How would you design an odor control system for a wastewater treatment plant?

Design approach: identify odor sources (headworks, sludge handling), measure H2S levels and flow rates. Control strategies: source control (covers/enclosures, chemical addition to sewers), containment (negative pressure enclosures with air changes), and treatment. Treatment technologies: biofilters (EBRT 30-60 sec for H2S <50 ppm), chemical scrubbers (caustic + hypochlorite, >99% efficiency), activated carbon (polishing), and thermal oxidation (high concentrations). Stack dispersion modeling for residual odors. Ventilation design: 6-12 air changes/hour for enclosed areas. Consider buffer zones and community complaints history.