Animal dung conversion to compost and biogas – slaughtering house case in Abu Dhabi City

Abu Dhabi City’s slaughtering houses activity produces several animal waste streams. Animal dung is one of them, which is also a source of biomass potentially convertible to compost and/or biogas. This conversion can prevents public health issues and nuisance related to disposal of animal waste. The objective of this work is to perform an economic and Emergy assessment of the slaughtering house animal dung conversion into compost and biogas. The software SuperPro designer was used for this aim. Two different conversion systems, based on anaerobic digestion, were selected: 1) non-pretreatment (NPT) where animal dung is feed into an anaerobic digester, and 2) thermal pretreatment (TPT), where animal dung is first pretreated at 120ºC and 2 atm for 1 hour, then feed into an anaerobic digester.In Abu Dhabi City the annual number of sacrificed animals is 397,200 (last 5 years average). The estimated average of animal dung collected is 230 ton/year (dry basis). The estimated compost (dry basis) and biogas production for the NPT are 210 ton/year and 19,500 m³/year, respectively, and for the TPT are 70 ton/year and 144,000 m³/year, respectively. The estimated annual profits are 2,970 USD/year and 41,700 USD/year, for NPT and TPT respectively. The Emergy estimation gave an energy return on investment of 380 and 62 for NPT and TPT, respectively. Hence, the TPT is economically more attractive, while the NPT is more attractive from Emergy considerations.