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Joint data envelopment analysis and life cycle assessment for environmental impact reduction in broiler production systems
Accepted Manuscript Applying data envelopment analysis method for environmental impact reduction in broiler production system
Z. Payandeh, K. Kheiralipour, M. Karimi, B. Khoshnevisan PII:
S0360-5442(17)30504-2
DOI:
10.1016/j.energy.2017.03.112
Reference:
EGY 10579
To appear in:
Energy
Received Date:
02 December 2016
Revised Date:
23 March 2017
Accepted Date:
24 March 2017
Please cite this article as: Z. Payandeh, K. Kheiralipour, M. Karimi, B. Khoshnevisan, Applying data envelopment analysis method for environmental impact reduction in broiler production system, Energy (2017), doi: 10.1016/j.energy.2017.03.112
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ACCEPTED MANUSCRIPT
The environmental impacts of broiler farms in Isfahan Providence, Iran were determined. The efficient and inefficient farms were identified by data envelopment analysis. The inefficient farms were optimized to reach efficient level. The environmental impacts of all studied farms were calculated after optimization. All impact indexes were decreased after optimization.
ACCEPTED MANUSCRIPT
1
Applying data envelopment analysis method for
2
environmental impact reduction in broiler production
3
system
4 5 6
Z. Payandeh1, K. Kheiralipour1*, M. Karimi2, B. Khoshnevisan3
7 8
9
1Mechanical
Engineering of Biosystems Department, Ilam University, Ilam, Ilam, Iran.
10
11
2Mechanical
Engineering of Biosystems Department, Arak University, Arak, Markazi, Iran.
12
13 14
15
3Department
of Agricultural Machinery, University of Tehran, Karaj, Alborz, Iran. *Corresponding
Author:
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E-mail Address: [email protected]
17
Tell& Fax: +98-8432227015 1
ACCEPTED MANUSCRIPT 1
Abstract
2
In recent years, livestock production sector has been significantly grown
3
associated with increasing of environmental impacts. In the present
4
research 90 broiler farms in Isfahan Providence, Iran, were considered to
5
be evaluated in point view of environmental impacts. The aim of the
6
present research is reducing environmental impacts of the studied farms
7
by data envelopment analysis. By the method, efficiency of the farms was
8
determined and inefficient farms were reduced to reach efficient level
9
through reducing energy and resources use. Before and after comparison
10
all farms, eleven environmental impacts of the farms were calculated
11
using life cycle assessment method. The results showed that the used
12
energy in farms can be reduced by 10.16 %. The contribution of food
13
production to environmental impacts was especially high in almost all
14
environmental indicators. All environmental impacts were reduced by 12-
15
57 %. The highest reduction was seen in ozone layer depletion, abiotic
16
depletion, marine aquatic ecotoxicity and human toxicity as 57.37, 31.32,
17
27.59 and 26.73 %, respectively. The research methodology and obtained
18
results can be used to reduce environmental emissions through managing
19
the resources and energy use in broiler production systems.
20
Keywords:
21
Environmental impacts; Life cycle assessment.
Chicken;
Energy
use;
2
Data
envelopment
analysis;
ACCEPTED MANUSCRIPT 1
1. Introduction
2
The livestock sector has been expanded rapidly in recent decades and it is
3
projected to be continually grown as a result of increasing trend of food
4
demand. One of the main parts in this dynamic and growing sector is
5
broiler production [1]. The Middle East is the highest per capita consumer
6
of broiler meat in the world. Increasing trend of population growth,
7
urbanization and purchasing power has been caused to increase broiler
8
meet consumption.
9
The worldwide broiler chicken industry has been continuously grown
10
over the last 40 years. Broiler meat is an important source of high quality
11
proteins, minerals and vitamins to balance the human diet [2]. The global
12
broiler production in 2013 was estimated over 96 million tonne of meat
13
and after beef and pork is the third most consumed meat. At the moment,
14
Iran is the seventh broiler producer in the world with annual production
15
of 2 million tonne [3].
16
The livestock production has significant role in emission greenhouse
17
gases. There is estimated that broiler meat and egg production sector
18
emits annually 606 million tonne of CO2 equivalent as about 8 % of the
19
total greenhouse gases emitted in livestock sector. About 343 million
20
tonne of CO2 equivalent in 2013 is the share of broiler meat production
21
[4].
3
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To evaluate environmental impacts of systems, life cycle assessment
2
(LCA) method is a powerful tool that is vastly used in agriculture sector.
3
In this method, the life cycle of a system is considered as well as
4
predetermined its inputs and outputs. The life cycle perspective allows a
5
comprehensive assessing procedure, i.e. the possibility of taking the
6
whole production chain into account to improve the environmental
7
performance of products [5].
8
LCA method has been used to calculate the environmental impacts of
9
broiler production systems. Pelletier used LCA to predict macro scale
10
environmental impacts along the US broiler supply chain. In his research,
11
contribution of food provision in some impact category was calculated
12
[6]. Ewemoje et al. assessed environmental impacts of production
13
processes from hatchery to point-of-lay using LCA method. Their results
14
showed that total contributions to global warming were 9.708 kg of CO2
15
equivalent, 11.34 kg of CH4 equivalent and 0.2 kg of NO2 equivalent.
16
Contributions to acidification were 2.713×10-4 kg of SO2 equivalent,
17
1.948×10-3 kg of NH3 equivalent, 2.167×10-3 kg of NOx equivalent and
18
energy consumption was 59.79 KJ per bird [7]. Another research was
19
reported by Gonzalez-Garcia et al. to investigate environmental impacts
20
of broiler production. They determined contribution of environmental
21
impacts in all categories with significant contributions to eutrophication
22
potential (EP), acidification potential (AP), photo-oxidant formation 4
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potential (POFP) and global warming potential (GWP) as 99%, 98%,
2
99% and 93% of total contributing emissions, respectively [8].
3
Data envelopment analysis (DEA) has been used for evaluating the
4
performance and efficiency of industrial and agricultural systems. DEA is
5
a nonparametric method to estimate the relative efficiency of decision
6
making units (DMU), frontier DMUs and optimal values of each DMU
7
to reach frontiers [9].
8
Different studies have been conducted for assessing agricultural
9
production systems by DEA approach in view point of energy. Chauhan
10
et al. applied this method to determine the efficiencies of rice production
11
farms. Their results revealed that about 11.6% of the total input energy
12
could be saved [10]. Begum et al. calculated technical efficiency of
13
commercial broiler farms using DEA method. They considered constant
14
returns to scale (CRS) and variable returns to scale (VRS) model to
15
estimate the efficiency of DMUs [11]. Heidari et al. determined technical
16
efficiency (TE), pure technical efficiency (PTE) and scale efficiency (SE)
17
of energy use in broiler farms as 0.90, 0.93 and 0.96, respectively. In
18
addition their results revealed that about 11% of the total input resources
19
could be saved [2].
20
As stated above, some researches were conducted to evaluate
21
environmental impacts of broiler production systems by LCA method and
22
in some other researches DEA method was used to estimate energy 5
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efficiency and energy use reduction in the systems. But in the literature, a
2
research was not reported to reduce environmental impacts in broiler
3
production system. So, the aim of the present research was reducing
4
environmental impacts of broiler production systems in Isfahan
5
Providence, Iran. In this study, DEA method was applied to estimate and
6
optimize efficiency of energy consumption in the systems. Energy
7
reduction of the systems was calculated by subtracting the energy use
8
before and after comparison. Then, LCA method was used to calculate
9
the environmental impacts of the systems before and after comparison
10
and calculate the potential reduction of the impacts by subtracting the
11
emitted impacts before and after comparison.
12 13
2. Materials and Methods
14
A flowchart of calculation steps in the present research has been shown in
15
Fig. 1.
16
Fig. 1.
17
The first step was started after data collection. In this step, real amounts
18
of used recourses inputs in all broiler production farms were determined.
19
After that, real amounts of energy consumption and the environmental
20
impacts in the broiler production farms were calculated according to the
21
consumed input recourses by LCA method. All broiler production farms 6
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were reduced in point of energy consumption by DEA method and then
2
the reduced amounts of energy consumption and also energy reduction in
3
the farms were calculated. The reduced amounts of input resources were
4
calculated according to the reduced energy consumption. Finally, the
5
environmental impacts were calculated based on the reduced input
6
resources by LCA method and then reduction of environmental impacts
7
were determined.
8 9
2.1. Data Collection
10
In this study, 90 broiler farms in Isfahan, Najafabad and Nain Township,
11
the most broiler producers of Isfahan Province, Iran, were randomly
12
selected to be studied. Isfahan Province is located within 30.65 north
13
latitude and 51.67 east longitude. The data were gathered by
14
questionnaires and interview with the farm owners in August-September
15
growing period, 2014. The average of growing period was 58 days. The
16
used resources (inputs) in the studied growing period were: total amount
17
of food, diesel and electricity consumptions and total working hours of
18
labors. The outputs of the studied broiler farms were meat and manure.
19 20
7
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2.2. Data Envelopment Analysis
2
Data envelopment analysis (DEA) is a non-parametric method which the
3
relationships between all inputs and outputs are taken into account
4
simultaneously [12]. The method compares the studied broiler farms as
5
DMUs, and finds out the relative efficiency of the farms and examines
6
their positions in relation to the frontiers. DEA method includes two
7
models: CCR (Chames, Cooper and Rhodes) and BCC (Banker, Chames
8
and Cooper) models [13]. CCR model is constant returns to scale and
9
BCC model is variable returns to scale method. Each of these models is
10
divided to output oriented and input oriented approaches. Input oriented
11
approach means that an inefficient DMU must decrease input to become
12
an efficient one, while the output is fixed. Whereas, the output oriented
13
method fixes the input levels and increase the output values.
14
In DEA method, three efficiencies are estimated as technical efficiency
15
(TE), scale efficiency (SE) and pure technical efficiency (PTE).
16
Technical efficiency (or global efficiency) is determined by evaluation
17
the performance of DMUs relative to each other [13]. Scale efficiency is
18
the potential productivity which is obtained based on the achieved
19
optimal size of a DMU [14]. Pure technical efficiency or local efficiency
20
is the technical efficiency that removes the effect of scale efficiency [15].
21
The difference between three efficiencies has been explained in Fig. 2.
8
ACCEPTED MANUSCRIPT Fig. 2.
1 2
Two DEA models have been shown in Fig. 2. The MN line that passes
3
from the extreme data points represents a constant return to scale. Each
4
DMU on MN line is efficient one and its efficiency is equal to unit. Also,
5
pure technical efficiency of the DMUs on break line (P1, P2, P3 and P4)
6
is equal to unit. Having both technical efficiency and pure technical
7
efficiency, scale efficiency of DMUs can be estimated. The scale
8
efficiency of a DMU is equal to unit if its technical and pure technical
9
efficiencies are equal to unit. So, P2 DMU is efficient but other DMUs
10
are not and they are called as inefficiency DMUs. The three efficiencies
11
can be explained by following equations [7]: AB
TE = PTE =
SE = 12
(1)
AD
AC
(2)
AD
AB
(3)
AC
From above equations can be derived that: (4)
TE = PTE × SE 13
From Eq. 4 can be argued that TE is actual efficiency and SE shows an
14
efficiency ratio between ideal and actual efficiency. EMS 1.3 Software
15
[16] was used in this study to analyze the data by DEA method.
9
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In order to optimize the input resources of all studied farms, firstly the
2
energy of all inputs were calculated. The inputs and outputs recourses
3
were converted to energy (actual) by multiplying the quantity of each
4
input/output to its corresponding energy equivalent. The used energy
5
equivalents in this study and their references were listed in Table 1.
6
Table 1.
7
The actual energy amounts of all input recourses were used as input of
8
DEA method via EMS 1.3 Software. In this study input oriented approach
9
was used to identify efficient (frontiers) and inefficient farms. The EMS
10
Software identifies efficient and inefficient farms based on actual energy
11
inputs of the farms by comparison them with each other. After identifying
12
and classifying the efficient and inefficient farms, the inefficient farms
13
were reduced to reach an efficient position in point of energy
14
consumption.
15
The energy comparison process is done by comparison inefficient farms
16
to efficient ones to determine the ideal energy use. The saved energy can
17
be determined by subtracting ideal from actual energy use [2; 14].
18
The reduced input resources are calculated considering reduced input
19
energies divided by those corresponding energy equivalents (Table 1).
20
These data were used as LCI data before and after comparison. The input
10
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recourses of broiler farms before and after comparison were considered to
2
determine the environmental impacts by LCA method.
3 4
2.3. Life Cycle Assessment
5
Life cycle assessment is an approach to estimate environmental impacts
6
related to a product, process or activity. LCA approach includes four
7
phases based on ISO 14040 and ISO 14044: goal and scope definition,
8
inventory analysis, impact assessment and interpretation of results [5;
9
24]. In the present study, LCA method was used to calculate
10
environmental impacts before and after DEA comparison of the broiler
11
farms.
12 13
2.3.1. Goal and Scope Definition
14
Goal and scope definition is the first phase of LCA that explain the
15
purpose of the study, the expected product of the study, the system
16
boundary and the assumptions. In the present study, LCA method was
17
used for calculating environmental impacts of production process of
18
broiler farms before and after DEA comparison. The system boundary
19
was farm gate including fuel, electricity and food and emissions
20
associated with live chicks (Fig. 3). Broiler breeder production, slaughter,
11
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chicken packaging and salon construction were not considered in this
2
research.
3
The functional unit of this study was one tonne live mass of broiler. This
4
functional unit is in agreement with previous studies [9; 11; 25]. Since
5
both energy and environmental impact reduction were simultaneously
6
investigated, mass allocation method was considered in the present study
7
[11; 26]. Fig. 3.
8 9 10
2.3.2. Life Cycle Inventory
11
The second phase of LCA study is life cycle inventory (LCI). Various
12
input resources and environmental impacts were quantified in this phase.
13
The actual and ideal inputs of the farms were considered as LCI data.
14
Further information (for production of food, electricity, transportation,
15
etc.) was taken from the SimaPro 8.0 Software Database. Fuel, electricity
16
and food were considered as input resources in the LCA study and
17
outputs were chicken meet and manure. Same to other studies, cleaning
18
agents used for disinfection of poultry salons were neglected in the LCA
19
study [27; 28].
20
Electricity is utilized for different purposes in the studied broiler
21
production farms such as: ventilating, lighting and water pumping.
12
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Electricity supply has been delivered from the grid region. Two kinds of
2
fuels, 99 % natural gas and 1 % Mazut are used in electricity grid of
3
Isfahan Province. The environmental impacts of each electricity supply
4
method were calculated according to fuel consumption percentage.
5
The used fuel for heating system in the studied broiler farms was included
6
diesel and natural gas. In this study, the fuel consumptions were high
7
because Isfahan Province is located in a dry region. Emission factors for
8
using diesel fuel and natural gas were considered based on [24]. The
9
USLCI Database was used in this study [29].
10
The share of maize and soybean was more than 90 % of the broiler foods.
11
The information related to foods was taken from the SimaPro 8.0
12
Software Database. In this study, crop production was not included in the
13
system boundary and it wasn’t considered in assessment process. The
14
largest emission of live chicks comes from the litter manure. N2O (direct
15
and indirect) and CH4 are emission factors of litter manure that were
16
determined based on IPCC guideline [24].
17 18
2.3.3. Life Cycle Impact Assessment
19
Environmental impact assessment method was selected based on CML-
20
IA baseline V3.02/EU25/Characterization. Totally 11 impact categories
21
were studied in this study (Table 5). These impact categories were 13
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selected based on the inputs of the broiler production farms. Impact
2
assessment calculations were conducted using SimaPro 8.05 Software
3
from PRé Consultants [29].
4 5
3. Results and Discussion
6
3.1. Farm efficiency
7
In this study, the CCR and BCC models were considered to evaluate
8
technical, pure technical and scale efficiency of poultry production.
9
Efficiency values of the studied farms were presented in Table 2.
10
Table 2.
11
The mean values of TE, PTE and SE were calculated as 0.91, 0.96 and
12
0.92, respectively. It is clear that the mean efficiency of all farms were
13
less than unit that shows inefficient amount of resources and energy
14
consumption in the studied farms. The highest value of standard deviation
15
(0.13) was belonged to technical efficiency with a range of 0.49 to 1. This
16
indicated that technical efficiency better than other efficiencies shows the
17
variation and also revealed that more farms loss the energy or
18
inefficiently use energy and so need more cares to improve their
19
operating practices for enhancing energy and resources consumption
20
efficiency.
14
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In the literature, TE, PTE and SE of broiler farmers of Yazd Providence,
2
Iran, were reported as 0.90, 0.93 and 0.96 [2], technical efficiency of
3
poultry egg production as 0.873 [12] and TE and PTE for broiler farms as
4
0.70-0.73 [8].
5
According to Duncan Multiple Range Test, the studied DMUs were
6
significantly separate by different efficiency classes (Fig. 4).
7
Fig. 4.
8
The result of CCR model showed that between total of 90 farmers, only
9
46 farmers were relatively efficient (TE=1) and the remaining were
10
inefficient, i.e. their efficiency value were less than unit. Whereas the
11
result of BCC model indicated that 57 farmers were efficient (PTE=1).
12
Because of the lower number of indicated efficient DMUs based on CCR
13
model, the TE values were considered for comparison of the inefficient
14
DMUs.
15 16
3.2. Energy use
17
The input energy before and after comparison and also amount of saved
18
energy has been presented in Table 3.
19
Table 3.
20
As can be seen in table 3, all energy inputs can be decreased based on
21
DEA method. The total energy use can be reduced by 10.16 %. The 15
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highest amount of energy save was belonged to diesel, gas, food and
2
electricity, respectively. Although Table 3 says that use of equipment in
3
broiler farms can be decreased (from 169.78 to 70.12 MJ/1000bird), but
4
increasing the level of technology of used equipment in the farms,
5
mechanized systems (heating and feeding), air conditioning and applied
6
appropriate management method to optimize the farm inputs lead to
7
reduce consumption of fuel, electricity and food.
8 9
3.3. Resource use
10
Amount of reduced energy use related to each input was divided by its
11
corresponding energy equivalent (Table 1) to obtain the reduced
12
resources use. The consumed resources before and after comparison were
13
presented in Table 4. These data were used as LCI data before and after
14
comparison. Table 4.
15 16 17
3.4. Environmental impacts
18
In this section, the mean values of environmental impact of all broiler
19
farms were calculated before comparison (actual). The corresponding
20
ideal values were calculated after DEA comparison. Impact reduction was
21
calculated as the difference between actual and ideal impacts. The 16
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environmental impacts before and after comparison and impact reduction
2
was presented in Table 5.
3
Table 5.
4
Some previous studies reported global warming, eutrophication and
5
acidification indicators related to emissions from chicken production
6
farms to produce 1 tonne of chicken meat in different countries. Dasilva
7
et al. estimated the emission in France for the mentioned indicators as
8
2216 kg CO2 eq, 13.8 kg PO4 eq and 28.7 kg SO2 eq, respectively.
9
Dasilva et al. reported their findings in Brazil as 2058 kg CO2 eq, 14.4 kg
10
PO2 eq and 34.5 kg SO2 eq, respectively [25]. In Finland, Katajajuuri et
11
al achieved 2079 kg CO2 eq, 2.1 kg PO4 eq and 35 kg SO2 eq,
12
respectively [30]. Pelletier studied emission of broiler farms in USA and
13
obtained indicators as 1395 kg CO2 eq, 3.9 kg PO4 eq and 15.8 kg SO2
14
eq, respectively [9]. Williams et al. expressed emission values for the
15
indicators in United Kingdom as 1800 kg CO2 eq, 14 kg PO4 eq and 25.9
16
kg SO2 eq, respectively [31]. In another research, Leinonen et al. studied
17
emission of United Kingdom and expressed 3087 kg CO2 eq, 14.2 kg
18
PO4 eq and 32.7 kg SO2 eq, respectively [32].
19
The global warming, eutrophication and acidification indicators for
20
production of 1 tonne chicken meat in the present research were equal to
21
5782.380 kg CO2 eq, 9.881kg PO4 eq and 35.755 kg SO2 eq,
22
respectively. The amounts of eutrophication and acidification indicators 17
ACCEPTED MANUSCRIPT 1
in Iran are same as corresponding values in different studied countries.
2
But, global warming is higher in compare with other countries that must
3
be decreased by considering better managing use of input resources.
4
Contribution of inputs to environmental impact categories for producing
5
1 tonne chickens before comparison has been shown in Fig. 5.
6
Fig. 5.
7
As can be seen in Fig. 5, the contribution of food to environmental
8
impacts derived from the studied farms was especially high, except for
9
human toxicity and marine aquatic toxicity indicators. The share of food
10
in the abiotic depletion, depletion of fossil resources, global warming,
11
ozone layer depletion, fresh water toxicity, terrestrial toxicity,
12
photochemical
13
eutrophication indicators was equal to 75.1, 41.8, 58.3, 64.6, 72.6, 46.5,
14
25.3, 58.9 and 94.6 %, respectively. Maize and soybean are most
15
important ingredients of food in broiler farms. They had highest
16
contributions in all categories due to its cropping stage.
17
The impact of livestock food on human toxicity and marine aquatic
18
toxicity was low (1.43 and 1.08 %, respectively) but the share of live
19
chicken on the indicators was high.
20
The most important input in the potential of global warming was food due
21
to releasing carbon dioxide into the air (91 %). Equipment (steel) had the
oxidation,
potential
18
acidification
and
potential
ACCEPTED MANUSCRIPT 1
highest share in ozone layer depletion indicator (52.78 %). Contribution
2
of the heating systems to environmental impacts was 22.4 % in
3
acidification potential, 2.73 % in eutrophication potential, 1.54 % in
4
ozone depletion and 22.3 % in global warming. Emissions of heating
5
systems in the studied broiler farms were correspond to burning natural
6
gas and diesel.
7
Methane was the main source of emission into the air in ozone layer
8
depletion indicator. In acidification potential, ammonia with amount of
9
13.49 kg SO2 eq (39 %) had the highest greenhouse gas emissions and in
10
eutrophication indicator, nitrate with amount of 5.61 kg PO4 eq had a
11
share of 57 % of the emissions to the water.
12
As reported by several researchers, food is the most important input for
13
increasing environmental impacts associated with farm-related activities
14
[9; 27; 30; 33; 34]. da Silva et al. studied the emissions from poultry
15
production in Brazil and France. They concluded that food input had the
16
highest emissions in the global warming, soil toxicity and eutrophication
17
indicators. In toxicity indicators, food had the highest share in Brazil, but
18
live chicken had the highest emission in France due to NH3 emissions.
19
Due to high use of fossil fuels, food had high effect on global warming
20
indicator. The use of nitrogenous fertilizers for food in Brazil caused to
21
increase the toxicity indictors [25].
19
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Nielsen et al. investigated the greenhouse gas emissions of poultry
2
production in Denmark. They reported that the main factor in emissions
3
of global warming potential was the food input with a share of 91 %
4
because of high use of fossil fuels [26].
5
Bengtsson and Seddon studied the emissions of broiler production in
6
Australia to identify environmentally sensitive areas in this sector. They
7
reported that food input is the biggest impact point in broiler chain with
8
emission amount of 1885 kg CO2 eq [33].
9
According to the results of the present and previous studies there was
10
concluded that the food input has the highest emissions. The use of fossil
11
fuels in the production of agricultural products increases the amount of
12
emissions. Also in food production step or any step that fossil fuel is
13
used, the environmental impacts can be minimized by using high fuels
14
efficiency equipment. Renewable energies are good alternative for fossil
15
fuels that reduce the environmental impacts.
16
Environmental impact values after comparison were presented in the
17
fourth column of Table 5. Also, the comparison of present and reduced
18
environmental impacts for all DMUs, have been shown in Fig. 6.
19
Fig. 6.
20
As seen in Table 5 and Fig. 6, amount of all studied indicators was
21
decreased after comparison. For example, depletion of fossil resources by
20
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the studied farms was equal to 40924.976 MJ before comparison which
2
decreased to 35358.585 MJ after comparison. Considerable impact
3
reduction can be detected in depletion of the ozone layer. The present
4
ozone layer depletion (ODP) was 4.225 kg CFC-11 eq that can be
5
reduced to 1.801 kg CFC-11 eq (57.37 % reduction). The global warming
6
indicator was 5782.380 kg CO2 eq before comparison whereas the
7
corresponding reduced emission will be 5004.346 kg CO2 eq after
8
comparison. So, emission reduction of GWP can be 778.034 kg CO2 eq.
9
Human toxicity reduced from 41447.050 to 30366.805 kg 1.4-DB eq.
10
Acidification can be reduced by 12.89 % and eutrophication reduced
11
from 9.881 kg PO4 eq to 8.620 kg PO4 eq (12.80 % reduction).
12 13
Conclusions
14
In the present research, the energy use and environmental impacts of
15
poultry production in Isfahan, Iran, was evaluated before and after
16
comparison by DEA and LCA methods. The total energy use can be
17
reduced by 10.16 %. Environmental impacts were significantly reduced
18
after comparison. The indicator including, abiotic depletion, abiotic
19
depletion (fossil), global warming, ozone layer depletion, human toxicity,
20
fresh water aquatic ecotoxicity, marine aquatic ecotoxicity, terrestrial
21
ecotoxicity, Photochemical oxidation, potential of acidification and 21
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eutrophication were decreased by 31.32, 13.60, 13.46, 57.37, 26.73,
2
16.12, 27.59, 17.43, 17.38, 12.89 and 12.80 %, respectively. As food
3
input has the highest contribution to the emissions due to high amount of
4
fossil fuels consumption, it is needed to apply efficient management
5
method to optimize food consumption, decrease food losses in the broiler
6
farms and decrease fuel consumption in food producing farms. Also,
7
improving mechanization and management level in broiler farm to reduce
8
fuel, electricity and other inputs are recommended. The results of this
9
study can be useful for farmers and agricultural organizations to reduce
10
energy and resource consumption and environmental emissions. Also,
11
more technical and economic aspects can be considered to improve the
12
management of poultry production systems.
13 14
Acknowledgements
15
The authors would thank the Ilam University to spurt this research. Also,
16
poultry farmers in Isfahan Province, Iran, are appreciated for their assists
17
and providing the required information.
18 19 20
22
ACCEPTED MANUSCRIPT 1
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[23] Kizilaslan H. Input–output energy analysis of cherries production in
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inventories. In: Eggleston, H.S., Buendia, L., Miwa, K., Ngara, T.,
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222-231.
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performance of milk production on a typical Portuguese dairy farm.
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Agricultural Systems 2010; 103: 498-507.
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[30] Katajajuuri JM, Grönroos J, Usva K. Environmental impacts and
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related improvement options of supply chain of chicken meat. 6th
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2
Switzerland, 12-14 November 2008.
3
[31] Williams AG, Audsley E, Sandars DL. A lifecycle approach to
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reducing the environmental impacts of poultry production. 2009. In:
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[32] Leinonen I, Williams AG, Wiseman J, Guy J, Kyriazakis I.
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Predicting the environmental impacts of chicken systems in the
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[33] Bengtsson J, Seddon J. Cradle to retailer or quick service restaurant
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15
of galician milk production. International Dairy Journal 2003; 13:
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783-796.
28
ACCEPTED MANUSCRIPT
Start
Determination of real input resources
Calculation of real energy consumption
Calculation of real environmental impacts
Estimation of reduced energy consumption
Calculation of energy use reduction
Calculation of reduced input resources Calculation of reduced environmental impacts
Calculation of environmental impacts reduction
End Fig. 1. The main calculation steps of environmental impacts reduction.
ACCEPTED MANUSCRIPT
Fig. 2. Graphical representation of different DEA efficiency types (Chauhan et al., 2006).
ACCEPTED MANUSCRIPT
Electricity
Fuel
Chicken
Poultry
Meet
Manure
Emission
Fig. 3. Poultry system boundaries.
Feed
ACCEPTED MANUSCRIPT
57
No. of DMUs
60 50
46
TE
PTE
40 29
30
21
20
12
10
11 4
0
0 1
1-0.9 0.9-0.8 Efficiency class
<0.8
Fig. 4. Efficiency distribution of DMUs.
ACCEPTED MANUSCRIPT
Fig. 5. Contribution of inputs to environmental impact categories for producing 1 tonne chickens before comparison of the units by DEA method. .
ACCEPTED MANUSCRIPT
Fig. 6. The environmental impact categories to produce 1 tonne chickens before and after comparison of the units by DEA method. .
ACCEPTED MANUSCRIPT
Table 1. Energy equivalents (MJ/unit) of inputs and outputs in broiler production. Input/Output Unit Energy equivalent
Reference
Inputs Labor
kg
1.96
[2]
l
47.80
[17]
m3
49.50
[17]
Maize
kg
7.90
[18]
Soybean
kg
12.60
[18]
Di calcium Phosphate
kg
10.00
[19]
Minerals
kg
1.59
[20]
Vitamins
kg
1.59
[20]
Fatty acid
kg
37.00
[21]
Salt
kg
1.59
[20]
kWh
11.93
[14]
Broiler
kg
10.33
[22]
Manure
kg
0.30
[23]
Fuel Diesel Gas Food
Electricity Outputs
ACCEPTED MANUSCRIPT Table 2. Efficiency scales of studied poultry farms. Efficiency scale
Minimum
Mean
Maximum Standard deviation
Technical efficiency
0.49
0.91
1.00
0.13
Pure technical efficiency
0.84
0.96
1.00
0.03
Scale efficiency
0.49
0.92
1.00
0.12
ACCEPTED MANUSCRIPT
Table 3. Amount of input energy (Mj/1000 bird) before and after comparison of the DMUs by DEA method. Energy value Saved energy Input Present Reduced Chicks
499.50
497.00
2.50
Labor
107.02
102.84
4.18
Diesel
29001.60
20281.15
8720.45
Gas
53695.87
50747.15
2948.72
Food
50242.88
48455.11
1787.77
Electricity
17102.63
15341.25
1761.38
Equipment
169.78
70.12
99.66
150819.29
135494.62
15324.67
Fuel
Total
ACCEPTED MANUSCRIPT
Table 4. Amount of input and output resources before and after comparison of the DMUs by DEA method. Resources value Unit Input/Output Present Reduced Inputs Chicks
Kg
48.35
48.11
m3
1048.77
1019.70
Diesel
L
602.90
424.29
Food
Kg
5104.99
4528.52
Electricity (gas)
kWh
1419.25
1285.94
Electricity (Mazut)
kWh
14.34
12.86
Steel
kg
92.52
1.71
Polyethylene
kg
28.78
0.72
Broiler
kg
2400.53
2400.53
Manure
kg
1691.71
1691.71
Fuel Gas
Equipment
Outputs
ACCEPTED MANUSCRIPT
Table 5. Environmental impacts of poultry production before and after comparison of the DMUs by DEA method. Impact value Impact Impact category Unit reduction Present Reduced Abiotic depletion
kg Sb eq
0.0022
0.0015
0.0007
Abiotic depletion (fossil fuels)
MJ
40924.976
35358.585
5566.391
Global warming (GWP 100a)
kg CO2 eq
5782.380
5004.346
778.034
Ozone layer depletion (ODP)
kg CFC-11 eq
4.225
1.801
2.424
Human toxicity
kg 1,4-DB eq
41447.050
30366.805
11080.25
Fresh water aquatic ecotoxicity
kg 1,4-DB eq
5866.113
4920.248
945.865
Marine aquatic ecotoxicity
kg 1,4-DB eq
Terrestrial ecotoxicity
kg 1,4-DB eq
1952.126
1611.852
340.274
Photochemical oxidation
kg C2H4 eq
1.237
1.022
0.215
Acidification potential
kg SO2 eq
35.755
31.145
4.61
Eutrophication
kg PO4 eq
9.881
8.620
1.261
32057072.300 23211337.520
8845735
Z. Payandeh, K. Kheiralipour, M. Karimi, B. Khoshnevisan PII:
S0360-5442(17)30504-2
DOI:
10.1016/j.energy.2017.03.112
Reference:
EGY 10579
To appear in:
Energy
Received Date:
02 December 2016
Revised Date:
23 March 2017
Accepted Date:
24 March 2017
Please cite this article as: Z. Payandeh, K. Kheiralipour, M. Karimi, B. Khoshnevisan, Applying data envelopment analysis method for environmental impact reduction in broiler production system, Energy (2017), doi: 10.1016/j.energy.2017.03.112
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.
ACCEPTED MANUSCRIPT
The environmental impacts of broiler farms in Isfahan Providence, Iran were determined. The efficient and inefficient farms were identified by data envelopment analysis. The inefficient farms were optimized to reach efficient level. The environmental impacts of all studied farms were calculated after optimization. All impact indexes were decreased after optimization.
ACCEPTED MANUSCRIPT
1
Applying data envelopment analysis method for
2
environmental impact reduction in broiler production
3
system
4 5 6
Z. Payandeh1, K. Kheiralipour1*, M. Karimi2, B. Khoshnevisan3
7 8
9
1Mechanical
Engineering of Biosystems Department, Ilam University, Ilam, Ilam, Iran.
10
11
2Mechanical
Engineering of Biosystems Department, Arak University, Arak, Markazi, Iran.
12
13 14
15
3Department
of Agricultural Machinery, University of Tehran, Karaj, Alborz, Iran. *Corresponding
Author:
16
E-mail Address: [email protected]
17
Tell& Fax: +98-8432227015 1
ACCEPTED MANUSCRIPT 1
Abstract
2
In recent years, livestock production sector has been significantly grown
3
associated with increasing of environmental impacts. In the present
4
research 90 broiler farms in Isfahan Providence, Iran, were considered to
5
be evaluated in point view of environmental impacts. The aim of the
6
present research is reducing environmental impacts of the studied farms
7
by data envelopment analysis. By the method, efficiency of the farms was
8
determined and inefficient farms were reduced to reach efficient level
9
through reducing energy and resources use. Before and after comparison
10
all farms, eleven environmental impacts of the farms were calculated
11
using life cycle assessment method. The results showed that the used
12
energy in farms can be reduced by 10.16 %. The contribution of food
13
production to environmental impacts was especially high in almost all
14
environmental indicators. All environmental impacts were reduced by 12-
15
57 %. The highest reduction was seen in ozone layer depletion, abiotic
16
depletion, marine aquatic ecotoxicity and human toxicity as 57.37, 31.32,
17
27.59 and 26.73 %, respectively. The research methodology and obtained
18
results can be used to reduce environmental emissions through managing
19
the resources and energy use in broiler production systems.
20
Keywords:
21
Environmental impacts; Life cycle assessment.
Chicken;
Energy
use;
2
Data
envelopment
analysis;
ACCEPTED MANUSCRIPT 1
1. Introduction
2
The livestock sector has been expanded rapidly in recent decades and it is
3
projected to be continually grown as a result of increasing trend of food
4
demand. One of the main parts in this dynamic and growing sector is
5
broiler production [1]. The Middle East is the highest per capita consumer
6
of broiler meat in the world. Increasing trend of population growth,
7
urbanization and purchasing power has been caused to increase broiler
8
meet consumption.
9
The worldwide broiler chicken industry has been continuously grown
10
over the last 40 years. Broiler meat is an important source of high quality
11
proteins, minerals and vitamins to balance the human diet [2]. The global
12
broiler production in 2013 was estimated over 96 million tonne of meat
13
and after beef and pork is the third most consumed meat. At the moment,
14
Iran is the seventh broiler producer in the world with annual production
15
of 2 million tonne [3].
16
The livestock production has significant role in emission greenhouse
17
gases. There is estimated that broiler meat and egg production sector
18
emits annually 606 million tonne of CO2 equivalent as about 8 % of the
19
total greenhouse gases emitted in livestock sector. About 343 million
20
tonne of CO2 equivalent in 2013 is the share of broiler meat production
21
[4].
3
ACCEPTED MANUSCRIPT 1
To evaluate environmental impacts of systems, life cycle assessment
2
(LCA) method is a powerful tool that is vastly used in agriculture sector.
3
In this method, the life cycle of a system is considered as well as
4
predetermined its inputs and outputs. The life cycle perspective allows a
5
comprehensive assessing procedure, i.e. the possibility of taking the
6
whole production chain into account to improve the environmental
7
performance of products [5].
8
LCA method has been used to calculate the environmental impacts of
9
broiler production systems. Pelletier used LCA to predict macro scale
10
environmental impacts along the US broiler supply chain. In his research,
11
contribution of food provision in some impact category was calculated
12
[6]. Ewemoje et al. assessed environmental impacts of production
13
processes from hatchery to point-of-lay using LCA method. Their results
14
showed that total contributions to global warming were 9.708 kg of CO2
15
equivalent, 11.34 kg of CH4 equivalent and 0.2 kg of NO2 equivalent.
16
Contributions to acidification were 2.713×10-4 kg of SO2 equivalent,
17
1.948×10-3 kg of NH3 equivalent, 2.167×10-3 kg of NOx equivalent and
18
energy consumption was 59.79 KJ per bird [7]. Another research was
19
reported by Gonzalez-Garcia et al. to investigate environmental impacts
20
of broiler production. They determined contribution of environmental
21
impacts in all categories with significant contributions to eutrophication
22
potential (EP), acidification potential (AP), photo-oxidant formation 4
ACCEPTED MANUSCRIPT 1
potential (POFP) and global warming potential (GWP) as 99%, 98%,
2
99% and 93% of total contributing emissions, respectively [8].
3
Data envelopment analysis (DEA) has been used for evaluating the
4
performance and efficiency of industrial and agricultural systems. DEA is
5
a nonparametric method to estimate the relative efficiency of decision
6
making units (DMU), frontier DMUs and optimal values of each DMU
7
to reach frontiers [9].
8
Different studies have been conducted for assessing agricultural
9
production systems by DEA approach in view point of energy. Chauhan
10
et al. applied this method to determine the efficiencies of rice production
11
farms. Their results revealed that about 11.6% of the total input energy
12
could be saved [10]. Begum et al. calculated technical efficiency of
13
commercial broiler farms using DEA method. They considered constant
14
returns to scale (CRS) and variable returns to scale (VRS) model to
15
estimate the efficiency of DMUs [11]. Heidari et al. determined technical
16
efficiency (TE), pure technical efficiency (PTE) and scale efficiency (SE)
17
of energy use in broiler farms as 0.90, 0.93 and 0.96, respectively. In
18
addition their results revealed that about 11% of the total input resources
19
could be saved [2].
20
As stated above, some researches were conducted to evaluate
21
environmental impacts of broiler production systems by LCA method and
22
in some other researches DEA method was used to estimate energy 5
ACCEPTED MANUSCRIPT 1
efficiency and energy use reduction in the systems. But in the literature, a
2
research was not reported to reduce environmental impacts in broiler
3
production system. So, the aim of the present research was reducing
4
environmental impacts of broiler production systems in Isfahan
5
Providence, Iran. In this study, DEA method was applied to estimate and
6
optimize efficiency of energy consumption in the systems. Energy
7
reduction of the systems was calculated by subtracting the energy use
8
before and after comparison. Then, LCA method was used to calculate
9
the environmental impacts of the systems before and after comparison
10
and calculate the potential reduction of the impacts by subtracting the
11
emitted impacts before and after comparison.
12 13
2. Materials and Methods
14
A flowchart of calculation steps in the present research has been shown in
15
Fig. 1.
16
Fig. 1.
17
The first step was started after data collection. In this step, real amounts
18
of used recourses inputs in all broiler production farms were determined.
19
After that, real amounts of energy consumption and the environmental
20
impacts in the broiler production farms were calculated according to the
21
consumed input recourses by LCA method. All broiler production farms 6
ACCEPTED MANUSCRIPT 1
were reduced in point of energy consumption by DEA method and then
2
the reduced amounts of energy consumption and also energy reduction in
3
the farms were calculated. The reduced amounts of input resources were
4
calculated according to the reduced energy consumption. Finally, the
5
environmental impacts were calculated based on the reduced input
6
resources by LCA method and then reduction of environmental impacts
7
were determined.
8 9
2.1. Data Collection
10
In this study, 90 broiler farms in Isfahan, Najafabad and Nain Township,
11
the most broiler producers of Isfahan Province, Iran, were randomly
12
selected to be studied. Isfahan Province is located within 30.65 north
13
latitude and 51.67 east longitude. The data were gathered by
14
questionnaires and interview with the farm owners in August-September
15
growing period, 2014. The average of growing period was 58 days. The
16
used resources (inputs) in the studied growing period were: total amount
17
of food, diesel and electricity consumptions and total working hours of
18
labors. The outputs of the studied broiler farms were meat and manure.
19 20
7
ACCEPTED MANUSCRIPT 1
2.2. Data Envelopment Analysis
2
Data envelopment analysis (DEA) is a non-parametric method which the
3
relationships between all inputs and outputs are taken into account
4
simultaneously [12]. The method compares the studied broiler farms as
5
DMUs, and finds out the relative efficiency of the farms and examines
6
their positions in relation to the frontiers. DEA method includes two
7
models: CCR (Chames, Cooper and Rhodes) and BCC (Banker, Chames
8
and Cooper) models [13]. CCR model is constant returns to scale and
9
BCC model is variable returns to scale method. Each of these models is
10
divided to output oriented and input oriented approaches. Input oriented
11
approach means that an inefficient DMU must decrease input to become
12
an efficient one, while the output is fixed. Whereas, the output oriented
13
method fixes the input levels and increase the output values.
14
In DEA method, three efficiencies are estimated as technical efficiency
15
(TE), scale efficiency (SE) and pure technical efficiency (PTE).
16
Technical efficiency (or global efficiency) is determined by evaluation
17
the performance of DMUs relative to each other [13]. Scale efficiency is
18
the potential productivity which is obtained based on the achieved
19
optimal size of a DMU [14]. Pure technical efficiency or local efficiency
20
is the technical efficiency that removes the effect of scale efficiency [15].
21
The difference between three efficiencies has been explained in Fig. 2.
8
ACCEPTED MANUSCRIPT Fig. 2.
1 2
Two DEA models have been shown in Fig. 2. The MN line that passes
3
from the extreme data points represents a constant return to scale. Each
4
DMU on MN line is efficient one and its efficiency is equal to unit. Also,
5
pure technical efficiency of the DMUs on break line (P1, P2, P3 and P4)
6
is equal to unit. Having both technical efficiency and pure technical
7
efficiency, scale efficiency of DMUs can be estimated. The scale
8
efficiency of a DMU is equal to unit if its technical and pure technical
9
efficiencies are equal to unit. So, P2 DMU is efficient but other DMUs
10
are not and they are called as inefficiency DMUs. The three efficiencies
11
can be explained by following equations [7]: AB
TE = PTE =
SE = 12
(1)
AD
AC
(2)
AD
AB
(3)
AC
From above equations can be derived that: (4)
TE = PTE × SE 13
From Eq. 4 can be argued that TE is actual efficiency and SE shows an
14
efficiency ratio between ideal and actual efficiency. EMS 1.3 Software
15
[16] was used in this study to analyze the data by DEA method.
9
ACCEPTED MANUSCRIPT 1
In order to optimize the input resources of all studied farms, firstly the
2
energy of all inputs were calculated. The inputs and outputs recourses
3
were converted to energy (actual) by multiplying the quantity of each
4
input/output to its corresponding energy equivalent. The used energy
5
equivalents in this study and their references were listed in Table 1.
6
Table 1.
7
The actual energy amounts of all input recourses were used as input of
8
DEA method via EMS 1.3 Software. In this study input oriented approach
9
was used to identify efficient (frontiers) and inefficient farms. The EMS
10
Software identifies efficient and inefficient farms based on actual energy
11
inputs of the farms by comparison them with each other. After identifying
12
and classifying the efficient and inefficient farms, the inefficient farms
13
were reduced to reach an efficient position in point of energy
14
consumption.
15
The energy comparison process is done by comparison inefficient farms
16
to efficient ones to determine the ideal energy use. The saved energy can
17
be determined by subtracting ideal from actual energy use [2; 14].
18
The reduced input resources are calculated considering reduced input
19
energies divided by those corresponding energy equivalents (Table 1).
20
These data were used as LCI data before and after comparison. The input
10
ACCEPTED MANUSCRIPT 1
recourses of broiler farms before and after comparison were considered to
2
determine the environmental impacts by LCA method.
3 4
2.3. Life Cycle Assessment
5
Life cycle assessment is an approach to estimate environmental impacts
6
related to a product, process or activity. LCA approach includes four
7
phases based on ISO 14040 and ISO 14044: goal and scope definition,
8
inventory analysis, impact assessment and interpretation of results [5;
9
24]. In the present study, LCA method was used to calculate
10
environmental impacts before and after DEA comparison of the broiler
11
farms.
12 13
2.3.1. Goal and Scope Definition
14
Goal and scope definition is the first phase of LCA that explain the
15
purpose of the study, the expected product of the study, the system
16
boundary and the assumptions. In the present study, LCA method was
17
used for calculating environmental impacts of production process of
18
broiler farms before and after DEA comparison. The system boundary
19
was farm gate including fuel, electricity and food and emissions
20
associated with live chicks (Fig. 3). Broiler breeder production, slaughter,
11
ACCEPTED MANUSCRIPT 1
chicken packaging and salon construction were not considered in this
2
research.
3
The functional unit of this study was one tonne live mass of broiler. This
4
functional unit is in agreement with previous studies [9; 11; 25]. Since
5
both energy and environmental impact reduction were simultaneously
6
investigated, mass allocation method was considered in the present study
7
[11; 26]. Fig. 3.
8 9 10
2.3.2. Life Cycle Inventory
11
The second phase of LCA study is life cycle inventory (LCI). Various
12
input resources and environmental impacts were quantified in this phase.
13
The actual and ideal inputs of the farms were considered as LCI data.
14
Further information (for production of food, electricity, transportation,
15
etc.) was taken from the SimaPro 8.0 Software Database. Fuel, electricity
16
and food were considered as input resources in the LCA study and
17
outputs were chicken meet and manure. Same to other studies, cleaning
18
agents used for disinfection of poultry salons were neglected in the LCA
19
study [27; 28].
20
Electricity is utilized for different purposes in the studied broiler
21
production farms such as: ventilating, lighting and water pumping.
12
ACCEPTED MANUSCRIPT 1
Electricity supply has been delivered from the grid region. Two kinds of
2
fuels, 99 % natural gas and 1 % Mazut are used in electricity grid of
3
Isfahan Province. The environmental impacts of each electricity supply
4
method were calculated according to fuel consumption percentage.
5
The used fuel for heating system in the studied broiler farms was included
6
diesel and natural gas. In this study, the fuel consumptions were high
7
because Isfahan Province is located in a dry region. Emission factors for
8
using diesel fuel and natural gas were considered based on [24]. The
9
USLCI Database was used in this study [29].
10
The share of maize and soybean was more than 90 % of the broiler foods.
11
The information related to foods was taken from the SimaPro 8.0
12
Software Database. In this study, crop production was not included in the
13
system boundary and it wasn’t considered in assessment process. The
14
largest emission of live chicks comes from the litter manure. N2O (direct
15
and indirect) and CH4 are emission factors of litter manure that were
16
determined based on IPCC guideline [24].
17 18
2.3.3. Life Cycle Impact Assessment
19
Environmental impact assessment method was selected based on CML-
20
IA baseline V3.02/EU25/Characterization. Totally 11 impact categories
21
were studied in this study (Table 5). These impact categories were 13
ACCEPTED MANUSCRIPT 1
selected based on the inputs of the broiler production farms. Impact
2
assessment calculations were conducted using SimaPro 8.05 Software
3
from PRé Consultants [29].
4 5
3. Results and Discussion
6
3.1. Farm efficiency
7
In this study, the CCR and BCC models were considered to evaluate
8
technical, pure technical and scale efficiency of poultry production.
9
Efficiency values of the studied farms were presented in Table 2.
10
Table 2.
11
The mean values of TE, PTE and SE were calculated as 0.91, 0.96 and
12
0.92, respectively. It is clear that the mean efficiency of all farms were
13
less than unit that shows inefficient amount of resources and energy
14
consumption in the studied farms. The highest value of standard deviation
15
(0.13) was belonged to technical efficiency with a range of 0.49 to 1. This
16
indicated that technical efficiency better than other efficiencies shows the
17
variation and also revealed that more farms loss the energy or
18
inefficiently use energy and so need more cares to improve their
19
operating practices for enhancing energy and resources consumption
20
efficiency.
14
ACCEPTED MANUSCRIPT 1
In the literature, TE, PTE and SE of broiler farmers of Yazd Providence,
2
Iran, were reported as 0.90, 0.93 and 0.96 [2], technical efficiency of
3
poultry egg production as 0.873 [12] and TE and PTE for broiler farms as
4
0.70-0.73 [8].
5
According to Duncan Multiple Range Test, the studied DMUs were
6
significantly separate by different efficiency classes (Fig. 4).
7
Fig. 4.
8
The result of CCR model showed that between total of 90 farmers, only
9
46 farmers were relatively efficient (TE=1) and the remaining were
10
inefficient, i.e. their efficiency value were less than unit. Whereas the
11
result of BCC model indicated that 57 farmers were efficient (PTE=1).
12
Because of the lower number of indicated efficient DMUs based on CCR
13
model, the TE values were considered for comparison of the inefficient
14
DMUs.
15 16
3.2. Energy use
17
The input energy before and after comparison and also amount of saved
18
energy has been presented in Table 3.
19
Table 3.
20
As can be seen in table 3, all energy inputs can be decreased based on
21
DEA method. The total energy use can be reduced by 10.16 %. The 15
ACCEPTED MANUSCRIPT 1
highest amount of energy save was belonged to diesel, gas, food and
2
electricity, respectively. Although Table 3 says that use of equipment in
3
broiler farms can be decreased (from 169.78 to 70.12 MJ/1000bird), but
4
increasing the level of technology of used equipment in the farms,
5
mechanized systems (heating and feeding), air conditioning and applied
6
appropriate management method to optimize the farm inputs lead to
7
reduce consumption of fuel, electricity and food.
8 9
3.3. Resource use
10
Amount of reduced energy use related to each input was divided by its
11
corresponding energy equivalent (Table 1) to obtain the reduced
12
resources use. The consumed resources before and after comparison were
13
presented in Table 4. These data were used as LCI data before and after
14
comparison. Table 4.
15 16 17
3.4. Environmental impacts
18
In this section, the mean values of environmental impact of all broiler
19
farms were calculated before comparison (actual). The corresponding
20
ideal values were calculated after DEA comparison. Impact reduction was
21
calculated as the difference between actual and ideal impacts. The 16
ACCEPTED MANUSCRIPT 1
environmental impacts before and after comparison and impact reduction
2
was presented in Table 5.
3
Table 5.
4
Some previous studies reported global warming, eutrophication and
5
acidification indicators related to emissions from chicken production
6
farms to produce 1 tonne of chicken meat in different countries. Dasilva
7
et al. estimated the emission in France for the mentioned indicators as
8
2216 kg CO2 eq, 13.8 kg PO4 eq and 28.7 kg SO2 eq, respectively.
9
Dasilva et al. reported their findings in Brazil as 2058 kg CO2 eq, 14.4 kg
10
PO2 eq and 34.5 kg SO2 eq, respectively [25]. In Finland, Katajajuuri et
11
al achieved 2079 kg CO2 eq, 2.1 kg PO4 eq and 35 kg SO2 eq,
12
respectively [30]. Pelletier studied emission of broiler farms in USA and
13
obtained indicators as 1395 kg CO2 eq, 3.9 kg PO4 eq and 15.8 kg SO2
14
eq, respectively [9]. Williams et al. expressed emission values for the
15
indicators in United Kingdom as 1800 kg CO2 eq, 14 kg PO4 eq and 25.9
16
kg SO2 eq, respectively [31]. In another research, Leinonen et al. studied
17
emission of United Kingdom and expressed 3087 kg CO2 eq, 14.2 kg
18
PO4 eq and 32.7 kg SO2 eq, respectively [32].
19
The global warming, eutrophication and acidification indicators for
20
production of 1 tonne chicken meat in the present research were equal to
21
5782.380 kg CO2 eq, 9.881kg PO4 eq and 35.755 kg SO2 eq,
22
respectively. The amounts of eutrophication and acidification indicators 17
ACCEPTED MANUSCRIPT 1
in Iran are same as corresponding values in different studied countries.
2
But, global warming is higher in compare with other countries that must
3
be decreased by considering better managing use of input resources.
4
Contribution of inputs to environmental impact categories for producing
5
1 tonne chickens before comparison has been shown in Fig. 5.
6
Fig. 5.
7
As can be seen in Fig. 5, the contribution of food to environmental
8
impacts derived from the studied farms was especially high, except for
9
human toxicity and marine aquatic toxicity indicators. The share of food
10
in the abiotic depletion, depletion of fossil resources, global warming,
11
ozone layer depletion, fresh water toxicity, terrestrial toxicity,
12
photochemical
13
eutrophication indicators was equal to 75.1, 41.8, 58.3, 64.6, 72.6, 46.5,
14
25.3, 58.9 and 94.6 %, respectively. Maize and soybean are most
15
important ingredients of food in broiler farms. They had highest
16
contributions in all categories due to its cropping stage.
17
The impact of livestock food on human toxicity and marine aquatic
18
toxicity was low (1.43 and 1.08 %, respectively) but the share of live
19
chicken on the indicators was high.
20
The most important input in the potential of global warming was food due
21
to releasing carbon dioxide into the air (91 %). Equipment (steel) had the
oxidation,
potential
18
acidification
and
potential
ACCEPTED MANUSCRIPT 1
highest share in ozone layer depletion indicator (52.78 %). Contribution
2
of the heating systems to environmental impacts was 22.4 % in
3
acidification potential, 2.73 % in eutrophication potential, 1.54 % in
4
ozone depletion and 22.3 % in global warming. Emissions of heating
5
systems in the studied broiler farms were correspond to burning natural
6
gas and diesel.
7
Methane was the main source of emission into the air in ozone layer
8
depletion indicator. In acidification potential, ammonia with amount of
9
13.49 kg SO2 eq (39 %) had the highest greenhouse gas emissions and in
10
eutrophication indicator, nitrate with amount of 5.61 kg PO4 eq had a
11
share of 57 % of the emissions to the water.
12
As reported by several researchers, food is the most important input for
13
increasing environmental impacts associated with farm-related activities
14
[9; 27; 30; 33; 34]. da Silva et al. studied the emissions from poultry
15
production in Brazil and France. They concluded that food input had the
16
highest emissions in the global warming, soil toxicity and eutrophication
17
indicators. In toxicity indicators, food had the highest share in Brazil, but
18
live chicken had the highest emission in France due to NH3 emissions.
19
Due to high use of fossil fuels, food had high effect on global warming
20
indicator. The use of nitrogenous fertilizers for food in Brazil caused to
21
increase the toxicity indictors [25].
19
ACCEPTED MANUSCRIPT 1
Nielsen et al. investigated the greenhouse gas emissions of poultry
2
production in Denmark. They reported that the main factor in emissions
3
of global warming potential was the food input with a share of 91 %
4
because of high use of fossil fuels [26].
5
Bengtsson and Seddon studied the emissions of broiler production in
6
Australia to identify environmentally sensitive areas in this sector. They
7
reported that food input is the biggest impact point in broiler chain with
8
emission amount of 1885 kg CO2 eq [33].
9
According to the results of the present and previous studies there was
10
concluded that the food input has the highest emissions. The use of fossil
11
fuels in the production of agricultural products increases the amount of
12
emissions. Also in food production step or any step that fossil fuel is
13
used, the environmental impacts can be minimized by using high fuels
14
efficiency equipment. Renewable energies are good alternative for fossil
15
fuels that reduce the environmental impacts.
16
Environmental impact values after comparison were presented in the
17
fourth column of Table 5. Also, the comparison of present and reduced
18
environmental impacts for all DMUs, have been shown in Fig. 6.
19
Fig. 6.
20
As seen in Table 5 and Fig. 6, amount of all studied indicators was
21
decreased after comparison. For example, depletion of fossil resources by
20
ACCEPTED MANUSCRIPT 1
the studied farms was equal to 40924.976 MJ before comparison which
2
decreased to 35358.585 MJ after comparison. Considerable impact
3
reduction can be detected in depletion of the ozone layer. The present
4
ozone layer depletion (ODP) was 4.225 kg CFC-11 eq that can be
5
reduced to 1.801 kg CFC-11 eq (57.37 % reduction). The global warming
6
indicator was 5782.380 kg CO2 eq before comparison whereas the
7
corresponding reduced emission will be 5004.346 kg CO2 eq after
8
comparison. So, emission reduction of GWP can be 778.034 kg CO2 eq.
9
Human toxicity reduced from 41447.050 to 30366.805 kg 1.4-DB eq.
10
Acidification can be reduced by 12.89 % and eutrophication reduced
11
from 9.881 kg PO4 eq to 8.620 kg PO4 eq (12.80 % reduction).
12 13
Conclusions
14
In the present research, the energy use and environmental impacts of
15
poultry production in Isfahan, Iran, was evaluated before and after
16
comparison by DEA and LCA methods. The total energy use can be
17
reduced by 10.16 %. Environmental impacts were significantly reduced
18
after comparison. The indicator including, abiotic depletion, abiotic
19
depletion (fossil), global warming, ozone layer depletion, human toxicity,
20
fresh water aquatic ecotoxicity, marine aquatic ecotoxicity, terrestrial
21
ecotoxicity, Photochemical oxidation, potential of acidification and 21
ACCEPTED MANUSCRIPT 1
eutrophication were decreased by 31.32, 13.60, 13.46, 57.37, 26.73,
2
16.12, 27.59, 17.43, 17.38, 12.89 and 12.80 %, respectively. As food
3
input has the highest contribution to the emissions due to high amount of
4
fossil fuels consumption, it is needed to apply efficient management
5
method to optimize food consumption, decrease food losses in the broiler
6
farms and decrease fuel consumption in food producing farms. Also,
7
improving mechanization and management level in broiler farm to reduce
8
fuel, electricity and other inputs are recommended. The results of this
9
study can be useful for farmers and agricultural organizations to reduce
10
energy and resource consumption and environmental emissions. Also,
11
more technical and economic aspects can be considered to improve the
12
management of poultry production systems.
13 14
Acknowledgements
15
The authors would thank the Ilam University to spurt this research. Also,
16
poultry farmers in Isfahan Province, Iran, are appreciated for their assists
17
and providing the required information.
18 19 20
22
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ACCEPTED MANUSCRIPT
Start
Determination of real input resources
Calculation of real energy consumption
Calculation of real environmental impacts
Estimation of reduced energy consumption
Calculation of energy use reduction
Calculation of reduced input resources Calculation of reduced environmental impacts
Calculation of environmental impacts reduction
End Fig. 1. The main calculation steps of environmental impacts reduction.
ACCEPTED MANUSCRIPT
Fig. 2. Graphical representation of different DEA efficiency types (Chauhan et al., 2006).
ACCEPTED MANUSCRIPT
Electricity
Fuel
Chicken
Poultry
Meet
Manure
Emission
Fig. 3. Poultry system boundaries.
Feed
ACCEPTED MANUSCRIPT
57
No. of DMUs
60 50
46
TE
PTE
40 29
30
21
20
12
10
11 4
0
0 1
1-0.9 0.9-0.8 Efficiency class
<0.8
Fig. 4. Efficiency distribution of DMUs.
ACCEPTED MANUSCRIPT
Fig. 5. Contribution of inputs to environmental impact categories for producing 1 tonne chickens before comparison of the units by DEA method. .
ACCEPTED MANUSCRIPT
Fig. 6. The environmental impact categories to produce 1 tonne chickens before and after comparison of the units by DEA method. .
ACCEPTED MANUSCRIPT
Table 1. Energy equivalents (MJ/unit) of inputs and outputs in broiler production. Input/Output Unit Energy equivalent
Reference
Inputs Labor
kg
1.96
[2]
l
47.80
[17]
m3
49.50
[17]
Maize
kg
7.90
[18]
Soybean
kg
12.60
[18]
Di calcium Phosphate
kg
10.00
[19]
Minerals
kg
1.59
[20]
Vitamins
kg
1.59
[20]
Fatty acid
kg
37.00
[21]
Salt
kg
1.59
[20]
kWh
11.93
[14]
Broiler
kg
10.33
[22]
Manure
kg
0.30
[23]
Fuel Diesel Gas Food
Electricity Outputs
ACCEPTED MANUSCRIPT Table 2. Efficiency scales of studied poultry farms. Efficiency scale
Minimum
Mean
Maximum Standard deviation
Technical efficiency
0.49
0.91
1.00
0.13
Pure technical efficiency
0.84
0.96
1.00
0.03
Scale efficiency
0.49
0.92
1.00
0.12
ACCEPTED MANUSCRIPT
Table 3. Amount of input energy (Mj/1000 bird) before and after comparison of the DMUs by DEA method. Energy value Saved energy Input Present Reduced Chicks
499.50
497.00
2.50
Labor
107.02
102.84
4.18
Diesel
29001.60
20281.15
8720.45
Gas
53695.87
50747.15
2948.72
Food
50242.88
48455.11
1787.77
Electricity
17102.63
15341.25
1761.38
Equipment
169.78
70.12
99.66
150819.29
135494.62
15324.67
Fuel
Total
ACCEPTED MANUSCRIPT
Table 4. Amount of input and output resources before and after comparison of the DMUs by DEA method. Resources value Unit Input/Output Present Reduced Inputs Chicks
Kg
48.35
48.11
m3
1048.77
1019.70
Diesel
L
602.90
424.29
Food
Kg
5104.99
4528.52
Electricity (gas)
kWh
1419.25
1285.94
Electricity (Mazut)
kWh
14.34
12.86
Steel
kg
92.52
1.71
Polyethylene
kg
28.78
0.72
Broiler
kg
2400.53
2400.53
Manure
kg
1691.71
1691.71
Fuel Gas
Equipment
Outputs
ACCEPTED MANUSCRIPT
Table 5. Environmental impacts of poultry production before and after comparison of the DMUs by DEA method. Impact value Impact Impact category Unit reduction Present Reduced Abiotic depletion
kg Sb eq
0.0022
0.0015
0.0007
Abiotic depletion (fossil fuels)
MJ
40924.976
35358.585
5566.391
Global warming (GWP 100a)
kg CO2 eq
5782.380
5004.346
778.034
Ozone layer depletion (ODP)
kg CFC-11 eq
4.225
1.801
2.424
Human toxicity
kg 1,4-DB eq
41447.050
30366.805
11080.25
Fresh water aquatic ecotoxicity
kg 1,4-DB eq
5866.113
4920.248
945.865
Marine aquatic ecotoxicity
kg 1,4-DB eq
Terrestrial ecotoxicity
kg 1,4-DB eq
1952.126
1611.852
340.274
Photochemical oxidation
kg C2H4 eq
1.237
1.022
0.215
Acidification potential
kg SO2 eq
35.755
31.145
4.61
Eutrophication
kg PO4 eq
9.881
8.620
1.261
32057072.300 23211337.520
8845735