Environmental Impact Assessment of the Tofu Industry Using Life Cycle Assessment (LCA)
(Case Study: Sari Murni Tofu Factory, Kampung Krajan, Surakarta
) Rahma Audia Pertiwi1*, Sarah Josina Lamaret Nainggolan2*, Siti Nur Habibah3*1,2,3Environmental Engineering Department, Faculty of Infrastructure Planning, Universitas Pertamina, South Jakarta, DKI Jakarta 12220
*Corresponding author: [email protected], [email protected], [email protected]
1. Introduction
Tofu is a traditional food that contains protein and can be used as a meat substitute. Simple tofu processing technology makes the production process and waste disposal system resulting from tofu production less effective. Due to high costs and lack of knowledge about waste management, most manufacturers realize that they do not process the waste generated from their production.
Tofu production will increase along with increasing demand from consumers. The tofu industry is one of the food processing industries that produces quite significant waste. Proper and sustainable management of tofu industry waste is very important to protect the environment, maintain human health, increase production efficiency, and improve the company's image. An industrial process or activity has a greater environmental impact, not only affecting the surrounding environment but also the environment as a whole. To achieve a sustainable food industry, it is necessary to assess the environmental impact of food products consumed every day in large quantities. Thus, there is an expansion of understanding to analyze the environmental impact of the tofu production life cycle, one of which is through engineering Life Cycle Assessment (LCA).
LCA is an approach used to evaluate the environmental impact that a product, procedure or action may have over its entire life cycle. This method measures resource use and environmental emissions associated with the system being evaluated (Hermawan, 2013). LCA can be used to find out how much waste will be generated, how much energy will be consumed, and the raw materials needed during the production process (Thom, 2011). LCA was chosen for several reasons, including the use of comprehensive methods. LCA considers all stages of the product life cycle, from raw material extraction to waste disposal. This allows a comprehensive analysis of the environmental impacts of tofu production. In addition, LCA can be applied universally, for example it can be applied to various products and industries, including the tofu industry. This allows comparison of the environmental impact of tofu with other products. Another advantage is that using this method helps in decision making. LCA results can be used to identify areas where the environmental impact of tofu production can be reduced. This can help the industry know to make more sustainable decisions.
In the tofu industry, several studies have used other methods to analyze environmental impacts, such as Environmental Impact Assessment (EIA) and Life Cycle Costing (LCC). However, LCA has several advantages over these other methods.
EIA, EIA focuses on the environmental impact of a specific project or activity, whereas LCA considers the entire product life cycle.
LCC, LCC only considers the economic costs of the product life cycle, while LCA also considers the environmental impact.
Based on these considerations, LCA is the most appropriate method for analyzing the environmental impacts of the tofu production life cycle. This research uses a gate-to-gate approach to LCA, which means that this research only considers the tofu production stages, from raw material procurement to waste disposal. Pre-production and post-production stages, such as soybean cultivation and tofu consumption by consumers, were not included in this study because they were considered outside the scope of the research. The gate-to-gate approach was chosen because the data required for the pre-production and post-production stages was difficult to collect.
In addition, these stages have a relatively small environmental impact compared to the production stage (Thom, 2011).
2. Methods
2.1 Identification and Assessment of Environmental Aspects and Impact
Observations were carried out by following the Life Cycle Assessment (LCA) stages based on SNI ISO-14040, starting from determining the objectives and scope, carrying out inventory analysis, calculating life cycle impacts and interpretation. The initial stage of tofu production is that the raw material, that is soybeans, is soaked in water for 4-10 hours, then from. Later, this process produces waste is produced in the form of liquid waste (Harjanto, 2022). Followed by grinding the soybeans to produce fine soybeans or soybean powder, this process is carried out by machine. This process will produce emissions into the air due to the use of machines. Then in the process of boiling soybean powder followed by filtering and molding the tofu, it will produce emissions in the form of emissions into the air, effluent in the form of solid waste in the form of tofu dregs and waste water containing organic materials and nutrients. The output of this process is tofu that is suitable for consumption and distribution.
Based on the process of making tofu, data will be obtained in the form of primary data and secondary data. However, in this observation all the data taken came from secondary data which refers to previous research. The approach used is quantitative descriptive to examine environmental aspects and potential environmental impacts in the tofu making process.
The application of the Life Cycle Assessment (LCA) concept has not yet been implemented in the tofu making industry in Kampung Krajan, where the tofu making process uses inefficient energy, solid waste such as leftover production dregs has not been handled properly, no further processing
has been carried out, and the waste is in the form of wastewater. There is still a lot of organic material in it which is thrown away without prior processing which causes pollution to the river.
Liquid waste is one of the results of the process of washing, boiling, pressing, and molding tofu, so the quantity is very high. Liquid waste still contains high levels of organic matter and levels of Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD) are also still relatively high so it is not suitable to be disposed of directly into water bodies, because the environmental carrying capacity will greatly decrease (Enterprises, 2020).
2.2 Life Cycle Assessment (LCA) Methodology
Goal and Scope:
The aim of the LCA assessment at the Kampung Krajan Sari Murni Tofu Factory is to find out what and how big the impact is due to the use of materials and energy during the tofu making process on the environment. The scope of the research is an analysis carried out only on process inputs (ingredients) and energy at each stage in the tofu making process starting from soybean production, Life cycle processes in activities tofu production starts from providing raw materials, namely soybeans, firewood as an energy source, then stages are carried out washing soya bean, immersion soybeans where the energy required at this stage, this is electricity for the water pump. Milling Soybeans until smooth with a machine, then continue with boiling soy porridge, after the boiling stage is complete, then porridge soybeans will then be filtered and separated from the dregs. And the final stage is soybean extract which has been filtered then settled and given vinegar or soda to make soybean juice clumps, once the soybean juice starts to clump, then process furthermore that is pressing and cutting process tofu, so you get a tofu product. Then the last step is sending soybeans to consumers, the tofu making process at the Sari Murni Tofu Factory to delivery to consumers, in this case to the market. traditional, restaurant and household. So, in this case the scope used is cradle to gate.
Picture 1. Scope of Cradle to Gate Production Tofu Source: 2021 Research Data.
Life Cycle Inventory (LCI):
The process of making tofu in this factory is carried out for 8 hours a day, including the process of sending tofu to consumers. With the scope of the cradle to gate category, the analysis starts from the raw material processing stage to the production process.
Table 1. Inventory Data of Sari Murni Tofu Factory, Krajan, Mojosongo
No Material Amount Information
Input
1 Soya bean 350 Kg Average 300-400 kg in 1 day, produce 250 kg of tofu
2 Water 210 liter For all processes in 1 day
3 Transportation 14.969 km=5239,15 t*km
Company Address: Global Agro Inc., 708 Lotus Blossom St., 92024, ENCINITAS, USA.
4 Electricity
a) Soybean milling machine.
b) Water pump
machine (GrunDfos) c) Sawdust
d) Biogas
- 3,04 Kwh - 2,6 Kwh - 12 Kwh
- 2,975 Kwh
- 380 watt (8 hours per day) - 0,65 KW (4 hours per day) -4 drums of sawdust of 10 kg = 40 kg.
The calorific value of wood = 18 KJ/gram
- The calorific value of biogas from tofu liquid waste = 138.59 KJ for 36 liters of tofu liquid waste.
138.59/36 liters = 3.57 kJ. The amount of liquid waste from the Sari Murni tofu factory=50 liters=3.57x 50=178.5 KJ 5 Asam cuka/acetic
acid/CH3COOH
2 liters In 1 day Output
1 Tofu 250 kg
2 Wastewater 2600 liters
3 Solid waste (tofu dregs) 300 kg
4 CO2 24,80
5 CH4 12 Kg
6 N2O 0,585 Kg
7 PO43- 0,066 Kg
No Material Amount Information 8
SO2
NO2 0,044 Kg
0,42 Kg 3. Results and Discussion
The aim of the LCA assessment at the Kampung Krajan Sari Murni Tofu Factory is to find out what and how big the impact is due to the use of materials and energy during the tofu making process on the environment. The scope of the research is an analysis carried out only on process inputs (ingredients) and energy at each stage in the tofu making process starting from soybean production, sending soybeans to consumers, the tofu making process at the Sari Murni Tofu Factory to delivery to consumers, in this case to the market. traditional, restaurant and household.
So, in this case the scope used is cradle to gate.
3.1 Environmental Aspect and Impact
The potential environmental impacts that could be caused by the tofu production process at the Sari Murni Kampung Krajan Tofu Factory according to research by Elvis et al. can be seen in the following list:
1. Climate Change
Climate change can be interpreted as changes in the earth's temperature caused by the greenhouse effect due to human activities. Now, increasing emissions can have a real impact on climate change. Climate change is one of the most difficult environmental impacts to overcome because of the large impact on economic and social activities. The types of gas that influence climate change are methane and CO2. The Sari Murni tofu industry uses energy from sawdust, biogas, and PLN electricity, resulting in CO2, CH4, N2O, SO2, NO2 and dust emissions. In this research, the step of cooking tofu porridge is the biggest step and uses sawdust with an energy value of 16,200 kWh, thus contributing to the environmental burden of 57.48%. Wood sawdust has higher emissions than LPG or biogas because the combustion process is incomplete and produces dust and soot. The CO2, CH4 and N2O emission factors for burning wood flour are also much higher than for burning biogas. The next highest energy consumption during the cooking stage of tofu porridge is the use of biogas with an energy value of 29,042 kWh. Finally, PLN electricity is used for soybean crushers, water pumps and lighting, with an energy value of 5.64 kWh.
2. Eutrophication
Eutrophication is the process of gradual over-fertilization with nutrient compounds, especially nitrogen and phosphorus. Eutrophication includes the potential impact of excessive amounts of macronutrients such as nitrogen (N) and phosphorus (P) in the environment. High nutrient concentrations can make surface water unusable for drinking.
In aquatic ecosystems, increased biomass production can reduce oxygen levels due to additional oxygen consumption (measured as biological oxygen demand) during biomass
decomposition. In this study, the tofu cooking stage had the greatest environmental impact, namely 47%, because some of the cooking residue was thrown into the canals and rivers around the tofu factory. Tofu factory wastewater contains high amounts of organic matter as indicated by high levels of BOD, COD and phosphate. When the remaining liquid tofu is thrown into the river, the phosphate contained in the tofu dregs decomposes in the river water, polluting the river.
3. Acidification
The stages in the tofu production process at the Sari Murni Factory that contribute the most to the potential for acidification are the grinding stage at 51.61% and the tofu porridge boiling stage at 47.54%. This is because the fuel for grinding soybeans uses electricity, with the main source being fossil fuel, coal. Burning coal will produce SO2 gas. Apart from SO2 emissions, another parameter that contributes to acidity is NO2 emissions, which are produced from the process of burning wood sawdust to heat a steam boiler to produce heat which is used to cook tofu porridge.
4. Human Toxicity
Human toxicity refers to the effect of harmful substances on the human body in the form of respiratory diseases caused by inorganic substances released into the atmosphere. In this research, in the tofu production process at the Sari Murni Tahu Factory, Kampung Krajan, the stages that influence the effectiveness of tofu for humans are the grinding and cooking stages. tofu (90.71% and 9.14% respectively), and burning sawdust produces particles (PM) of various sizes that cause respiratory problems. The electricity system in Indonesia still uses coal, and the combustion process releases gases and particles.
A summary of the potential environmental impacts that can be generated by the tofu production process at the Sari Murni Kampung Krajan Tofu Factory can be seen in the following table.
Table 2. Percentage of impact contribution at the production stage of the year at the Sari Murni Kampung Krajan Factory
Stage Climate Change Potention
Eutrophication Potential
Acidification Potential
Human Toxicity
Washing 0,13% 0,01% 0,10% 0%
Immersion 0,25% 0,02% 0,2% 0,01%
Milling 41,57% 52,24% 51,61% 90,71%
Boiling 57,48% 47,05% 47,54% 9,41%
Filtering 0,57% 0,67% 0,55% 0,15%
3.2 Goal and Scope Definition
As previously explained, the goal to be achieved is to find out what factors and the magnitude of the impact on the environment from the use of materials and energy use during the tofu making process starting from the soybean production process until it becomes tofu. The aim of the LCA assessment at the Kampung Krajan Sari Murni Tofu Factory is to find out what and how big the impact is due to the use of materials and energy during the tofu making process on the environment.
The scope of the research is an analysis carried out only on process inputs (ingredients) and energy at each stage in the tofu making process starting from soybean production, sending soybeans to consumers, the tofu making process at the Sari Murni Tofu Factory to delivery to consumers, in this case to the market. traditional, restaurant and household. The scope used in this case is Cradle to Gate.
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