A^(2)O工艺城市污水处理厂恶臭物质逸散特征及风险评估

Characteristics and risk assessment of odors released from a wastewater treatment plant with A^(2)O treatment process

污水处理过程释放的大量恶臭气体对人体感官和健康产生不利影响。本研究在城市污水处理厂设置采样点,研究主要污水处理单元恶臭物质的逸散特征。结果表明,恶臭物质的排放主要集中在进水区,硫化氢、氨、二硫化碳、磷化氢的平均浓度分别为1.07、0.19、44.32和0.58 mg·m^(-3)。污泥脱水间也是恶臭物质氨的主要释放源。硫化氢是主要的致臭物质,其在各工艺段的异味贡献率超过75%。二硫化碳和磷化氢的慢性致病风险较高,有必要采取相应的措施削减和控制其在污水处理厂内的影响。在厂界外300 m处,二硫化碳和磷化氢的慢性致病风险值可忽略,同时,硫化氢、氨、以及二硫化碳的厂界浓度均远远低于《恶臭污染物排放标准》(GB 14554-93)规定的相关限值。

The large amount of malodorous gases released by the sewage treatment process adversely affects the human senses and health.In this study,sampling points were set up in urban sewage treatment plants to study the fugitive characteristics of odorous substances in major sewage treatment units.The results showed that the discharge of malodorous substances was mainly concentrated in the influent zone,and the average concentrations of hydrogen sulfide,ammonia,carbon disulfide and phosphine were 1.07,0.19,44.32 and 0.58mg·m^(-3),respectively.The sludge dewatering room was also the main source of the release of the malodorous substance ammonia.Hydrogen sulfide was the main odor-causing substance,and its odor contribution rate in each process section exceeded 75%.The risk of chronic disease of carbon disulfide and phosphine was high,and measures are necessary to reduce and control their impact in wastewater treatment plants.At 300 meters outside the plant boundary,the chronic pathogenic risk values of carbon disulfide and phosphine were negligible,and the concentrations of hydrogen sulfide,ammonia and carbon disulfide in the plant boundary were far below the relevant limits stipulated in the Odorous Pollutant Emission Standard(GB14554-93).