In this study, a mixture of primary sludge and waste activated sludge was pre-treated using thermal hydrolysis at 145, 160, 175, and 190 °C, with processing time varying from 5 to 30 min before anaerobic digestion. The aim was to analyse the biogas production and the formation of compounds inhibiting methanogenesis in the sludge under each pre-treatment condition. For the mixed sludge (55% primary sludge and 45% waste-activated sludge) used in this study, thermal hydrolysis at 145 °C for 30 min is the condition that provided the highest biogas yield (389 ± 6 mL biogas/g VS). Thermal hydrolysis at 145 °C did not increase the free ammonia concentration in sludge. Also, the treated condition created the highest amount of acetic acid (1.32 × 10 mg/L). By contrast, the level of propionic acid was lower than 0.59 × 10 mg/L, which is the most suitable of the conditions tested for anaerobic digestion. However, the condition did not provide the highest solubilisation degree for sewage sludge.

中文翻译：

---

初级污泥和废弃活性污泥混合物的热水解：沼气的产生和抑制剂的形成

在这项研究中，初级污泥和废弃活性污泥的混合物在 145、160、175 和 190 °C 的温度下进行热水解预处理，厌氧消化前的处理时间为 5 至 30 分钟。目的是分析在每种预处理条件下污泥中沼气的产生和抑制甲烷生成的化合物的形成。对于本研究中使用的混合污泥（55％初级污泥和45％废物活性污泥），145℃热水解30分钟是提供最高沼气产量的条件（389±6mL沼气/gVS） 。 145℃热水解并没有增加污泥中游离氨的浓度。此外，处理后的条件产生了最高量的乙酸（1.32 × 10 mg/L）。相比之下，丙酸水平低于0.59×10 mg/L，这是最适合厌氧消化测试的条件。然而，该条件并没有为污水污泥提供最高的溶解度。