A process for treating waste includes reacting an organic feedstock in a reactor. The organic feedstock is part of a reaction mixture that includes a first oxidizing acid (e.g., sulfuric acid) and nitric acid. In one embodiment, the reaction mixture, excluding solids, includes no more than 7.5 wt % of the total of the first oxidizing acid and the nitric acid. In another embodiment, the reaction mixture, excluding solids, includes no more than 1 wt % nitric acid. In another embodiment, the process includes separating heavy metals from the effluent.