标题：Sustainable Circular Bioeconomy—Feasibility of Recycled Nutrients for Biomass Production within a Pulp and Paper Integration in Indonesia, Southeast Asia
摘要：Sustainable biomass production based on efficient carbon and nutrient recycling is crucial in materially efficient, sustainable biobased production. A circular bioeconomy model of the replacement of mineral fertilizers with recycled nutrients from pulp and paper mill sludge is tested here within a hypothetical case from Indonesia, Southeast Asia. First, the financial feasibility of the use of recycled nutrients originating from pulp and paper processes was analyzed in fast-growing pulpwood production. Secondly, the comprehensive social and environmental benefits of the practice were analyzed through qualitative sustainability analysis. The availability of the basic material of all required parameters referring to Indonesia limited the analysis period to be from 1996 to 2013. The establishment costs of a pulpwood plantation were adjusted according to a reference study, while the other data were compiled from various sources. The financial profitability of the circular model was analysed by using two indicators, net present value (NPV) and internal rate on return (IRR). The application of sludge-based recycled nutrients slightly increased the establishment costs in some circumstances but had no direct impact on the financial profitability, as the financial profitability was not sensitive to the establishment costs. The results showed that the financial profitability of biomass production is not sensitive to the plantation establishment and management costs. The profitability depends on the mean annual increment and product price. The qualitative analysis showed a holistic value of the practice that goes beyond the direct benefits. The use of sludge-based recycled nutrients in the production of pulpwood closed the economic loop, which is illustrative of the circular bioeconomy within the integrated pulp and paper sector including the raw material source, forest plantation.
