A review of sulfide emissions in sewer networks: overall approach and systemic modelling

Abstract

The problems related to hydrogen sulfide in terms of deterioration of sewer networks, toxicity and odor nuisance have become very clear to the network stakeholders and the public. The hydraulic and (bio)chemical phenomena and parameters controlling sulfide formation, emission and their incidences in sewer networks are very complex. Recent research studies have been developed in gravity and pressure sewers and some transfer models have been published. Nevertheless, the models do not take into account all the physical phenomena influencing the emission process. After summing up the main scientific knowledge concerning the production, oxidation, transfer and emission processes, the present review includes: (i) a synthetic analysis of sulfide and hydrogen sulfide emission models in sewer networks, (ii) an estimation of their limit, (iii) perspectives to improve the modelling approach. It shows that sulfide formation and uptake models still need refinements especially for some phenomena such as liquid to gas mass transfer. Transfer models that have been published so far are purposely simplified and valid for simple systems. More efforts have to be undertaken in order to better understand the mechanisms and the dynamics of hydrogen sulfide production and emission in real conditions.

Using computational fluid dynamics to describe H2S mass transfer across the water–air interface in sewers

“…The gas phase velocity is estimated as a proportion of the water phase velocity (less than 35 to 50 %), dispersion of transported substances is not considered (Hvitved-Jacobsen et al, 2013). Carrera et al (2016) give an overview over the capabilities of existing model approaches and discuss the ability of the WATS model to describe turbulent effects. Different simplified expressions have been used in different applications to link H 2 S emissions to O 2 emissions or to flow properties in the pipe.…”

“…An overview of existing model approaches has been given in Carrera et al (2016) and the need for further research has been highlighted.…”

“…The WATS model additionally uses different approaches to account for turbulent H 2 S transfer rates across the water surface in various applications. These different approaches are empirical or theoretical connections between oxygen and H 2 S transfer on the one hand and empirical models linking H 2 S emissions to flow properties in the pipe on the other hand (Carrera et al, 2016). Wang et al (2018) highlight the shortcomings of the two-film theory.…”

“…This has already led to wide applications of CFD models for mass transfer applications in the chemical industry (Wang et al, 2018). Carrera et al (2016) identified the models' lack to describe mass transfer processes across the water surface, the current approaches of which were considered to be simplified, especially when considering hydraulic structures such as gravity sewers, junctions and water falls. Recent research on water falls or drop structures in sewer systems led to improved formulations to account for the effect of local turbulence (Matias et al, 2017), but these approaches are still empirical equations which are fed into the model.…”

Hydrogen Sulfide (H2S) Removal via MOFs

“…In this regard, different physicochemical methods have been developed and commercially adopted, such as biological treatment, chemical oxidation, chemical scrubbing, etc. Among these methods, the dry adsorption process has received the most attention for both large-and small-scale applications due to its superior performance in terms of H 2 S removal efficiency even at low temperatures and pressures [5,6].…”