Disintegration of compostable foodware and packaging and its effect on microbial activity and community composition in municipal composting

- Disintegration of compostable foodware and packaging (CFP) was determined in-situ.
- 90% of poly-lactic acid based CFP was decomposed in the in-vessel and static pile operations.
- High CFP amendments (2 vs.1% w/w) increased microbial activity in composting process.
- CFP amendments increased microbial community, especially Gram-positive bacteria in composting.

Despite the compostability certification of compostable foodware and packaging (CFP) in lab conditions, composting facilities are reluctant to accept CFP. Certified CFP at 10 and 20% by volume were examined in four types of composting practices in British Columbia, Canada to assess disintegration. Laboratory studies were conducted to determine CFP amended with compost feedstocks at 1 and 2% by weight effects on microbial activity and community structure. Results showed disintegration varied significantly by CFP and facility type. Nearly 90% of poly-lactic acid based CFP completely disintegrated in the in-vessel and static pile, followed by turned windrow (63%) but only 30% of CFP in the anaerobic digestion operation. The disintegration of fibre based CFP was significantly lower than other CFP across composting practices. Increased concentration of CFP enhanced disintegration only in the static pile. Doubling the concentration of CFP (2 vs.1%) in laboratory conditions significantly increased microbial activity (150% of CO2 respiration) and abundance of microbial community groups, i.e., total phospholipid fatty acids, and those of gram-positive bacteria and fungi by 45, 330 and 28%, respectively. These results indicate that under ideal composting conditions CFP products are likely to disintegrate completely and higher concentrations may enhance their biodegradation.