**3. Results and Discussion**

*3.1. Status of Industrial Food Waste Generation in Taiwan*

According to the project ("Food Use for Social Innovation by Optimizing Waste Prevention Strategies") funded by the European Commission [22], the definition of food waste refers to "any food, and inedible parts of food, removed from the food supply chain to be recovered or disposed". In this regards, food waste will be often generated from the retailers, consumers, and food service providers or food processing manufacturers due to the expiration, discard during the sorting operation, leftover, and other wastage reasons [23]. Figure 1 shows the categories of food waste based on its generation sources. In the present study, the industrial sources referred to the agricultural farms (e.g., s laughterhouse, hatchery, oyster farm, aquafarm, and truck farm), and animal-based or plant-based food processing plants or sites. By contrast, the non-industrial sources included the residential, commercial (e.g., office, retail, wholesale, warehouse and distribution, hotel, and restaurant), and service (e.g., hospital) and institutional (school) facilities [3].

**Figure 1.** Food waste category and its generation sources.

In order to manage food waste from the industrial sources efficiently, the Taiwan EPA announced that the se sources with over specified amount of food waste generated annually were required to submit their industrial waste management plans by on-line reporting system based on the requirements of the WMA. According to the on-line reports during the period of 2015–2019 [24], Table 1 listed the reported amounts of industrial food waste, showing that the organic food waste from alcoholic beverage manufacturers (i.e., lees, dregs, or alcohol mash) and inorganic food waste from oyster farms (i.e., waste oyster shell) accounted for about half (about 250,000 metric ton) of industrial food waste generation in Taiwan. Table 2 showed the reported amounts of kitchen waste and waste cooking oil during the period of 2015–2019, which were categorized into the industrial sources and non-industrial sources. Obviously, the amount of kitchen waste generation was mostly from the non-industrial sources, indicating a stable amount of about 600,000 metric tons. It should be noted that the significant increases in kitchen waste generation from industrial sources and waste cooking oil from non-industrial sources in 2017 was attributed to the regulatory requirements due to the "food safety scandal" event and circular bioeconomy promotion [14,15]. It can be seen that total reported amounts of waste cooking oil significantly increased from 12,877 metric tons in 2015 to 29,507 metric tons in 2019.


**Table 1.** Current status of industrial food waste generation during the period of 2015–2019 [24].

**Table 2.** Current status of kitchen waste and waste cooking oil generation during the period of 2015–2019 [24].


*3.2. Promotion Policies for the Valorization of Food Waste from Industrial Sources*

Regarding the on-line reporting amount and the regulatory measures for the reuse (or valorization) status of food waste from the non-industrial (residential and commercial) sources in Taiwan, the data during the period of 2010–2017 have been addressed in the

previous study [15]. Table 3 further updated the data [13], indicating that the increasing trend in composting valorization during the period of 2015–2019 could be due to the driving force by the "food safety scandal" event in September 2014 and the prevention of African swine fever (ASF) spread since 2019 [25]. Under the authorization of the WMA, the Taiwan EPA subsequently promulgated and/or revised some promotion policies for the valorization of mandatory recyclable food waste (including kitchen waste and waste cooking oil) from all sources to avoid entering the food chain and the 24 larger-scale MSW incineration plants [14]. According to the regulatory definition, the valorization (or reuse) of food waste refers to the production of value-added resources like organic fertilizer, animal feed, and biomass energy. From the regulatory joint-efforts by the central governing authorities [16], including EPA, COA, MOF, and MOEA, Tables 4 and 5 summarized the regulatory measures for the valorization (or reuse) options of urban food waste (kitchen waste and waste cooking oil) and industrial food waste, respectively.

**Table 3.** Amounts of urban kitchen waste in terms of recycling method over the past decade in Taiwan <sup>1</sup> .


<sup>1</sup> Source [13]; Unit: metric ton.

3.2.1. Promotion Policies for the Production of Value-Added Materials from Food Waste

Over the past two decades, industrial ecology concepts, including Cradle to Cradle (C2C) and circular economy, played a prevailing role in the waste management [4]. The approach for the "zero waste" aimed at reusing the food waste as raw material (or feedstock) for new products and applications. In Taiwan, the promotion policies for the production of value-added materials from food waste were based on the legislations by the governing authorities, including the Council of Agriculture (COA), the Ministry of Economic Affairs (MOEA), and the EPA [16]. Therefore, the central governing agency (i.e., COA) jointly promulgated some regulatory measures for ensuring the bio-products from the food waste valorization under the acts, including the Fertilizer Management Act, the Feed Management Act, and the Animal Industry Act. Based on the Fertilizer Management Act, the organic fertilizer produced from food waste must meet the specifications for the soil-based nutrients/compositions like organic matter, nitrogen and phosphorus, and the limits of toxic metals, including arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), nickel (Ni), lead (Pb), and zinc (Zn).


**Table 4.** Regulatory measures and generation sources for urban food waste (kitchen waste and waste cooking oil) valorization under the authorization of the Waste Management Act (WMA).


**Table 5.** Regulatory measures and generation sources for industrial Food waste valorization under the authorization of the WMA.
