Biopower and biofertilizer production from organic municipal solid waste: An exergoenvironmental analysis

In this study, the environmental performance of a genset-coupled anaerobic digestion plant is analyzed at component-level using an exergoenvironmental method. The plant digests organic municipal solid waste (MSW) while producing two main products, i.e., biopower and biofertilizer. A comprehensive exergoenvironmental modeling of the plant is conducted using actual operating data in order to highlight the main units consuming exergy and causing environmental burdens. The exergoenvironmental indicators of all units of the system are computed by integrating exergy and environmental impact balances. The unitary exegetic environmental impact of biopower and biofertilizer are determined at 11.10 and 0.36 mPts/GJ, respectively. This means that the biofertilizer generation causes less environmental burden over the biopower due to the ease of its production. The highest total environmental impact rate (37.05 mPts/h) is caused by the genset followed far behind by the digester (8.56 mPts/h). Although the genset has the highest operation -related environmental impact rate (36.97 mPts/h), the highest component -related environmental impact rate (7.87 mPts/h) is associated with the digester. Therefore, the exergoenvironmental performance of the plant can be boosted by minimizing the rate of exergy dissipation of the genset while mitigating the environmental impacts related to the development and construction of the digester. (C) 2019 Elsevier Ltd. All rights reserved.