Beijing Key Lab for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science & Engineering, Beijing Forestry University, Beijing 100083, China.
College of Environment, Zhejiang University of Technology, Hangzhou 310014, China.
Sci Total Environ. 2021 Nov 10;794:148741. doi: 10.1016/j.scitotenv.2021.148741. Epub 2021 Jun 29.
Anoxic/anaerobic/oxic (A/O) wastewater treatment has emerged as a major process for treatment of domestic wastewater. One of the issues with wastewater treatment plants (WWTPs) is that volatile sulfur compounds (VSCs) are discharged from them and pose numerous health risks. This study characterized VSC emissions at the water-air interface and concentrations of ambient air exposure from different treatment units in an A/O WWTP. AERMOD modeling was used to simulate the atmospheric behaviors of discharged VSCs. Results demonstrated that VSC emission fluxes and exposure concentrations had followed a descending order of pretreatment>biological treatment>advanced treatment. Emissions were affected by sulfate concentrations and chemical oxygen demand in the wastewater, and control strategies based on these values were proposed. The AERMOD results indicated that the majority of the total hydrogen sulfide (87%) and methyl mercaptan (65%) emissions came from the primary sedimentation tank, while the majority of dimethyl sulfide (81%), carbon disulfide (84%), and dimethyl disulfide (93%) were emitted from the oxic area. MT and DMS were the main odorous components of the VSCs in ambient air based on the indicator of odor activity values. Noncancer health risks, determined by having a hazard quotient >1, of the measured VSCs were beyond acceptable limits. Overall, efforts should be made to minimize noncancer health risks as individuals are exposed to VSCs not only in treatment units but also in areas surrounding WWTPs.
缺氧/厌氧/好氧（A/O）废水处理已成为处理生活污水的主要工艺。污水处理厂（WWTP）存在的一个问题是，挥发性硫化合物（VSCs）会从其中排放出来，并对健康造成诸多风险。本研究在 A/O WWTP 中对水-气界面的 VSC 排放和不同处理单元的环境空气中暴露浓度进行了特征描述。使用 AERMOD 模型模拟了排放 VSCs 的大气行为。结果表明，VSC 排放通量和环境空气中的暴露浓度遵循预处理>生物处理>深度处理的递减顺序。排放受到废水中硫酸盐浓度和化学需氧量的影响，并提出了基于这些值的控制策略。AERMOD 结果表明，总硫化氢（87%）和甲硫醇（65%）的排放主要来自初沉池，而二甲基硫（81%）、二硫化碳（84%）和二甲基二硫（93%）的排放主要来自好氧区。根据气味活性值指标，空气中 VSCs 的主要异味成分是 MT 和 DMS。根据危害商>1 确定的测量 VSCs 的非癌症健康风险超过了可接受的限制。总的来说，应努力将个人在处理单元以及 WWTP 周边地区暴露于 VSCs 中的非癌症健康风险降到最低。
