Water treatment method and water treatment device

Abstract

Provided are a water treatment method and a water treatment device that can be introduced in a standard tank with an effective water depth of 5 m or less during treatment of water to be treated that contains organic matter and a nitrogen component, and that allow improvement in efficiency of removing nitrogen from the water to be treated and suppressing energy consumption for aeration while maintaining a high MLSS. The water treatment method is for treating water to be treated that contains organic matter and a nitrogen component, and includes, in a biological treatment device (10) comprising at least an aerobic tank (40): a biological treatment step for biologically treating inflowing water to be treated aerobically by using sludge that contains granules; a solid-liquid separation step for separating die biological treatment solution in the aerobic tank (40) into treated water and concentrated sludge using a solid-liquid separation device (12); and a sludge return step for returning the concentrated sludge obtained in the solid-liquid separation step to a stage before the biological treatment device (10). The concentration of ammonium nitrogen remaining due to the nitrification reaction in the aerobic tank (40) is measured with an ammonium nitrogen concentration measurement device (16), and the amount of gas containing oxygen dispersed to the aerobic tank (40) is controlled with a blower (18) so that the measured ammonium nitrogen concentration is within a prescribed range.

Dependencies are inferred from the claim text.