Odor Emission Rate Estimation of Indoor Industrial Sources Using a Modified Inverse Modeling Method

Abstract

ABSTRACT Odor emission rates are commonly measured in the laboratory or occasionally estimated with inverse modeling techniques. A modified inverse modeling approach is used to estimate source emission rates inside of a postdigestion centrifuge building of a water reclamation plant. Conventionally, inverse modeling methods divide an indoor environment in zones on the basis of structural design and estimate source emission rates using models that assume homogeneous distribution of agent concentrations within a zone and experimentally determined link functions to simulate airflows among zones. The modified approach segregates zones as a function of agent distribution rather than building design and identifies near and far fields. Near-field agent concentrations do not satisfy the assumption of homogeneous odor concentrations; far-field concentrations satisfy this assumption and are the only ones used to estimate emission rates. The predictive ability of the modified inverse modeling approach was validated with measured emission rate values; the difference between corresponding estimated and measured odor emission rates is not statistically significant. Similarly, the difference between measured and estimated hydrogen sulfide emission rates is also not statistically significant. The modified inverse modeling approach is easy to perform because it uses odor and odorant field measurements instead of complex chamber emission rate measurements. IMPLICATIONS Emission rates of odor and odorant sources are used to assess and predict indoor environmental quality. The modified inverse modeling approach is an efficient, effective, and validated method for estimating emission rates using only odor and odorant concentrations measured indoors in the postdigestion centrifuge building of a water reclamation plant. The modified inverse modeling approach provides an easier method to predict odor and odorant emission rates in an indoor industrial environment than the conventional complex approach that simulates field conditions and then measures odor and odorant concentrations in the laboratory.