College of Engineering, China Agricultural University, Key Laboratory for Clean Renewable Energy Utilization Technology, Ministry of Agriculture, Beijing 100083, PR China.
College of Engineering, China Agricultural University, Key Laboratory for Clean Renewable Energy Utilization Technology, Ministry of Agriculture, Beijing 100083, PR China.
Waste Manag. 2017 Sep;67:43-50. doi: 10.1016/j.wasman.2017.05.015. Epub 2017 May 15.
The volatile fatty acids (VFAs) concentration has been considered as one of the most sensitive process performance indicators in anaerobic digestion (AD) process. However, the accurate determination of VFAs concentration in AD processes normally requires advanced equipment and complex pretreatment procedures. A simplified method with fewer sample pretreatment procedures and improved accuracy is greatly needed, particularly for on-site application. This report outlines improvements to the Nordmann method, one of the most popular titrations used for VFA monitoring. The influence of ion and solid interfering subsystems in titrated samples on results accuracy was discussed. The total solid content in titrated samples was the main factor affecting accuracy in VFA monitoring. Moreover, a high linear correlation was established between the total solids contents and VFA measurement differences between the traditional Nordmann equation and gas chromatography (GC). Accordingly, a simplified titration method was developed and validated using a semi-continuous experiment of chicken manure anaerobic digestion with various organic loading rates. The good fitting of the results obtained by this method in comparison with GC results strongly supported the potential application of this method to VFA monitoring.
挥发性脂肪酸（VFAs）浓度被认为是厌氧消化（AD）过程中最敏感的过程性能指标之一。然而，AD 过程中 VFAs 浓度的准确测定通常需要先进的设备和复杂的预处理程序。因此，非常需要一种具有更少样品预处理步骤和更高准确性的简化方法，特别是对于现场应用。本报告概述了对 Nordmann 方法的改进，Nordmann 方法是最受欢迎的用于 VFA 监测的滴定法之一。讨论了滴定样品中离子和固体干扰子系统对结果准确性的影响。滴定样品中的总固体含量是影响 VFA 监测准确性的主要因素。此外，在传统 Nordmann 方程和气相色谱（GC）之间，总固体含量与 VFA 测量差异之间建立了高度线性相关性。因此，使用不同有机负荷率的鸡粪厌氧消化半连续实验开发并验证了一种简化的滴定方法。与 GC 结果相比，该方法获得的结果拟合良好，这有力地支持了该方法在 VFA 监测中的潜在应用。
