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Water SA

On-line version ISSN 1816-7950
Print version ISSN 0378-4738


HEY, T; SANDSTROM, D; IBRAHIM, V  and  JONSSON, K. Evaluating 5 and 8 pH-point titrations for measuring VFA in full-scale primary sludge hydrolysate. Water SA [online]. 2013, vol.39, n.1, pp.17-22. ISSN 1816-7950.

An evaluation of 5 and 8 pH-point titrimetric methods for determining volatile fatty acids (VFAs) was conducted, and the results were compared for tap water and primary treated wastewater at the laboratory scale. These techniques were then applied to full-scale primary sludge hydrolysate, and the results were compared with those obtained via gas chromato-graphy. The comparison showed that the VFA concentrations measured with the two titration methods were higher than those obtained via gas chromatography, differing by 9 and 13 mg COD-£-1 for the hydrolysate and by 5 and 6 mg COD-£-1 for the ordinary primary settler effluent. No improvement in the accuracy of VFA concentration measurement was obtained from applying the 8 pH-point titration method instead of the 5 point method. The 5 pH-point method was successfully applied to determine VFA in full-scale primary sludge hydrolysate and was shown to be equally efficient to the methods that are routinely-used for this purpose.

Keywords : Multiple pH-point titration; volatile fatty acids; wastewater; full-scale; primary sludge hydrolysis.

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