Low voltage, low energy submerged pulsed arcs were used to break-down Sulfadimethoxine (SDM) contamination in aqueous solutions. The SDM concentration decreased exponentially with rate constants of 0.13-1.9 min(-1) during processing by pulsed arcs with a pulse repetition rate of 100 Hz, energies of 2.6-192 mJ and durations of 20, 50 and 100 mu s. The electrical energy consumption was minimized with short duration pulses-1.5 kW-hr/m(3) with 7.5 mJ, 20 mu s pulses for 90% SDM removal.