Coffee is the most widely consumed beverage in the world, with 7.4 million tons of coffee beans produced and distributed annually. It also takes up the second-highest trade volume after petroleum, implying its critical role in the economy (Jo et al. 2017). Coffee consumption by Koreans has been increasing continuously and, according to 2017 statistics, the annual coffee consumption by an average Korean adult has reached approximately 512 cups. According to the Korea Customs Service and the coffee industry, the national coffee market valuation has reached 11 trillion Korean won, which is more than three times larger than that 10 years ago (Yonhap News 2018). However, with increasing coffee consumption, the amount of spent coffee grounds, a byproduct of coffee consumption, is also increasing accordingly. The Seoul Metropolitan Government estimated that the daily amount of discarded spent coffee grounds in Seoul would reach about 140 tons in 2014 (Maekyung economy news 2016). Unlike the