1. Introduction
1.1 Background
Food waste is a problem faced by Singapore and countries all around the world. Food waste is defined as “the removal of food from the supply chain which is fit for consumption, or which has spoiled or expired, mainly caused by economic behavior, poor management or neglect” (FAO, 2014, p.4). As the global population increases, the global food supply would be strained to meet the rising demand. Between 2012 to 2014, 805 million people were chronically undernourished while food was wasted or lost in other areas around the world (Galanakis, 2015). While food is scarce in developing regions in the world, food is also being wasted and lost from the food chain in other places such as Singapore. According to the National Environment Agency (NEA), in 2017, food waste accounted for 10% of total waste generated in Singapore, but only 16% of the food waste was recycled (NEA, 2018). The remainder of food waste which is not recycled will be sent to incineration plants to be incinerated. This process of incinerating food waste can be harmful to the environment as it produces large amounts of carbon emissions. It is beneficial to increase the amount of food waste recycled in Singapore as it would reduce overall carbon emissions.
Regarding the issue on food waste, the main stakeholders would be the government and government agencies as well as businesses related to the food industry. The government is responsible for formulating and implementing policies which will greatly affect the actions taken to reduce food wastage. Such policies can help facilitate the adoption of new technologies for local businesses. The government can also launch campaigns to raise awareness for the management of food waste. In a survey conducted regarding this issue (see Appendix A), 32.5% of respondents felt that lack of awareness among Singaporeans is one of the main factors which limited the recycling rate of food waste at hawker centers. Furthermore, 22% of respondents responded that inadequate policies being implemented by relevant authorities is a contributing factor which limits food waste recycling in Singapore. Businesses that have a stake in this issue include local food businesses such as hawker centers, food vendors, supermarkets, wet markets and food recycling plants. These businesses are responsible for the management of food waste as it is an important factor to ensure that they have a sustainable business. Food wastage also accounts for the loss in profits businesses due to overstocking of perishables, resulting in uncooked food being thrown away.
The issue of food waste affects all Singaporeans as the vast majority of Singaporeans contribute to food waste in Singapore. According to a study conducted by Grandhi and Singh (2016), the general public believed that food waste was not an issue since it was natural and biodegradable. Half of the respondents from the study acknowledged that they could have taken steps to avoid food waste generated from leftovers after a meal, food becoming spoilt, and throwing away blemished fruits and vegetables. It was also noted through the study that there was a lack in sorting of food waste in Singapore. This showed that there was a lack of awareness among Singaporeans about the consequences of massive amount of food waste. Hawker centers and wet markets contribute to a portion of the total food waste in Singapore, as it is a place where Singaporeans go to have their meals and thus leaving food waste if they do not finish their food. Hawker vendors and market stall owners also contribute to food wastage when the amount of food ingredients prepared exceeds the demand and is thrown away because the food is spoilt or expired. To tackle the problem of food waste in Singapore, government agencies such as the NEA must work towards ensuring food waste is handled in a sustainable manner. Food waste recovery can improve the sustainability of food systems by making full use of the valuable compounds which can be recovered from food waste.
1.2 Problem Statement
Ideally, food waste generated by local food centers should be thoroughly sorted in preparation for processing to be fully utilized in other means, instead of being disposed of. In 2017, Singapore produced 809,800 tons of food waste, while recycling only a mere 16% of it, with the remaining being incinerated (NEA, 2018). This is mainly due to the lack of an efficient recycling system at locations (hawker centers) where a significant amount of food waste is being produced.
1.3 Purpose Statement
This report aims to propose to the NEA Hawker Center Division in implementing a closed-loop system to maximize the food waste utilization rate of hawker centers in Singapore by providing them with an efficient system to sort and recycle food waste generated by food vendors and customers.
2. Proposed solution
The proposed solution to deal with the problem of food waste in hawker centers is to implement a closed loop system to maximize the food waste utilization rate of hawker centers. This closed-loop system consists of different stages: collection and sorting, treatment and utilization of end products. In the sorting stage, food waste is separated according to their valuable compounds to facilitate the treatment process. The sorted food waste will then be treated using two waste treatment methods, anaerobic digestion and composting.
2.1 Collection and sorting
Both composting and anaerobic digestion can be implemented simultaneously to maximize the utilization of food waste in hawker centers. Using both composting and anaerobic digestion draws benefits from each method while mitigating the drawbacks. These two systems complement each other as they reduce the cost of recycling food waste as well as ensuring all types of food waste produced at the hawker center is fully utilized. Composting helps keep the cost of processing food waste low and produces compost suitable for gardening. Anaerobic digestion is able to process most forms of food waste not suitable for composting and produces methane which can be turned to other forms of energy.
2.2 Treatment
2.2.1 Composting
Composting is a process which involves microorganisms breaking down food waste in the presence of oxygen. “Composting has been used as a method to dispose food waste (FW) and recycle organic matter to improve soil structure and fertility” (Li, Lu, Ren & He, 2013). The product of composting can be used as fertilizer or soil conditioner. The by-products of composting are heat, water and carbon dioxide. Composting is a cheap and simple way of processing food waste. Composting would be ideal for food waste such as vegetables and fruits classified as “greens”. Other types of food waste from hawker centers suitable for composting include bones or egg shells which are left after cooking. Other compounds such as meats are not ideal as they produce a foul odor and may attract stray animals.
2.2.2 Anaerobic digestion
Anaerobic digestion (AD) is a process which involves microorganisms breaking down food waste in the absence of oxygen (Zero Waste Singapore, 2008). This process produces biogases (mainly methane) and digestate, which can be utilized to produce energy and as a compost respectively. Anaerobic digestion of food waste is able to treat a “wide range of substrates of both agricultural and industrial origin” (Pesta, 2007). This method is applicable for any liquid or solid organic waste. However, due to the complexity and additional machineries needed for this process, anaerobic digestion has a higher capital and operational cost as compared to composting, in treating food waste.
2.3 Utilization of end products Through the treatment processes (composting and anaerobic digestion), food waste are being turned into bioproducts; mainly compost and methane. These bioproducts produced are usable resources that could be utilized to supplement the hawker center’s daily operational needs. This would provide an opportunity for an in-house garden to be situated at the rooftops of hawker centers. This garden would allow stall owners to grow their own ingredients, thereby reducing the stall’s dependency on external sources. Thus, the utilization of these end products creates a closed-loop system for the center, which in turn promotes self-sustainability through the reduction in reliance on external sources for its daily operations. Examples of the utilization of these end products would be the usage of compost produced at the in-house rooftop garden and recirculation of methane produced into the center’s gas pipelines.
3. Benefits
The proposed solution focuses on having a closed-loop system being implemented in the hawker center. This closed-loop system taps on food waste generated by turning them into usable resources through treatment processes. This resources produced would then be used extensively in the hawker center to meet its operational needs. It is beneficial to have such system in place as it reduces reliance on external sources and maximizes the utilization of food waste.
3.1 Reduced dependency on external resources
Operating cost of a stall in hawker center is high due to the fluctuating utilities prices. This is a significant impact to the vendors’ income as utilities cost contributes 9% to the daily operating cost (The Straits Times, 2015). Thus, having a closed-loop system in place in the hawker center is beneficial to the vendors. This system allows the food waste generated within the center to be turned into usable resources, such as biogases. These biogases produced can be recirculated into the center’s gas pipeline, which in turn reduces the utilities cost as the recirculated biogases would reduce the need for gases supplied externally (used for stoves etc.).
3.2 Maximized utilization of food waste
As mentioned earlier, in Singapore, food waste accounted for 10% of total waste generated and only 16% of it is being recycled (NEA, 2018)(see Appendix B), with the remaining being incinerated. The process of incineration does not eradicate the waste; instead, it reduces the volume of it by reducing them into ashes which are dumped into landfill subsequently. This is not sustainable as according to the Ministry of the Environment and Water Resources (MEWR) in 2019, based on the rate of waste currently being disposed, Singapore’s only landfill would be running out of space by 2035. Therefore, the ideal solution to prolong the landfill’s lifespan would be to maximize the utilization of waste instead of having them disposed of.
3.3 Inclusion of an in-house garden
Supporting the closed-loop system, there is opportunity for an in-house garden to be included at rooftops of hawker centers. Hawker centers generate up to an average of 1 ton of food waste daily. This contributes a significant amount to the overall food waste that Singapore generates. According to Yahya (2011), 1 ton of food waste will return approximately 1000 liters in reclaimed water. The reclaimed water can be used for irrigation for the in-house garden’s hydroponics system to grow local produce for use within the hawker center. Furthermore, the compost produced from the recycled food waste collected from the hawker center can be used as an enriching medium for the growing of produce in the in-house garden.
4. Evaluation
4.1 Site limitations
Space constraints are a possible challenge most hawker centers would have to deal with prior to the implementation of the system. Due to the limitation of space, the installation of required treatment equipment and having an in-house garden may not be feasible for small hawker centers.
4.2 Operational cost
The installation of an anaerobic digester on site would have a high capital cost and could potentially increase the hawker centers’ overall operational cost; which may not be favorable to the investing stakeholders. However, in ensuring the long term sustainability of their businesses, the stakeholders have to take into account that the benefits of implementing such system would eventually outweigh the capital cost, profiting in the long run.
4.3 Inertia of hawker centers to adopt new system
As composting and anaerobic digestion are not familiar terms to stall owners and managers of hawker centers, it will take time for hawker centers to become familiar and adopt the new technology. The initial stages of implementation would be difficult as it requires a change of mindset towards how food waste is to be handled. Thus, courses must be provided to educate the stall owners and managers the proper operational procedures of the equipment.
5. Methods/Procedure
5.1 Primary research In efforts to explore the need for food waste recycling and to identify the limitation that was limiting the recycling of food waste in hawker centers, a quantitative survey research and on-site observations were carried out. In the survey (see Appendix A), respondents were asked about their contributions to food waste at hawker centers, their opinion on the food waste recycling rate and the main factor that limits food waste recycling at hawker centers. On-site observations were conducted to enhance the accuracy of the survey responses gathered, as well as to gain further insight in how food waste at hawker centers was being handled.
5.2 Secondary research
To further complement the findings obtained through primary research, a secondary research was conducted. Research articles related to food waste, the treatment methods and the utilization of end products from treatments were used to affirm the obtained findings and also to gain new information which would aid in the development of a closed-loop system for recycling food waste at hawker centers. Statistics from local government sources are also analyzed for trends to supplement the findings.
6. Concluding statement
The problem on food waste has serious social and environmental implications. Even so, a majority of the population in Singapore takes the problem lightly, continuing on the daily habits that would contribute to the generation of food waste. With the increased rate of waste generation due to the increase in population, Singapore’s one and only Semakau landfill is filling up. Thus, there is compelling need to increase the recycling rate of food waste that is being sent for incineration and dumping. The proposed closed-loop system would be the sustainable approach in tackling this problem, giving food waste a second life. Through this closed-loop system, food waste generated in hawker centers are converted into a usable bioproducts and be utilized to supplement the hawker center daily operational needs. The implementation of this system in hawker centers would be beneficial not only to the centers themselves, it would also be beneficial to Singapore’s constant pursuit of environmental sustainability.
Therefore, since the National Environment Agency has a huge role to play in increasing the recycling rate of food waste, the implementation of the proposed closed-loop system would be a good head start to encourage hawker centers to recycle food waste; thereby keeping Singapore’s mission on environmental sustainability, on track.
References
Food waste recycling(2008, December 8). Zero Waste SG. Retrieved from http://www.zerowastesg.com/tag/anaerobic-digestion/
Food Waste Management(2018, September 27). National Environment Agency. Retrieved from https://www.nea.gov.sg/our-services/waste-management/3r-programmes-and-resources/food-waste-management
Galanakis, C. M. (2015). Food Waste Recovery – Processing Technologies and Industrial Techniques.Retrieved from https://app.knovel.com/hotlink/toc/id:kpFWRPTIT1/food-waste-recovery-processing/food-waste-recovery-processing
Grandhi, B., Singh, J. A. (2016). What a Waste! A Study of Food Wastage Behavior in Singapore. Journal of Food Products Marketing, 26(4), 471-485. https://doi.org/10.1080/10454446.2014.885863
Half of food thrown away by Singapore households can be avoided: NEA study(2017, December 4).Channel News Asia. Retrieved from https://www.channelnewsasia.com/news/singapore/half-of-food-thrown-away-by-singapore-households-can-be-avoided-9464560
Li, Z., Lu, H., Ren, L., & He, L. (2013). Experimental and modeling approaches for food waste composting: A review. Chemosphere, 93(7), 1247-1257. https://doi.org/10.1016/j.chemosphere.2013.06.064
Pesta, G. (2007). Anaerobic Digestion of Organic Residues and Wastes. Utilization of By-Products and Treatment of Waste in the Food Industry, 53-72. https://doi.org/10.1007/978-0-387-35766-9_4
Siau, M. (2014, April 28). Recycling of foodwaste yet to catch on in Singapore. Today Online. Retrieved from https://www.todayonline.com/singapore/recycling-foodwaste-yet-catch-singapore
Tan, A. (2015, March 11). Singapore Budget 2015: 10 more hawker centres to be built by 2027. The Straits Times. Retrieved from https://www.straitstimes.com/singapore/singapore-budget-2015-10-more-hawker-centres-to-be-built-by-2027
Yahya, Y. (2011, December 28). Turning food waste into water. Eco-Business. Retrieved fromhttps://www.eco-business.com/news/turning-food-waste-into-water/
Communication is an enjoyable learning process 