Department of Chemical Engineering, School of Engineering, Universidade de Santiago de Compostela, E- 15782 Santiago de Compostela, Spain.
Sci Total Environ. 2019 Nov 10;690:534-542. doi: 10.1016/j.scitotenv.2019.06.492. Epub 2019 Jul 3.
Pretreatment technologies prior to anaerobic digestion (AD) have been developed with the aim of enhancing biogas productivity and reducing the presence of pathogens in digested sludge. Among them, thermal hydrolysis (TH) appears as the most promising one. In wastewater treatment plants (WWTPs) sludge is the end point of many organic micropollutants (OMPs), which was proved to lead to important environmental and human risks since sludge is commonly used in agriculture. The objective of this work is to determine the fate OMPs in TH and subsequent AD. Sewage sludge was pretreated in a TH pilot plant at 170 °C for 20 min. Afterwards, two anaerobic digesters with a working volume of 14 L fed with fresh and pretreated sludge were operated in parallel in mesophilic conditions. TH proved to be an effective technology to partially or totally remove the dissolved fraction of OMPs as well as the fraction sorbed into those suspended solids that are solubilised after this pretreatment. However, it did not affect the OMPs sorbed concentration into solids that are not solubilised. Globally, the OMPs removal efficiency during TH appears to be linked to the solids solubilisation during this process. Afterwards, the OMPs biotransformation efficiency in AD of fresh and pretreated sludge was determined. Noticeable differences between the microbiome of both reactors was determined, but the anaerobic biotransformation was not substantially different for most of the OMPs. However, it affected musk fragrances, which presented considerably lower biotransformation efficiency in the reactor fed with pretreated sludge. Therefore, TH was proved effective in partially removing OMPs but not in enhancing their bioavailability and subsequent anaerobic biotransformation.
预处理技术在厌氧消化（AD）之前已经被开发出来，目的是提高沼气产量和减少消化污泥中病原体的存在。其中，热水解（TH）似乎是最有前途的一种。在污水处理厂（WWTP）中，污泥是许多有机微污染物（OMPs）的终点，这被证明会导致重要的环境和人类风险，因为污泥通常用于农业。这项工作的目的是确定 TH 和随后的 AD 中 OMPs 的命运。污水污泥在 170°C 的 TH 中进行了 20 分钟的预处理。之后，两个工作体积为 14L 的厌氧消化器在中温条件下并行运行，分别使用新鲜和预处理的污泥作为进料。TH 被证明是一种有效的技术，可以部分或完全去除 OMPs 的溶解部分以及那些悬浮固体中被吸附的部分，这些悬浮固体在这种预处理后会被溶解。然而，它并没有影响那些不被溶解的固体中吸附的 OMPs 浓度。总的来说，TH 过程中 OMPs 的去除效率似乎与该过程中固体的溶解有关。之后，确定了新鲜和预处理污泥在 AD 中的 OMPs 生物转化效率。两个反应器的微生物组之间存在明显差异，但大多数 OMPs 的厌氧生物转化没有显著差异。然而，它影响了麝香香料，这些香料在进料为预处理污泥的反应器中的生物转化效率明显较低。因此，TH 被证明在部分去除 OMPs 方面是有效的，但不能提高它们的生物利用度和随后的厌氧生物转化。
