Metawater Co., Ltd.

Tokyo Metropolitan Sewerage Service Corporation

Shigehiro Suzuki

Hiroyuki Takahashi

Makoto Maeda

Tsutomu Wada

Motoharu Noguchi

Nobuki Tsuboi

Yuji Furuya

Noriaki Inagaki

Hideki Kozono

Koichiro Kando

Kouji Kassai

Keiichi Sone

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.

Wastewater treatment apparatus, wastewater treatment method, wastewater treatment system, control device, and control method

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.

A method of wastewater reutilization by which reusable water can be stably obtained from a wastewater. Ozone is added to a wastewater, such as water resulting from sewage treatment, in such a small amount as to result in a residual ozone concentration as measured before membrane filtration of 0.01-1.0 mg/L. Ozone is thus brought into contact with fine solids contained in the wastewater to alter the surface properties of the fine solids so that the solids are easily to coagulate. Thereafter, a coagulant, e.g., PACl, is added from a coagulant addition device (). The fine solids are coagulated in a coagulation tank () or a line mixer and the resultant water is subjected to membrane filtration with an ozone-resistant separation membrane () such as ceramic membrane. Thus, reusable water is obtained which has a residual ozone concentration, as measured after filtration through the membrane, less than 0.5 mg/L.

Method for recycling wastewater

The invention provides a side stream type membrane bioreactor process which does not cause an excessive fall in the MLSS concentration in a bioreactor, does not require any additional effluent treatment facility for discharging backwash effluent, and can further ensure the stability of the membrane filtration performance of a separation membrane. According to the invention, in a side stream type membrane bioreactor process, a backwash effluent containing foulants that are generated by backwashing a separation membrane is collected in a backwash effluent tank, and subjected to ozone treatment, and the resultant is returned to a bioreactor. By this ozone treatment, the foulants close to the membrane pore size of the separation membrane are made fine or are made into a state be easily taken into activated sludge flocs. Therefore, even when the treated effluent is returned to the bioreactor, the membrane filtration performance of the separation membrane is not deteriorated.

Side stream type membrane bioreactor process

Growing community of inventors

Tokyo, Japan

Shigehiro Suzuki