Biogas production from strong organic waste, including livestock waste, food waste, and sewage treatment sludge, is newly highlighted in developing countries, i.e., Korea, China, and East Asian countries. Up-flow Anaerobic Sludge Blanket (UASB) type digester is widely accepted for anaerobic digestion due to its efficiency. However, there are two different directions to modify and improve the technology. One is to achieve short hydraulic retention time (HRT) by reducing solid loading rate of the digester, and to yield higher methane contents by remaining good methane bacteria granules. The other is to achieve higher gas production by increasing solid loading rate of digester, and to improve the rate of solid conversion to biogas. Two systems were hypothesized in order to investigate efficiency and technological feasibility. One system (A) has lower solid loading rate (less than 3 %) and shorter HRT (about 4 days). The other (B) has higher solid loading rate (about 10 %) and longer HRT (about 20 days). The two conditions are similar with the actual conditions of plants known as a good system with having stability and efficiency in Korea. The comparisons of the two system show that B has higher construction cost (more than 20 % in Korea), but 3 times larger gas production. If the gas price and waste treatment fees are hypothesized in Korea, the benefit of B is 30 % higher than the benefit of A. If there will be full investment for the plants, 5-year breakpoint for B and 9-year breakpoint for A are estimated. The result indicated that renewable energy from organic waste can be more effectively produced by the system B. That is, higher solid loading rate and gas conversion rate are more important than short HRT for better wastewater treatment. Consequently, the technology development and policy making direction should be system B instead of system A. The direction is also well matched with new environmental management paradigm, from waste to energy.