A sewer process model as planning and management tool--hydrogen sulfide simulation at catchment scale

Area of Science:

• Environmental Engineering
• Wastewater Management
• Atmospheric Science

Background:

• Sewer systems in major cities can release significant amounts of hydrogen sulfide (H2S) and other gases into the urban atmosphere.
• Effective management of H2S is crucial for public health and environmental protection in densely populated areas.

Purpose of the Study:

• To develop and apply a sewer process model (WATS) for simulating H2S and sewer gas release in a major Persian Gulf city.
• To utilize the model as a planning tool for identifying problem areas and designing control strategies.
• To calibrate and validate the model using real-time monitoring data for accurate performance assessment.

Main Methods:

• Exporting sanitary sewer geometry and dry weather flow data from a Mike Urban database.
• Importing data into the WATS sewer process model to simulate sewage and gas flow, including physical, chemical, and biological processes.
• Installing and utilizing monitoring equipment (flow meters, level gauges, UV-Vis spectroscopes, H2S gas sensors) for model calibration and validation.

Main Results:

• The non-calibrated model effectively identified problem areas and guided the placement of monitoring equipment and preliminary control strategies.
• Model calibration and validation using monitoring data improved simulation accuracy.
• The calibrated model demonstrated its utility in assessing compliance with service levels and designing effective dosing strategies for iron and nitrate salts.

Conclusions:

• A calibrated sewer process model is a valuable tool for managing H2S and sewer gas emissions in urban environments.
• The model aids in identifying critical areas, optimizing monitoring, and designing targeted control strategies, such as chemical dosing.
• This approach supports the assessment of service level compliance and enhances overall wastewater management efficiency.