Coffee usually packed in 60 kg bags

Coffee usually packed in 60 kg bags is one of the second traded commodities after petroleum and is one of the most consumed beverages totaling about eight million metric tons in 2009/10 (ICO, 2013). According to the International Coffee Organization (ICO) the coffee per capita consumption in kg significantly varies from country to country, where Nordic countries are distinguished among the highest in the world and thus dispatching high volumes of coffee waste. Although there are different byproducts generated during the coffee processing steps from the green cherries to the brown beans after roasting, the largest residue is obtained after extraction of the soluble compounds. The coffee extract residue (CER) resulting in a ratio of between 2 and 4:1 to ground coffee obtained by filtration on a filter paper and through percolation by hot dripping water in a coffee machine is a substantial source of agricultural waste, which can be used in a number of application areas, such as substrate for mushroom cultivation, compost, direct removal of dyes, activated carbon and biosorbents, ethanol, as a fuel in industrial boilers for cogeneration of heat and/or electricity, biodiesel, briquettes and for a range of other chemical compounds (Mussatto et al., 2011a; Murthy and Naidu, 2012). Although the heating value of CER on dry basis 21.5 MJ/kg (Tsai et al., 2012) is comparable to fossil coal and other agricultural wastes and residues, the high humidity of the CER significantly decreases its overall heat content with eventual release of particulate matter and other gaseous byproducts if fired or co-fired with other precursors for district heating or electricity. Thus, search for other approaches to harness value-added chain of products from the disposal of thou- sands of tons of CER are essential for a sustainable environmental, cleaner and process technology solutions. Utilization of a product in its subsequent cycle of cradle-product-waste-product has a far reaching strategy in our holistic appraisal and solution of environ- mental significance. Ethanol and activated carbon are not only ob- tained from CER, but also other possible products can be extracted.