Carbon footprint and energy recovery of waste

Porast globalne populacije i gospodarski razvoj potaknuli su snažnu potrošnju energije i stvaranje otpada. Više od 2 milijarde t/god miješanog komunalnog otpada (eng. MSW -municipal solid waste ) nastaje na globalnoj razini, a procjenjuje se da će se premašiti 2.200 milijuna tona godišnje do 2025.. Globalno jedna osoba u prosjeku proizvodi 0,74 kg/d otpada (Ying-Chu Chen i Hsiao-Man Liu, 2021.). Toplinska pretvorba, biološka pretvorba i odlaganje tri su najčešće korištene tehnike gospodarenja otpadom. Odlaganje se češće koristi u zemljama u razvoju. Odlaganje komunalnog otpada bez povrata energije ili sustava kontrole emisija uzrokuje probleme javnog zdravlja i opterećenja okoliša, kao što su emisije stakleničkih plinova (eng. GHG - greenhouse gas). Otpad od hrane koji se odlaže na odlagalište ima iznimno visok potencijal emisije stakleničkih plinova. Anaerobna digestija (AD) općenito se smatra najboljom opcijom za obradu hrane i drvnog otpada. Spaljivanje je jedna od najčešćih tehnika gospodarenja otpadom koja se koristi u razvijenim zemljama. Procjenjuje se da je dnevna količina stakleničkih plinova proizvedenih spaljivanjem mnogo manja od one od odlaganja otpada. Tehnologija energije iz otpada ( eng. WtE – Waste to energy) također je dobro ugrađena u Agendi 2030. Ujedinjenih naroda o budućnosti za održivi razvoj u Cilju 7 kojem je namjera osigurati pristup pouzdanoj, održivoj i suvremenoj energiji po pristupačnim cijenama za sve (Nael AlQattan et al, 2018.). Shodno tome u ovom se radu potonje obrađuje tematika ugljičnog otiska u segmentu energetske oporabe otpada, kao i sama energetska oporaba otpada te se prikazuje ugljični otisak svake pojedine tehnologije za energetsku oporabu otpada. Također, prezentiraju se scenariji ugljičnog otiska za neke pojedine tehnologije energetske oporabe otpada u Hrvatskoj.Global population growth and economic development have caused heavy energy consumption and excessive waste generation. More than 2 billion t/year of mixed municipal waste (MSW -municipal solid waste) are generated on a global level, and it is estimated that it will have exceeded 2,200 million tons per year by 2025. Globally, one person produces on average 0.74 kg/ d of waste (Ying-Chu Chen and Hsiao-Man Liu, 2021). Thermal conversion, biological conversion and waste disposal are three common waste management techniques. Waste disposal is more commonly used in developing countries. Disposal of municipal waste without energy recovery or emission control systems causes problems concerning public health and the environment, such as greenhouse gas (GHG) emissions. Food waste that is disposed of in a landfill has an extremely high potential for greenhouse gas emissions. Anaerobic digestion (AD) is generally considered to be the best option for food and wood waste processing. Incineration is one of the most common waste management techniques used in developed countries. It is estimated that the amount of greenhouse gases produced by incineration per day is much less than that from waste disposal. WtE technology is also well embedded in the 2030 Agenda of the United Nations on the Future of Sustainable Development in Goal 7, which aims to ensure access to reliable, sustainable, and modern energy at affordable prices for all (Nael AlQattan et al, 2018). According to this, the paper deals with the topic of carbon footprint in the segment of energy recovery of waste, as well as the energy recovery of waste itself and it shows the carbon footprint of each individual technology for energy recovery of waste. Also, the paper presents carbon footprint scenarios for some individual waste energy recovery technologies in Croatia