Simultaneous activated sludge wastewater treatment and odour control

Area of Science:

• Environmental Engineering
• Microbiology
• Wastewater Treatment

Background:

• Hydrogen sulfide (H2S) is a common malodorant in wastewater treatment plants (WWTPs).
• Effective H2S mitigation is crucial for odor control and environmental compliance.
• Activated sludge processes are widely used in WWTPs, but their capacity to treat H2S is not fully understood.

Purpose of the Study:

• To evaluate the efficacy of different activated sludges in removing hydrogen sulfide (H2S).
• To investigate the impact of H2S on activated sludge performance and process stability.
• To compare activated sludge treatment with conventional wet scrubbing for H2S removal.

Main Methods:

• Laboratory-scale experiments using static vessels to test various activated sludge types and H2S concentrations (5-75 ppm).
• Pilot-scale studies to assess activated sludge diffusion efficiency under typical WWTP H2S levels (~5 ppm).
• Analysis of sludge characteristics, removal efficiency, and impact on mixed liquor quality.

Main Results:

• Activated sludge demonstrated effective H2S removal, outperforming wet scrubbing.
• Sludge type (carbonaceous, nitrifying, with/without coagulant) significantly influenced H2S removal efficiency.
• At typical WWTP concentrations (~5 ppm), activated sludge diffusion treated H2S without compromising overall process performance.
• Observed effects included brief nitrification interruption and decreased sludge species diversity.

Conclusions:

• Specific activated sludges are suitable for H2S odor control in WWTPs.
• Activated sludge diffusion is a viable technology for managing H2S emissions.
• While minor impacts on nitrification and diversity occur, the overall wastewater treatment process is not compromised.