The effect of recycling bin design on PET bottle collection performance

Abstract

Many municipalities in Japan have collected PET bottles as recyclable waste since 1980s. When caps are removed from bottles, it reduces collection and transportation costs because bottles can be easily compressed by collection trucks. However, PET bottles collected from recycling bins are usually capped and include other materials. This study designed 10 recycling bins for PET bottle to investigate the effect of design on cap removal efficiency and recycling contamination (foreign waste mixture). Recycling bins for PET bottle were designed focusing on four design items. They are (1) individual recycling bins specifically for bottles and caps or all-in-one recycling bin for both bottle and cap collections, (2) inside-visibility (see-through), (3) signage (wording like “Bottle” and “Cap”) near insert slot and (4) insert slot shape. PET bottle collection performance of designed recycling bins was monitored in Suzukakedai campus of Tokyo Tech. Perceptive preferences of recycling bin designs and insert slot shapes were measured by online surveys. Experimental results indicate that insert slot with round shape contributed to significantly lower recycling contamination than bottle-like shape although perceptive preference of insert slots with bottle-like shape was higher than that of the round shape. Signage and all-in-one design is significantly effective to promote cap removal only when it was set with other recycling bins. On the other hand, signage is effective to decrease recycling contamination in a single setting. This study found that design effect depended on the setting condition of recycling bins in terms of cap removal and foreign waste disposal.