Abstract:In order to monitor and early warn the operational stability of anaerobic fermentation system timely and effectively, an automatic titrator for monitoring total volatile fatty acids (VFA) and alkalinity in term of total inorganic carbon (TIC) concentration in scaled biogas project was designed following the principle of Nordmann titration method. The titrator was designed based on the LabVIEW software. It can not only accurately measure the concentration of VFA and bicarbonate alkalinity, but also achieve the functions of automatic pH meter calibration, automatic titration and rehydration, generating, displaying, storing titration data and curving in realtime, etc. with the support of the host application software. The titrator was tested for examining its properties by titrating the artificially prepared mixed analog sample solution and anaerobically digested pig manure slurry. The results showed that the achieved relative standard deviations of VFA and TIC concentration in both the mixed analog sample solution and the digested pig manure slurry were less than 5%, which were lower than those in manual titration and indicated a higher measurement accuracy. Additionally, it can effectively avoid manmade error in process of traditional manual titration, improve work efficiency and reduce labor intensity. Moreover, even in the continuous long run for 15h, the titration results were stable, indicating titrator’s operational stability and good performance. The results indicated that the automatic titrator would have an important practical application value for the biogas project.
