METHOD AND APPARATUS FOR BIOLOGICAL TREATMENT OF NITRATE NITROGEN

摘要

PROBLEM TO BE SOLVED: To remove a proper amt. of nitrogen corresponding to fluctuations in the generation amt. of nitrate nitrogen by calculating the reduction amt. from the generation amt. of nitrate nitrogen necessary for setting nitrate nitrogen contained in waste water to a predetermined target concn. or less and applying a nutrient source soln. to microorganisms in the amt. corresponding to this reduction amt. SOLUTION: A processing circuit 71 predetermines target concn. to obtain respective values at first from the input of respective signals to calculate the generation amt. of waste water and that of nitrate nitrogen contained in waste water and calculates the reduction amt. from the generation amt. of nitrate nitrogen necessary for setting nitrate nitrogen to the amt. corresponding to a predetermined target concn. Further, the processing circuit 71 calculates the amt. of a BOD source (nitrient source) soln. to be applied to denitrifying bacteria contained in sludge in a denitrification tank 27. The calculated amt. of the BOD source soln. is pumped up by a BOD source soln. supply pump 52 to be applied to the denitrification tank 27. By this constitution, the concn. of nitrate nitrogen in waste water can be reduced to a predetermined target concn. or less.