Volatile methylsiloxanes are wastewater organic pollutants originating from industrial and personal care products. They accumulate in sewage sludge and hamper biogas production through the formation of silicon dioxide on the surfaces of gas engines and turbines, yet there is few knowledge on their fate in sludge treatment systems. Here we studied the occurrence and removal of seven volatile methylsiloxanes along the solid treatment line of an urban wastewater treatment plant. We analyzed 75 sludge samples from seven locations using ultrasound-assisted solid–liquid extraction followed by gas chromatography-mass spectrometry. Results show that volatile methylsiloxanes occur in all samples with a predominance of cyclic homologues, particularly decamethylcyclopentasiloxane. Total siloxane levels reach 6087 ng/g dry weight in the secondary sludge, average at 3575 ng/g in digested sludge, and 5703 ng/g in the dewatered sludge, the latter being likely due to the addition of a polyelectrolyte. Overall, these levels call for measures to reduce methylsiloxane levels before the biogas production step.

挥发性甲基硅氧烷是源自工业和个人护理产品的废水有机污染物。它们积聚在污水污泥中，并通过在燃气发动机和涡轮机表面形成二氧化硅而阻碍了沼气的产生，但是对于污泥处理系统的命运却知之甚少。在这里，我们研究了城市污水处理厂的固体处理线中七种挥发性甲基硅氧烷的产生和去除情况。我们使用超声辅助固液萃取，气相色谱-质谱法分析了七个地点的75个污泥样品。结果表明，挥发性甲基硅氧烷在所有样品中均以环状同系物为主，尤其是十甲基环五硅氧烷。二级污泥中的总硅氧烷含量达到6087 ng / g干重，消化污泥中的平均浓度为3575 ng / g，脱水污泥中的平均浓度为5703 ng / g，后者可能是由于添加了聚电解质所致。总体而言，这些水平要求采取措施降低沼气生产步骤之前的甲基硅氧烷水平。