Insights into siloxane removal from biogas in biotrickling filters via process mapping-based analysis

•Simultaneous removal of D4 and D5 from biogas in BTF is evaluated.•A competitive D4 and D5 removal mechanism is pointed out.•A preferential pathway towards performance minimization is identified.•Main hidden causes limiting system performance are depicted.•Performance depends on mass transfer, biomass density, siloxane breakdown.

Data process mapping using response surface methodology (RSM)-based computational techniques is performed in this study for the diagnosis of a laboratory-scale biotrickling filter applied for siloxane (i.e. octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5)) removal from biogas. A mathematical model describing the process performance (i.e. Si removal efficiency, %) was obtained as a function of key operating parameters (e.g biogas flowrate, D4 and D5 concentration). The contour plots and the response surfaces generated for the obtained objective function indicate a minimization trend in siloxane removal performance, however a maximum performance of approximately 60% Si removal efficiency was recorded. Analysis of the process mapping results provides indicators of improvement to biological system performance.