Design and Construction of oil palm fronds (OPF) Compost Mixer Machine Type Rotary Double Helix Drum

Palm oil (Elaeis guineensis Jacq) is a plant that provides many benefits. However, oil palm plantations contribute a lot of waste, especially oil palm fronds (OPF). But OPF can be processed into compost. The compost processing made from palm fronds requires mixing to make the material evenly distributed. This process requires machines and equipment called mixer machine. Therefore, the purpose of this study was to design and construct a rotary double machine helix drum type. Machine testing was carried out at three mixer rotation speed levels (100 rpm, 300 rpm, and 500 rpm), two levels of mixing process time (10 minutes and 15 minutes) and two compost method (natural and bokashi). The parameters observed were the productive capacity of the machine, the percentage of compost material left on the machine and the percentage of compost material that was unmixing. In the natural composting method, it is obtained that with the increase of the mixer rotational speed, the engine capacity will also increase at all processing times. However, it is different from the percentage of compost material left on the machine and the percentage of compost material that clot when mixer decreases with increasing mixing speed of the mixer at all processing times. In the method of composting, it was found that with the increase of the mixing machine's rotational speed to 500 rpm it would increase machine capacity at each process time of 10 minutes and 15 minutes to 63.94 kg/hr and 42.69 kg/hr. However, for the percentage of compost left on the machine and the percentage of compost material that unmixing when mixer will decrease to 11.2% (10 minutes processing time), 11.1% (15 minutes processing time), 20.83% (10 minutes process time), 19.94% (15 minute processing time) with increasing mixing machine speed to 500 rpm.