020 showed the
variation of voltage generation was affected by the anode materials such
as stainless steel, graphite materials or bamboo charcoals. However, he
did not show how much power generation has been affected by the number
of anode.

\textbf{4.3 Effects of temperature on voltage generation}

Figure 4 illustrates the effects of temperature on the voltage
generation in the laboratory experiment. It was seen that when the
temperature was 25\textsuperscript{0} C then the amount of voltage was
also higher compared to 5\textsuperscript{0} C. The average winter and
spring temperature in the Yamaguchi bay is around 5\textsuperscript{0} C
and 25\textsuperscript{0} C, respectively and for this reason we fixed
those temperature during the laboratory experiment. The bacterial
activities increased in the increased temperature and consequently
increased the voltage generation. At the 25\textsuperscript{0} C, the
peak voltage reached around 85 mV and at the 5\textsuperscript{0} C the
peak voltage reached around 48 mV. This proved that the temperature is
one of the biggest affecting factors for the voltage output in the
SMFCs. Lovley 2006 showed that the temperature is also a affecting
factor for the waste water MFCs. The possible shortcomings of this
particular research could be the effect of temperature in the field. The
lower winter temperature could affect the power generation and
consequently it could be affect the power supply to the sensors in the
field. To minimize this problem, SMFCs could be developed and connec in
a series connection and set in the tidal flat area.

\textbf{4.4 Variation of AVS (AVS) in different kinds of sediment}

Figure 5 illustrates that the AVS value varied with time in all types of
sediment. The river sediment showed a lower value of AVS is probably due
to the size of the sediment during the starting of the experiment. The
larger particle size of the river sediment can be one of the reasons why
the AVS is lower value. The another probable reason of the lower AVS in
river sediment is due to the pollution level of the river water. The
various human activities such as using the chemical products to grow the
sea weed in the sea is one of the main reasons of the higher AVS in the
sea sediment. However, AVS reduced for all the samples from the
1\textsuperscript{st} week of the experiment and after 3 weeks, SMFC 1,
2 and 3 showed a dramatic reduction of the sulfide content.
Nevertheless, all of the 4 samples showed that the sulfide content
reduction trend after using the SMFCs compare to blank sediment (without
using the SMFC). The probable reason of AVS reduction in the SMFC is
that the electron movement is frequent in the SMFC and this condition is
favorable for the geo-bacteria who work in the bioelectricity generation
from the polluted sediments which was discussed in the earlier research
(Moqsud 2020).

\textbf{4.5 Variation of AVS with time in different circuit conditions}

Figure 6 demonstrates the variation of AVS with time for the SMFC system
in different circuit conditions. Three samples were prepared with
different circuit conditions but the same amount of sediment to compare
the effect of the circuit for AVS reduction. One MFC was designed with
an open circuit, another one is used for 100  external resistance and
another one is without electrode or circuit (blank) condition.

It was seen that the AVS reduction was faster when SMFC was used. The
open circuit and the circuit with 100  were more effective to reduce
the AVS than the sample without the circuit system. This figure confirms
that by using the SMFC system, the AVS reduction will be faster than
without using MFC for the sediment contaminated with higher AVS. This
type of phenomena is mainly due to the enhanced flow of electron inside
the MFCs (Rabaet et al. 2006; Zhang and Zhou 2009). The
geo-environmental condition of the high AVS contaminated sediment can be
improved by applying this method. The benefit of this method is that it
could be used as a safe source of bioelectricity generation in the
remote places and this electricity can be used for small applications
such as to power the environmental monitoring sensors.

\textbf{4.6 Variation of voltage generation and AVS reduction in the
field}

The field test in the marine sediment in the Yamaguchi bay was carried
out in a similar size of the laboratory SMFCs. It was interesting that
the AVS reduction trend was similar in the field, however, the voltage
generation is not similar with the laboratory experiments. The voltage
generation was higher in the field than the laboratory experiments for
the similar size SMFCs. The probable reason of this trend is that the
various nutrients supply in the intertidal region naturally and that
might increase the activities of the bacteria and hence increase the
voltage. The tidal effect and the other environmentl factors such as
solar radiation could also affect the power generation in the field.
This was the first time to compare the voltage generation between the
laboratory experiment and field experiment with the similar SMFC in the
high sulfide content contaminated sediment. Kubota et al. 2019 showed
that AVS value has reduced in the Tokyo bay tidal flat sediment during a
field test in the high eutrophic water enclosed bay.

By utilizing the SMFC, the rate of flow of electrons can be probably
increased and the process of AVS (mainly FeS and H\textsubscript{2}S)
reduction will be increased. The resulting electron flows promote
remediation of sediment by enhancing physicochemical and microbial
metabolic reactions. So the voltage generation and the AVS reduction
were happened together in the field experiment (Erable et al., 2017).
Though the vaoltage and power generation is higher in the field but the
seasonal temperature variations could be a factor in the field to supply
power to the environmental monitoring sensors. This present field test
was carried out in relatively warm (ambient temperature varied from
20-25\textsuperscript{0} C). The field test during the winter might show
some lower power generation due to the lower surrounding temperature. In
this particular research, the similar size single anode SMFC was used
both in the laboratory and the field experiments. The series connection
of the SMFCs could increase the voltage and power generation and hence
could be a potential source of power supply to the various
geo-environmental monitoring sensors. The mechanisms of the AVS
reduction was discussed in details in our previous paper (Moqsud 2020).

\textbf{5. CONCLUSIONS}

The bioelectricity generated by the SMFC can be used to supply the power
to the environmental monitoring sensors. This power source can be a
sustainable and green source of electricity. The performance of the
system with two anodes was about twice higher than that of with one
anode regarding bioelectricity generation. The variation of AVS value
was observed and decreased about 0.2 mg/g-dry mud indicated the
improvement of the geoenvironment for the marine sediments after using
SMFCs in the contaminated sediments both in the laboratory and in the
field . By observing the different circuit conditions, it was found that
the rate of AVS decreasing was the fastest and slowest when a close
circuit and no circuit (blank) condition was set, respectively. It
showed the similar trend as Abbas et al. 2019 have been observed. Higher
temperature is better for enhancement of voltage generation because the
bacterial activities enhanced with the enhancement of the temperature.
It was observed that voltage at 25\textsuperscript{0} C was almost 8
times higher than that of at 5\textsuperscript{0} C. From the laboratory
test and the field test result comparison, it was found that voltage
generation is more durable in the tidal flat areas however, during the
winter, the voltage generation might be deceased due to colder
surrounding temperature in Japan. So, proposed SMFC system can both
generate bioelectricity and improve the geoenvironmental condition of
the marine sediment at the same time and extra measure should be taken
at the winter season for sustainable power supply from SMFC. Economic
analysis and the feasibility of the large scale SMFCs in the field
should be carried out in the future.

REFERENCES

Abbas, S. Z., Rafatullah, M., Khan, M.A., Siddiqui, M. R., 2019.
Bioremediation and Electricity Generation by Using Open and Closed
SMFCs. Frontiers in Microbiology, 9, 3348.

Baeta-HallL, S., Anselmo, M.L., Rosa, M. , 2004. Bio-degradation of
olive oil husks in composting aerated piles. Bioresource Technology, 96:
69-78.

Erable, B., Byrne, N., Etcheverry, L., Achouck, W. , Bergel, A., 2017.
Single medium MFC: stainless steel and graphite electrode materials
select bacterial communities resulting in opposite electrocatalytic
activities. International Journal of Hydrogen Energy, 42, 26059-26067.

Hong, S. W., Chang, I., Choi, Y., Chung, T., 2009. Experimental
evaluation of influential factors for electricity harvesting from
sediment using MFC. Bioresource Technology 100, 3029-3035.

Kubota, K., Watanabe, T., Maki, H., Kanaya, G., Higashi, H., Stutsubo,
K., 2019. Operation of SMFCs in Tokyo Bay, an extremely eutrophicated
coastal sea. Bioresource Technology Reports 6, 39-45.

Logan, B.E., Regan, J.M., 2006. Electricity-Producing Bacterial
Communities in MFCs. Trends Microbiology 14 , 512-518.

Lovely, D.R. 2006. Bug Juice: harvesting electricity with
microorganisms. Nature Review Microbiology, 4, 497-508.

Moqsud, M.A. 2020.bioelectricity generation and remediation of sulfide
contaminated tidal flat sediment. International Journal of sediment
research 35: 91-96..

Moqsud, M. A, Omine, K., Yasufuku, N., Hyodo, M., Nakata, Y.
2014.bioelectricity from bamboo and kitchen garbage. Waste Management
and Research 32(2),124-30.

Moqsud, M.A., Omine, K., Yasufuku, N., Hyodo, M., Nakata, Y. 2013. MFC
(MFC) for bioelectricity generation from organic waste. Waste
Management.\emph{,} 33 (11), 2465-2471.

Moqsud, M.A., Sato, K., Hasan, M., Nakata,Y., Omine, K., 2017. Seasonal
variation of contaminated geo-environmental condition of Yamaguchi bay
tidal flat, Japan. Regional studies in Marine science. 10, 27-31.

Rabaet, K., Van de Sompel, K., Maignien, L., Boon, N., Alterman, P.,
2006. MFCs for sulfide removal. Environmental science and technology 40,
5218-5224.

Rickard, D., Morse, W. J., 2005. AVS. Marine chemistry 97, 141-197.

Song, N., Jiang, H. 2018. Effects of initial sediment properties on
start-up times for SMFCs. International Journal of Hydrogen Energy 43,
10082-10093.

Spiegel, R.J., Preston, J.L., 2003. Technical assessment of fuel cell
operation on anaerobic digester gas at the Yonkers wastewater treatment
plant. Waste management, 23,709-717.

Wang, D.B., Song, T.S., Guo, T., Zeng, Q.L., Xie, J.J. 2014. Electricity
generation from SMFCs with algae-assisted cathodes. International
Journal of Hydrogen Energy 39, 13224-13230.

Zhuang, L., Zhou, S. 2009. Substrate cross-conduction effect on the
performance of serially connected MFC stack. Electrochemical
Communication 11, 937-940.

\textbf{Hosted file}

\verb`3 table 2020 april 27 rsms.docx`  available at \url{https://authorea.com/users/530669/articles/597417-bioelectricity-generation-and-remediation-of-contaminated-intertidal-zone-of-yamaguchi-bay-japan}

\textbf{Hosted file}

\verb`2 figure 2020 april 27 rsms.docx`  available at \url{https://authorea.com/users/530669/articles/597417-bioelectricity-generation-and-remediation-of-contaminated-intertidal-zone-of-yamaguchi-bay-japan}

\textbf{Hosted file}

\verb`1 text 2020 april 27 rsms.docx`  available at \url{https://authorea.com/users/530669/articles/597417-bioelectricity-generation-and-remediation-of-contaminated-intertidal-zone-of-yamaguchi-bay-japan}

\selectlanguage{english}
\FloatBarrier
\end{document}

