Civil & Environmental Engineering, University of Utah, Salt Lake City, USA.
Timpanogos Special Service District, American Fork, UT, 84003, USA.
Chemosphere. 2023 Sep;336:138984. doi: 10.1016/j.chemosphere.2023.138984. Epub 2023 Jun 13.
Enhanced hydrolysis of sludges during fermentation is an important factor to achieve solubilization of complex carbon sources and increase the amount of soluble COD that microorganisms could use as food during biological nutrient removal processes. This research shows that a combination of mixing, bioaugmentation, and co-fermentation can be used to increase the hydrolysis of sludges and enhanced the production of volatile fatty acids (VFA). Mixing of primary sludge (PS) at 350 revolutions per minute (RPM) during fermentation increased the hydrolysis of the sludge and increased the soluble chemical oxygen demand (sCOD) by 72% compared to no mixing. Mixing also increased the production of VFA by 60% compared to no mixing conditions. PS hydrolysis was also evaluated using bioaugmentation with the bacteria Bacillus amyloliquefacients, a known producer of the biosurfactant surfactin. Results showed that bioaugmentation enhanced the hydrolysis of the PS by increasing the amount of soluble carbohydrates and soluble proteins present in the form of sCOD. Methanogenesis experiments performed with co-fermentation of decanted primary sludge (PS) and raw waste-activated sludge (WAS) at 75:25 and 50:50 ratios displayed a decreased in production of total biogas by 25.58% and 20.95% and a reduction on methane production by 20.00% and 28.76% respectively, compared to co-fermentation of raw sludges. Compared to fermentation of the sludges separately, co-fermentation of PS and WAS increased the production of VFA and it was determined that 50:50 was the optimum co-fermentation ratio for production of VFA while reducing the reintroduction of nutrients produced during the fermentation process to BNR processes.
发酵过程中增强污泥的水解作用是实现复杂碳源溶解以及增加微生物在生物脱氮过程中可用的可溶性 COD 量的重要因素。本研究表明，混合、生物强化和共发酵的组合可用于提高污泥的水解作用并增强挥发性脂肪酸（VFA）的产生。在发酵过程中以 350 转/分（RPM）的速度混合初沉污泥（PS）可使污泥水解增加 72%，与不混合相比，可溶性化学需氧量（sCOD）增加了 72%。与不混合条件相比，混合还使 VFA 的产量增加了 60%。还使用细菌解淀粉芽孢杆菌进行了 PS 水解的生物强化，该细菌是生物表面活性剂表面活性剂的已知产生菌。结果表明，生物强化通过增加以 sCOD 形式存在的可溶性碳水化合物和可溶性蛋白质的量来增强 PS 的水解作用。用沉降的初沉污泥（PS）和原废水活性污泥（WAS）以 75:25 和 50:50 的比例进行共发酵的甲烷生成实验显示，与原污泥共发酵相比，总沼气产量分别减少了 25.58%和 20.95%，甲烷产量分别减少了 20.00%和 28.76%。与单独发酵污泥相比，PS 和 WAS 的共发酵增加了 VFA 的产生，并且确定 50:50 是生产 VFA 的最佳共发酵比例，同时减少了发酵过程中产生的营养物质重新引入到生物脱氮过程中的量。
