As the energy crisis and resource shortage continue, the development of new energy, energy conservation and carbon reduction have become important goals of the current policy for the government. The usage of densified refuse derived fuel (RDF-5) assisted in reducing the emission of greenhouse gases so as to possess high potential to be used as the biomass energy. Based on the international environmental consciousness, the life-cycle assessment (LCA) has become an environmental assessment tool for improving product design to achieve goals of pollution prevention and sustainable development. The objectives of this project were to manufacture RDF-5 from waste bioplastics (polylactic acid, PLA), biowastes (rice straw), and waste glycerol by means of green design and environmental benefit assessment. In addition, the induced green design concept of LCA assisted in the search for the optimum operating parameters. The RDF-5 from the large-scale production was used as a fuel in a real scale boiler and the emissions from the stack were monitored in order to investigate the feasible application. The production rate of RDF-5 reached 50 kg/h under the lack of heating equipment during the mixing. The ratio used in the scale-up manufacturing process was rice straw: PLA: waste glycerol equal to 8: 8: 1. The density, bulk density, durability, water content of the resulting RDF-5 were 1.34 g/cm3, 648.6 kg/m3, 95.6%, and 2.78%, respectively, which showed that the obtained RDF-5 possessed good quality as biofuel. The combustion of the mixture fuel of palm kernel shell (PKS) and RDF-5 at a ratio of 2:1 produced 2.4 ton steam/h/ton fuel under the total feedstock rate of around ton/h. The emission of air pollutants during the combustion process satisfied the emission standard of the boiler factory. The results from the green design showed that the manufacturing costs of the RDF-5 containing PLA of 21 wt.% and PLA of 45 wt.% were about 510,000 NT/ton, and 530,000 NT/ton, respectively. The Scenario analyses were done for two production scales: 2 and 8 ton/day. The former showed that the production costs were 7,845 NT/ton, 13,526 NT/ton, 16,898 NT/ton for low, medium and high material prices, respectively. In addition, the latter indicated the production costs were 5558 NT/ton, 10,103 NT/ton, 14,628 NT/ton for low, medium and high material prices, respectively. In summary, this project has successfully produced RDF-5 from waste PLA, rice straw with/without waste glycerol in a large scale and the real-scale combustion study showed the emission of air pollutants from the stack all satisfied the emission standard as the RDF-5 was used as fuel for the boiler. The usage of obtained RDF-5 in this study indeed reduces the emission of greenhouse gases and reaches the goal of sustainability and zero waste.

Densified refuse derived fuel, Bioplastics, Life cycle assessment, Environmental benefits, Green design