Abstract: A wastewater treatment apparatus includes: an air diffusing unit that supplies gas to nitrogen-containing water, so that ammonia contained in the nitrogen-containing water is nitrified to nitrate according to a flow of the water, and each desired proportion of the nitrate is denitrified at each position along the flow direction; a denitrification confirming unit provided at a halfway position between an upstream-side denitrification zone for obtaining a requisite minimum denitrified nitrogen amount and a downstream-side nitrification zone for obtaining ultimately required nitrified water quality, which follows the upstream-side denitrification zone on a downstream side thereof; and a gas supply-amount control unit that controls a gas supply amount from the air diffusing unit at least on an upstream side of the denitrification confirming unit, so that a desired proportion of the nitrate is denitrified at the halfway position, based on the denitrification state confirmed by the denitrification confirming unit.

Abstract: A wastewater treatment apparatus includes an air diffusing unit, a denitrification confirming unit, a nitrification confirming unit, a gas supply-amount control unit. The air diffusing unit supplies gas to nitrogen-containing water. The denitrification confirming unit provided at a first predetermined position confirms a denitrification state whether a desired proportion of the nitrate has been denitrified. The nitrification confirming unit provided at a second predetermined position confirms a nitrification state whether a desired proportion of the ammonia has been nitrified. The gas supply-amount control unit controls a gas supply amount at least on an upstream side of the denitrification confirming unit, so that the desired proportion of the nitrate is denitrified at the first predetermined position, and controls the gas supply amount at least on an upstream side of the nitrification confirming unit, so that the desired proportion of the ammonia is nitrified at the second predetermined position.

Abstract: A wastewater treatment apparatus includes an air diffusing unit, a denitrification confirming unit, a nitrification confirming unit, a gas supply-amount control unit. The air diffusing unit supplies gas to nitrogen-containing water. The denitrification confirming unit provided at a first predetermined position confirms a denitrification state whether a desired proportion of the nitrate has been denitrified. The nitrification confirming unit provided at a second predetermined position confirms a nitrification state whether a desired proportion of the ammonia has been nitrified. The gas supply-amount control unit controls a gas supply amount at least on an upstream side of the denitrification confirming unit, so that the desired proportion of the nitrate is denitrified at the first predetermined position, and controls the gas supply amount at least on an upstream side of the nitrification confirming unit, so that the desired proportion of the ammonia is nitrified at the second predetermined position.

Abstract: A wastewater treatment apparatus includes: an air diffusing unit that supplies gas to nitrogen-containing water, so that ammonia contained in the nitrogen-containing water is nitrified to nitrate according to a flow of the water, and each desired proportion of the nitrate is denitrified at each position along the flow direction; a denitrification confirming unit provided at a halfway position between an upstream-side denitrification zone for obtaining a requisite minimum denitrified nitrogen amount and a downstream-side nitrification zone for obtaining ultimately required nitrified water quality, which follows the upstream-side denitrification zone on a downstream side thereof; and a gas supply-amount control unit that controls a gas supply amount from the air diffusing unit at least on an upstream side of the denitrification confirming unit, so that a desired proportion of the nitrate is denitrified at the halfway position, based on the denitrification state confirmed by the denitrification confirming unit.

Abstract: A method for treating an organic sludge is provided which can sufficiently and efficiently solubilize an organic sludge to afford a high load of anaerobic digestion treatment with an improved digestion ratio and methane gas recovery amount thereby to widely decrease the amount of the organic sludge discharged from the method. The method includes a hot alkaline treatment for causing the organic sludge to become alkaline while maintaining the temperature of the sludge to ambient -100.degree. C. to solubilize organic matters in the sludge, and an anaerobic digestion treatment of anaerobically digesting the organic sludge after the hot alkaline treatment at a temperature of 20.degree.-60.degree. C. at a pH of 7.3-9.2.