A total of 10 t/d of bio-solid (BS) fuel was produced from 45 t/d of organic solid waste (OSW) containing 80 wt% water using a fry-drying and torrefaction (FDT) plant. This study aimed at evaluating economic feasibility of the FDT plant in terms of the total capital investment (TCI), total production cost (TPC), return on investment (ROI) and payback period (PBP). Two different heating sources for steam generation were used: Case 1 using BS produced in this plant, and Case 2 using LNG provided externally. A four level economic potential approach was applied to evaluate economic feasibility. A sensitivity analysis was conducted to determine the major factors influencing ROI. Case 1 using BS showed a higher ROI than Case 2 using LNG because the LNG cost overwhelmed the TCI increment of Case 1. For Case 1 with 45 t/d of OSW, the TCI, TPC, ROI and PBP were $3.6 million, $13 million/yr, 6.0%/yr and 9.8 yr, respectively. To achieve a desired ROI of 10%/yr, the plant sizes of Cases 1 and 2 were 60 and 90 t/d, respectively. When the OSW treatment credit increased from 100 $/t to 120 Sit, ROI exceeded 10% in Case 1 With 45 t/d. (C) 2017 Elsevier Ltd. All rights reserved.