Sequential and continuous configurations at pilot scale. Display omitted •Butyraldehyde removal by plasma and photocatalysis is studied at pilot scale.•Effects of some operating parameters on performance of each process are tested.•A synergetic effect is confirmed by plasma DBD and photocatalysis combined.•Sequential and continuous configurations have been investigated.•Possible reasons of synergetic effect have been discussed. This work investigated the performance of butyraldehyde decomposition with the help of dielectric barrier discharge (DBD) plasma coupled with photocatalysis (TiO2+UV) at room temperature. Effects of flow rate and initial butyraldehyde concentration on the decomposition and the distribution of byproducts were examined and discussed. The combination of these two technologies led to an enhancement of butyraldehyde abatement compared to the separate systems at pilot scale from 5 to 10m3h−1 of flowrate. The synergy factor due to combination processes ranged from 1.13 to 1.27. In the same way, CO2 selectivity was significantly improved when compared to the DBD plasma alone. In this research, DBD plasma system and an immobilized TiO2 photocatalysis system is sequentially combined to oxidize the target pollutant. Indeed, different ways to combine sequentially DBD plasma with photocatalytic materials are listed. Results at pilot scale showed that when photocatalyst is placed in the post discharge, the performance of sequential coupling plasma–photocatalyst process is improved in term of decomposition, by-products formation and energy yield.