GRANULE-FORMING METHOD AND WASTE WATER TREATMENT METHOD

摘要

A granule-forming method using a semi-batch reaction tank, wherein: operation cycles of a first operation cycle for performing a biological treatment step at a first sludge load and after the first operation cycle, a second operation cycle for performing the biological treatment step at a second sludge load are performed repeatedly; the first sludge load is set so that the soluble BOD concentration in the semi-batch reaction tank at the time of completion of the biological treatment step of the first operation cycle does not decrease to a threshold value or less; and the second sludge load is set so that the soluble BOD concentration in the semi-batch reaction tank at the time of completion of the biological treatment step of the second operation cycle is at or below the threshold value.