The paper was initially submitted for the VASS & FFTC-AP Policy Forum titled 'Circular Agriculture for Sustainable Healthy Diets: Perspectives and Policy Implications in the Asian and Pacific Region,' which took place on July 19, 2022. It was subsequently completed after the workshop and was submitted to the AP Platform, where it was accepted on October 11, 2023.
ABSTRACT
In response to the impacts of climate change, the United Nations has taken action by promoting the Sustainable Development Goals (SDGs) as a crucial pathway to achieve environmental sustainability and net-zero carbon targets. In 2015, with the support of government policies and technological applications, Taiwan’s government actively promoted industrial innovation and a circular economy. Meanwhile, business operators have also adopted and implemented sustainable business models. As an important component of the agricultural circular economy model, the livestock industry adheres to three fundamental principles: reduction, reuse, and recycling. Furthermore, the concept of Life Cycle Assessment (LCA) is used to evaluate the material flows of the entire livestock feed project. This includes implementing Internet of Things (IoT) livestock management, optimizing feed formulations, promoting sustainable livestock management practices, and establishing biogas and sludge treatment centers. Biogas and sludge are utilized for irrigation of Miscanthus grass, crop cultivation, water-based aquaculture of duckweed, seaweed, and fish. This article will also discuss how the LonSen Livestock Farm serves as an example of transforming a traditionally highly polluting pig farm into a sustainable circular economy business model. It can be considered a classic case for the transformation of pig farms in Taiwan. Overall, the proactive measures taken by Taiwan’s government, combined with the adoption of sustainable business models by industry operators, exemplify the country's commitment to addressing the impacts of climate change. Through the implementation of the circular economy model in the livestock industry, Taiwan aims to achieve environmental sustainability and contribute to the global efforts in combating climate change and achieving the SDGs.
Keywords: livestock farm, circular economy, business model
INTRODUCTION
According to Taiwan's Green National Income Account, Taiwan's agriculture generates approximately 5 million metric tons of agricultural byproducts each year. These byproducts include rice straw, mushroom bags, livestock manure, slaughterhouse residues, oyster shells, market fruit peel residues, and surplus products from the food manufacturing process (Figure 1). Livestock and agricultural residues are the major components of these agricultural byproducts. These residues are rich in nutrients such as phosphorus and nitrogen. However, due to the practice of onsite plowing, burying, piling, or discharging by farmers, approximately 30% of these reusable resources are lost, wasted, and contribute to environmental pollution. Currently, there are various methods for handling these residues.
The main methods for recycling and utilizing agricultural byproducts include using them for thermal power generation, material applications, animal feed, biorefining, composting, and biochar production (Figure 2). These methods can be broadly categorized into energy conversion, material utilization, and resource recovery. Among them, energy conversion achieves the goal of internal agricultural circulation most effectively but has the lowest value. However, for industrial application and investment, high-value products are crucial, and the adequacy, stability, and cost reduction of material sources have become key factors in industrial development.
Furthermore, by adopting the concept of circular agriculture, it is possible to properly manage the surplus materials and create new value. For example, collecting livestock manure for anaerobic digestion can produce biogas and digestate, which can be used as organic fertilizers for agricultural fields, thus reducing the cost of chemical fertilizers. Other products, such as biogas, can be converted into electricity or fuel through energy transformation for use in agricultural buildings, machinery, and equipment. By incorporating the concept of circular agriculture in this way, it not only helps manage a large amount of livestock waste but also allows seemingly useless waste to return to the source of the value chain, benefiting other economic activities.
Since 2016, the Council of Agriculture (COA) has been promoting the reuse of biogas for power generation and pollution control programs in pig farms, as well as collaborating with the Environmental Protection Administration (EPA) to promote biogas slurry irrigation in farmland. In addition, since 2017, water pollution prevention and control fees have been levied on livestock farmers. These policies have encouraged livestock farmers to improve pollution control facilities and move towards circular agriculture. To accelerate Taiwan's industrial transformation and upgrading, Taiwan’s government launched the "Five Plus Two" Industrial Innovation Program in 2017, which includes "circular economy" and "new agriculture" as two key projects. In response, the COA has set a goal to fully utilize agricultural byproducts by 2050 and plans to establish "value-added business application models," "promotion of agricultural circular industrialization," and "stable material supply models" as three major approaches, aiming to accelerate the development of circular agriculture-related industries in Taiwan.
Due to the focus on implementing circular agriculture in Taiwan, the pig farming industry plays a crucial role. According to statistics from the COA, the annual output value of Taiwan's pig farming industry is approximately US$2.4 billion, accounting for 13.91% of the total agricultural output value in Taiwan (National Animal Industry Foundation, 2020)). The importance of the industry in Taiwan's agriculture is undeniable. However, for a long time, Taiwanese people have criticized the livestock industry for its odor and water pollution issues. On average, pigs produce 7.2-7.7% of their body weight in feces and urine daily. Taking a pig farm with 10,000 pigs as an example, based on an average pig weight of 60 kilograms, each pig generates 4.32-4.62 kilograms of manure per day. Without proper treatment of these livestock wastes, it can easily lead to environmental pollution and the wastage of potentially useful materials.
In addition, the following section will use the LonSen Livestock Farm in Taiwan as an example to illustrate the transformation of Taiwan's pig farms towards circular agriculture.
LIVESTOCK BYPRODUCTS IN TAIWAN
From the above paragraph, it can be observed that livestock manure is considered a renewable resource in Taiwan. In the early days, countries used simple equipment to collect the methane generated from manure as fuel. Currently, the practice has evolved to include the utilization of urban waste, organic wastewater, corn stalks, and other materials mixed with livestock manure for biogas generation or reuse, and even the liquefaction of biogas as a substitute for natural gas. Approximately 60% of global greenhouse gas emissions come from carbon dioxide, while 20% originate from methane, indicating the significance of methane as a greenhouse gas (IPCC, 2013). According to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, the warming potential of methane is approximately 25 times that of carbon dioxide. Considering the substantial methane content in biogas, the application of livestock manure for biogas recovery not only reduces greenhouse gas emissions but also converts biomass into green energy.
Based on Taiwan's Green National Income Account data, considering the 5.5 million pigs raised in Taiwan, the national daily production of pig manure amounts to 24,585 tons (with an average daily excretion of 4.47 kg per pig), generating approximately 1,375,000 cubic meters of biogas per day. As biogas consists of a significant amount of methane and some carbon dioxide, it is also one of the contributors to the greenhouse effect. In the past, pig farm operators might have chosen to directly emit biogas and anaerobic digestion residue, resulting in severe pollution of rivers and the atmosphere. To proactively address these environmental issues, local governments in Taiwan have taken significant measures to improve the environmental conditions of livestock farms. These measures include farm environment renovations, enhanced environmental inspections, and stricter enforcement.
Since pig manure contains nutrients such as nitrogen, phosphorus, and potassium, if biogas is collected through anaerobic fermentation for energy utilization, the residual byproduct of anaerobic fermentation can be returned to farmland as fertilizer. This practice not only helps reduce environmental pollution caused by pig farms but also decreases Taiwanese farmers' reliance on chemical fertilizers while increasing their income from green energy. Moreover, implementing this approach can enhance the economic efficiency of farms and reduce overall greenhouse gas emissions.
TRANSITIONING TOWARDS A CIRCULAR ECONOMY MODEL
Developing an agricultural circular economy can integrate human society with nature, which is the most beneficial and positive approach. If properly managed and valued, livestock waste poses no potential threat to ecosystems and the environment and is an important raw material for energy and nutrient recovery (Duan et al., 2020). Although different countries have developed unique policies, environmental regulations, and procedures to minimize environmental risks related to fecal pollution, serious concerns remain regarding the appropriate implementation of such policies. Decision support systems focusing on fecal management are valuable tools at the farm and regional levels that can systematically identify and compare potential fecal treatment technologies that are technically and economically suitable for the area under consideration (Khoshnevisan et al., 2020).
At the regional level, this decision support system requires a fecal nutrient recommendation system to determine how many nutrients are available in different animal categories, as well as how many nutrients can be recycled in the agricultural production system. Livestock manure must be managed under the concept of the biobased circular economy to achieve the highest overall profit (Pretty et al., 2018; Ramos-Suárez et al., 2019; Tsapekos et al., 2020). Integrating fecal management into the concept of biological refining, combined with a comprehensive fecal nutrient recovery and fecal management plan, will accelerate the progress toward a biobased circular economy, minimize environmental risks, and maximize profits (Khoshnevisan et al., 2021). Under the concept of the circular economy, the main focus is on the effective and circular utilization of nutrients and energy in feces to have sustainable food and energy systems and reduce environmental emissions, nutrient dispersion, and waste streams (Lin et al., 2020; Dróżdż et al., 2020).
Conducting a renewable evaluation is essential. Factors such as market price and price volatility, social acceptance, product quality, reachability, transportation costs, price of competitive products, availability of other commodities, banned products, incentives, and subsidies are important in determining whether biological products can successfully stimulate market demand (Pe'er et al., 2020; Van Schalkwyk et al., 2020). The case of this article is based on the planning and design of a circular economy, establishing a framework for livestock waste management and local collaborative systems, combined with other relevant reuse technologies, towards a mutually beneficial environment.
The case study: LonSen Livestock Farm
Located in the coastal region of central Taiwan (Figure 3), LonSen Livestock Farm is a large-scale farm with over 5,000 pigs, making it one of the largest pig farms in Taiwan. The farm has been established for approximately 43 years and was acquired by the current management 8 years ago. Due to its long history, many of the livestock sheds are old and dilapidated. In recent years, LonSen Livestock Farm has actively introduced new equipment and revised its breeding strategies to become a sustainable farm. The newly formulated business development strategy of LonSen Livestock Farm is as follows:
- Group Management: Choosing breeds with less growth differentiation and implementing batch management for pigs of similar age and weight can reduce leftover feed, avoids spoilage or cross-contamination mixed with excreta and the risk of infections, particularly respiratory infections.
- Constructing High-Rise Negative Pressure Pig Houses: Providing pigs with a comfortable environment through elevated bedding floors and minimizing water usage for cleaning.
- Utilizing Intelligent Environmental Control Systems: Implementing intelligent feeding and environmental control systems to enhance management efficiency and reduce wastage of feed and electricity, thereby improving efficiency and reducing waste.
- Using Green Energy: Installing solar panels on the roofs of pig houses not only reduces the temperature inside the houses but also minimizes power loss from water irrigation and cooling equipment usage.
- Improvement of Livestock Buildings: Extending the roofs of pig houses, elevating sewage pipes to separate rainwater and wastewater, reinforcing the external structures of old sheds, and installing negative pressure ventilation systems.
- Separation of Solid and Liquid Pig Manure: Utilizing machinery to separate solid and liquid pig manure for ease of transportation.
- Conversion of Agricultural Waste into Fertilizer: Investing in refining equipment to convert animal carcasses into meat and bone meal within 48 hours, providing local farmers with composting materials.
For large-scale farms like LonSen Livestock Farm, corporate environmental, social, and governance (ESG) strategies, corporate social responsibility (CSR), and sustainable development goals (SDGs) have become responsibilities that need to be addressed. In order to move towards a more sustainable business model, LonSen Livestock Farm, in collaboration with the authors of this article, has developed a comprehensive plan that integrates the basic industry chain, builds a circular economy model, and aims for net-zero carbon emissions. The goal of the plan is to create an intertwined life cycle of local agriculture, livestock farming, and aquaculture, revitalizing the local fishing village. By 2031, LonSen Livestock Farm aims to establish a sustainable coastal circular park as a model for the development of agricultural circular economies.
With the goal of establishing a sustainable management system, LonSen Livestock Farm is not only transitioning its business model but also has committed to collaborating with other stakeholders in the ecosystem. The following are the conceptual transformations for the farm's industry:
- Business Model Transformation:
Previously, the primary source of income for the farm came from pig farming and sales, with waste management expenses being additional costs. Establishing a pig manure treatment system required substantial investment. However, by implementing a circular economy model, pig manure can be utilized as raw material for biogas generation, generating electricity and heat for on-farm use. The resulting digestate and sludge can be further utilized as organic fertilizers for agricultural and aquatic plants, achieving the ultimate goal of circular agriculture. LonSen Livestock Farm also collects pig manure and urine from nearby farms, transporting them to a centralized treatment center. 75% of the wastewater is used as organic fertilizer for crops and algae. The solid sludge can be composted or returned to farmland. Additionally, the algae cultivated using the wastewater can serve as feed for pigs, fish, shellfish, etc., achieving full-cycle utilization.
- Sustainable Development of the Industry:
The sustainable development strategies for pig farming include production and market sales strategies. In terms of production, in addition to traditional pig farming, water-saving measures and the development of green energy are adopted to create additional revenue for environmental improvements. In terms of sales, besides selling live pigs, the farm also focuses on developing processing technologies that utilize waste generated during the production process as raw materials for other products, thereby achieving the ultimate goal of circular agriculture.
- Industry-Government-Academia Collaboration:
LonSen Livestock Farm collaborates not only with relevant research units of the COA but also with local industry, government agencies, and academic research units. By leveraging the characteristics of local resources such as "land, industry, and people" and adopting a strategy of "creativity, innovation, and entrepreneurship," LonSen Livestock Farm contributes to talent cultivation, ecological construction of circular agriculture, and the local industry.
- Establishing a Local Cooperative Platform:
Technically, utilizing digestate as a nutrient recovery strategy is feasible. However, some farmers are concerned about over-fertilization of farmland or contamination of groundwater, which may affect their willingness to cooperate. Therefore, organizing farmer cooperatives and establishing a local cooperative platform for circular agriculture are crucial factors in determining the successful implementation of sustainable development. LonSen Livestock Farm also collaborates with nearby farms to establish a local cooperative platform, ensuring the smooth operation of the agricultural circular model.
- Setting a Vision and Timeline:
LonSen Livestock Farm has formulated a comprehensive strategic plan to achieve sustainable and circular agricultural practices. In the short term, from 2021 to 2023, the company's key development projects include wastewater recycling, digestate and sludge treatment centers, and seaweed cultivation models. These measures are expected to optimize resource utilization, improve wastewater management, and enhance the company's productivity.
In the medium term, from 2024 to 2026, the company plans to develop technologies such as black soldier fly cultivation, solar energy, fertilizer production, and feed processing to further improve sustainability and efficiency. These initiatives will enable the company to reduce its carbon footprint, optimize energy usage, and promote sustainable agricultural practices.
Looking ahead, from 2028 to 2030, the company aims to elevate its circular economy level through integrating the industry chain and establishing cooperative platforms with local partners. Additionally, the company will develop an irrigation plan to ensure efficient water usage and conservation. These measures will enhance the company's sustainability and promote collaboration between different agricultural sectors.
Ultimately, LonSen Livestock Farm aims to become a self-sustaining agricultural circular demonstration farm and achieve a net-zero carbon target after 2050. By integrating all processes and implementing sustainable practices, the company envisions becoming a net-zero carbon enterprise in Taiwan. The long-term vision of the company reflects its commitment to sustainable practices and its efforts to promote a greener and more sustainable future for agriculture.
CONCLUSION
The efficient utilization of agricultural and sideline products requires the integration of innovative technology research and development with the establishment of effective collaborative systems. Furthermore, it is necessary to prevent resource waste and minimize adverse environmental impacts in order to ensure the sustainable development of a circular economy. Additionally, the recycling and reuse of biomass must be accompanied by the development of regional industrial clusters and the establishment of stable material supply chains in order to sustain the operation of the circular economy industrial model.
From the case of LonSem Livestock Farm, it can also be observed that when businesses incorporate concepts such as ESG (Environmental, Social, and Governance) and CSR (Corporate Social Responsibility), they can not only extend the life cycle of agricultural biomass utilization and foster local technological innovation, but also promote regional industrial symbiosis. Ultimately, this leads to the formation of a commercial model for agricultural circular economy. Hence, it is imperative to incentivize all industries to prioritize technological advancements, ensure a steady supply of materials, devise suitable circular processes, and foster the development of sustainable business models. These actions are recognized as fundamental strategies aimed at accomplishing the ultimate objective of establishing a resilient agricultural circular economy system in Taiwan.
REFERENCES
Agriculture Statistics Yearbook. Council of Agriculture, Taiwan. Available online: https://agrstat.coa.gov.tw/sdweb/public/book/Book.aspx
Dróżdż, D., Wystalska, K., Malińska, K., Grosser, A., Grobelak, A., & Kacprzak, M. (2020). Management of poultry manure in Poland–Current state and future perspectives. Journal of Environmental Management, 264, 110327.
Duan, N., Zhang, D., Khoshnevisan, B., Kougias, P. G., Treu, L., Liu, Z., ... & Angelidaki, I. (2020). Human waste anaerobic digestion as a promising low-carbon strategy: Operating performance, microbial dynamics and environmental footprint. Journal of cleaner production, 256, 120414. Khoshnevisan, B., Duan, N., Tsapekos, P., Awasthi, M. K., Liu, Z., Mohammadi, A., ... & Liu, H. (2021). A critical review on livestock manure biorefinery technologies: Sustainability, challenges, and future perspectives. Renewable and Sustainable Energy Reviews, 135, 110033.
IPCC. (2013). Climate change 2013: The physical science basis. Contribution of working group I to the fifth assessment report of the intergovernmental panel on climate change. In T. F. Stocker, D. Qin, G.-K. Plattner, M. Tignor, S. K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex, & P. M. Midgley (Eds.). Cambridge and New York, NY: Cambridge University Press.
Khoshnevisan, B., Rafiee, S., Pan, J., Zhang, Y., & Liu, H. (2020). A multi-criteria evolutionary-based algorithm as a regional scale decision support system to optimize nitrogen consumption rate; A case study in North China plain. Journal of Cleaner Production, 256, 120213.
Lin, R., Man, Y., Lee, C. K., Ji, P., & Ren, J. (2020). Sustainability prioritization framework of biorefinery: a novel multi-criteria decision-making model under uncertainty based on an improved interval goal programming method. Journal of Cleaner Production, 251, 119729.
National Animal Industry Foundation (2020). The Livestock statistics year book 2019.
Pe'er, G., Bonn, A., Bruelheide, H., Dieker, P., Eisenhauer, N., Feindt, P. H., ... & Lakner, S. (2020). Action needed for the EU Common Agricultural Policy to address sustainability challenges. People and Nature, 2(2), 305-316.
Pretty, J., Benton, T. G., Bharucha, Z. P., Dicks, L. V., Flora, C. B., Godfray, H. C. J., ... & Wratten, S. (2018). Global assessment of agricultural system redesign for sustainable intensification. Nature Sustainability, 1(8), 441-446.
Ramos-Suárez, J. L., Ritter, A., González, J. M., & Pérez, A. C. (2019). Biogas from animal manure: A sustainable energy opportunity in the Canary Islands. Renewable and Sustainable Energy Reviews, 104, 137-150.
Tsapekos P, Khoshnevisan B, Alvarado-Morales M, Symeonidis A, Kougias P, Angelidaki I. Tsapekos, P., Khoshnevisan, B., Alvarado-Morales, M., Symeonidis, A., Kougias, P. G., & Angelidaki, I. (2019). Environmental impacts of biogas production from grass: Role of co-digestion and pretreatment at harvesting time. Applied Energy, 252, 113467.
Van Schalkwyk, D. L., Mandegari, M., Farzad, S., & Görgens, J. F. (2020). Techno-economic and environmental analysis of bio-oil production from forest residues via non-catalytic and catalytic pyrolysis processes. Energy Conversion and Management, 213, 112815
The Agricultural Circular Economy Model of Pig Farm in Taiwan: Using LonSen Livestock Farm as an Example
The paper was initially submitted for the VASS & FFTC-AP Policy Forum titled 'Circular Agriculture for Sustainable Healthy Diets: Perspectives and Policy Implications in the Asian and Pacific Region,' which took place on July 19, 2022. It was subsequently completed after the workshop and was submitted to the AP Platform, where it was accepted on October 11, 2023.
ABSTRACT
In response to the impacts of climate change, the United Nations has taken action by promoting the Sustainable Development Goals (SDGs) as a crucial pathway to achieve environmental sustainability and net-zero carbon targets. In 2015, with the support of government policies and technological applications, Taiwan’s government actively promoted industrial innovation and a circular economy. Meanwhile, business operators have also adopted and implemented sustainable business models. As an important component of the agricultural circular economy model, the livestock industry adheres to three fundamental principles: reduction, reuse, and recycling. Furthermore, the concept of Life Cycle Assessment (LCA) is used to evaluate the material flows of the entire livestock feed project. This includes implementing Internet of Things (IoT) livestock management, optimizing feed formulations, promoting sustainable livestock management practices, and establishing biogas and sludge treatment centers. Biogas and sludge are utilized for irrigation of Miscanthus grass, crop cultivation, water-based aquaculture of duckweed, seaweed, and fish. This article will also discuss how the LonSen Livestock Farm serves as an example of transforming a traditionally highly polluting pig farm into a sustainable circular economy business model. It can be considered a classic case for the transformation of pig farms in Taiwan. Overall, the proactive measures taken by Taiwan’s government, combined with the adoption of sustainable business models by industry operators, exemplify the country's commitment to addressing the impacts of climate change. Through the implementation of the circular economy model in the livestock industry, Taiwan aims to achieve environmental sustainability and contribute to the global efforts in combating climate change and achieving the SDGs.
Keywords: livestock farm, circular economy, business model
INTRODUCTION
According to Taiwan's Green National Income Account, Taiwan's agriculture generates approximately 5 million metric tons of agricultural byproducts each year. These byproducts include rice straw, mushroom bags, livestock manure, slaughterhouse residues, oyster shells, market fruit peel residues, and surplus products from the food manufacturing process (Figure 1). Livestock and agricultural residues are the major components of these agricultural byproducts. These residues are rich in nutrients such as phosphorus and nitrogen. However, due to the practice of onsite plowing, burying, piling, or discharging by farmers, approximately 30% of these reusable resources are lost, wasted, and contribute to environmental pollution. Currently, there are various methods for handling these residues.
The main methods for recycling and utilizing agricultural byproducts include using them for thermal power generation, material applications, animal feed, biorefining, composting, and biochar production (Figure 2). These methods can be broadly categorized into energy conversion, material utilization, and resource recovery. Among them, energy conversion achieves the goal of internal agricultural circulation most effectively but has the lowest value. However, for industrial application and investment, high-value products are crucial, and the adequacy, stability, and cost reduction of material sources have become key factors in industrial development.
Furthermore, by adopting the concept of circular agriculture, it is possible to properly manage the surplus materials and create new value. For example, collecting livestock manure for anaerobic digestion can produce biogas and digestate, which can be used as organic fertilizers for agricultural fields, thus reducing the cost of chemical fertilizers. Other products, such as biogas, can be converted into electricity or fuel through energy transformation for use in agricultural buildings, machinery, and equipment. By incorporating the concept of circular agriculture in this way, it not only helps manage a large amount of livestock waste but also allows seemingly useless waste to return to the source of the value chain, benefiting other economic activities.
Since 2016, the Council of Agriculture (COA) has been promoting the reuse of biogas for power generation and pollution control programs in pig farms, as well as collaborating with the Environmental Protection Administration (EPA) to promote biogas slurry irrigation in farmland. In addition, since 2017, water pollution prevention and control fees have been levied on livestock farmers. These policies have encouraged livestock farmers to improve pollution control facilities and move towards circular agriculture. To accelerate Taiwan's industrial transformation and upgrading, Taiwan’s government launched the "Five Plus Two" Industrial Innovation Program in 2017, which includes "circular economy" and "new agriculture" as two key projects. In response, the COA has set a goal to fully utilize agricultural byproducts by 2050 and plans to establish "value-added business application models," "promotion of agricultural circular industrialization," and "stable material supply models" as three major approaches, aiming to accelerate the development of circular agriculture-related industries in Taiwan.
Due to the focus on implementing circular agriculture in Taiwan, the pig farming industry plays a crucial role. According to statistics from the COA, the annual output value of Taiwan's pig farming industry is approximately US$2.4 billion, accounting for 13.91% of the total agricultural output value in Taiwan (National Animal Industry Foundation, 2020)). The importance of the industry in Taiwan's agriculture is undeniable. However, for a long time, Taiwanese people have criticized the livestock industry for its odor and water pollution issues. On average, pigs produce 7.2-7.7% of their body weight in feces and urine daily. Taking a pig farm with 10,000 pigs as an example, based on an average pig weight of 60 kilograms, each pig generates 4.32-4.62 kilograms of manure per day. Without proper treatment of these livestock wastes, it can easily lead to environmental pollution and the wastage of potentially useful materials.
In addition, the following section will use the LonSen Livestock Farm in Taiwan as an example to illustrate the transformation of Taiwan's pig farms towards circular agriculture.
LIVESTOCK BYPRODUCTS IN TAIWAN
From the above paragraph, it can be observed that livestock manure is considered a renewable resource in Taiwan. In the early days, countries used simple equipment to collect the methane generated from manure as fuel. Currently, the practice has evolved to include the utilization of urban waste, organic wastewater, corn stalks, and other materials mixed with livestock manure for biogas generation or reuse, and even the liquefaction of biogas as a substitute for natural gas. Approximately 60% of global greenhouse gas emissions come from carbon dioxide, while 20% originate from methane, indicating the significance of methane as a greenhouse gas (IPCC, 2013). According to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, the warming potential of methane is approximately 25 times that of carbon dioxide. Considering the substantial methane content in biogas, the application of livestock manure for biogas recovery not only reduces greenhouse gas emissions but also converts biomass into green energy.
Based on Taiwan's Green National Income Account data, considering the 5.5 million pigs raised in Taiwan, the national daily production of pig manure amounts to 24,585 tons (with an average daily excretion of 4.47 kg per pig), generating approximately 1,375,000 cubic meters of biogas per day. As biogas consists of a significant amount of methane and some carbon dioxide, it is also one of the contributors to the greenhouse effect. In the past, pig farm operators might have chosen to directly emit biogas and anaerobic digestion residue, resulting in severe pollution of rivers and the atmosphere. To proactively address these environmental issues, local governments in Taiwan have taken significant measures to improve the environmental conditions of livestock farms. These measures include farm environment renovations, enhanced environmental inspections, and stricter enforcement.
Since pig manure contains nutrients such as nitrogen, phosphorus, and potassium, if biogas is collected through anaerobic fermentation for energy utilization, the residual byproduct of anaerobic fermentation can be returned to farmland as fertilizer. This practice not only helps reduce environmental pollution caused by pig farms but also decreases Taiwanese farmers' reliance on chemical fertilizers while increasing their income from green energy. Moreover, implementing this approach can enhance the economic efficiency of farms and reduce overall greenhouse gas emissions.
TRANSITIONING TOWARDS A CIRCULAR ECONOMY MODEL
Developing an agricultural circular economy can integrate human society with nature, which is the most beneficial and positive approach. If properly managed and valued, livestock waste poses no potential threat to ecosystems and the environment and is an important raw material for energy and nutrient recovery (Duan et al., 2020). Although different countries have developed unique policies, environmental regulations, and procedures to minimize environmental risks related to fecal pollution, serious concerns remain regarding the appropriate implementation of such policies. Decision support systems focusing on fecal management are valuable tools at the farm and regional levels that can systematically identify and compare potential fecal treatment technologies that are technically and economically suitable for the area under consideration (Khoshnevisan et al., 2020).
At the regional level, this decision support system requires a fecal nutrient recommendation system to determine how many nutrients are available in different animal categories, as well as how many nutrients can be recycled in the agricultural production system. Livestock manure must be managed under the concept of the biobased circular economy to achieve the highest overall profit (Pretty et al., 2018; Ramos-Suárez et al., 2019; Tsapekos et al., 2020). Integrating fecal management into the concept of biological refining, combined with a comprehensive fecal nutrient recovery and fecal management plan, will accelerate the progress toward a biobased circular economy, minimize environmental risks, and maximize profits (Khoshnevisan et al., 2021). Under the concept of the circular economy, the main focus is on the effective and circular utilization of nutrients and energy in feces to have sustainable food and energy systems and reduce environmental emissions, nutrient dispersion, and waste streams (Lin et al., 2020; Dróżdż et al., 2020).
Conducting a renewable evaluation is essential. Factors such as market price and price volatility, social acceptance, product quality, reachability, transportation costs, price of competitive products, availability of other commodities, banned products, incentives, and subsidies are important in determining whether biological products can successfully stimulate market demand (Pe'er et al., 2020; Van Schalkwyk et al., 2020). The case of this article is based on the planning and design of a circular economy, establishing a framework for livestock waste management and local collaborative systems, combined with other relevant reuse technologies, towards a mutually beneficial environment.
The case study: LonSen Livestock Farm
Located in the coastal region of central Taiwan (Figure 3), LonSen Livestock Farm is a large-scale farm with over 5,000 pigs, making it one of the largest pig farms in Taiwan. The farm has been established for approximately 43 years and was acquired by the current management 8 years ago. Due to its long history, many of the livestock sheds are old and dilapidated. In recent years, LonSen Livestock Farm has actively introduced new equipment and revised its breeding strategies to become a sustainable farm. The newly formulated business development strategy of LonSen Livestock Farm is as follows:
For large-scale farms like LonSen Livestock Farm, corporate environmental, social, and governance (ESG) strategies, corporate social responsibility (CSR), and sustainable development goals (SDGs) have become responsibilities that need to be addressed. In order to move towards a more sustainable business model, LonSen Livestock Farm, in collaboration with the authors of this article, has developed a comprehensive plan that integrates the basic industry chain, builds a circular economy model, and aims for net-zero carbon emissions. The goal of the plan is to create an intertwined life cycle of local agriculture, livestock farming, and aquaculture, revitalizing the local fishing village. By 2031, LonSen Livestock Farm aims to establish a sustainable coastal circular park as a model for the development of agricultural circular economies.
With the goal of establishing a sustainable management system, LonSen Livestock Farm is not only transitioning its business model but also has committed to collaborating with other stakeholders in the ecosystem. The following are the conceptual transformations for the farm's industry:
Previously, the primary source of income for the farm came from pig farming and sales, with waste management expenses being additional costs. Establishing a pig manure treatment system required substantial investment. However, by implementing a circular economy model, pig manure can be utilized as raw material for biogas generation, generating electricity and heat for on-farm use. The resulting digestate and sludge can be further utilized as organic fertilizers for agricultural and aquatic plants, achieving the ultimate goal of circular agriculture. LonSen Livestock Farm also collects pig manure and urine from nearby farms, transporting them to a centralized treatment center. 75% of the wastewater is used as organic fertilizer for crops and algae. The solid sludge can be composted or returned to farmland. Additionally, the algae cultivated using the wastewater can serve as feed for pigs, fish, shellfish, etc., achieving full-cycle utilization.
The sustainable development strategies for pig farming include production and market sales strategies. In terms of production, in addition to traditional pig farming, water-saving measures and the development of green energy are adopted to create additional revenue for environmental improvements. In terms of sales, besides selling live pigs, the farm also focuses on developing processing technologies that utilize waste generated during the production process as raw materials for other products, thereby achieving the ultimate goal of circular agriculture.
LonSen Livestock Farm collaborates not only with relevant research units of the COA but also with local industry, government agencies, and academic research units. By leveraging the characteristics of local resources such as "land, industry, and people" and adopting a strategy of "creativity, innovation, and entrepreneurship," LonSen Livestock Farm contributes to talent cultivation, ecological construction of circular agriculture, and the local industry.
Technically, utilizing digestate as a nutrient recovery strategy is feasible. However, some farmers are concerned about over-fertilization of farmland or contamination of groundwater, which may affect their willingness to cooperate. Therefore, organizing farmer cooperatives and establishing a local cooperative platform for circular agriculture are crucial factors in determining the successful implementation of sustainable development. LonSen Livestock Farm also collaborates with nearby farms to establish a local cooperative platform, ensuring the smooth operation of the agricultural circular model.
LonSen Livestock Farm has formulated a comprehensive strategic plan to achieve sustainable and circular agricultural practices. In the short term, from 2021 to 2023, the company's key development projects include wastewater recycling, digestate and sludge treatment centers, and seaweed cultivation models. These measures are expected to optimize resource utilization, improve wastewater management, and enhance the company's productivity.
In the medium term, from 2024 to 2026, the company plans to develop technologies such as black soldier fly cultivation, solar energy, fertilizer production, and feed processing to further improve sustainability and efficiency. These initiatives will enable the company to reduce its carbon footprint, optimize energy usage, and promote sustainable agricultural practices.
Looking ahead, from 2028 to 2030, the company aims to elevate its circular economy level through integrating the industry chain and establishing cooperative platforms with local partners. Additionally, the company will develop an irrigation plan to ensure efficient water usage and conservation. These measures will enhance the company's sustainability and promote collaboration between different agricultural sectors.
Ultimately, LonSen Livestock Farm aims to become a self-sustaining agricultural circular demonstration farm and achieve a net-zero carbon target after 2050. By integrating all processes and implementing sustainable practices, the company envisions becoming a net-zero carbon enterprise in Taiwan. The long-term vision of the company reflects its commitment to sustainable practices and its efforts to promote a greener and more sustainable future for agriculture.
CONCLUSION
The efficient utilization of agricultural and sideline products requires the integration of innovative technology research and development with the establishment of effective collaborative systems. Furthermore, it is necessary to prevent resource waste and minimize adverse environmental impacts in order to ensure the sustainable development of a circular economy. Additionally, the recycling and reuse of biomass must be accompanied by the development of regional industrial clusters and the establishment of stable material supply chains in order to sustain the operation of the circular economy industrial model.
From the case of LonSem Livestock Farm, it can also be observed that when businesses incorporate concepts such as ESG (Environmental, Social, and Governance) and CSR (Corporate Social Responsibility), they can not only extend the life cycle of agricultural biomass utilization and foster local technological innovation, but also promote regional industrial symbiosis. Ultimately, this leads to the formation of a commercial model for agricultural circular economy. Hence, it is imperative to incentivize all industries to prioritize technological advancements, ensure a steady supply of materials, devise suitable circular processes, and foster the development of sustainable business models. These actions are recognized as fundamental strategies aimed at accomplishing the ultimate objective of establishing a resilient agricultural circular economy system in Taiwan.
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