Data are reported on photocatalytic mineralization rates of sodium alginate (SA), which is representative of polysaccharides commonly encountered in surface waters and effluents requiring purification. An agitated vessel-type photocatalytic reactor was employed, with suspended TiO2 nanoparticles, to study the effect of UV-A radiant power per unit volume P-R (W per L reactor fluid) for which there are insufficient data. Using initial SA concentration similar to 30 mg/L, mineralization rates were determined, by monitoring Total Organic Carbon (TOC) reduction, in the range of UV-A P-R = 2.15 to 8.57 W L-1 and TiO2 concentrations 0.5 to 1.5 g/L For this well-mixed heterogeneous photocatalytic environment, the measured fairly high polysaccharide mineralization rates were fitted to a first order kinetic expression. In the parameter range studied, the kinetic constants k (of order 10(-2) min(-1)) were linearly dependent on P-R with a slope in the range similar to 0.6 x 10(-2) to similar to 1.0 x 10(-2) L/(W min). An optimum catalyst concentration near 1 g/L TiO2 was observed. The experimental techniques developed and the type of kinetic data obtained are considered useful for designing photocatalytic reactors for practical applications. Moreover, it is encouraging that the measured mineralization rates are in accord with those from a continuously operated hybrid photocatalytic membrane reactor of different geometry. (C) 2013 Elsevier B.V. All rights reserved.