Catalytic Denitrification in a Trickle Bed Reactor: Ion Exchange Waste Brine Treatment


A. M. Bergquist, Bertoch, M., Gildert, G., Strathmann, T. J., and Werth, C. J., “Catalytic Denitrification in a Trickle Bed Reactor: Ion Exchange Waste Brine Treatment,” Journal-American Water Works Association, vol. 109, no. 5, pp. E129-E143, 2017.


Catalytic reduction of nitrate in ion exchange (IX) waste brine for reuse is a promising option for reducing IX costs and environmental impacts. A recycling trickle bed reactor (TBR) was designed and optimized using 0.5 percent by
weight (wt%) palladium–0.05 wt% indium catalysts supported on US mesh size 12 × 14 or 12 × 30 activated carbon particles. Various liquid superficial velocities (Ur) and hydrogen gas superficial velocities (Ug-H2) were evaluated to assess performance in different flow regimes; catalyst activity increased with Ug-H2 at all Ur for both catalysts and was greatest for the 12 × 30 catalyst at the
lowest Ur (8.9 m/h). The 12 × 30 catalyst demonstrated up to 100% higher catalytic activity and 280% higher mass transfer rate compared with the 12 × 14 catalyst. Optimal TBR performance was achieved with both catalysts in the
trickle flow regime. The results indicate that the TBR is a promising step forward, and continued improvements are possible to overcome remaining mass transfer limitations.


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