Influence of solid polymers on the response of multi-phase bioreactors treating α-pinene-polluted air

The use of biological techniques for the removal of hydrophobic and recalcitrant volatile compounds at industrial scale has recently significantly increased. In the present work, studies were undertaken aimed at comparing the performance of a continuous stirred tank bioreactor (CSTB) with either a single liquid phase or in the presence of a solid non-aqueous phase (NAP), for the biodegradation of α-pinene. Specifically, 3.5 mm diameter beads of Hytrel G3548L were selected as solid NAP based on their affinity for α-pinene. Performance was evaluated over a period of 322 days. However, the experimental results showed no significant enhancement of α-pinene biodegradation in presence of the NAP compared to the reactor with a single liquid phase. Under steady-state conditions, when Hytrel G3548L (5%) was added to the CSTB, the maximum elimination capacity (ECmax) achieved was ∼60 g m−3 h−1, which was similar as in the absence of the NAP. Under transient shock-load conditions similar results were obtained with or without NAP, although attenuation was observed in the decrease of the removal efficiency (RE) during overload when polymer beads were present.