Emergy Evaluation of the IBK-recirculation
aquaculture system for fisheries production in Korea
Puji Rahmadi, Suk Mo Lee*
Department of Ecological Engineering, Pukyong National
University
Abstract
A continuous
decrease in fisheries capture production led Korea to pay greater attention on
aquaculture. The
Intensive Bio-culture Korean (IBK)-system has believed as a solution method for
fisheries production. This study was
trying to analyze the energy and emergy flow inside the IBK-system. Further
analysis was done with emergy indices calculation to predict the future
application of IBK-system. The result of study shows
the energy required in fish harvested
from IBK-system (fish transformity) was 2.26E+09 J/g fish. This number represents it is needed more energy to produce per
gram fish in IBK system compared to conventional fisheries in Ecuador and in
Sri Lanka, but less energy needed than intensive aquaculture in China. The EYR in this study was 1.02, even though
the number is relatively low, this system has accepted to be consumer products or transformation steps than actual energy sources
since the value is higher than 1. The value of ELR and EIR was pointed in the
same number (68.74) because the system doesn’t have
non-renewable sources, which is purchased input compared to renewable
environmental loading (F/R). System more likely depend on purchased input which
was indicated by very high EIR but in contrary relatively low EYR. Even though the EYR is low, EIR and ELR are high, and ESI has shown
high risk condition, it doesn’t mean the system is not feasible to operate. In
the real condition, higher price per kilogram fish could bring higher benefit
in term of economic, therefore this system only suitable to apply in developed
countries with limited area, limited of natural sources and fish consumptions
relatively high.
Keyword: Emergy, Intensive Bio-culture Korean System, emergy indices
1.
Introduction
Korea is a peninsula with long coastline
and covering huge number of islands within the territory. Endowed with an
abundance of fisheries resources, Koreans have developed a distinct fish food
culture-based on marine products (FAO, 2003). Aquaculture production has
increased from 667,883 tons in 2000 to 839,845 tons in 2003 and 935,650
tons in 2009 (FAO, 2003; KOSTAT, 2010). Aquaculture has become a very
important sector in the Republic of Korea. It provides food security, revenue
and employment to the country. With the development of new technologies,
aquaculture production has increased more than 40% of total fisheries
production in 2010. In
Korea fisheries production generally drives to the degradation of water quality
in coastal, causing seawater intrusion and some places event reducing the
quality of drinking water, and degradation of natural stock. Therefore,
fisheries production should be practiced with waste water
treatment for the reduction of pollution in the environment. The best
solution believed by the ecologist and fisheries realm to produce sustainable
fisheries production in the future is feeding aquaculture in inland water and
in the protected coastal seas with the certain aquaculture method. Therefore we
need to develop the technology of environmentally friendly aquaculture systems
as completely as possible not only to preserve our natural environment but also
to sustain aquaculture production.
Korea
has a small land area and highly limited for water resources. The
pollution of water and air has been a serious problem for the survival of the
nation. Therefore several fisheries production
method applied in some country like China, Sri
Lanka, Ecuador or Philippine were not applicable in small developed country
such as Korea and the other country with similar characteristic. In Philippine,
Sri Lanka and even Ecuador (Bergquist, 2008; Odum&Arding, 1991), the
conventional method and traditional way were still dominant, but in China they had practicing intensive aquaculture
but still using huge area to produce fish in the aquaculture (Li, L., et al, 2010). In l998 the central
government of Korea declared that all cage farms
in the inland waters be discontinued after the terms originally permitted,
almost all of which fall in before l999. Majority of the cage fans has already
been dismantled. The bulk of freshwater fish has so far been produced from the
net cage farms. The only substitution for outgoing fish production from the
cage farms is expected by the development of the closed recirculating fish culture
system which should be environmentally friendly as well as economically
feasible especially in the era of the global open market. Recently recirculation aquaculture system (RAS) is well developed
regarding as the best solution to substitute in fisheries production method. Considering
the limit of water supply for fish growing experiments, many of researchers
have been using closed recirculating aquaculture systems (RAS) for various fish
growing experiments in the laboratory. This recirculating aquaculture system
has been developed and redesigned as an Intensive Bio-production Korean System
(IBK System). The
IBK system, which was originated from the system by Professor In-Bae Kim (Korea-US Aquaculture, 2008) has continued
improvement though modification up to now. Main principles for the system
development of the RAS have been based
on the basic principles for the high-density fish culture. The system design is
very simple and does not employ highly sophisticated parts. The system
structurally consists of rearing tanks, small sedimentation tanks, a pumping
station, and multiple sections of the biological filter.
In order to increase fisheries production, fish farmer should
consider the risk and negative effect of production activity to the
environment. Therefore, before IBK-system could be well applied, it is better
to explore the benefit and feasibility from the system. In this research, an
aquaculture system of IBK-system was analyzed and emergy analyses were done to
determine the efficiency and potential of sustainability. In the economic realm,
typically we will easily calculate the amount of capital and yielded production
to predict or analyze the benefit, yet when we try to compare the economic and the
impact of production activity into our environment, we must be facing the
constraints in terms of units, proportion and so on, here therefore the EMERGY
method could be apply. Odum (1983, 1988, 1996) using
the principles of Energy Systems Theory developed a comprehensive ecological
economic evaluation method (i.e., emergy synthesis) to evaluate different energy,
material and monetary flows in terms of their emergy. Emergy is defined as the
amount of available energy of one type previously used up directly and
indirectly to make a product or service (Odum, 1996), usually expressed as solar
emjoules (sej). Emergy per unit values, i.e., transformity (sej/J), specific
emergy (sej/g) and emergy/money ratio (sej/money unit), can be used to convert
energy, material and monetary flows of all kinds to solar emjoules allowing
direct comparison, addition and subtraction among them (Lan et. al., 2002).
Thereby, emergy analysis can evaluate properly environmental contributions
formerly missing from economic evaluations (Odum, 1988, 1996, 2007; Lanet. al.,
2002).
Since the IBK-system has considered as ones of
solution methods on fisheries production, analysis of system efficiency are needed.
The analyses were purposed on viability, benefit, and sustainability potentials
from the system. In order to analyze economic and ecological factor, emergy
analysis were then try to apply. Emergy analysis had completed with some emergy
indices calculation, to describe and to predict the present condition also thereafter.
Based on emergy analysis and those indices, some recommendations are expected
for the application of IBK-system.
2.
Material and Method
Generally there are
three main approaches to do emergy analyses (input, process and output), but
various intermediate forms exist. Therefore emergy analysis can be done simply
through some steps, which are; determining the boundary, defining the important source, listing the process, diagraming
energy flows, composing emergy table,
and indices calculation.
In emergy analysis, each form of energy supporting the system will
be translated into the same energy quality (mostly solar energy). The
translations of energy could be done through conversion ratio, this ration
called “transformity”. Base on the transformity, various kind of energy could
be converted into the same kind of energy and can easily analyze each
contribution to the system. In this study we also try to collect the raw data from
each energy supporting the IBK system, and converted those data into solar
energy equivalency. Furthermore, emergy indices are used for better evaluation
of the concerned system. These indices indicate various performance of the
system in term of efficiency and sustainability (Campbell, 1997). Associated with an
aquaculture, some basic indices of ecological interest (Odum and Odum, 1983;
Ulgiati et al., 1995; Odum, 1996; Brown and Ulgiati, 1997; Ulgiati and Brown,
1998) are calculated, those were Emergy Yield Ratio (EYR), Emergy Investment
Ratio (EIR), Environmental Loading Ratio (ELR), and Environmental
Sustainability Index (ESI).
2.1. Application of IBK- system
The IBK system has been successfully tested to grow a number of
freshwater fish species including tilapia, Israel strain of common carp,
channel catfish and eels both Anguilla japonica and A. anguilla, but in this research, tilapia farming
is the major species cultured in the experiment system;
therefore tilapia culture using IBK-system has been evaluated by emergy analysis.
IBK-system subjected for this experiment was located at Sangju, Gyeongsang Bukdo, South Korea. The system was built 30 years ago and
will last long for 10 years more before the renovation. This system was made
and designed for growing of fish at high densities with
the minimum natural sources. Author was visiting, survey and interviewing the
system in charge person. System was built on the area of 750 m2,
inside the greenhouse with phenyl as a cover. There were 24 culture tank with
some sediment chamber and bio-filter tank. The system could hold 400 m3
of fresh water as a media culture. This system was using daily exchange water about
1% of total volume, and whole water body was changed annually.
Fig.
1. Sketch of IBK-system
Normal density of tilapia in this system has been at least 5% of the
water volume in the rearing tank and could keep on normal growth until higher
than 10% to 20% of water volume though the growth rate was decreased.
Fingerling was used as a starter in a culture with the number of 500 individual
per tank, along with the culture time (1 year) it will have survival rate about
80% and could achieve the harvesting size ±850gr/indv. Instead of fingerling,
fish farmer should prepare the suitable feed for fish. In this experiment, farmer divide
feeding regimes into 4 different group, those were <100 gr, <250
gr, <500gr, and >500 gr of body weight (BW), with the feeding ration of
2%, 1%, 0.7%, and 0.5% of BW respectively. Using those different feeding
regimes, farmer counted to spend 7941 kg of feed/yr.
Korea is a country
with the winter season; it is always being the problem for aquaculture in
temperate country. To solve this problem, farmer in this experiment using boiler to keep the water temperature. Boiler consumes 300 L of
fuel in average for a year. The other cost which should be loaded
by farmer were electricity as much 3650 kWh/year, labor cost, system maintenance cost 1.5 million₩/year, water quality and diseases controlling cost for 1.5 million₩/year. Detail of cost and energy spends by farmer will then converted
into emergy unit which is listed in the Table 1.
2.2. Energy Diagram
For better
understanding, evaluating, and simplify, procedure of
emergy analysis always start with diagraming the system of concern and followed
by emergy table. The diagram of energy flow in the IBK-system were then has
composed to figuring the energy circulation in the system.
2.3.
Emergy Table
Data which was collected in this experiment were listed into
emergy table, priority has been made, and all energy was converted into solar
energy equivalency using some transformity which has been published in some
references.
2.4.
Emergy Indices
2.4.1. Emergy Yield
Ratio (EYR)
EYR is the
ratio between total emergy feedbacks with the total emergy yield. In EYR, to avoid losing out from the point of view of energy, the output of a
system should be at least equal to the investment that is when the emergy yield
ratio is equal to one. The higher the value of this index, the greater the
return obtained per unit of emergy invested.
EYR = Y/F
2.4.2. Emergy Investment Ratio
(EIR):
EIR is the
ratio of purchased resources to renewable and nonrenewable local inputs. It
will tend to be economical if its ratio is less or equal to the one prevailing
in the region (Odum, 1996). The less the ratio, the less the
economic cost, so the process with lower ratio tends to compete, prosper in the
market (Li, L., et al., 2010).
EIR = F/(R+N)
2.4.3.
Environmental Loading Ratio (ELR):
ELR
is given by the ratio from purchased and nonrenewable local inputs, to the
emergy from renewable resources. It is an indicator of the pressure of a
transformation process on the environment and can be considered a measure of
ecosystem stress due to a production. ELR = <
2 indicate of relatively low environmental impacts, when the number of ELRs = 3 – 10 indicate of
moderate environmental impacts, otherwise ELRs = > 10 indicate of
extremely high impacts to the environmental due to largeflows of concentrated
nonrenewable emergy (Brown and Ulgiati, 2004).
ELR = (F+N)/R
2.4.4.
Environmental Sustainability Index (ESI)
This
index is used to analyze the environmental and ecological sustainability in
order to support the viability (continuity) of process.
The larger the ESI, the higher the sustainability of a system.
ESI = EYR/ELR
3.
Results and Discussions
3.1.Energy Diagram
Fig.2.
Diagram of energy flow in the IBK-system.
3.2.Energy Table
Table 1. EMERGY evaluation of IBK-system in
Korea, annual flow per m2
Item
|
Data / Units
|
Transformity
|
Solar Emergy
|
Em value
|
||
(J, g, ₩) / yr
|
(sej/unit)
|
(sej/yr)
|
(Em₩/yr)
|
|||
Environmental
Input
|
||||||
Pumped
Water
|
1.53E+06
|
J
|
2.72E+05
|
a
|
4.16E+11
|
1.56E+02
|
Purchased
Input
|
||||||
Fingerling
|
5.02E+05
|
J
|
5.60E+05
|
a
|
2.81E+11
|
1.06E+02
|
Feed
|
2.85E+05
|
J
|
1.40E+05
|
b
|
3.99E+10
|
1.50E+01
|
Fuel
|
4.20E+07
|
J
|
1.81E+05
|
c
|
7.60E+12
|
2.86E+03
|
Good
and Service
|
||||||
Electric
|
1.75E+07
|
J
|
2.91E+05
|
d
|
5.10E+12
|
1.92E+03
|
Labor
|
1.06E+06
|
J
|
2.36E+06
|
a
|
2.50E+12
|
9.40E+02
|
Maintenance
Cost
|
2.00E+03
|
₩
|
2.66E+09
|
e
|
5.32E+12
|
2.00E+03
|
Water
quality control Cost
|
1.33E+03
|
₩
|
2.66E+09
|
e
|
3.55E+12
|
1.33E+03
|
Disease
control cost
|
6.67E+02
|
₩
|
2.66E+09
|
e
|
1.77E+12
|
6.67E+02
|
Farm
Installation
|
||||||
a. Stone
|
2.25E+02
|
g
|
1.68E+09
|
f
|
3.79E+11
|
1.42E+02
|
b. Sand
|
1.35E+02
|
g
|
2.24E+09
|
f
|
3.02E+11
|
1.13E+02
|
c. Concrete
|
8.32E+01
|
g
|
2.58E+09
|
g
|
2.15E+11
|
8.07E+01
|
d. Iron + Steel
|
1.65E+01
|
g
|
1.90E+10
|
h
|
3.14E+11
|
1.18E+02
|
e. Phenyl
|
4.63E+02
|
₩
|
2.66E+09
|
e
|
1.23E+12
|
4.63E+02
|
Annual
yield (Y)
|
1.28E+04
|
g
|
2.26E+09
|
i
|
2.90E+13
|
1.09E+04
|
Table 2. EMERY indices of fisheries
production in Korea and other systems
Indices
|
EYR
|
EIR
|
ELR
|
ESI
|
|
This Study
|
1.02
|
68.74
|
68.74
|
0.02
|
This Study
|
Weever
|
1.04
|
1.95
|
26.15
|
0.04
|
Li, et al., 2010
|
Ophicephalus
|
1.05
|
2.47
|
20.18
|
0.05
|
Li, et al., 2010
|
Eel
|
1.04
|
4.09
|
23.42
|
0.05
|
Li, et al., 2010
|
fisheries in Philippines
|
1.21
|
5
|
4.8
|
0.25
|
Bergquist, 2008
|
fisheries in Sri Lanka
|
1.03
|
29
|
33.8
|
0.03
|
Bergquist, 2008
|
Fisheries in Ecuador
|
1.38
|
2.67
|
2.67
|
0.52
|
Odum & Arding, 1991
|
3.3.Transformity
The results of study were listed in the
Table 1 and Table 2 following. The data shows transformity for fish produced by
IBK-system is 2.26E+09 J/g fish. This number was far higher compare to pelagic
fish and ponded shrimp from Ecuador also semi intensive shrimp production in
Sri Lanka, which only 2.20E+05 J/g, 3.17E+07 (Odum & Arding, 1991) and
8.11E+06 J/g respectively (Bergquist, 2008). Those mentioned aquaculture were
using conventional method, out door and wide area of production, therefore the system
more likely to dependent on natural resources and need less energy from
purchased input. However fish transformity in this study was not really high
compared to the same high-technology aquaculture applied in china, which were 5.79E+09 J/g fish for weever, 7.77E+09 J/g fish for ophicephalus, and 7.79E+09 J/g fish for eel culture. Those mentioned result
shows while aquaculture method involving technology; the higher technology used
the higher emergy needed to produce fish. However, when we look back the emergy
table, there shows extra energy was swelled up from purchased input than from environmental
loading, since the technology needs extra energy to maintain. Study were
continued to analyze the factor supporting the processes on IBK-system,
therefore emergy indices were calculated.
3.4.Emergy Indices
3.4.1. Emergy Yield Ratio (EYR)
Analyses of EYR and other
emergy indices from Table 1 were shown in Table 2. The EYR in this study was
1.02 and was the lowest compared to EYR in other several fisheries productions.
In term of emergy, this EYR number describing there was almost no energy
benefit from system (benefit only 2%), the system only altering many kind of
energy type with various portion into energy in the form of fish meat. Yet, fisheries in Philippines and Ecuador
has a greater benefit because those were conventional fisheries activity, which
need less emergy input either from purchased or from environmental. However, this not means the IBK system is not
applicable, because EYR only consider about energy term, and fish is not energy
sources as Brown and Ulgiati (2002) had reported for EYR higher than 1 has accepted
to be consumer
products or transformation steps than actual energy sources. In the other consent like economic benefit, it is
need deeply study about IBK system economic proses for viability since
renewable sources such as water were received freely from the environment. The
underline result here was, as long as there is no loosing of energy invested
(EYR<1), the system is permitted to apply if other consideration could
support to the system operation.
3.4.2. Emergy Investment Ratio
(EIR):
The EIR has pointed at 68.74, which mean the system has very high
economic cost. These also explain the system need more economic investment
compare to other system in the table.2 (The less the ratio, the less the
economic cost) because the system more depend on purchased energy than energy
loaded from environmental. The value of ELR and EIR in this experiment was
pointed in the same number because the system not involving non-renewable
sources, practice ELR and EIR has similar factor which is purchased input compared
to renewable environmental loading (F/R). System more likely depend on
purchased input was indicated by very high EIR but in contrary relatively
small/low EYR (Vassallo, et al. 2006). Hence effect from the system to the
environment indicated by ELR value.
3.4.3. Environmental Loading Ratio
(ELR):
The result of ELR calculated
in this experiment is 68.74, this number is very high even compare to other
system with different realm. Based on the data, the system has extremely high
ELR’s might resulted from the investment in a relatively small local
environment, very concentrated inputs derived from purchased energies. A
simultaneous increase of both EYR and EIR, indicates that a larger stress is
being placed on the environment (Brown
and Ulgiati, 2002), but this system was shows the opposite condition, while EYR recorded
in low number followed by very high number of ELR, this means stress is not
placed on the environment but rather to purchased factor (Bergquist 2008).
Identic to interpretation for EIR, high ELR here can be assumed to produce 1
unit of fish meat, it was needed 1 part of environmental loading factor and
more than 68 portion of purchased factor.
3.4.4. Emergy Sustainability Index
(ESI)
Subjected system in this study has
calculated for ESI value of 0.02. The higher ESI indicating more economic
relies on renewable and environmental loading. Since the non-renewable sources
were not involved here, the ESI formula also distributed into ratio of yield
emergy and environmental loading compared to quadratic power of purchased
input, formula were listed below:
ESI = EYR/ELR
à EYR = Y/F
à ELR = (F+N)/R à N~0 than ELR = F/R
= (Y/F) / (F/R)
ESI = (Y*R)/F2
Based on above formula, it shows how ESI
has effected by F as F factor were squared and independent to make division on
Y and R factor. This mean, since R and F factor are predictable and Y as total
harvested product is unpredicted, system is risky to have unsustainable in term
of energy. Because a few decrement on harvested product, it could promote the
degradation of ESI into 0 or even worse to minus, which mean energy contained
in fish is lower than energy to produce it.
Even though the EYR is low, EIR and ELR
are high, and ESI has shown high risk condition, those not mean that the system
is not feasible to operate. Those conditions was happed as explained before, it
was caused by high number of purchased factor needed, not caused by high consuming
of non-renewable sources. In the real condition, price for each kilogram of
fish also much higher than in the calculation as interaction with factor excluded
in the boundary for this study (i.e. import and export, stock availability,
price competition, etc.). Higher price per kilogram fish could bring high
benefit in term of economic; therefor this system is acceptable to apply in
Korea and other developed country with similar environment characteristic,
especially which were natural sources are limited and fish consumptions are
relatively high. Consider on area needed, environmental sources used, and degradation
of fish population in natural stock, aquaculture especially IBK system has suitability
to applied in Korea.
4.
Conclusions
Energy
needed to produce fish in IBK system is higher compare to natural and
conventional fish production. The relatively low number of EYR is indicating
the system only altering many kind of energy type with various portion into
energy in the form of fish meat. The IBK system has high investment needed to
produce fish since the system more depend on purchased energy than the environmental
loading, indicate by high number of EIR and ELR. The system
is risky to have unsustainable in term of energy if yield production less than
expectations. Higher price per kilogram fish could bring high benefit in term
of economic, therefore this system only suitable to apply in developed
countries with limited area, limited of natural sources and fish consumptions
are relatively high. The system not applicable in the developing countries with
huge area since the IBK system needs very high investment. In the future, we need to
develop the aquaculture method which has high benefit, low investment and low
risk in ecologically as well as economically.
5.
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