Use of a Monte Carlo technique to complete a fragmented set of H2S emission rates from a wastewater treatment plant

•The H2S emission of a wastewater treatment plant of a tannery was recalculated.•By the ambient H2S concentration the emission rate was calculated by an inverse dispersion model.•This emission rate was used by a Monte Carlo model to calculate a complete time series.•The model was validated using the emission rate and the ambient H2S concentration. The impact of ambient concentrations in the vicinity of a plant can only be assessed if the emission rate is known. In this study, based on measurements of ambient H2S concentrations and meteorological parameters, the a priori unknown emission rates of a tannery wastewater treatment plant are calculated by an inverse dispersion technique. The calculations are determined using the Gaussian Austrian regulatory dispersion model. Following this method, emission data can be obtained, though only for a measurement station that is positioned such that the wind direction at the measurement station is leeward of the plant. Using the inverse transform sampling, which is a Monte Carlo technique, the dataset can also be completed for those wind directions for which no ambient concentration measurements are available. For the model validation, the measured ambient concentrations are compared with the calculated ambient concentrations obtained from the synthetic emission data of the Monte Carlo model. The cumulative frequency distribution of this new dataset agrees well with the empirical data. This inverse transform sampling method is thus a useful supplement for calculating emission rates using the inverse dispersion technique.