Hydrogen sulfide emission in sewer networks: a two-phase modeling approach to the sulfur cycle

2004 ◽  
Vol 50 (4) ◽  
pp. 161-168 ◽  
Author(s):  
C. Yongsiri ◽  
J. Vollertsen ◽  
T. Hvitved-Jacobsen
Keyword(s):  
Mass Transfer ◽  
Hydrogen Sulfide ◽  
Health Risk ◽  
Water Mass ◽  
Sulfur Cycle ◽  
Water Phase ◽  
Emission Scenarios ◽  
Two Phase ◽  
Potential Problems ◽  
Sewer Networks

Wherever transport of anaerobic wastewater occurs, potential problems associated with hydrogen sulfide in relation to odor nuisance, health risk and corrosion exist. Improved understanding of prediction of hydrogen sulfide emission into the sewer atmosphere is needed for better evaluation of such problems in sewer networks. A two-phase model for emission of hydrogen sulfide along stretches of gravity sewers is presented to estimate the occurrence of both sulfide in the water phase and hydrogen sulfide in the sewer atmosphere. The model takes into account air-water mass transfer of hydrogen sulfide and interactions with other processes in the sulfur cycle. Various emission scenarios are simulated to illustrate the release characteristics of hydrogen sulfide.

Liquid-gas mass transfer at drop structures

2017 ◽  
Vol 75 (10) ◽  
pp. 2257-2267 ◽  
Author(s):  
Natércia Matias ◽  
Asbjørn Haaning Nielsen ◽  
Jes Vollertsen ◽  
Filipa Ferreira ◽  
José Saldanha Matos
Keyword(s):  
Mass Transfer ◽  
Hydrogen Sulfide ◽  
Water Mass ◽  
Film Theory ◽  
Free Fall ◽  
Free Surface Flows ◽  
Sulfur Cycle ◽  
Physical Models ◽  
Physical Parameters ◽  
Emission Rates

Over the last decades, considerable progress has been made in the understanding of the sulfur cycle in sewer systems. In spite of a wealth of experimental and field studies that have addressed the release of hydrogen sulfide from free surface flows in gravity sewers and the corresponding air-water mass transfer, little is known about hydrogen sulfide emission under highly turbulent conditions (e.g., drop structures, hydraulic jumps). In this study, experimental work was carried out to analyze the influence of characteristics of drops on reaeration. Physical models were built, mimicking typical sewer drop structures and allowing different types of drops, drop heights, tailwater depths and flow rates. In total, 125 tests were performed. Based on their results, empirical expressions translating the relationship between the mass transfer of oxygen and physical parameters of drop structures were established. Then, by applying the two-film theory with two-reference substances, the relation to hydrogen sulfide release was defined. The experiments confirmed that the choice of the type of drop structure is critical to determine the uptake/emission rates. By quantifying the air-water mass transfer rates between free-fall and backdrop types of drop, the latter resulted in considerably lower oxygen uptake rates.

scholarly journals Erratum: Water Science and Technology 75 (10), 2257–2267: Liquid-gas mass transfer at drop structures, Natércia Matias, Asbjørn Haaning Nielsen, Jes Vollertsen, Filipa Ferreira and José Saldanha Matos, doi: 10.2166/wst.2017.103

2017 ◽  
Vol 76 (6) ◽  
pp. 1584-1594 ◽  
Author(s):  
Natércia Matias ◽  
Asbjèrn Haaning Nielsen ◽  
Jes Vollertsen ◽  
Filipa Ferreira ◽  
José Saldanha Matos
Keyword(s):  
Mass Transfer ◽  
Hydrogen Sulfide ◽  
Water Mass ◽  
Film Theory ◽  
Free Fall ◽  
Free Surface Flows ◽  
Sulfur Cycle ◽  
Physical Models ◽  
Physical Parameters ◽  
Emission Rates

Over the last decades, considerable progress has been made in the understanding of the sulfur cycle in sewer systems. In spite of a wealth of experimental and field studies that have addressed the release of hydrogen sulfide from free surface flows in gravity sewers and the corresponding air-water mass transfer, little is known about hydrogen sulfide emission under highly turbulent conditions (e.g., drop structures, hydraulic jumps). In this study, experimental work was carried out to analyze the influence of characteristics of drops on reaeration. Physical models were built, mimicking typical sewer drop structures and allowing different types of drops, drop heights, tailwater depths and flow rates. In total, 125 tests were performed. Based on their results, empirical expressions translating the relationship between the mass transfer of oxygen and physical parameters of drop structures were established. Then, by applying the two-film theory with two-reference substances, the relation to hydrogen sulfide release was defined. The experiments confirmed that the choice of the type of drop structure is critical to determine the uptake/emission rates. By quantifying the air-water mass transfer rates between free-fall and backdrop types of drop, the latter resulted in considerably lower oxygen uptake rates.

Introducing the emission process of hydrogen sulfide to a sewer process model (WATS)

2003 ◽  
Vol 47 (4) ◽  
pp. 85-92 ◽  
Author(s):  
C. Yongsiri ◽  
T. Hvitved-Jacobsen ◽  
J. Vollertsen ◽  
N. Tanaka
Keyword(s):  
Hydrogen Sulfide ◽  
Process Model ◽  
Molecular Form ◽  
Engineering Application ◽  
Sulfur Cycle ◽  
Extended Model ◽  
Water Interface ◽  
Emission Process ◽  
Air Water Interface ◽  
Sewer Networks

Emission of hydrogen sulfide in sewer networks results in odor, health and corrosion problems. These problems generally occur when wastewater is transported under anaerobic and turbulent conditions. Studies on integrated aerobic/anaerobic processes in sewers have led to a conceptual sewer process model, WATS (Wastewater Aerobic/anaerobic Transformations in Sewers). The WATS model accounts for the carbon cycle, reaeration and sulfide formation. However, to handle odor, health and corrosion problems more efficiently, other aspects of the sulfur cycle need to be included. Emphasis in this study is on an extension of the WATS model in terms of hydrogen sulfide emission. A fundamental concept of this extended model is related to emission of the molecular form of hydrogen sulfide and thereby to pH of wastewater. An engineering application of the extended WATS model includes different scenarios of sewer performance concerning hydrogen sulfide emission under dissolved oxygen-limited conditions. By applying the extended WATS model, users can more realistically cope with the fate of hydrogen sulfide. Consequently, when dealing with the sulfur cycle, users need no longer be restricted to the sulfide formation process but can also take transfer of hydrogen sulfide across the air-water interface into account.

Simulation of sulfide buildup in wastewater and atmosphere of sewer networks

2005 ◽  
Vol 52 (3) ◽  
pp. 201-208 ◽  
Author(s):  
A.H. Nielsen ◽  
C. Yongsiri ◽  
T. Hvitved-Jacobsen ◽  
J. Vollertsen
Keyword(s):  
Hydrogen Sulfide ◽  
Sulfide Oxidation ◽  
Sulfur Cycle ◽  
Model Concept ◽  
Concrete Corrosion ◽  
Sulfide Production ◽  
Oxidation Of Hydrogen ◽  
Sulfide Precipitation ◽  
Further Development ◽  
Sewer Networks

A model concept for prediction of sulfide buildup in sewer networks is presented. The model concept is an extension to – and a further development of – the WATS model (Wastewater Aerobic-anaerobic Transformations in Sewers), which has been developed by Hvitved-Jacobsen and co-workers at Aalborg University. In addition to the sulfur cycle, the WATS model simulates changes in dissolved oxygen and carbon fractions of different biodegradability. The sulfur cycle was introduced via six processes: 1. sulfide production taking place in the biofilm covering the permanently wetted sewer walls; 2. biological sulfide oxidation in the permanently wetted biofilm; 3. chemical and biological sulfide oxidation in the water phase; 4. sulfide precipitation with metals present in the wastewater; 5. emission of hydrogen sulfide to the sewer atmosphere and 6. adsorption and oxidation of hydrogen sulfide on the moist sewer walls where concrete corrosion may take place.

Stability of acoustic wave in two-phase dilute flow with mass transfer

AIAA Journal ◽  
2001 ◽  
Vol 39 ◽  
pp. 2121-2130
Author(s):  
Eric Daniel ◽  
Nicolas Thevand
Keyword(s):  
Mass Transfer ◽  
Acoustic Wave ◽  
Two Phase

A novel approach in numerical simulation of contaminant removal by air sparging

2007 ◽  
Vol 7 (3) ◽  
pp. 163-170
Author(s):  
N. Jacimovic ◽  
T. Hosoda ◽  
M. Ivetic ◽  
K. Kishida
Keyword(s):  
Mass Transfer ◽  
Deterministic Model ◽  
Water Phase ◽  
Air Sparging ◽  
Order Kinetic ◽  
Contaminant Removal ◽  
Water Compartments ◽  
Novel Approach ◽  
Adopted Model ◽  
Air Channels

The paper presents a mechanistic/deterministic model for simulation of mass removal during air sparging. From the point of numerical modeling, there are two issues considering air sparging: modeling of air flow and distribution and modeling of mass transport and transfer. Several processes, which are commonly neglected, such as air channeling and pollutant advection by the water phase, are taken into account. The numerical model presented in this paper considers all relevant for mass transfer during the air sparging. Model includes hydrodynamics of air and water phase; calculated air volume content is divided into a number of air channels surrounded by the water phase, which is divided into two compartments. First compartment is immobile and it is in contact with air phase, while the second compartment is mobile. This “mobile-immobile” formulation is a common approach for description of solute transport by groundwater. Mass transfer between two water compartments is modeled as a first order kinetic, where the mass transfer coefficient, representing diffusion and advection in the water phase towards the air channels, is parameter needed to be calibrated. Sorption for both water compartments is considered. The adopted model of contaminant evaporation at the air-water interface is verified by comparison with experimental results available from published sources. Model is used for simulation of two-dimensional air sparging laboratory experiment. Good overall agreement is observed. It is showed that the efficiency of air sparging can be influenced by natural groundwater flow.

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