Two phase partitioning membrane bioreactor: A novel biotechnique for the removal of dimethyl sulphide, n-hexane and toluene from waste air

• Increasing Henry coefficient decreases the removal efficiency in a MBR.
• A TPPMB combines a two phase partitioning reactor with a membrane bioreactor.
• A TPPMB is reliable to treat a mixture of hydrophobic and hydrophilic compounds.

This study is a comparative study between a flat sheet composite membrane bioreactor (MBR) and a new type of MBR, the two phase partitioning membrane bioreactor (TPPMB) to examine the merits of using silicone oil to improve the mass transfer in a membrane type bioreactor. Dimethyl sulphide (DMS), n-hexane and toluene removal from a waste air was carried out by a MBR under continuous feeding conditions. The performance of this reactor was compared with the performance of a TPPMB. In the TPPMB a 60/40 V% water/silicone oil emulsion inoculated with activated sludge was used as recirculation liquid in order to reach an acceptable removal for both hydrophobic and hydrophilic compounds. Removal efficiencies (RE) of respectively 76.8 ± 7.7, 77.6 ± 13.0 and 12.1 ± 12.3% were reached for toluene, DMS and hexane inlet concentrations ranging up to 2.6 g m−3 for each compound (Inlet load (IL) ⩽312 g m−3 h−1) in a MBR. This indicates that a MBR is suitable to treat DMS and toluene, but unreliable to treat hexane. In a TPPMB RE of 85 ± 5, 62 ± 5 and 53 ± 6% were reached for toluene, DMS and hexane inlet concentrations ranging up to 2.8 g m−3 for each compound (IL ⩽ 336 g m−3 h−1) respectively. The RE for hexane is significantly higher in a TPPMB, while the variability of the hexane removal decreased, so the TPPMB is suitable and more reliable for degrading hexane than a MBR. The increase in RE of hexane and toluene can be related to the increase in transfer when applying 40 V% silicone oil.