Process for biologically purifying waste waters
AssigneeSchering Corporation
InventorTheodor Stein
Life of this patent
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Abstract
A continuous process by which waste water containing low to high concentrations of organic constituents and total nitrogen is biologically purified to such an extent that the organic constituents are minimized, the content of total nitrogen is completely nitrified, if it exceeds the assimilation demand, and the nitrate formed is reduced by aerating the waste water or exposing it to oxygen while not exceeding a preselected redox potential. In the subject process, the expenditure on the oxygen introduction and the expenditure on the denitrification are minimized. Further, the amount of excess sludge produced is extremely small.
Claims6
In a process for biologically purifying waste waters containing low to high concentrations of organic constituents and total nitrogen in which said waste water to be purified is aerated or exposed to oxygen in two stages, a portion of the waste water/activated sludge mixture draining from the second stage is recycled to the first stage, and the remainder of the waste water/activated sludge mixture draining from the second stage is separated in a settling tank, and the settled activated sludge is recycled to the first stage and the purified waste water is removed, the improvement which comprises mixing the components of the first stage and maintaining a redox potential E.sub.h (pH 7) of below +100 mV in the first stage while the components thereof are aerated or exposed to oxygen.
Dependencies are inferred from the claim text.