Recently, recycling has been considered as the most useful method to solve the problems related to foodwastes, and its ratio in the treatment of foodwastes has increased continuously. One of the most common choices for recycling has been composting. However, the use of composts which were made from foodwastes has been avoided due to poison of salts, mainly sodium chloride. Therefore, the purpose of this study is to develop a new process for removal of sodium chloride from foodwastes.
Main removal mechanisms were washing and electromigration by electrokinetics. In the operation of pilot-scale reactor, screw speed and current were selected as main factors affecting the removal efficiency. Considering only washing effect, removal efficiency was proportional to the screw speed at the low value, however, was almost a plateau over 10 rpm. Most results of washing were not sufficient for meeting the criteria (i.e., less than 1.0 wt%). Removal efficiency increased with current because current is the driving force for electromigration. The increase of the screw speed under constant current caused a maximum of removal efficiency because the screw speed contributed not only to the increase of washing effect but also to the decrease of residence time of foodwastes in the reactor. Statistical analysis was carried out in order to determine the optimum screw speed and current. As a result, the removal of NaCl was 82.7 % at 11.33 rpm and 52.52 A.