Abstract

In the production of natural rubber, formate or acetate is added to the latex solution to coagulate the rubber; therefore, the wastewater contains high concentrations of organic acids, requiring the application of anaerobic treatment technology. In this study, a two-phase continuous flow experiment using a laboratory-scale upflow anaerobic sludge blanket (UASB) was conducted to investigate the influence of formate inflow on the microbial and physical characteristics of the retained granular sludge. In phase 1, acetate-based wastewater was used as feed, while in phase 2, formate-based wastewater was used as feed. In phase 1, the UASB exhibited high COD removal efficiency (97.2%); in addition, the retained sludge showed increased methane production from acetate and proliferation of acetate-utilizing Methanosaeta species. In phase 2, the UASB performed as well as phase 1, with 98.2% COD removal efficiency. Microbial community structure analysis confirmed that relatives of Methanobacterium formicicum present in the retained sludge were responsible for the degradation of formate in phase 2. However, decreased diameter and slight deterioration of granular sludge settleability were observed. In conclusion, formate inflow has low risk of interference with the process performance of the UASB, but it has negative effects on the physical properties of the granular sludge.

摘要

在天然橡胶的生产中，在胶乳溶液中加入甲酸盐或醋酸盐使橡胶凝固；因此，废水中含有高浓度的有机酸，需要应用厌氧处理技术。在这项研究中，使用实验室规模的上流式厌氧污泥层 (UASB) 进行了两相连续流动实验，以研究甲酸盐流入对滞留颗粒污泥的微生物和物理特性的影响。在第 1 阶段，醋酸基废水用作进料，而在第 2 阶段，甲酸盐基废水用作进料。在第一阶段，UASB 表现出较高的 COD 去除效率（97.2%）；此外，滞留污泥表明乙酸产生的甲烷增加和利用乙酸的Methanosaeta的增殖物种。在第 2 阶段，UASB 的表现与第 1 阶段一样好，COD 去除效率为 98.2%。微生物群落结构分析证实，存在于滞留污泥中的Methanobacterium formicum的亲属是第 2 阶段甲酸盐降解的原因。然而，观察到颗粒污泥直径减小和沉降性略有下降。总之，甲酸盐流入对 UASB 工艺性能的干扰风险较低，但对颗粒污泥的物理性质有负面影响。