污泥好氧发酵过程中挥发性有机物（VOCs）污染风险研究

摘要

Volatile organic compounds (VOCs) produced during sewage sludge aerobic composting is becoming an important secondary pollutant. The GC/MS method was used to analyze the components of VOCs at different positions in a Sludge Treatment Plant. A total of 19 VOCs were emitted during sewage sludge composting process. The main odor components, such as methanethiol, dimethyl sulfide and sulfide, have higher concentration than olfactory threshold at all four of the gas recovery points, and can do great harm to human beings. The concentration of total volatile organic compounds (TVOC) was 47.21 mg·m-3 inside the composting pile, and decreased to 1.73 mg·m-3 by a percentage of 96.3% after the emission to working area. Using the method of Maximum Incremental Reactivity to research the reactivity and Ozone Formation Potential of VOCs. VOCs components, such as alkanes, aromatic hydrocarbons, ketones, and olefin, have higher maximum ozone formation potential value, 1-butene and propylene have the maximum OFP, which were 947.70 μg·m-3 and 875.67 μg·m-3, respectively. Methyl mercaptan was an appropriate indicator to evaluate the emission of VOCs after a correlation analysis. The concentration of Methyl mercaptan in the researched plant was 0.04 mg·m-3, which was far lower than the limit of 2.5 mg·m-3 in GBZ 2-2002.%污泥好氧堆肥发酵过程所产生的可挥发性有机物已经成为重要的二次污染物，采用气质联用（GC/MS）的方法分析了郑州某污泥处置厂发酵车间不同位置的挥发性有机物（VOCs）组分。结果表明：污泥堆肥过程可检测出的VOCs共有19种，主要致臭组分是甲硫醇、二甲二硫醚、甲硫醚，它们在所有采气点中的质量浓度均高于检知嗅阈值，对人类嗅觉具有较大危害；总挥发性有机物（TVOC）的质量浓度由堆体内部产生时的47.2 mg·m-3，降为车间工人活动处的1.73 mg·m-3，迁移过程中总浓度减少了96.3%；利用最大增量反应活性法研究VOCs的反应活性和对近地层臭氧的生成潜势影响，VOCs组分中烷烃、芳香烃、酮类、烯烃类的最大臭氧生成潜势值依次增加，其中，最大臭氧生成潜势值（OFP）贡献量最高的组分为1-丁烯和丙烯，OFP分别达到了947.70μg·m-3和875.67μg·m-3，存在大气污染风险。通过主要VOCs组分间的相关性分析，发现甲硫醇宜作为评估VOCs排放情况的指示气体，其在工人活动处的质量浓度为0.04 mg·m-3，远低于GBZ 2-2002《工作场所有害因素职业接触限值》所规定的2.5 mg·m-3限量值。