Hydrogen sulphide and VOC removal in biotrickling filters: Comparison of data from a full-scale, low-emission unit with kinetic models

Abstract

In this paper, data is published on the removal of H2S and VOCs by a biotrickling filter (BTF) demonstration plant, namely a SULPHUS™, 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 mg2 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 mg2 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 mg2 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™ experiments and data in the literature for other BTFs destroying H2S under the zero-order regime, at Vmax value of about 0.3 g/m3/s. This paper represents an attempt to harmonise a literature that was previously disparate, which has not previously been attempted.