SUSTAINABLE WASTE MANAGEMENT Converting environmental risks to benefits by using spent coffee grounds (SCG) as a valuable resource Marinos Stylianou 1 & Agapios Agapiou 2 & Michalis Omirou 3 & Ioannis Vyrides 4 & Ioannis M. Ioannides 3 & Grivas Maratheftis 3 & Dionysia Fasoula 3 Received: 15 December 2017 /Accepted: 22 May 2018 # Springer-Verlag GmbH Germany, part of Springer Nature 2018 Abstract Coffee is perhaps one of the most vital ingredients in humans’ daily life in modern world. However, this causes the production of million tons of relevant wastes, i.e., plastic cups, aluminum capsules, coffee chaff (silver skin), and spent coffee grounds (SCG), all thrown untreated into landfills. It is estimated that 1 kg of instant coffee generates around 2 kg of wet SCG; a relatively unique organic waste stream, with little to no contamination, separated directly in the source by the coffee shops. The produced waste has been under researchers’ microscope as a useful feedstock for a number of promising applications. SCG is considered a valuable, nutrients rich source of bioactive compounds (e.g., phenolics, flavonoids, carotenoids, lipids, chlorogenic and protocatechuic acid, melanoidins, diterpenes, xanthines, vitamin precursors, etc.) and a useful resource material in other processes (e.g., soil improver and compost, heavy metals absorbent, biochar, biodiesel, pellets, cosmetics, food, and deodorization products). This paper aims to provide a holistic approach for the SCG waste management, highlighting a series of processes and applications in environmental solutions, food industry, and agricultural sector. Thus, the latest developments and approaches of SCG waste management are reviewed and discussed. Keywords Bioactive compounds . Circular economy . Coffee . Food waste . Landfills . Recycling . SCG valorization . Solid waste Introduction Coffee consumption in recent years has grown considerably, making it one of the most important consumer goods (Obruca et al. 2015). Notwithstanding, the worldwide coffee produc- tion is under 3.3 million bags relative to its consumption. World coffee consumption reached was 157,382 of 60 kg bags in 2016–2017, from which 32.8% were used in Europe, 21.9% in Asia and Oceania, 18.7% in North America, 16.1% in South America,7.2% in Africa, and 3.3% in Central America and Mexico (ICO 2016). Arabica and Robusta are the most preferable coffee species worldwide. In the literature, there is a plethora of articles on the beneficial effects of coffee consumption in human health, whereas others supported the opposite effects. The negative effects of caffeine were bypassed through decaffeinated coffee, produced by chemical decaffeination (methylene chloride/ethyl acetate) or through physical methods (extraction by water, supercritical CO 2 methods). The main coffee-brewing methods are the boiling (Greek/Turkish, Scandinavian, etc., with caffeine con- tent less than 50 mg cup -1 ), the filter (filter coffee: caffeine content, 100–150 mg cup -1 ), the dissolving (instant/soluble coffee: caffeine content, 65–100 mg cup -1 ), and the pressure method (espresso: caffeine content, 60 mg cup -1 ) (Argyrides 2016). Espresso coffee residues are considered the main waste product of coffee shops (cafeterias) widespread all over the world. Responsible editor: Philippe Garrigues * Marinos Stylianou stylianou.a.marinos@ucy.ac.cy 1 NIREAS-International Research Center, Department of Civil and Environmental Engineering, University of Cyprus, P.O. Box 20537, CY-1678 Nicosia, Cyprus 2 Department of Chemistry, University of Cyprus, P.O. Box 20537, CY-1678 Nicosia, Cyprus 3 Agricultural Research Institute, P.O. Box 22016, CY-1516 Nicosia, Cyprus 4 Department of Environmental Science and Technology, Cyprus University of Technology, 30 Archbishop Kyprianos, CY-3036 Lemesos, Cyprus Environmental Science and Pollution Research https://doi.org/10.1007/s11356-018-2359-6