A method for determination of the readily fermentable organic fraction in municipal wastewater

A new method to determine the readily fermentable organic fraction in municipal wastewater has been developed. A simple batch procedure was used to measure the VFA potential, i.e. the sum of the volatile fatty acids (VFA) originally present in the wastewater and the amount of VFA that can be formed through fermentation of other organic wastewater constituents. The VFA potential represents the maximum amount of VFA, the principal substrate for polyphosphate accumulating bacteria, that can be made available to these bacteria in the anaerobic stage of an enhanced biological phosphorus removal (EBPR) process. The batch procedure is based on a spontaneous fermentation of organic matter in the wastewater until the fermentable organic matter is depleted, followed by measurement of the concentration of VFA. A comparison between two different municipal wastewaters, exhibiting different ratios between the VFA potential and the phosporus content of the wastewater, showed a clear correlation between a high value of this ratio and a good performance of EBPR.