Formation of biosolid cakes, which are one of the main wastes generated in wastewater treatment plants, is connected with emission of many hazardous chemical compounds, including odoriferous ones. To optimize particular processes of biosolid cake processing, it is necessary to assess chemical composition of the gas mixtures containing the compounds released from the cakes. The paper proposes application of two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GCxGC–TOF–MS) to identification of the compounds released from four main types of biosolid cakes and to quantitative determination of the markers characteristic for particular types of cake. Based on the analysis of variance, the following compounds, which could be potential markers of the investigated biosolid cakes, were selected: 1-propanol, 2-hexanone, toluene, o-xylene, p-xylene, and organosulfur compounds (methanethiol, ethanethiol, dimethyl sulfide, dimethyl disulfide, and diethyl disulfide). Theoretical odour concentrations of four investigated types of biosolid cakes were determined, based on measured concentrations and olfactory thresholds of the aforementioned compounds. The highest concentration was revealed for a primary cake (634 ou/m³), whereas the lowest concentration was found for an excess cake (136 ou/m³) (ou/m³—odour unit per m³; one odour unit is equivalent to collective odour threshold of odorants mixture present in 1 m³). The proposed methodology allows preliminary evaluation of the odour nuisance markers connected with formation of the biosolid cakes, without a need for quantitative analysis of all determined compounds.

Graphical abstract

中文翻译：

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结合使用GCxGC-TOF-MS和统计数据来区分生物固体样品中的多样性。

生物固体滤饼的形成是废水处理厂产生的主要废物之一，它与许多有害化学化合物的排放有关，包括有气味的化合物。为了优化生物固体饼处理的特定过程，有必要评估包含从饼中释放的化合物的气体混合物的化学组成。本文提出了将二维气相色谱与飞行时间质谱联用（GCxGC–TOF–MS）的应用，以鉴定从四种主要类型的生物固体滤饼中释放的化合物，并定量确定特定类型的标记物特征蛋糕 根据方差分析，选择了以下可能作为研究的生物固体饼的潜在标志物的化合物：1-丙醇，2-己酮，甲苯，邻二甲苯，对二甲苯和有机硫化合物（甲硫醇，乙硫醇，二甲硫，二甲基二硫和二乙基二硫）。基于上述化合物的测量浓度和嗅觉阈值，确定了四种研究类型的生物固体滤饼的理论气味浓度。初级蛋糕的最高浓度为（634 ou / m ³），过量蛋糕的最低浓度为（136 ou / m ³）（ou / m ^3-气味单位/ m ³；一种气味单位为等于1 m ^3中存在的混合气味混合物的总气味阈值）。所提出的方法允许对与生物固体滤饼的形成有关的臭味标记物进行初步评估，而无需对所有确定的化合物进行定量分析。

图形概要