S-P-R odor risk sensory assessment method and application in the sewage treatment plant

Odor, as a special category of air pollution, has the obvious characteristics of suddenness and uncertainty. In order to optimize management resources and strengthen early warning control, a scientific and efficient risk classification evaluation system must be established. According to the whole process from odor exposure to complaint, the research comprehensively considered source potential (S), pathway efficiency (P) and receptor sensitivity (R), proposed a reasonable classification standard for the index grade, and established S-P-R odor risk sensory assessment method. A sewage treatment plant in Tianjin was taken as an example to evaluate the risk level of sensitive points around it, and the assessment result was compared with the odor complaints of this region during the past 3 years. The results show that: (1) The sewage treatment plant is large in scale with the key odorants of hydrogen sulfide, methyl mercaptan, and methyl sulfide which can be easily perceived by human beings. Besides, the odor intensity and the degree of aversion are maximum. Therefore, the source potential level of the plant is high. (2) Combining pollution exposure and receptor sensitivity, the odor risk level of residential 1#—4# is high, 5#—15# is medium, and the industrial area is low. (3) The odor complaints in high risk areas are more serious than those of medium and low risk areas. Studies have shown that in order to predict the odor risk accurately, it is necessary to sufficiently understand the essential characteristics of odor pollution and fully consider the influencing factors in each link of the source-pathway-receptor process.