Quantifying Wastewater Odor Exposure with Two Practical Approaches: Odor Plume Measurement Using Trained Field Human Assessors, and Dispersion Modelling

摘要

Odor exposure quantification forms a major step towards scientifically assessing the odor impact. The present study applied two approaches to quantify the odor exposure levels surrounding a wastewater treatment site: field odor intensity measurement by trained human assessors and odor concentration prediction using air dispersion models. The odor intensity measurement results showed that during the August measurement period, the odor intensities were low. In fact, the resident complaint history in that area showed that odor seemed to reach a peak level around early spring. Further study should be conducted during that peak period. The Weber-Fechner model applicable to N-butanol (C = 8 * e~(1.1*Ⅰ)) was employed to convert the measured odor intensities to odor concentrations in order to be comparable to the modeled results. The peak-to-mean (PTM) ratio was then generated using least square method. By comparing the converted measured odor concentrations to the modeled results, the resultant PTM was 11 and 17 for AERMOD and CALPUFF, respectively. Correlating the PTM adjusted modeled concentrations and the measured concentrations, AERMOD predictions had satisfactory linear correction with measured values (r~2 = 0.63), while CALPUFF predictions showed good correlation for individual plumes (r~2 = 0.53 to 0.94) but a weak correction (r~2=0.09) if pooling all plumes together. Since few researches has been found on the odor emission and dispersion from wastewater treatment facilities, this study made the first effort in quantifying the odor emission and impact levels. Further studies will be in the peak emission season to evaluate the odor impact.