A nine-point pH titration method to determine low-concentration VFA in municipal wastewater

摘要

Characterization of volatile fatty acid (VFA) in wastewater is significant for understanding thenwastewater nature and the wastewater treatment process optimization based on the usage ofnActivated Sludge Models (ASMs). In this study, a nine-point pH titration method was developed fornthe determination of low-concentration VFA in municipal wastewater. The method was evaluatednusing synthetic wastewater containing VFA with the concentration of 10–50 mg/l and the possibleninterfering buffer systems of carbonate, phosphate and ammonium similar to those in realnmunicipal wastewater. In addition, the further evaluation was conducted through the assay of realnwastewater using chromatography as reference. The results showed that the recovery of VFA innthe synthetic wastewater was 92%–102 and the coefficient of variance (CV) of reduplicatenmeasurements 1.68%–4.72%. The changing content of the buffering substances had little effect onnthe accuracy of the method. Moreover, the titration method was agreed with chromatography innthe determination of VFA in real municipal wastewater with R2¼ 0.9987 and CV ¼1.3-1.7. Thennine-point pH titration method is capable of satisfied determination of low-concentration VFA innmunicipal wastewater.