Design considerations for high-temperature respirometric biodegradation of polymers in compost

As interest in the field of biodegradable plastics grows so too must the methods to accurately assess them. The use of respirometric units to control and monitor in-situ degradation is one popular method to achieve this, however little is understood about the consequences of their design when applied to high-temperature large-scale replications of bioreactors. In this paper we discuss the design characteristics of a laboratory scale aerobic biodegradation unit and compare a number of key design features with a particular focus on the effect of internal bioreactor design and aeration rate on the compost moisture content and overall sample biodegradation. The internal design of the bioreactors was shown to produce different air and moisture circulation patterns within the bioreactor compost-sample mix. Optimised design of the bioreactor systems to maximise biodegradation was shown to increase the biodegradation of base cellulose from 72 to 81% over a 90 day period.