[Substrate Flow by Different Biochemical Activities in the Urban Sewage Network]

Area of Science:

• Environmental Engineering
• Environmental Microbiology
• Water Quality Management

Background:

• Urban sewage networks face challenges in managing organic contaminants.
• Understanding contaminant fate in sediment-sewage interactions is crucial for effective wastewater treatment.

Purpose of the Study:

• To investigate organic contaminant consumption mechanisms in urban sewage networks.
• To analyze the migration and transformation of key substances (COD, methane, nitrate, sulfate) between sediment and sewage.

Main Methods:

• A pilot-scale system using urban sewage sediment and artificial sediment was operated.
• Studied the characteristics of chemical oxygen demand (COD), methane, nitrate, and sulfate migration and transformation.

Main Results:

• Deposition accounted for 65.38% of the total chemical oxygen demand (COD) variation in sewage.
• Bioreaction accounted for 34.62% of COD variation, with methane generation, denitrification, and sulfate degradation being key processes.
• Calculated COD consumption: 32.51 mg·L⁻¹ for methane generation, 8.04 mg·L⁻¹ for denitrification, and 6.41 mg·L⁻¹ for sulfate degradation.

Conclusions:

• Deposition is the dominant pathway for organic contaminant removal in sewer systems.
• Biochemical activities, including methane generation, denitrification, and sulfate degradation, play vital roles in contaminant removal.
• The study provides insights into the complex interplay of physical and biological processes governing contaminant fate in urban wastewater.