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. 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 thinks 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 amounts 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, Singaporeans 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 tonnes 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 centres) where a significant amount of food waste is being produced.
1.3 Purpose Statement
This report aims to propose to the NEA Hawker Centre Division in implementing a closed-loop system to maximize the food waste utilization rate of hawker centres by providing an efficient system to sort and utilize food waste generated by food vendors and customers.
2. Proposed solution
The proposed solution to deal with the problem of food waste in hawker centres is to provide a closed loop system to maximize the food waste utilization rate of hawker centres. 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 it reduces 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
a. 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 compounds such as meats are not ideal as they produce a foul odor and may attract stray animals.
b. 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. 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 centre. 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 centre to meet its operational needs. It is beneficial to have such system in place as it reduces dependency on external resources, maximizes the utilization of food waste and
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 on, in Singapore, food waste accounted for 10% of total waste generated and only 16% of it is being recycled (NEA, 2018), 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 only solution to prolong the landfill’s lifespan would be to maximize the utilization of waste instead of having them disposed of.
3.3 Hawker center localised garden for growing of small produce
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 litres in reclaimed water. The reclaimed water can be used for irrigation for a hydroponics system to grow local produce for use within the hawker centre that the farm is located in.
Furthermore, the compost produced from the recycled food waste collected from the hawker centre can be used to enrich the growing medium for the produce grown in the hawker centre garden for use by the vendors for their own use in their stalls.
As for the biogas produced from anaerobic digestion, it can be used to fuel the generators the systems that run the hydroponics farm like water pumps for irrigation and UV lamps to keep the produce in optimum lighting levels throughout the day.
4. Evaluation
4.1 Site limitations
One possible challenge which the proposed treatment system may face would be the limited space which most hawker centers have. Installing equipment to treat the food waste may not be feasible for small hawker centers as there would be no space for the equipment. The proposed garden would also be limited to the space around the hawker center.
4.2 Operational cost
Installing an anaerobic digester on site would be costly and could potentially cost the hawker center more money to maintain its operation. From the point of view of stakeholders who invest money in installing an anaerobic digester on site, the benefits of the treatment system must outweigh the cost of operation. Stakeholders must weigh the benefits of recycling food waste against the cost of such a system to ensure their business is sustainable and that the system will eventually cover the capital cost.
4.3 Inertia of hawker centers to adopt new system
As composting and anaerobic digestion are not familiar terms to hawker stall owners and managers of hawker centers, it may be difficult to implement a new system as it will take time for hawker centers to familiarize and adopt new technology. Hawker vendors may also not be well trained to operate equipment to treat food waste. The initial stage of implementation would be difficult as it requires a change of mindset towards handling food waste as opposed to the traditional method of dumping food waste in a bin.
Basic lesson on using those machinery can be taught free to all hawker stall owners, at the same time explaining to them the benefits on adopting these new technology.
5. Methods/Procedure
5.1 Primary research
A survey was conducted to identify the problem with regards to food waste in hawker centers. Respondents were asked about their contributions to food waste at hawker centers and their opinion on the rate of recycling food waste at hawker centers as well as the main factor which limits food waste recycling. The survey was conducted to justify the need for food waste recycling at hawker centers as well as identify the current problem which limits the food waste recycling rate. Interviews with hawker stall owners were also carried out to gain further insight into how food waste at hawker centers is being handled.
5.2 Secondary research
Secondary research was conducted by reading research articles related to food waste treatment methods and utilization of products from recycling food waste, which will help in developing a closed-loop system for recycling food waste at hawker centers. Local statistics on the rate of food waste recycling were taken from the NEA website.
6. Concluding statement
Food waste has serious social and environmental implication but many of us don’t think twice about it. Furthermore, with the increase of population, landfills running out of space and human living longer. There is compelling need to increase the recycling rate then letting food waste be send for incineration. Our proposed on closed loop system could be a sustainable approach by the end-product could be a usable resources that could be utilized to supplement the hawkers center daily operational needs.
The benefits of implementing a closed-loop system for food waste in hawker centers would be limited by the willingness of hawker centers to adopt such a system. The NEA could play a big role in encouraging hawker centers to recycle food waste. To ensure this system is well received by hawker centers around Singapore, some incentives could be given to hawker centers which are willing to adopt the system. In a survey conducted regarding this issue, 32.5% of respondents said 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 said that inadequate policies being implemented by relevant authorities is a contributing factor which limits food waste recycling in Singapore. To ensure successful implementation, it is vital that NEA takes initiative in campaigning for food waste recycling and educating Singaporeans on the importance of recycling food waste.
A pilot project is recommended to test the feasibility of implementing the recycling system in hawker centers around Singapore. The pilot project will involve upgrading a hawker center by installing food waste treatment equipment as well as planting a garden in close proximity to the hawker center. The project should be monitored and if successful can be adapted and implemented in hawker centers all around Singapore.
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 on, in Singapore, food waste accounted for 10% of total waste generated and only 16% of it is being recycled (NEA, 2018), 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 only solution to prolong the landfill’s lifespan would be to maximize the utilization of waste instead of having them disposed of.
3.3 Hawker center localised garden for growing of small produce
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 litres in reclaimed water. The reclaimed water can be used for irrigation for a hydroponics system to grow local produce for use within the hawker centre that the farm is located in.
Furthermore, the compost produced from the recycled food waste collected from the hawker centre can be used to enrich the growing medium for the produce grown in the hawker centre garden for use by the vendors for their own use in their stalls.
As for the biogas produced from anaerobic digestion, it can be used to fuel the generators the systems that run the hydroponics farm like water pumps for irrigation and UV lamps to keep the produce in optimum lighting levels throughout the day.
4. Evaluation
4.1 Site limitations
One possible challenge which the proposed treatment system may face would be the limited space which most hawker centers have. Installing equipment to treat the food waste may not be feasible for small hawker centers as there would be no space for the equipment. The proposed garden would also be limited to the space around the hawker center.
4.2 Operational cost
Installing an anaerobic digester on site would be costly and could potentially cost the hawker center more money to maintain its operation. From the point of view of stakeholders who invest money in installing an anaerobic digester on site, the benefits of the treatment system must outweigh the cost of operation. Stakeholders must weigh the benefits of recycling food waste against the cost of such a system to ensure their business is sustainable and that the system will eventually cover the capital cost.
4.3 Inertia of hawker centers to adopt new system
As composting and anaerobic digestion are not familiar terms to hawker stall owners and managers of hawker centers, it may be difficult to implement a new system as it will take time for hawker centers to familiarize and adopt new technology. Hawker vendors may also not be well trained to operate equipment to treat food waste. The initial stage of implementation would be difficult as it requires a change of mindset towards handling food waste as opposed to the traditional method of dumping food waste in a bin.
Basic lesson on using those machinery can be taught free to all hawker stall owners, at the same time explaining to them the benefits on adopting these new technology.
5. Methods/Procedure
5.1 Primary research
A survey was conducted to identify the problem with regards to food waste in hawker centers. Respondents were asked about their contributions to food waste at hawker centers and their opinion on the rate of recycling food waste at hawker centers as well as the main factor which limits food waste recycling. The survey was conducted to justify the need for food waste recycling at hawker centers as well as identify the current problem which limits the food waste recycling rate. Interviews with hawker stall owners were also carried out to gain further insight into how food waste at hawker centers is being handled.
5.2 Secondary research
Secondary research was conducted by reading research articles related to food waste treatment methods and utilization of products from recycling food waste, which will help in developing a closed-loop system for recycling food waste at hawker centers. Local statistics on the rate of food waste recycling were taken from the NEA website.
6. Concluding statement
Food waste has serious social and environmental implication but many of us don’t think twice about it. Furthermore, with the increase of population, landfills running out of space and human living longer. There is compelling need to increase the recycling rate then letting food waste be send for incineration. Our proposed on closed loop system could be a sustainable approach by the end-product could be a usable resources that could be utilized to supplement the hawkers center daily operational needs.
The benefits of implementing a closed-loop system for food waste in hawker centers would be limited by the willingness of hawker centers to adopt such a system. The NEA could play a big role in encouraging hawker centers to recycle food waste. To ensure this system is well received by hawker centers around Singapore, some incentives could be given to hawker centers which are willing to adopt the system. In a survey conducted regarding this issue, 32.5% of respondents said 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 said that inadequate policies being implemented by relevant authorities is a contributing factor which limits food waste recycling in Singapore. To ensure successful implementation, it is vital that NEA takes initiative in campaigning for food waste recycling and educating Singaporeans on the importance of recycling food waste.
A pilot project is recommended to test the feasibility of implementing the recycling system in hawker centers around Singapore. The pilot project will involve upgrading a hawker center by installing food waste treatment equipment as well as planting a garden in close proximity to the hawker center. The project should be monitored and if successful can be adapted and implemented in hawker centers all around Singapore.
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