Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
Int J Environ Res Public Health. 2018 Jun 11;15(6):1225. doi: 10.3390/ijerph15061225.
Faecal indicator bacteria of faecal coliform, spp., and faecal are present at high levels in faecal sludge and affect human health. Mesophilic anaerobic digestion cannot reduce faecal indicator bacteria to meet the standards for biosolids; therefore, the thermal pretreatment of faecal sludge is essential. The main objectives of this research were to evaluate the effect of thermal (70 °C) pretreatment time (20, 40, 60, 80, 100, and 120 min) and mixing velocity gradient (no mixing, 133, 191, and 238 s) on faecal indicator bacteria inactivation and determine the kinetics of the inactivation. The results showed that mixing has a more positive effect on pretreatment; thermal pretreatment with mixing was able to completely inactivate faecal indicator bacteria within 80 min, and inactivation followed first-order kinetics. In addition, under optimal mixing at a velocity gradient 191 s, the thermal pretreatment with mixing had a positive effect on the sludge solubilisation. Soluble chemical oxygen demand (SCOD, 71,430 mg L) and soluble protein (7.96 g L) were higher than the values obtained with thermal pretreatment without mixing, which were a SCOD value of 63,600 mg L and soluble protein of 6.78 g L.
粪便中存在大量粪便大肠菌群、 和 等粪便指示菌，会对人体健康造成影响。中温厌氧消化无法将粪便指示菌降低到符合生物固体标准的水平；因此，粪便污泥的热预处理是必不可少的。本研究的主要目的是评估热（70°C）预处理时间（20、40、60、80、100 和 120 分钟）和混合速度梯度（不混合、133、191 和 238 s）对粪便指示菌灭活的影响，并确定灭活动力学。结果表明，混合对预处理有更积极的影响；在混合条件下，热预处理在 80 分钟内即可完全灭活粪便指示菌，灭活遵循一级动力学。此外，在最佳混合速度梯度 191 s 下，混合热预处理对污泥的溶解有积极影响。可溶性化学需氧量（SCOD，71430 mg/L）和可溶性蛋白质（7.96 g/L）均高于不混合热预处理的相应值，分别为 63600 mg/L 的 SCOD 值和 6.78 g/L 的可溶性蛋白质。
