In this paper, data is published on the removal of H2S and VOCs by a biotrickling filter (BTF) demonstration plant, namely a SULPHUS (TM), which was installed by Thames Water in late 2015. These data, along with some data already published by Sempere et al. (2018), were compared to the predictions of a number of existing and novel models for the removal of a single pollutant by a biofilm. The two widely used models of Ottengraf and van den Oever (1983) were found to be inadequate with sum of squares of errors of 11 and 41 mg(2) m(-6) respectively. These models are based on zero-order kinetics in the biofilm which according to the M-M kinetic model, are likely to be inaccurate at low pollutant concentration. The odour control unit was designed to produce low emission levels of less than 1 mg m(-3) of H2S, rendering the zero-order assumption unlikely to be accurate. A model based on first-order kinetics, which also has some support in the literature, was found to be a better, but not a good, fit to the data with a sum of squares of errors of 4.7 mg(2) m(-6). A novel model for the BTF based on M-M kinetics was found to be a good fit to the shape of the data with the lowest sum of squares of errors of 2.5 mg(2) m(-6). This novel M-M model was also identified as the best fit for VOC data from the same unit. Other publications support the M-M approach with a product of saturation constant and Henry's Law constant of about 50 mg m(-3), which is equivalent to an H2S level in the gas phase of about 40 ppmv. Broad agreement was found between the SULPHUS (TM) experiments and data in the literature for other BTFs destroying H2S under the zero-order regime, at V-max value of about 0.3 g/m(3)/s. This paper represents an attempt to harmonise a literature that was previously disparate, which has not previously been attempted. (C) 2019 Elsevier Ltd. All rights reserved.