THE DEVELOPMENT OF A SAMPLING SYSTEM FOR THE DETERMINATION OF ODOR EMISSION RATES FROM AREAL SURFACES .2. MATHEMATICAL-MODEL

An improved design for an odor emission hood was examined in the labor atory using ammonia emission from a water surface. The experimental am monia convective mass transfer coefficients from a diluted ammonia sol ution were determined at velocities of 0.3 m/s to 0.8 m/s using the od or emission hood. The theoretical ammonia convective mass transfer coe fficients were also predicted by boundary layer theory under laminar f low conditions. It was found that experimental data were only 10% belo w theoretical predictions at an air velocity of 0.3 m/s to 0.6 m/s. Th e maximum velocity was limited to 0.6 m/s by the geometric size, shape and aerodynamic stability of the hood. At 0.33 m/s, the smallest vari ation of mass transfer coefficients was measured. The odor emission ra te was found to be a function of air velocity to the power 0.5 in acco rdance with boundary layer theory. An odor sampling system based upon the odor emission hood provides a way to quantify the potential odor e mission strength in sewage treatment plants, for odor dispersion model ing and odor control.