Modelling hydrogen sulphide emission in a WWTP with UASB reactor followed by aerobic biofilters

Hydrogen sulphide (H₂S) represents one of the main odorant gases emitted from wastewater treatment plants (WWTP) and a mathematical model can be a fast and low cost tool to estimate its emission. In this work H₂S emission rates in a WWTP, composed of an up-flow anaerobic sludge blanket (UASB) reactor and an aerobic biofilter (BF), are estimated using four mathematical models available in the literature (AP-42, GPC, TOXCHEM+ and WATER8). The results show that the GPC model leads to the best agreement with the experimental data, except for the biofilter due to its lack of capability to include biodegradation as a H₂S removal process. On the other hand, the AP-42 and WATER8 models showed a slightly better ability to predict H₂S removal in the biofilter than the TOXCHEM+ model, as all models underestimate the H₂S concentration decay.