摘要 |
An improved process is disclosed for the treatment of aqueous waste streams containing nitrogenous matter (nitrate or nitrite ions or matter capable of forming nitrate and nitrite ions) in the presence of sufficient carbonaceous matter to permit substantially complete denitrification of the aqueous effluent. The process comprises introducing an aqueous waste stream having a pH less than 6 into an anaerobic treatment zone containing anaerobic activated sludge at a rate such that the concentrations of nitrate and nitrite ions in the anaerobic treatment zone are maintained at a level less than 3 milligrams/liter. In embodiments, the effluent from the anaerobic treatment zone is passed to an aerobic treatment zone effluent from which is recycled at a rate at least equal to that at which untreated waste is fed to the anaerobic treatment zone. The waste stream feed may contain phenol.
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