To resolve problems in chain restaurants of a central kitchen system wherein, while all foods except fresh vegetables are packed in soft resin bags which are retort packs having been subjected to cooking and delivered to the specific shops throughout the country, after using inner foods in the restaurants, the packs are simply charged into backyard waste containers, which causes large volume due to their forms, and collection and dispersion of harmful insects by the hoods attached inside the bags, takes labor of sterilization of hands of waste charging workers, intermediate treatment contractors take back the waste based on the volume of necessity charging high cost, with no way but to incinerate on the same day.

In a family restaurant normally collecting guests including Tokyo and its vicinity, waste amounts to a full state of a 2m3 waste container every day, and 95% of the content is soft resin bags of the retort packs. By crushing and washing the bags in water and filtering and separating, by installing an invertedly set grinder pump in a water tank 1m in diameter and 1m in height set in a backyard, daily waste volume is greatly reduced, being effective for recycling for reducing resin amount and as auxiliary high calorie fuel.