Odor Pollution Characterization and Health Risk Assessment of An Animal Innocuous Treatment Plant
Based on the monitoring data of odor generation sources,discharge outfalls and boundaries of an animal innocuous treatment plant in Shanghai,its odor pollution characteristics were explored and its impact on the surrounding environment and human health was further evaluated.The results showed that the main sources of odor were the corruption of animal carcasses(incineration workshop)and the microbial activities of sewage treatment(sewage station).The main odor pollutants were hydrogen sulfide(H2S),ammonia(NH3),dimethyl disulfide(C2H6S2)and methanethiol(CH3SH),with the maximum source contents of 5.710,2.462,0.659 and 0.292 mg/m3,respectively.The incineration workshop was the major contributor of NH3,while the sewage station was the major contributor of H2S.The contents at the outfalls and boundaries satisfied the standards of DB 31/1025-2016 Emission Standards of Odor Pollutants.The main odor-causing factors were H2S,CH3SH,C2H6S2 and NH3,with the maximum threshold dilution times of 9 154,1 496,57 and 50,respectively.Comparison of the monitoring data revealed that there were low olfactory threshold factors other than NH3,H2S and CH3SH at the outfalls and boundaries,which were not included in the routine monitoring program.Subsequent consideration should be given to increasing the routine monitoring factors and monitoring frequency to better monitor the odor emission and its impact.Although the odor substance contents in the workshop were lower than the occupational exposure limit,non-carcinogenic risks were identified with the risk index ranged from 4.481 to 1 956.440.The limited space in the workshop should be strictly controlled,and incoming operators should be equipped with protective equipment.The normal operation of the waste gas treatment facilities must be ensured,preventing leakage and protecting health risks from staff.