NIBIO, Norwegian Institute of Bioeconomy Research, P.O. Box 115, N-1431, Ås, Norway.
Cambi AS, Skysstasjon 11A, 1383, Asker, Norway.
Water Res. 2018 Apr 1;132:158-166. doi: 10.1016/j.watres.2018.01.008. Epub 2018 Jan 4.
Post-anaerobic digestion (PAD) treatment technologies have been suggested for anaerobic digestion (AD) to improve process efficiency and assure hygenization of organic waste. Because AD reduces the amount of organic waste, PAD can be applied to a much smaller volume of waste compared to pre-digestion treatment, thereby improving efficiency. In this study, dewatered digestate cakes from two different AD plants were thermally hydrolyzed and dewatered, and the liquid fraction was recirculated to a semi-continuous AD reactor. The thermal hydrolysis was more efficient in relation to methane yields and extent of dewaterability for the cake from a plant treating waste activated sludge, than the cake from a plant treating source separated food waste (SSFW). Temperatures above 165 °C yielded the best results. Post-treatment improved volumetric methane yields by 7% and the COD-reduction increased from 68% to 74% in a mesophilic (37 °C) semi-continuous system despite lowering the solid retention time (from 17 to 14 days) compared to a conventional system with pre-treatment of feed substrates at 70 °C. Results from thermogravimetric analysis showed an expected increase in maximum TS content of dewatered digestate cake from 34% up to 46% for the SSFW digestate cake, and from 17% up to 43% in the sludge digestate cake, after the PAD thermal hydrolysis process (PAD-THP). The increased dewatering alone accounts for a reduction in wet mass of cake leaving the plant of 60% in the case of sludge digestate cake. Additionaly, the increased VS-reduction will contribute to further reduce the mass of wet cake.
厌氧消化（AD）后的处理技术已被建议用于提高 AD 工艺效率并确保有机废物的消毒。因为 AD 减少了有机废物的数量，所以与预处理相比， PAD 可以应用于更小体积的废物，从而提高效率。在这项研究中，来自两个不同 AD 工厂的脱水消化饼分别进行了热水解和脱水处理，并且液体部分被循环到半连续 AD 反应器中。对于处理废活性污泥的工厂的饼，与处理源分离食品废物（SSFW）的饼相比，热水解在甲烷产量和脱水能力方面更为有效。温度高于 165°C 时，效果最佳。后处理使中温（37°C）半连续系统中的体积甲烷产量提高了 7%，COD 去除率从 68%提高到 74%，尽管与传统系统相比，固体停留时间（从 17 天降低至 14 天）降低。热重分析的结果表明，对于 SSFW 消化饼，经过 PAD 热水解处理（PAD-THP）后，脱水消化饼的最大 TS 含量从 34%预期增加到 46%，对于污泥消化饼，从 17%增加到 43%。仅增加脱水就可使污泥消化饼离开工厂的湿饼质量减少 60%。此外，增加的 VS 减少将有助于进一步减少湿饼的质量。
