BIOLOGICAL FILTRATION PROCESS OF ULTRAHIGH TREATMENT

摘要

A biological filtration process for ultrahigh advanced treatment is provided to operate the anoxic tank and the aerobic tank and secure excellent treated water easily by operating an anoxic tank for denitrification in an upflow state and operating an aerobic tank for nitrification of organic matters in a downflow state. A biological filtration process for ultrahigh advanced treatment comprises: an upflow biological filtration step performed in an upflow anoxic tank(10) of an anoxic condition; a downflow biological filtration step performed in a downflow aerobic tank(20) of an aerobic condition; and a step of returning a portion of effluent in the downflow biological filtration step of the aerobic condition to influent of the upflow biological filtration step to remove oxidized nitrogen through denitrification. The biological filtration process further comprises a step of doubly injecting a coagulant into treated water of the upflow biological filtration step and return water of the downflow biological filtration step of the aerobic condition in order to maximize the removal of phosphorous. The upflow biological filtration step of the anoxic condition is performed by using a floating filter media or a submersed filter media having a size of 2 to 5 mm. The downflow biological filtration step of the aerobic condition is performed by using a floating filter media or a submersed filter media having a size of 1 to 3 mm.