A Comprehensive Study of Biodegradation of Cigarette Filters and Bidi Butts

Biodegradation is the process by which organic substances are broken down into carbon dioxide (CO₂) and water (H₂O) by living microbial organisms. With the advancement in analytical techniques, standard methods have been developed and published by the International Organization for Standardization (ISO), eliminating the ambiguity associated with biodegradation testing for several materials. There is no data available on biodegradation of cigarette filters that follows a standardized and validated ISO method.

The objective of this study is to understand the biodegradation of conventional and non-conventional cellulose acetate (CA) Cigarette Filters, Infused Paper Filter (IP), and Combined Material Filter (CMF), Condensed Tobacco End Filter (CTEC) and bidi butts. In this study, cigarettes and bidis were smoked on a smoking machine following the standard ISO 3308 for cigarettes and the standard ISO 17175 for bidis. After smoking, cigarette filters and bidi butts were subjected to biodegradation testing, adopting the standard ISO 14855-1.

The study demonstrated 92.1% biodegradation in 151 days for cellulose acetate cigarette filters, 91.9% biodegradation in 97 days for DE-Tow^TM (Cellulose acetate with additives) filters, 96.2% biodegradation in 86 days for CMF, 93.4% biodegradation in 55 days for paper filters, 92.1% biodegradation in 54 days for bidi butts, and 95.3% biodegradation in 37 days for CTEC filters were recorded. This study provided an unbiased proof that the cigarette filters made of cellulose acetate are biodegradable as per the standard ISO 14855-1. Also, Gel Permeation Chromatography (GPC) analysis was carried out on the smoked cigarette filters of Cellulose acetate, DE-Tow^TM and CMF as well as their resulting compost to detect any cellulose acetate remaining in the final compost. The GPC analysis indicated cellulose acetate peaks in smoked cigarette filters of cellulose acetate, DE-Tow^TM and CMF samples, whereas no cellulose acetate peak was observed in resulting compost samples. Hence it is concluded that cellulose acetate is not present in any of the resulting composts of cellulose acetate filters, DE-Tow^TM filters and CMF samples.

It is inferred from the results that cigarette filters and bidi butts chosen for the study have achieved the criteria of more than 90% biodegradation, which is well within the specified criteria of 180 days.

This article will be beneficial for entire scientific community, regulators as well as manufacturers in understanding the biodegradability of cigarette filters.