Waste-to-wealth for valorization of food waste to hydrogen and methane towards creating a sustainable ideal source of bioenergy

Accepted Manuscript Waste-to-wealth for valorization of food waste to hydrogen and methane towards creating a sustainable ideal source of bioenergy Ngoc Bao Dung Thi, Chiu-Yue Lin, Gopalakrishnan Kumar PII:

S0959-6526(16)00179-7

DOI:

10.1016/j.jclepro.2016.02.034

Reference:

JCLP 6718

To appear in:

Journal of Cleaner Production

Received Date: 29 September 2015 Revised Date:

3 February 2016

Accepted Date: 5 February 2016

Please cite this article as: Dung Thi NB, Lin C-Y, Kumar G, Waste-to-wealth for valorization of food waste to hydrogen and methane towards creating a sustainable ideal source of bioenergy, Journal of Cleaner Production (2016), doi: 10.1016/j.jclepro.2016.02.034. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

AC C

EP

TE D

M AN U

SC

RI PT

ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT

Waste-to-wealth for valorization of food waste to hydrogen and methane towards creating a sustainable ideal source of bioenergy

Faculty of Environment and Labour Safety, Ton Duc Thang University, Ho Chi Minh City, Vietnam

c

Green Energy Technologies, Ton Duc Thang University, Ho Chi Minh City, Vietnam

SC

b

Green Energy Development Center, Feng Chia University, Taichung, Taiwan

d

Center for Materials Cycles and Waste Management Research, National Institute for Environmental

M AN U

a

RI PT

Ngoc Bao Dung Thia*, Chiu-Yue Linb,c*, Gopalakrishnan Kumard

*Corresponding authors:

TE D

Studies, Tsukuba, Japan

Ngoc Bao Dung Thi; Tel: +84-906905901; Fax: +84 08 37755055;

EP

E-mail address: [email protected]

AC C

Chiu-Yue Lin, Tel: +886-4-24517250 ext. 6200; Fax: +886-4-35072114; E-mail address: [email protected]; [email protected]

1

ACCEPTED MANUSCRIPT

Anaerobic Digestion

ABR

Anaerobic Baffled Reactors

ASBR

Anaerobic Sequencing Batch Reactors

AEBIOM

European Biomass Association

CSTR

Continuously-Stirred Tank Reactors

FW

Food Waste

GWh

Gigawatt-hour

KWh

Kilowatt-hour

HHV

Higher Heating Values

HPR

Hydrogen Production Rate

HRT

Hydraulic Retention Time

MJ

Megajoules

MPR

Methane Production Rate

NG

Natural Gas

NTP

Normal Temperature and Pressure

OLR

Organic Loading Rate

M AN U

TE D

EP

AC C

SCR

SC

AD

RI PT

Nomenclatures

Semi-Continuous Reactors

SWOT

Strengths – Weaknesses – Opportunities – Threats

TWh

Tegawatt-hour

UASB

Upflow Anaerobic Sludge Blanket

2

ACCEPTED MANUSCRIPT Abstract This review provides the insights for the conversion of food waste (FW) to electricity and heat energy and also to use FW as a source of bioenergy. The evaluations of bioenergy from

RI PT

FW conversion to commercially fulfill the energy demands of various nations were elucidated. Five countries attained the highest heating values from annual FW were: Canada4915 MJ/capita, the Netherlands-3367 MJ/capita, the United Kingdom-1497 MJ/capita,

SC

Japan-1608 MJ/capita, and Sweden-1278 MJ/capita. It is also shown that some countries

M AN U

could derive electricity from annual FW production and contribute a high percentage of total national electricity generation, such as the Netherlands-2.9% (164.4 KWh/capita), Canada1.35% (240 KWh/capita), Japan-0.92% (78.5 KWh/capita), the United Kingdom-1.31% (73.1 KWh/capita), and Ireland-1.23% (68 KWh/capita). Moreover, an analysis of Strengths –

TE D

Weaknesses – Opportunities – Threats (SWOT) was used to assess three forms of FW biotreatment processes including composting, anaerobic digestion, fermentation for bio-hythane gas, and thereby illustrating future directions in the development of fermenting FW to

EP

hydrogen and methane. The SWOT analysis indicates that the fermentative hydrogen and

AC C

methane production was a promising option for commercializing FW into bioenergy. However, there is also a need to implement specific prevailing policies and regulations to stimulate this environment-friendly form of bioenergy production technology. Based on the above considerations, a conceptual model to develop the FW fermentation of bioenergy production was suggested. Key words: Bioenergy, Electricity, Heat, Hydrogen, Methane, SWOT analysis

3

ACCEPTED MANUSCRIPT 1. Introduction: Fermentation of gaseous fuels and food waste as energy source Bioenergy production by fermentation reaction is gaining attraction due to its easy operation and wide selection of organic wastes feedstock. Anaerobic fermentation of organics

RI PT

is a major cost-effective and matured technology, which has dual benefits as waste treatment and simultaneous energy production (Gopalakrishnan et al., 2015; Lin et al., 2012). Generation of gaseous fuels such as hydrogen (H2) and methane (CH4) gases is of more

SC

importance, since they have many direct applications as fuels in the automobile industries.

M AN U

Additionally, gaseous fuels bear high energy than those of liquid fuels. Besides, they could be converted to heat and electricity in many industries and used by the industry themselves to heat the boiler and machineries (Saidura et al., 2011). Here food waste (FW), an abundant organic matter has been focused as an energy resource with respect to heat and electricity

TE D

generation which is enlightened in further sections.

There were few reviews investigating FW valorization for some specific bioproducts such as biogas, biomaterial, biochemicals and biofuels (Sen et al., 2016). Besides, some studies

EP

worked on analyzing process parameters involved in FW to bioenergy production by various

AC C

biotechnologies, analyses of the co-digest FW with other feedstock for bioenergy generation, and methodology review for solution model of hybrid energy from recycling FW. However, there has no report considering energy recovery evaluation in terms of heat and electricity generation through fermentative processes using FW feedstock. FW is currently being raised as a global issue that is related to greenhouse gas emissions. It is estimated that each tonne of FW could generate 3.8 tonnes of carbon dioxide equivalent (eCO2) (Peter et al., 2010). The United Kingdom was given here as an example to show the greenhouse gas emission

4

ACCEPTED MANUSCRIPT situation. The FW generation in the United Kingdom is reported to be approximately 15 million tonnes which composes about 3% of domestic greenhouse gas emissions in the United Kingdom (Maaike, 2014). In addition, when FW is buried at landfills, its energy

RI PT

content is lost if not collected for use. The FW could be biologically converted into biogas for electricity or heat utilization. Theoretically, one tonne of FW could be converted into 847 KWh of electricity and 89.78 GJ of heating potential. If all Australian FW is treated by

SC

anaerobic digestion, it could generate 1915 GWh of electricity contributing to 3.5% of the

M AN U

total current energy supply from renewable sources (Lou et al., 2013).

In European countries, FW at consumer levels shares the largest amount, or 42% of the total food wastage in the whole food supply chain expected to rise to about 126 million tonnes by 2020 (Ivana, 2014). In Asian countries, the FW problem is also expected to

TE D

increase in the next 25 years while corresponding to economic development, population growth, and urbanization. Fig. 1 shows global food wastage in consumption phase (retailers and consumers) according to the regions reported by Gustavsson et al. (2011). Currently, over

EP

one third of globally produced food is disposed into landfill sites as waste, while ironically,

AC C

there are 868 million people who still suffer by starvation and malnutrition (Bond et al., 2013). Therefore, one must keep in mind that the FW issue is not only associated with social, economic, environmental aspects, but it is also an ethical problem, that needs to be seriously considered.

Few studies investigated the current status and future trends in FW valorization for the production of chemicals, materials and fuels (Carol et al., 2014; Daniel and Carol, 2013). Some other studies have focused on specific by-products, such as anaerobic digestion for

5

ACCEPTED MANUSCRIPT biogas production (Cunsheng et al., 2014), utilization of FW for hydrogen production under hydrothermal gasification (Rattana, 2013), FW and food processing waste for biohydrogen production (Gioannis et al., 2013; Nazlina et al., 2013), the production and applications of

RI PT

waste-derived volatile fatty acids (Lee et al., 2014), and the comparison of energy recoveries between one-stage and two-stage anaerobic digestion (Schievano et al., 2014). The most relevant study on FW to bioenergy via biotechnological conversion processes was conducted

SC

by Sen et al. (2016). They discussed the present available technologies, types of reactors and various process parameters involved in FW to bioenergy production, FW co-digestion with

M AN U

various substrates, and reviewing the available microbiomes in FW. Meanwhile, Emec et al. (2015) used hybrid energy and water generation to process agricultural products and to recycle organics such as FW (Emec et al., 2015).

TE D

However, there was no review or study considering energy recovery evaluation in terms of heat and electricity generation through fermentative processes and using FW as a specific biomass feedstock. Energy depletion is presently noted as a critical issue from the national to

EP

global levels. In the literature, bioenergy conversion from biomass is a sustainable renewable

AC C

energy solution that attracts a great deal of hope. Hence, converting FW into bioenergy is expected to become a considerable energy source in the future (Gold and Seuring, 2011). This current work mainly reviews and assesses the potential of the FW to bioenergy conversion in terms of heat and electricity generation. Besides, various biotechnological approaches for the valorization of FW to energy are also mentioned. In addition, a strengthweakness-opportunity-threaten (SWOT) analysis has been conducted to provide a clear insight into the strengths and weaknesses of converting the FW into bioenergy. Lastly, future

6

ACCEPTED MANUSCRIPT directions are determined to clarify the appropriate use of FW based on different forms of FW treatment biotechnology.

RI PT

2. Fermentation of food waste for hydrogen production The abundant organic fraction of the FW could be converted to hydrogen via various biotechnological processes, such as one-stage (H2) fermentation, two-stage (H2 + CH4)

SC

fermentation, dark-fermentation combined with anaerobic digestion, and photo-fermentation

M AN U

combined with anaerobic digestion. Table 1 presents the typical characteristics of FW across the globe. Depending on the typical characteristics of FW-based regions, relative biotreatment should be handled for each region. Hydrogen is used as a compressed gas with a high energy yield (142.35 kJ/g). In the literature, hydrogen fermentation from the FW is

TE D

limited by various factors. For example, H2 production yield depends on some influencing factors, such as co-substrate, pre-treatment, operating pH, control of initial cultivation pH and fermentation temperature (Gioannis et al., 2013). In general, as per the survey results, the FW

EP

rich in carbohydrate is suitable for H2 fermentation (Esra et al., 2014).

AC C

Table 2 reviews the case studies of batch and continuous H2 fermentations of FW using diverse forms of inoculum, such as cattle dung, compost, anaerobic sludge, and sewage sludge. Besides, a common pre-treatment method for seed sources towards hydrogen production is heat treatment, which has been applied to terminate methanogens (80-100oC for 15 to 30 minutes). There are many reports on hydrogen yield in dark fermentation of the FW. In a batch scale, there is a high H2 production yield of 5.4 mol H2/mol hexoseadded (Zong et al., 2009); in 7

ACCEPTED MANUSCRIPT the case of a lab-scale reactors, 4.9 mol H2/mol hexoseadded had been reported (Tawfik et al., 2011). The energy yield conversions from H2 production found in their studies were estimated to be 1724 KWh/tonne FW and 1564 KWh/tonne FW, respectively. However, in a

RI PT

full scale plant, H2 production significantly reduced to 0.5 mol H2/mol hexoseadded (Kim et al., 2010) with an energy conversion efficiency of 2.3% for the FW to H2; this resulted in a total energy yield of 12.5 KWh/tonne FW. Some pilot scale studies reported the H2 yields being

SC

0.29 m3/kg VSadded (Han and Shin, 2004) and 2.1 mmol H2/g COD (Wang et al., 2010).

M AN U

However, the efficiencies of H2 yield between lab and continuous reactors/pilot scale might be different. The total energy conversion by fermenting FW for H2 was also predicted at a low rate due to the fluctuations in H2 production, purification, storage, distribution and conversion efficiency (Esra et al., 2014). In addition, some important indicators leading to

TE D

optimize hydrogen yield such as biomolecule, hydraulic retention time (HRT), reactor type, pH and temperature. Besides, in practical application of fermenting FW for H2, some critical problems might be faced such as substrate loading shock, which might result in marked

EP

acidogenesis (Mohammadi et al., 2011; Sen et al., 2016).

AC C

Additionally, there are some other key technological challenges which still exist in dark fermentation systems, such as inocula pretreatment, process design and purification (Bakonyi et al., 2013, 2014a, 2014b). Based on these reports, the process of FW to bio-hydrogen via dark-

fermentation has the characteristics that hydrogen yield and energy conversion are reactorconfiguration-dependent.

8

ACCEPTED MANUSCRIPT 3. Fermentation of food waste for methane production The physical and chemical characteristics of FW, technical configuration, and the pretreatment process are the key factors of fermentation for methane (CH4) production

RI PT

(Cunsheng et al., 2014; Molino et al., 2013). Table 3 reviews the studies pertaining to fermenting FW for methane. The fermentation could be operated under mesophilic and thermophilic conditions. However, methane contents and yields obtained at thermophilic

SC

operation was higher than that of mesophilic operation (Liu et al., 2009).

M AN U

One-stage or one-phase process for methane production is well used than two-stage in full scale applications (Hartmann and Ahring, 2006). A two-stage system comprises of a hyperthermophilic reactor for hydrogen and another mesophilic, thermophilic or hyperthermophilic reactor for methane. However, two-phase anaerobic digestion is reported

TE D

to achieve higher overall degradation efficiency and is more advantageous than one-stage system in treating FW for bioenergy (Elbeshbishy and Nakhla, 2011).

EP

In a lab scale operation, one-stage process for methane provided a lower methane yield (364 mL CH4/g VS) (Pisutpaisal et al., 2014) than two-phase process (472 mL CH4/g VS)

AC C

(Jae et al., 1995) or anaerobic digestion (518 mL CH4/g VS) (Liu et al., 2009), whereas, the methane yield of a full scale anaerobic digestion (AD) plant could provide around 402 m3/tonne VS (net energy conversion 405 KWh/tonne FW) (Charles et al., 2010). A high methane yield of 464 mL CH4/g VS was obtained from continuous operation (Chu et al., 2008). Methane could be converted to electricity of 750 KWh/tonne FW according to the following Equation 1 (Gary and Jenkins, 2007): 


 = . .  .  . η 9

(1)

ACCEPTED MANUSCRIPT Where: − EAD (KWh): Electric bioenergy potential − CH4 (m3): The volume of CH4 (in NTP)

RI PT

− QCH4 = 36.4 MJ/m3: Volumetric heating value of CH4 − ηe (unitless): Engine generator efficiency of biogas (30-40%). Average value ηe= 35% (IDAE, 1994)

SC

Mitsubishi Heavy Industries has the world’s first full scale methane fermentation plant (capacity 52 tonne FW/day) to sell electric power (Youichi et al., 2007). It was one-stage

M AN U

methane fermentation for FW with an energy yield of 205 m3/tonne FW (equivalent to 383 KWh/tonne FW). Meanwhile, some large scale FW treatment facilities (7000 – 15,000 tonne FW/day) using AD technology in the US and Canada were observed to produce 220

TE D

KWh/tonne FW (Seldman, 2010).

EP

4. Fermentation of food waste for bio-hythane production Bio-hythane is a mixed biogas comprising hydrogen, methane and carbon dioxide with an

AC C

average composition of 10% H2, 30% CO2 and 60% CH4 (Cavinato et al., 2011). Bio-hythane is expected to bring economic benefits as a future energy resource, mainly since the direct use of this mixture together with the existing vehicle engines and have been commercialized as vehicle fuels in the US and India (Fulton et al., 2010). Bio-hythane is produced using biological processes of AD and dark-fermentation to convert biomass/bio-waste (Liu et al., 2013). Many studies have evaluated the possibility of producing bio-hythane from FW, such as one-stage AD, two-stage AD, and photo-fermentation combined with AD. Some studies

10

ACCEPTED MANUSCRIPT were conducted with dark-fermentation coupling with AD (Cavinato et al., 2012), a twophase thermophilic AD for bio-hythane production (Micolucci et al., 2014), thermophilic two-stage fermentation (Lee et al., 2010), two-phase hydrogen/methane fermentation (Lee

RI PT

and Chung, 2010), and AD of the FW with wastewater sludge (Chu et al., 2008). Table 4 presents some studies of batch and continuous bio-hythane fermentation.

Two-stage process of thermophilic H2 fermentation and mesophilic CH4 fermentation

SC

provided a H2 yield of 2.4 mol H2/mol hexoseadded and 0.24 L/g VS (CH4 content 65-68.8%)

M AN U

(Youn and Shin, 2005). Its total net energy was approximately 826 MJ/tonne FW, where the energy content in FW was converted to H2 (9.3%) and CH4 (70.5%). A three-stage process of lactate fermentation (2.5 L reactor) combined with photo-fermentation for H2 (50 mL reactor) and AD for CH4 (100 mL reactor) provided a high electrical energy yield of 1146 MJ/tonne

TE D

FW, where energy content in FW was converted to H2 (41%) and CH4 (37%), respectively (Kim and Kim, 2012). A pilot scale study using a semi-continuous reactor (SCR) with a 40 L working volume of H2 and CH4 fermentors had an electrical energy yield of 850 MJ/tonne

EP

FW based on the energy content from H2 (5.2%) and CH4 (82%) (Lee et al., 2010).

AC C

In comparison with two- or three-stage anaerobic processes for H2 and CH4 productions, the possibility of generating bio-hythane is expected to obtain a higher yield of electrical energy. Case studies by Cavinato et al. (2012) and Micolucci et al. (2014) were conducted with dark-fermentation coupled with AD, which had achieved a high net energy conversion from FW. The energy conversion obtained by Cavinato et al. (2012) was 404 KWh/tonne FW with a H2 yield of 66.7 L/kg TVSadded during the first phase and CH4 yield of 0.72 m3/kgTVSadded in the second phase. Its bio-hythane composition of the whole process was CH4 58%, H2 6.9% and CO2 36%. Micolucci et al. (2014) obtained a biogas yield of 0.69 11

ACCEPTED MANUSCRIPT m3/kgTVSadded and a bio-hythane composition of H2 7%, CH4 58% and CO2 35%. The results of electrical energy from this pilot scale study illustrated that bio-hythane has promising expectations in the energy sector. However, this bioconversion technology should be shown

RI PT

as being commercialization-feasible to implement energy/electricity extraction from the FW. 5. Energy evaluations

SC

Theoretically, FW has a sustainable higher heating gross and net value (HHV) of 6.4 MJ/kg (Faaij et al., 1997) and could be used as a vital fuel. Therefore, a calculation of FW

M AN U

HHV should be taken into consideration to promote FW recycling activities in many countries. Fig. 2 shows the estimation of the HHV per capita from annual FW amount in some countries, and the evaluation of potential heating from FW are available when compared to the national statistical natural gas consumption in these countries. The top five

TE D

countries that could attain a high amount of heat conversion from annual FW were Canada4915 MJ/capita, the Netherlands-3367 MJ/capita, the United Kingdom-1497 MJ/capita, Japan-1608 MJ/capita, and Sweden-1278 MJ/capita. The reason could be explained as that

EP

these countries have not only high need in using natural gas, but also have low population. It

AC C

elucidates that using the FW for generating energy should be critically considered as a main natural gas source in those developed countries with high demand of natural gas. Remarkably, the heat conversions from the FW have demonstrated that biogas could share as a vital part of national natural gas use. This is the case in the following examples: 38% of natural gas use in South Africa, 29% in Sweden, 23% in India, 20% in China and 14% in Brazil (Bob, 2014). However, in fact, the conversion efficiency of heat energy into electrical energy does not exceed 40% due to technical and physical factors (Miyamoto, 12

ACCEPTED MANUSCRIPT 2009). Therefore, in real practice of FW conversion from heat to electricity will not reach 100% of efficiencies depending on the devices employed. Table 5 summarizes energy values according to the electricity production by applying

RI PT

various biological processes for converting FW. There are several units presenting energy conversion efficiency from FW, such as mol H2/mol hexoseadded, m3/tonne FW, mL/g CODadded, L/kg TVSadded, m3/tonne VS (to perform biogas yield per feedstock), and

SC

KWh/tonne FW, MJ/tonne FW (to perform electricity generation per feedstock). This study

M AN U

mostly used kWh/tonne of FW to describe electricity yield and compare its efficiency from various fermentation methods using FW as the main feedstock. However, it is not easy to conclude which fermentation technology is the best one. These technologies are needed to be researched in large scale application or commercial practice. Current studies also show that

TE D

fermenting FW for hydrogen production still exists a huge energy yield variation between the lab scale (1724 KWh/tonne FW) and pilot scale (12.5 KWh/tonne FW). However, commercializing energy-based hydrogen fermentation from FW has to consider some

EP

problems of inoculums, operation parameters, and low energy conversion from hydrogen to

AC C

electricity. Therefore, this process was usually combined with other processing stages, such as a methanogenic phase or AD to optimize total energy conversion yields (Gioannis et al., 2013). The best result in FW conversion to energy was a case study by Chu et al. (2008), where energy recovery of a hydrogen reactor attained 139,333 kcal/tonne FW (equivalent 30 KWh/tonne FW with energy conversion from hydrogen is about 18.5%), and the energy recovery of a methane reactor was 1,722,925 kcal/tonne FW (equivalent 750 KWh//tonne FW with energy conversion from methane is about 37.4%). This indicates that a two-stage process combining thermophilic hydrogen production and mesophilic methane production 13

ACCEPTED MANUSCRIPT was a suitable process for producing hydrogen and methane in a feasible manner (Chu et al., 2008; Schievano et al., 2014). From the viewpoint of a practical scenario, AD was proven as the best and most

RI PT

economic method in commercializing FW conversion to electricity (Christian and Dübendorf, 2007; Thi et al., 2015). This was due to there being mature technology and known skills. This process could work alone as a single process or combining with a fermentation process to

SC

enhance biogas yield. The potential electricity based on the energy yield of FW treatment

M AN U

regarding AD facilities in the United States, Canada and the United Kingdom was 405 KWh/tonne FW for a hundred to a thousand tonnes of FW per year of treatment capacity (Charles et al., 2010), and 220 KWh/tonne FW for a hundred thousand tonnes of FW per year treatment capacity (Seldman, 2010). In the present study, the electricity generation value for

TE D

each tonne of FW is an average of these two values, or 313 KWh/tonne FW. Table 6 presents the computation of FW potential to electricity in some countries. According to the computations, the top five countries having high potential of electricity from annual FW

EP

production per capita were the Netherlands-164.4 KWh/capita, Canada-240 KWh/capita,

AC C

Japan-78.5 KWh/capita, the United Kingdom-73.1 KWh/capita, and Ireland-68 KWh/capita. Meanwhile, in considering electricity composing the national electricity consumptions in each country, five countries, including Brazil, India, the Netherlands, Thailand, and Vietnam, could expect to convert their FW to electricity with sharing 1.88%, 2.04%, 2.90%, 1.77%, and 1.38%, respectively, of national electricity. This is surprising, but the results critically indicate the generation of energy wealth from utilizing FW. Consequently, instead of landfilling FW and losing valuable bioenergy sources, it is the time for action to valorize FW towards H2 and CH4 bioenergy. 14

ACCEPTED MANUSCRIPT Generally, pre-treatment of the organic biomass would increase more cost to the overall process and make it not so economically viable. Some pre-treatment methods, conditions and possible issues were reviewed recently (Kondusamy and Kalamdhad, 2014) with highlighting

RI PT

thermal, ozonation, acid/alkali and biological treatments. Cost-effective pre-treatments such as thermal, acid/alkali treatment has been done previously (Kim et al., 2006; Kim and Shin, 2008; Kondusamy and Kalamdhad, 2014), however, enzymatic hydrolysis are quite

SC

expensive while considering the pilot scale operations, since it adds extra 20-30% equivalent cost to the whole process. Thus, developing some strategies such as thermal treatment or

M AN U

lactic acid fermentation could be of the future direction along with the energy extraction from FW (Kimet al., 2012).

TE D

6. Outlooks and future recommendations

Recently, biofuel production and their utilization are increasing tremendously due to the

EP

public awareness created by the organizations with regard to the pollution and climate change issues. However, the technologies for using it as fuels in vehicles are at infant stage which

AC C

needs further developments towards creating a sustainable community in the future. Bioenergy from FW would be a feasible solution to meet the energy demand of the world due to rapid industrialization. Utilizing FW for the formation of gaseous fuels of H2 and CH4 has a great value in terms of economic and environmental profits. According to different consumption behaviors, eating habits and economic levels, FW composition varies from region to region and people to people, while the major components of diet include rice, vegetables, fresh fruit/salads, meat/fish, eggs/dairy, baked goods and 15

ACCEPTED MANUSCRIPT other materials (Julian et al., 2014). The FW in African and Asian countries usually contain high amounts of carbohydrates due to their major consumption of rice in meals, while the FW in European countries contains more milk/meat, vegetable/salads, and baked goods (WRAP,

RI PT

2009). This fact resulted in high concentrations of total solid (TS), volatile solid (VS) and total COD contents in the FW. On the other hand, in a typical vegetarian country such as Turkey, fresh fruits and vegetables account for the highest proportions in Turkish FW

SC

(Pekcan et al., 2006). Meanwhile, in the US and Canada, the FW has a high composition of dairy/eggs and meat/fish, fruit and vegetable/salads, which resulted in high amounts of oil

M AN U

and grease (from dairy/eggs), protein (from meat/fish) and acetate (from fruits and vegetables) (Jones, 2006).

In addition, specific cases by country might be experienced (Table 1). Some countries,

TE D

such as Taiwan, have FW containing very high amounts of TS, VS, total COD, ammonia, and oil. The high oil usage in cooking culture and famous milk tea production could be considered as the reasons leading to high amounts of oil, TS, VS, and total COD in the

EP

Taiwanese FW. Fig. 3 illustrates the suggestion of FW characteristics based on suitable

AC C

biotechnology processes. Food wastes having high amounts of carbohydrates are suitable for H2 production and then CH4 production via a two-stage fermentation process. Besides, FW with the high carbohydrate also could be directly used for heat conversion. If FW feedstock has more fat or protein contents, it should be directly used to produce CH4 via a single stage fermentation process. For the FW having high amounts of TS or COD, an AD process is more suitable, and the by-products would be biogas and digestate.

16

ACCEPTED MANUSCRIPT Fig. 4 depicts a conceptual model to develop the FW fermentation of bioenergy production. This integrative system is based on the scheme of developing “zero waste” principles (Song et al., 2014). This system combines three particular processes, including

RI PT

project development, technology operation (project running), and product marketing development. These are detailed as follows.

The future recommendations could be categorized into three steps. At first, project scopes

SC

and goal are required to set the clear objectives and stakeholders relative to the project. The

M AN U

next step is to assess FW stream valorization and infrastructure. This step is essential to stabilize a purified FW feedstock into the project. Subsequently, a project could be launched with specific benchmarks, such as environmental, technological, economic benefits, and social affection as efficient evaluation indicators for the project. These review, implement,

TE D

and repeat project stages are necessary as the final steps for a project development process. Secondly, an in-depth explanation of a technology operation is demonstrated. It shows a stepwise FW fermentation via combining dark-fermentation, photo-fermentation, and AD

EP

technology. Among the whole process, inoculum collection and pretreatment are essential to

AC C

enhance the main process as efficient as possible. Product pre-treatment for efficient biogas production and giving a separator for digestate are also needed to improve both the quality and quantity of the final bio-products. H2 and CH4 could be indirectly converted into electricity, or be directly used as a heating gas, and soil amendment for agriculture or forestry use. Finally, marketing development is focused. The success of product market is reflected in a consistent systematic collaboration between the policy makers, manufacturers, and 17

ACCEPTED MANUSCRIPT customers. The successful results are ordinarily evaluated by customer consumption, and therefore some quality certification for standardizing raw materials and final products, such

RI PT

as eco-label, clean production, and ISO 9000 could be referred to for project application.

7. Strengths–Weaknesses–Opportunities–Threats (SWOT) analysis for feasibility of

SC

food waste to electricity

SWOT analysis is credited to Albert S. Humphrey as a management consulting method,

M AN U

which is defined as “A structured planning method used to evaluate the strengths, weaknesses, opportunities, and threats involved in a project or in a business venture.” (Albert, 2005) There have been certain studies using a SWOT analysis for an environmental management aspect such as “Utilisation options for biodegradable kitchen waste in Estonia.

TE D

SWOT analysis” (Viktoria B., 2014), “Low Cost Zero Waste Municipality, Phase 4.1. Transnational SWOT Analysis on waste management concepts” (European Commission,

2013).

EP

2009), and “Waste to Energy Background Paper - Zero Waste South Australia” (Kathryn,

AC C

When evaluating bioenergy production from the FW feedstock, a system/plan should consider some major components, such as the FW feedstock resource, FW supply system, conversion technology use, and energy services (McCormick and Kaberger, 2007). Since these considerations are important for the investment of bioenergy production from the FW feedstock, hence using a business venture method, such as SWOT analysis, is suitable for this study.

18

ACCEPTED MANUSCRIPT Besides, a SWOT analysis could help manufacturers and managers to understand many forms of biotechnology relating to FW treatment and their feasible benefits (environmental, economic, and technical aspects). Table 7 presents the SWOT analysis of three specific bio-

RI PT

treatments on FW, including composting, AD, and fermentation for producing H2 + CH4. In the view of electricity producers or manufacturers, the best productive method is an ideal investment that is the most attractive to them. In addition, this facilitates considerable

SC

factors relating to the decision making of a producer for a technology investment. In this

M AN U

aspect, fermentation for H2 + CH4 proved that it could yield high amounts of electricity and reduce electricity production costs (Cavinato et al., 2012; Chu et al., 2008). Moreover, in the view of environmental management, the lowest environmentally affected technology is preferred over the higher affected one, and therefore, FW fermentation for H2 and CH4

TE D

production with a lower carbon emission rate of 0.052 tonne eCO2/tonne FW is considered to acquire higher environmental benefits in comparison to composting (0.22 tonne eCO2/tonne FW) and landfill FW for biogas (0.364 tonne eCO2/tonne FW) (Jeffrey, 2007).

EP

However, in the view of governmental policymakers, the current forms of legislation in

AC C

many developed countries are incomplete to support the development of commercializing FW treatment via fermentation for H2 + CH4 (Gold and Seuring, 2011). In developing countries, the weaknesses are applying segregation, collection, and transportation of FW due to the incomplete FW management system. Those issues strongly affect the efficiency of a FW management system (Thi et al., 2015). Moreover, incomplete mechanism and government initiatives could create difficulties in initiating commercial applications of FW to energy-based fermentative technologies (Bettina et al., 2013). Moreover, although bioenergy

19

ACCEPTED MANUSCRIPT is an ideal balancing power, bioenergy from FW conversion is also a challenge in integrating renewable energy in an electricity grid. The current grid electricity connection for commercially-utilizing bioenergy from FW has not yet been broadly upgraded. Therefore,

RI PT

this issue could mitigate the approaching motivation for converting FW into bioenergy (AEBIOM, 2012).

The SWOT analysis indicates that the fermentation of FW to produce H2 + CH4 is

SC

promising and can bring economic benefits. However, countries need to have adequate

M AN U

prevailing policies and regulations to stimulate FW conversion to bioenergy. Moreover, for commercial applications of bio-refinery forms technology on FW to produce energy, countries also have to deal with some other constraints, such as high costs in technology development and infrastructure. Assuming countries handle these issues well, it could be

source.

TE D

highlighted that the valorization of FW towards H2 and CH4 production is a promising energy

Recently, there is a shift from non-renewable energy sources to renewable energy carriers

EP

which are green and sustainable. In this context bio-hydrogen, bio-methane and bio-hythane

AC C

production from FW via AD could be a feasible technology towards scale-up and commercialization. A recent review by Sen et al. (2016) covered many engineering and microbial aspects of FW conversion via AD process. In that study, authors have covered the aspects of reactor types, HRT, organic loading rate, pH, temperature regimes, microbes, codigestion possibilities and ended up with a future concept of commercialization. Thus, in this study, SWOT analysis towards the possibilities and overcoming strategies are discussed. Scaling-up FW to bioenergy production technology has some constraints especially regards

20

ACCEPTED MANUSCRIPT to cost and energy efficiency (Sen et al., 2016). Besides, applying bio-refinery concept could benefit the overall value of FW to energy production systems along with generating bio-

RI PT

products, enzyme, commercial commodities and algal cultivation systems (Sen et al, 2016).

8. Conclusions

This work provides a conceptual framework for approaching bioenergy from food waste

SC

via fermentation biotechnologies. The evaluation of bioenergy from food waste and the

M AN U

SWOT analysis were elucidated with covering the appropriation of approach-based bioenergy technologies for valorizing food waste and improving the eco-efficient conception on food waste management. It is demonstrated that the more environmentally friendly technology more greatly benefit food waste treatment, indicating the perspective of sustainable

TE D

development for food waste management. The blossom of food waste treatment biotechnologies can shorten the pathway of from “waste” to “wealth.” SWOT analyses for different biotechnological conversion processes revealed that the future trend of food waste

EP

valorization by hydrogen and methane fermentation is very promising. The outlooks of

AC C

utilisation food waste for bioenergy production were concluded as followings. The food waste having high amounts of carbohydrates is appropriate for producing hydrogen and methane via a two-stage fermentation process; the food waste containing high composition of protein and fat is suitable for producing methane via a single stage fermentation process. Ultimately, a conceptual model to commercialize the food waste fermentation of bioenergy production was suggested to promote some countries to have a sustainable food waste management and bioenergy production.

21

ACCEPTED MANUSCRIPT Acknowledgements The authors gratefully acknowledge the financial supports provided by Ton Duc Thang University and Feng Chia University. Gopalakrishnan Kumar particularly wishes to thank the

RI PT

Japanese Society for the Promotion of Science (JSPS ID 26-04209 and JSPS ID 25740056)

AC C

EP

TE D

M AN U

SC

for its financial support for this study.

22

ACCEPTED MANUSCRIPT Table 1. Characteristics of food waste across the globe. Parameters

Unit

Value Asia/ Malaysia(1)

Asia/ Taiwan(2)

America/ Canada(3)

Europe/ Egypt(4)

-

6.2

4.5 ± 0.2

6 ± 0.2

6.5

Total solids (TS)

g TS/L

255

266 ± 68

66.9 ± 2.2

61 ± 32

Volatile solids (VS)

g VS/L

-

256 ± 66

47 ± 1.1

56 ± 33

Suspended solids (SS)

g/L

-

212 ± 46

-

-

Volatile suspended solids (VSS)

g/L

-

206 ± 45

-

-

Total COD

g/L

-

346 ± 81

106.7 ± 2.8

64 ± 24

Soluble COD

g/L

-

152 ± 31

39.3 ± 2.3

32 ± 1

Total carbohydrate

g/L

-

143 ± 50

36.5 ± 1.2

-

Soluble carbohydrate

g/L

-

68 ± 31

5.5 ± 0.4

-

Total organic nitrogen

gN/L

-

5.5 ± 2.7

3.4 ± 0.4

-

Soluble organic nitrogen

gN/L

-

1.2 ± 0.6

-

-

Ammonia

mgNH4-N/L 0.2

69 ± 49

-

-

Oil and grease

g/L

25.7

24 ± 11

-

9.4 ± 11.9

g/L

-

8 ± 2.9

-

-

g/L

-

1.9 ± 1

4.3 ± 0.1

2.7 ± 1.3

g/L

27.8

-

SC

M AN U

TE D

Protein

EP

Acetate

(1) (Ismail et al., 2009); (2) (Wang et al., 2010); (3) (Zhou et al., 2013); (4) (Tawfik et al., 2011).

AC C

Lactate

RI PT

pH

23

7.3 ± 12.2

ACCEPTED MANUSCRIPT

OLR

Temperature (oC)

pH

Hydrogen yield

Cattle dung compost Anaerobic wastewater sludge

165a ABR-1: HRT 26 h, OLR 58b ABR-2: HRT 26 h, OLR 35b

35 26

5.6 5.06.0

5.4e 4.9e

1724k 1564k

(Zong et al., 2009) (Tawfik et al., 2011)

POME sludge

NR

55.7

7.5

120f

NR

(Ismail et al., 2009)

Granular sludge and suspended sludge

4c

37

6.5

154.8g

NR

(Danko et al., 2008)

Clostridium beijerinckii KCTC 1785

50c

40

7.0

1.12e

NR

(Kim et al., 2008)

Mesophilic acidogenic culture

6d

35

5.5

0.6-0.9e

NR

(Shin et al., 2004)

Thermophilic acidogenic culture 6d

55

5.5

1.8e

NR

(Shin et al., 2004)

37

6.7

0.33h

(Han and Shin, 2004)

EP

Table 2. Batch and continuous hydrogen fermentations from food waste. Inoculum used

Energy/electricity yield

References

(Kim et al., 2010) (Wang et al., 2010)

SC

M AN U

TE D

Continuous scale studies

RI PT

Batch scale studies

12.5d H2 reactor 50 L, CH4 reactor 50 L

Sewage sludge

ASBR working volume 150 L

35

5.3

0.5i

H2: 3.55l CH4: 1.83l Yield of H2: 0.29m Yield of CH4: 0.24m 12.5k

Mixed sludge

OLR: 39c

55

4.4

2.1j

2.2n

HRT: hydraulic retention time; OLR: organic loading rate; ABR: anaerobic bioreactor; ASBR: anaerobic sludge bed reactor. NR: not reported a: mL/L/h

3

b: kg COD/m /d c: g COD/L d: kg VS/m3/d e: mol H2/mol hexose f: mL H2/g carbonhydrate g: mL H2/g VSS h: L H2/h i: mol H2 mol/mol hexoseadded

AC C

Sewage sludge

24

(hexoseadded is the loading feedstock to feed reactor) j: mmol H2/g COD k: KWh/tonne FW l: m3/m3/d m: L/m3/kg VSadded n: L H2/L/d o: tonne FW/year p: mL CH4/g VS

q: mL/g VS r: m3/tonne FW s MJ/tonne FW t: mL/g CODadded u: L/kg TVSadded v: KWh/Nm3 w: kcal/tonne FW x: Nm3/d

ACCEPTED MANUSCRIPT

Table 3. Batch and continuous methane fermentations from food waste. OLR

Temperature (oC) pH

Methane yield

Energy yield

References

One-stage Methane fermentation

24c

NR

7

364.3 ± 7.4p

47k

(Pisutpaisal et al., 2014)

Two-phase anaerobic digestion

8c

37oC

NR

472p

NR

(Jae et al., 1995)

16

50 ± 2

7.3-7.6

518 Biogas yield: 784q

NR

(Liu et al., 2009)

Two-stage fermentation process

4.61d

40 ± 2

5-6

0.546 m

NR

(Wang and Zhao, 2009)

Anaerobic digestion

2.5d

42

8.13

CH4 yield: 98r Biogas yield: 156r (CH4 content 62.5% CO2 content 37.4%)

405k

(Charles et al., 2010)

Methane fermentation

NR

NR

NR

383k

(Youichi et al., 2007)

Anaerobic Digestion – East Bay Municipal Utility District One-stage fermentation

7000-15,000o

NR

NR

Biogas yield: 205r (CH4 content 60% CO2 content 40%). NR

220k

(Seldman, 2010)

12.8c

37

6.9-7.2

1.6n

NR

Two-stage anaerobic codigestion feedstock FW and the sewage sludge Two-phase process co-digested FW and sewage sludge

NR

35

522p

NR

(Elbeshbishy and Nakhla, 2011) (Zhu et al., 2011)

6.5±0.3 0.67m

NR

(Siddiqui et al., 2011)

l: m3/m3/d m: L/m3/kg VSadded n: L CH4/L/d o: tonne FW/year p: mL CH4/g VS q: mL/g VS r: m3/tonne FW

s MJ/tonne FW t: mL/g CODadded u: L/kg TVSadded v: KWh/Nm3 w: kcal/tonne FW x: Nm3/d

M AN U

TE D EP

No control

AC C

OLR: organic loading rate NR: not reported a: mL/L/h b: kg COD/m3 /d c: g COD/L d: kg VS/m3/d e: mol H2/mol hexose

1.59d

37±2

f: mL H2/g carbonhydrate g: mL H2/g VSS h: L H2/h i: mol H2 mol/mol hexoseadded (hexoseadded is the loading feedstock to feed reactor) j: mmol H2/g COD k: KWh/tonne FW

25

SC

Thermophilic digestion

d

Continuous scale studies

p

RI PT

Technique Batch scale studies

ACCEPTED MANUSCRIPT

Table 4. Batch and continuous hydrogen and methane fermentations from food waste. Temperature (oC)

pH

Biogas yield

Energy yield

References

Two-stage (H2 +CH4) dark fermentation

Stage 1: 35 ± 0.1 Stage 2: 55 ± 0.1

5.5 ± 0.1

H2 yield 2.4i CH4 yield 240p

Net energy 826s Energy content in FW convert to H2 (9.3%) and CH4 (70.5%)

(Youn and Shin, 2005)

Lactate fermentation combine with photo-fermentation, for H2 and AD for CH4

35 ± 0.1

Lactate: 7.0±0.1 H2: 5.0±0.1 CH4: 7.5±0.1

H2 yield 994t CH4 yield 308t

Electrical energy yield 1146s H2 (41%) and CH4 (37%)

(Kim et al., 2012)

55oC

First phase 5.7 ± 0.3 Second phase 8.4 ± 0.2

H2 yield: 66.7u CH4 yield: 720u (CH4 58%, H2 6.9%, CO2 36%)

404k

(Cavinato et al., 2012)

Two-phase thermophilic anaerobic digestion process

55oC

First phase 5.2 ± 0.2 Second phase 8.1 ± 0.1

Biogas yield 690u (7% H2, 58% CH4 and 35% CO2)

NR

(Micolucci et al., 2014)

Thermophilic two-stage fermentation Two-phase hydrogen/methane fermentation

55oC

No control

First phase 33±4 Second phase 36±4

First phase 5.3±0.2 Second phase 7.4±0.3

(Lee et al., 2010) (Lee and Chung, 2010)

Anaerobic wastewater sludge

55

5.5

Electrical energy yield 850s H2 (5.2%) and CH4 (82%) Energy densities of H2: 2.79v Energy densities of CH4: 11v Electricity potential of H2: 17.06k Electricity potential of CH4: 34.26k Energy from H2 reactor = 139,333w (equivalent 30k) Energy from CH4 reactor = 1,722,925w (equivalent 750k)

Technique

AD: anaerobic digestion NR: not reported a: mL/L/h b: kg COD/m3 /d c: g COD/L d: kg VS/m3/d

e: mol H2/mol hexose f: mL H2/g carbonhydrate g: mL H2/g VSS h: L H2/h i: mol H2 mol/mol hexoseadded (hexoseadded is the loading feedstock to feed reactor) j: mmol H2/g COD

26

SC

M AN U

TE D

EP

AC C

Continuous scale studies Dark fermentation coupled with AD process

RI PT

Batch scale studies

H2 yield 11.1n (2.5e) CH4 yield 47.4n (287t) Total biogas: 2446x H2 yield: 1223x

100r (wet) (52–56% total biogas). 265r (wet) (72-80% total biogas)

k: KWh/tonne FW l: m3/m3/d m: L/m3/kg VSadded n: L H2/L/d o: tonne FW/year p: mL CH4/g VS q: mL/g VS

r: m3/tonne FW s MJ/tonne FW t: mL/g CODadded u: L/kg TVSadded v: KWh/Nm3 w: kcal/tonne FW x: Nm3/d

(Chu et al., 2008)

ACCEPTED MANUSCRIPT Table 5. A summary of energy production-based food waste by all biotechnology processes. Reactor style /Reactor scale

References

0.5a

12.5e

Anaerobic sequencing batch reactor (ASBR)/Pilot scale

(Kim et al., 2010)

Two stage fermentation for hydrogen

5.4a

1724e

Two-step process of sequential anaerobic (dark) and photo-heterotrophic fermentation/Batch scale

(Zong et al., 2009)

Two step anaerobic baffled reactors for hydrogen

4.9a

1564e

Two-step anaerobic baffled reactor (ABR)/Lab scale

(Tawfik et al., 2011)

One stage fermentation for methane

NR

383e

Methane fermentation/Full scale plant

Anaerobic digestion for methane

402g

220-405e

Anaerobic digestion/Full scale plants

(Charles et al., 2010; Seldman, 2010)

Two-stage process for hydrogen + methane

100b

H2: 30e

Pilot scale

265b

CH4: 750e

(Chu et al., 2008)

1146f (318e)

Pilot scale

1454f (404e)

Batch scale

(Kim et al., 2012) (Cavinato et al., 2012)

H2: 994c, CH4: 308c

H2: 66.7d , CH4: 720d

EP

− Photo-fermentation couple with AD − Dark-fermentation couple with AD

TE D

Two phase fermentation for hydrogen + methane

RI PT

One stage fermentation for hydrogen

Energy yield

SC

Biogas yield

M AN U

Biotechnology process

AC C

NR: not reported a: mol H2/mol hexoseadded (hexoseadded is the loading feedstock to feed reactor) b: m3/tonne FW c: mL/g CODadded (CODadded is the loading feedstock to feed reactor) d: L/kg TVSadded (TVSadded is the loading feedstock to feed reactor) e: KWh/tonne FW f: MJ/tonne FW g: m3/tonne VS

27

(Youichi et al., 2007)

ACCEPTED MANUSCRIPT Table 6. Potential of food waste to electricity in some countries. National energy consumption (TWh)a

Total potential electricity-based FW (TWh)

Electricity potential from FW conversion per capita (KWh/capita)

Sharing percentage in total national electricity generation (%)

Australia

244.8

0.71

30.5

0.29

Brazil

557

10.47

52.2

1.88

Canada

627

8.44

240.0

China

5362

60.94

44.9

Denmark

35

0.25

44.0

Germany

634

3.83

47.5

0.60

India

1103

22.49

18.0

2.04

Ireland

25

0.31

68.0

1.23

Japan

1088

10.00

78.5

0.92

The Netherlands

95

2.76

164.4

2.90

New Zealand

43

0.08

18.1

0.19

Singapore

48

0.25

46.1

0.52

South Africa

256

2.83

47.4

1.10

South Korea

535

1.95

38.8

0.36

Sweden

160

0.60

62.4

0.37

Taiwan

252

0.72

31.1

0.29

Thailand

165

2.91

44.4

1.77

The United Kingdom

357

4.69

73.1

1.31

AC C

EP

TE D

M AN U

SC

RI PT

Country

1.35

1.14

0.71

The United States

4260

19.02

60.2

0.45

Vietnam

130

1.79

20.0

1.38

a: Data were documented in the 63rd edition of the BP Statistical Review of World Energy (Bob, 2014).

28

ACCEPTED MANUSCRIPT

Table 7. Strengths–Weaknesses–Opportunities–Threats (SWOT) analysis and comparisons between three different processes. Anaerobic Digestion − Good method for reducing FW generation and environmental impacts (Viktoria B., 2014). − FW could be co-digested with other organic forms of feedstock to enhance quantity and quality of by-products (Baere and Mattheeuws, 2013). − The AD process could be a rapidly operating cycle, and biogas production could be directly used for heating or to convert energy. − AD is a fully accepted proven forms of technology for treating FW with a controlled process, controlled gas, odour, and wastewater emissions control (Viktoria B., 2014). − AD is a mature technology and has been applied worldwide (Lord and Gregory, 2011). − Composting is a slow process in − AD process requires a stable input and comparison with other forms of well-sorted FW, and therefore has high technology (Viktoria B., 2014). investment and operation costs (Viktoria B., 2014). − Some environmental impacts, such as rodents, insects, and odours could occur − Post-treatment process is needed to in composting facility (Viktoria B., 2014). improve quality of digestate. − The GHG emissions of composting is − The odour from the anaerobic process higher 4 times than recover FW for could occur in AD facility. energy (Jeffrey, 2007).

SC

M AN U

EP

AC C

Weaknesses

29

Fermentation for H2 + CH4 − Many prevailing conversion forms of technology have been developed, and are expected to hold a primary position in the biorefinery aspect (Bettina et al., 2013; George and Joe, 2014). − Potential for jobs and economic activities related to the recycling waste industry (Bettina et al., 2013). − Fermentation for H2 + CH4 fetches a high electricity yield, which promises to reduce electricity production costs (Cavinato et al., 2012; Chu et al., 2008). − This method is the lowest carbon emission FW treatment process in comparison with composting (0.22 tonne eCO2/tonne FW) and landfill FW for biogas (0.364 tonne eCO2/tonne FW) (Jeffrey, 2007).

RI PT

Composting − Lowest investments and operational costs compared to other processes (Jeffrey, 2007). − Composting provide fertilizer, considered to be environmentally friendly product (Jeffrey, 2007). − Many countries have specific forms of legislation to enforce composting FW for FW treatment.

TE D

SWOT Strengths

− The unpurified FW could influence to the quality of by-products (Bettina et al., 2013). − Commercial applications of FW to energybased biorefinery technologies inevitably have to deal with some constraints, such as high costs, lack of financial mechanism to support developing innovative forms of technology (Bettina et al., 2013).

ACCEPTED MANUSCRIPT

SC

M AN U

TE D

EP

AC C

Threats

− AD could help to reduce of FW generation and greenhouse gas emissions, and lead to sustainable management (Viktoria B., 2014). − AD could be combined with H2 fermentation to increase by-products and energy yield (Cavinato et al., 2012). − Biogas production can be injected to the natural gas grid after upgrading, and be commercialized in use as renewable energy, while the digestate can be used as soil fertilizer. − The lack of awareness among citizens − The process strictly depends on the stable may result in poor quality of source sorted and high-quality input material flow. FW and lead to poor quality composts − At present, there is still no legislation for (Viktoria B., 2014). the utilization for digestate from the AD − Lack of demand in a market for compost process. production and it could be in competition − AD facilities could be faced with negative with many other fertilizer products. impacts on the value and prices of − Environmental controversies could occur surrounding real estate and properties due to the GHG emissions, odour and (Baere and Mattheeuws, 2013). hygiene issues around composting areas.

30

− That is expected to bring more jobs in the green economy (Bettina et al., 2013; Commission, 2009). − FW could be co-digested with other substrates to enhance energy yields (Edison, 2014; Satoto, 2010). − Many prevailing policies and regulations supporting waste-to-energy conversion and technology to utilize FW (Lord and Gregory, 2011), and Waste to Energy Background Paper - Zero Waste South Australia (Kathryn, 2013).

RI PT

Opportunities − Composting is suitable for decentralized treating FW in households in suburban areas (Viktoria B., 2014). − Composts as good products in the fertilizer market. − Composting could be upgraded by combining it with AD process as posttreatment of the digestate (Baere and Mattheeuws, 2013).

− Policy determination to reduce wastes in the food chain should increase future raw material costs (George and Joe, 2014). − The current political focus on bioenergy puts bio-based FW uses at a competitive disadvantage. The lack of sustainability criteria for FW materials in light of the on-going discussion on conventional bioenergy may undermine the renewable energy sector (George and Joe, 2014). − Bioenergy from biomass is also a challenge in integrating renewable energy in the electricity grid. However, the current grid electricity connection for commercial utilizing bioenergy from FW has not yet been broadly upgraded. Therefore, this issue could mitigate the approaching motivation for utilizing bionergy from FW (AEBIOM, 2012).

AC C

EP

TE D

M AN U

SC

RI PT

ACCEPTED MANUSCRIPT

Fig. 1. Food wastage at consumption phase by some regions (kg/year).

31

TE D

M AN U

SC

RI PT

ACCEPTED MANUSCRIPT

AC C

EP

Fig. 2. The highest heating value (HHV) per capita (MJ/capita) and the sharing percentage in natural gas (NG) consumption (%) from food waste conversion in different countries.

32

M AN U

SC

RI PT

ACCEPTED MANUSCRIPT

AC C

EP

TE D

Fig. 3. Suggestion of food waste characteristics based on biotechnological conversion processes.

33

AC C

EP

TE D

M AN U

SC

RI PT

ACCEPTED MANUSCRIPT

Fig. 4. A conceptual model to develop the food waste fermentation of bioenergy production.

34

ACCEPTED MANUSCRIPT

References

AC C

EP

TE D

M AN U

SC

RI PT

AEBIOM, 2012. European Biomass Association Bioenergy. Albert, S.H., 2005. SWOT Analysis for Management Consulting. SRI Alumni Association Newsletter, p.16. Baere, L.D., Mattheeuws, B., 2013. Anaerobic digestion of the organic fraction of municipal solid waste in Europe, p. 517-526. Bakonyi, P., Borza, B., Orlovits, K., Simon, V., Nemestóthy, N., Bélafi-Bakó, K., 2014a. Fermentative hydrogen production by conventionally and unconventionally heat pretreated seed cultures: A comparative assessment. Int. J. Hydrogen Energy (39), 5589-5596. Bakonyi, P., Nemestóthy, N., Bélafi-Bakó, K., 2013. Biohydrogen purification by membranes: An overview on the operational conditions affecting the performance of non-porous, polymeric and ionic liquid based gas separation membranes. Int. J. Hydrogen Energy (38), 9673–9687. Bakonyi, P., Nemestóthy, N., Simon, V., Bélafi-Bakó, K., 2014b. Review on the start-up experiences of continuous fermentative hydrogen producing bioreactors. Renew. Sust. Energ. Rev. (40), 806-813. Bettina, K., Claire, S., Emma, W., Ben, A., Allan, B., Jane, D., Daniel, K., 2013. Technology options for feeding 10 billion people Recycling agricultural, forestry & food wastes and residues for sustainable bioenergy and biomaterials, Europe. Bob, D., 2014. The 63rd edition of the BP Statistical Review of World Energy, The United Kingdom. Bond, M., Meacham, T., Bhunnoo, R., Benton, T.G., 2013. Food waste within global food systems, Global Food Security Programme (GFS), The United Kingdom, p.43. Carol, S.K.L., Apostolis, A.K., Katerina, S., Egid, B.M., Avtar, S.M., Nikolaos, K., Lucie, A.P., Seraphim, P., Tsz, H.K., Rafael, L., 2014. Current and future trends in food waste valorization for the production of chemicals, materials and fuels: A global perspective. Biofuels, Bioprod. Bioref. (8), 686-715. Cavinato, C., Giuliano, A., Bolzonella, D., Pavan, P., Cecchi, F., 2012. Bio-hythane production from food waste by dark fermentation coupled with anaerobic digestion process: A longterm pilot scale experience. Int. J. Hydrogen Energy (37), 11549-11555. Cavinato, C., Bolzonella, D., Fatone, F., Cecchi, F., Pavan, P., 2011. Optimization of two-phase thermophilic anaerobic digestion of biowaste for hydrogen and methane production through reject water recirculation. Bioresour. Technol. (102), 8605–8611. Charles, J.B., Michael, C., Sonia, H., Rebecca, A., 2010. Anaerobic digestion of sourcesegregated domestic food waste: Performance assessment by mass and energy balance. Bioresour. Technol. (102), 612-620. Christian, M., Dübendorf, 2007. Anaerobic Digestion of Biodegradable Solid Waste in Low- and Middle-Income Countries: Overview over existing technologies and relevant case studies. Eawag Aquatic Research, Switzerland, p.63. Chu, C.F., Li, Y.Y., Xu, K.Q., Ebie, Y., Inamori, Y., Kong, H.N., 2008. A pH- and temperaturephased two-stage process for hydrogen and methane production from food waste. Int. J. Hydrogen. Energy. (33), 4739-4746. Commission, E., 2009. Low Cost Zero Waste Municipality, Phase 4.1. Transnational SWOT Analysis on waste management concepts, Europe. Cunsheng, Z., Haijia, S., Jan, B., Tianwei, T., 2014. Reviewing the anaerobic digestion of food waste for biogas production. Renew. Sust. Energ. Rev. (38), 383-392. 35

ACCEPTED MANUSCRIPT

AC C

EP

TE D

M AN U

SC

RI PT

Daniel, P., Carol, S.K.L., 2013. Valorisation of food waste in biotechnological processes. Sustain. Chem. Process. (1), p.6. Danko, A.S., Pinheiro, F., Abreu, A.A., Alves, M.M., 2008. Effect of methanogenic inhibitors, inocula type, and temperature on biohydrogen production from food components. Environ. Eng. Manage. J. (7), 531-536. Edison, M., 2014. Bio-methane generation from organic waste: A review. Proceedings of the World Congress on Engineering and Computer Science, Volumn II, p.6. Elbeshbishy, E., Nakhla, G., 2011. Comparative study of the effect of ultrasonication on the anaerobic biodegradability of food waste in single and two-stage systems. Bioresour. Technol. (102), 6449-6457. Emec, S., Bilge, P., Seliger, G., 2015. Design of production systems with hybrid energy and water generation for sustainable value creation. Clean. Techn. Environ. Policy (17), 18071829. Esra, U.K., Antoine, P.T., Wun, J.N., Liu, Y., 2014. Bioconversion of food waste to energy: A review. Fuel (134), 389-399. European Commission, 2009. Low cost zero waste municipality. Phase 4.1. Transnational SWOT Analysis on waste management concepts. Europe. Faaij A., Doorn J.V., Curvers T., Waldheim L., Ols-son E., Wijk A.V, C., D.-O., 1997. Characteristics and availability of biomass waste and residues in The Netherlands for gasification. Biomass Bioenerg. (12), 225-240. Fulton, J., Marmaro, R., Egan, G., 2010. System for producing a hydrogen enriched, Eden Annual Report. Fuel. US Patent 7721682. Gary, C.M., Jenkins, B.M., 2007. Food and processing residues in California: Resource assessment and potential for power generation Bioresour. Technol. (98), 3098-3105. George, M.H., Joe, H., 2014. Energy from waste and the food processing industry. Process Saf. Environ. (90), 203-212. Gioannis, G.D., Muntoni, A., Polettini, A., Pomi, R., 2013. A review of dark fermentative hydrogen production from biodegradable municipal waste fractions. Waste Manage. (33), 1345-1361. Gold, S., Seuring, S., 2011. Supply chain and logistics issues of bio-energy production. J. Clean. Prod. (19), 32-42. Gopalakrishnan, K., Péter, B, Periyasamy, S, Nándor, N, Katalin, B.B., 2015. Lignocellulose biohydrogen: Practical challenges and recent progress. Renew. Sust. Energ. Rev. (44), 728737. Han, S.K., Shin, H.S., 2004. Biohydrogen production by anaerobic fermentation of food waste. Int. J. Hydrogen. Energy (29), 569-577. Hartmann, H., Ahring, B.K., 2006. Strategies for the anaerobic digestion of the organic fraction of municipal solid waste: an overview. Water Sci. Technol. (53), 7-22. IDAE, 1994. Energy from Biomass: Principles and Applications, A thermie programme action European Commission. Directorate - General for energy DGXVII, Europe, p.25. Ismail, F., Nor'Aini, A.R., Abd-Aziz, S., Chong, M.L., Hassan, M.A., 2009. Statistical optimization of biohydrogen production using food waste under thermophilic conditions. Open. Renew. Energ. J. (2), 124-131. Ivana, K., 2014. Tackling food waste: The EU's contribution to a global issue European Parliamentary Research Service, Europe.

36

ACCEPTED MANUSCRIPT

AC C

EP

TE D

M AN U

SC

RI PT

Jae, K.C., Soon, C.P., Chang, H.N., 1995. Biochemical methane potential and solid state anaerobic digestion of Korean food wastes. Bioresour. Technol. (2), 245-253. Jeffrey, M., 2007. Measuring the benefits of composting source separated organics in the Region of Niagara, Washington, the United States, p.44. Jones, T., 2006. Addressing food wastage in the US, The United States. Julian, P., Mark, B., Sarah, M., 2014. Food waste within food supply chains: quantification and potential of the change to 2050. Phil. Trans. R. Soc. B (356), 3056-3081. Kathryn, W., 2013. Waste to energy background paper - Zero waste South Australia. Australia, p.131. Kim, D.H., Kim, M.S., 2012. Development of a novel three-stage fermentation system converting food waste to hydrogen and methane. Bioresour. Technol. (127), 267-274. Kim, D.H., Kim, S.H., Kim, K.Y., Shin, H.S., 2010. Experience of a pilot-scale hydrogen producing anaerobic sequencing batch reactor (ASBR) treating food waste. Int. J. Hydrogen. Energy (35), 1590-1594. Kim, H.J., Kim, S.H., Choi, Y.G., Kim, G.D., Chung, T.H., 2006. Effect of enzymatic pretreatment on acid fermentation of food waste. J. Chem. Technol. Biotechnol (81), 974980. Kim, J.K., Nhat, L., Chun, Y.N., Kim, S.W., 2008. Hydrogen production conditions from food waste by dark fermentation with Clostridium beijerinckii KCTC 1785. Biotechnol. Bioprocess (E13), 499-504. Kim, S.H., Shin, H.S., 2008. Effects of base-pretreatment on continuous enriched culture for hydrogen production from food waste. Int. J. Hydrogen Energy (33), 5266–5274. Kondusamy, D., Kalamdhad, A.S., 2014. Pre-treatment and anaerobic digestion of food waste for high rate methane production – A review. J. Envi. Chem. Eng. (2), 1821–1830. Lee, Y.W., Chung, J.W., 2010. Bioproduction of hydrogen from food waste by pilot-scale combined hydrogen/methane fermentation. Int. J. Hydrogen Energy (35), 11746-11755. Lee, D.Y., Yoshitaka, E., Xu, K.Q., Li, Y.Y., Inamori, Y., 2010. Continuous H2 and CH4 production from high-solid food waste in the two-stage thermophilic fermentation process with the recirculation of digester sludge. Bioresourc. Technol. (101), 42-47. Lee, W.S., Chua, A.S.M., Yeoh, H.K., Ngo, G.C., 2014. A review of the production and applications of waste-derived volatile fatty acids. Chem. Eng. J. (235), 83-99. Lin, C.Y., Lay, C.H., Sen, B., Chu, C.Y., Gopalakrishnan, K., Chen, C.C., Chang, J.S., 2012. Fermentative hydrogen production from wastewaters: A review and prognosis. Int. J. Hydrogen Energy (37), 15632–15642. Liu, G.Q., Zhang, R.H., Hamed, M.E.M., Dong, R., 2009. Effect of feed to inoculum ratios on biogas yields of food and green wastes. Bioresour. Technol. (100), 5103-5108. Liu, Z., Zhang, C., Lu, Y., Wu, X., Wang, L., Wang, L.J., Han, B., Xing, X.H., 2013. States and challenges for high-value biohythane production from waste biomass by dark fermentation technology. Biosci., Biotechnol. (135), 292-303. Lord, H., Gregory, B., 2011. Anaerobic digestion strategy and action plan – A commitment to increasing energy from waste through anaerobic digestion, DEFRA, the United Kingdom, p. 56. Lou, X.F., Nair, J., Ho, J., 2013. Potential for energy generation from anaerobic digestion of food waste in Australia. Waste Manage. Res. (31), 283-294.

37

ACCEPTED MANUSCRIPT

AC C

EP

TE D

M AN U

SC

RI PT

Maaike, H.V.G., 2014. Food waste or wasted food: An empirical investigation of the determinants of food waste. Master of Science in Business Administration, University of Stavanger Business School, Norway. McCormick, K., Kaberger, T., 2007. Key barriers for bioenergy in Europe: Economic conditions, know-how and institutional capacity, and supply chain co-ordination. Biomass Bioenerg. (31), 443-452. Micolucci, F., Gottardo, M., Bolzonella, D., Pavan, P., 2014. Automatic process control for stable bio-hythane production in two-phase thermophilic anaerobic digestion of food waste. Int. J. Hydrogen Energy (39), 17567-17572. Miyamoto, K., 2009. Chapter 1 - Biological energy production. Renewable biological systems for alternative sustainable energy production. Food and Agriculture Organization of the United Nations. Mohammadi, P., Ibrahim, S., Mohamad, S.M.A., Sean, L., 2011. Effects of different pretreatment methods on anaerobic mixed microflora for hydrogen production and COD reduction from palm oil mill effluent. J. Clean. Prod. (19), 1654–1658. Molino, A., Nanna, F., Ding, Y., Bikson, B., Braccio, G., 2013. Biomethane production by anaerobic digestion of organic waste. Fuel (103), 1003-1009. Nazlina, H.M.Y., Tabassum, M., Mohd, A.H., Nor'Aini, A.R., 2013. Food waste and food processing waste for biohydrogen production: A review. Environ. Manage. (130), 375-385. Pekcan, G., Ko¨ ksal, E., Ku¨c¸u¨kerdo¨nmez, O., Ozel, H., 2006. Household food wastage in Turkey, Rome, Italy. Peter, L., Peter, W., Oakdene, H., 2010. Waste arising in the supply of food and drink to households in The UK, The United Kingdom. Pisutpaisal, N., Nathao, C., Sirisukpoka, U., 2014. Biological hydrogen and methane production in from food waste in two-stage CSTR. Energy Procedia (50), 719-722. Rattana, M., 2013. A review: utilization of food wastes for hydrogen production under hydrothermal gasification. Environ. Technol. Rev. (2), 85-100. Saidura, R., Abdelaziz, E.A., Demirbas, A., Hossain, M.S., Mekhile, S., 2011. A review on biomass as a fuel for boilers. Renew. Sust. Energ. Rev. (15), 2262–2289. Satoto, E.N., 2010. PhD thesis. Anaerobic digestion of organic solid waste for energy production, KIT scientific Publishing 2010. ISSN 0172-8709, ISBN 978-3-86644-464-5, Denmark, p.148. Schievano, A., Tenca, A., Lonati, S., Manzini, E., Adani, F., 2014. Can two-stage instead of onestage anaerobic digestion really increase energy recovery from biomass? Appl. Energy (124), 335-342. Seldman, N., 2010. Update on anaerobic digester projects using food wastes in North America. Institute for Local Self-Reliance, Division of Sustainability City of Atlanta, Georgia, the United States, p.19. Sen, B., Aravind, J., Kanmani, K., Lay, C.H., 2016. State of the art and future concept of food waste fermentation to bioenergy. Renew. Sust. Energ. Rev. (53), 547-557. Shin, H.S., Youn, J.H., Kim, S.H., 2004. Hydrogen production from food waste in anaerobic mesophilic and thermophilic acidogenesis. Int. J. Hydrogen Energy (29), 1355-1363. Siddiqui, Z., Horan, N.J., Salter, M., 2011. Energy optimisation from co-digested waste using a two-phase process to generate hydrogen and methane. Int. J. Hydrogen Energy (36), 47924799.

38

ACCEPTED MANUSCRIPT

M AN U

SC

RI PT

Song, Q.B., Li, J.H., Zeng, X.L., 2014. Minimizing the increasing solid waste through zero waste strategy. J. Clean. Prod., p.12. Tawfik, A., Salem, A., El-Qelish, M., 2011. Two stage anaerobic baffled reactor for biohydrogen production from municipal food waste. Bioresourc. Technol. (102), 8723-8726. Thi, N.B.D., Gopalakrishnan, K., Lin, C.Y., 2015. An overview of food waste management in developing countries: Current status and future perspective. Environ. Manage. (157), 220229. Viktoria B., J.P., Enn L., 2014. Utilisation options for biodegradable kitchen waste in Estonia: SWOT analysis. Wang, X., Zhao, Y., 2009. A bench scale study of fermentative hydrogen and methane production from food waste in integrated two-stage process. Int. J. Hydrogen Energy (34), 245-254. Wang, Y.H., Li, S.L., Chen, I.C., Tseng, I.C., Cheng, S.S., 2010. A study of the proces control and hydrolytic characteristics in a thermophilic hydrogen fermentor fed with starch-rich kitchen waste by using molecular-biological methods and amylase assay. Int. J. Hydrogen. Energy. (35), 13004-130012.

AC C

EP

TE D

WRAP, 2009. Household food and drink waste in the UK. ISBN: 1-84405-430-6, Banbury, The United Kingdom. Youichi, K., Hiroshi, M., Shinya, T., Hirotami, Y., Masayuki, T., Takeshi, A., 2007. Technical Review Vol. 44 No. 2. Mitsubishi Heavy Industries, Ltd. Japan. Youn, J.H., Shin, H.S., 2005. Comparative performace between temperature-phased and conventional mesophilic two-phased processed in terms of anaerobically produced bioenergy from food waste. Waste Manag. Res. (23), 32-38. Zhou, P., Elbeshbishy, E., Nakhlaa, G., 2013. Optimization of biological hydrogen production for anaerobic co-digestion of food waste and wastewater biosolids. Bioresour. Technol. (130), 710-718. Zhu, H., Parker, W., Conidi, D., Basnar, R., Seto, P., 2011. Eliminating methanogenic activity in hydrogen reactor to improve biogas production in a two-stage anaerobic digestion process co-digesting municipal food waste and sewage sludge. Bioresour. Technol. (102), 70867092. Zong, W., Yu, R., Zhang, P., Fan, M., Zhou, Z., 2009. Efficient hydrogen gas production from cassava and food waste by a two-step process of dark fermentation and photo-fermentation. Biomass. Bioenerg. (33), 1458-1463.

39

ACCEPTED MANUSCRIPT

•

Food waste conversion to bioenergy in terms of heat and electricity was reviewed.

•

Three forms of fermenting food waste for H2, CH4, and bio-hythane production were evaluated.

•

Production potential of heat and electricity from food waste in some countries were

•

RI PT

elucidated.

SWOT analysis was employed to assess different kinds of bio-treatment for food waste.

A conceptual model to develop food waste-to-bioenergy via anaerobic processes was

EP

TE D

M AN U

SC

suggested.

AC C

•