Abstract: During the dry anaerobic fermentation process of kitchen waste, the concentration of volatile fatty acids is an important monitoring index. By determining the concentration of volatile fatty acids daily, the operation situation of the anaerobic fermentation system could be understood. The Nordmann titration method, gas chromatography method, and colorimetric method were used to determine the concentration of volatile fatty acids in dry anaerobic fermentation process of kitchen waste. The experimental results showed that, due to the many pretreatment processes of the samples to be tested, the results of determination of volatile fatty acids by colorimetric method were unstable. Gas chromatography was cumbersome, had more sample pretreatment process, and the experiment time of a single sample was longer, which was suitable for determining the concentration of a single volatile fatty acid. Nordmann titration method could overcome these shortcomings and had the advantages of simple operation and high accuracy. Therefore, it was recommended to prioritize the use of Nordmann titration method to determine the concentration of volatile fatty acids in the anaerobic fermentation process of kitchen waste.

Key words: kitchen waste, volatile fatty acids, Nordmann titration method, gas chromatography method, colorimetric method