The products obtained from these waste organic materials are in the form of Refuse-Derived Fuel. RDF can be used in many ways to generate electricity or even used alongside with traditional sources of fuel in coal power plants. The rest of the hazardous and unwanted inorganic wastes are transferred to landfill to be disposed. These post-treatment processes are crucial to sustain the environment. The research on high frequency screens has led to new developments in the field which enhance the operation and performance of the equipment. These new developments include the stacking of up to 5 individual screen decks placed on top of the other and operating in parallel. A divider system splits the feed slurry to each Stack Sizer screen, then to each screen deck on the machine. Each screen deck has an undersize and oversize collection pan which will respectively go into their common outlet. The stacking of the machines thus allows more production while using less space. Another new development is the fabrication of Polyweb urethane screen surfaces that have openings as fine as 45 μm and open areas from 35% - 45%. This leads to the screen being able to separate finer particles. The screens can be used for both wet and dry applications and urethane formulation is still an ongoing process. Thus, research and development is still being invested in high frequency screening equipment to improve the overall separation efficiency and also to lower costs. To further optimize the performance for high frequency vibrating equipment, a "variable speed" hydraulic vibrator is being developed and used to drive the screen decks. It utilizes fluid hydraulic force which then can be converted into rotary power in order to generate high frequency vibration. This modification allows equipment to operate at higher frequency range, up to 8200 RPM, compared to the conventional electric vibrators. Besides that, the induced vibration also creates an excellent condition for separating finer particles and improves the contacting probability for the materials. Another variation that could be applied to the equipment is the "rotary tensioning system", in which it helps to provide a quicker screen media change. Therefore, multiple applications can be achieved by single equipment, as with different size of feed material can be deal by replacing screens in a very small downtime. Hence, it improves the economic benefits of plants.