Kuraray Co., Ltd.

Hiroaki Fujii

Yasuhiro Baba

Goro Kobayashi

Tsutomu Miura

Tadao Shiotani

Masanobu Abe

Hidehiko Okabe

Naoshi Nakagawa

Eiji Tanaka

Takanori Kitamura

Keiko Oka

Shinji Komori

Tamio Higashi

Kiichirou Oka

Takeshi Matsuda

To provide an inexpensive wastewater treatment method which facilitates downsizing of tanks and requires less withdrawal of an excessive sludge, the use is made of an aeration tankin which wastewater is contacted with a particulate carrier under an aerobic condition, and a total oxidization tankin which the volume of a sludge generated in the aeration tankis reduced under an aerobic condition, a coefficient of self-oxidization of the sludge flowing into the total oxidization tankis set to 0.05 (per day), and the method includes a step of adding a coagulant to the total oxidization tankfor the purpose of improving the solid-liquid separating characteristic of the sludge within the total oxidization tank.

Wastewater treatment method using immobilized carrier

A method of wastewater treatment that reduced equipment cost and running cost and realizes high efficiency implementation and further tank miniaturization, and that reduces excess sludge withdrawal. There is provided a method of wastewater treatment with excess sludge withdrawal reduced, characterized in that there are installed an aeration tank wherein wastewater is brought into contact with carrier particles under aerobic conditions, a total oxidization tank and a sedimentation tank, and that operation is made while maintaining the BOD sludge load in the total oxidization tank at 0.08 kg-BOD/Kg-MLSS*day or smaller, and that a coagulant is charged in the complete oxidization tank in order to improve the setting in the sedimentation tank.

Method of wastewater treatment with excess sludge withdrawal reduced

Provided are an apparatus and a method for waste water treatment not generating excessive sludge, for which down-sized tanks are usable. The apparatus comprises an aeration tank where waste water to be treated is kept in contact with carrier particles in an aerobic condition, and a complete oxidation tank. In this, the liquid in the complete oxidation tank is filtered through a separation membrane and the resulting filtrate is discharged out of the system. The s-BOD sludge load to the complete oxidation tank is preferably at most 0.1 kg-BOD/kg-MLSS&middot;day.

Apparatus and method for waste water treatment

A polyvinyl alcohol hydrogel has a surface layer comprising a net-like structure formed by entanglement of fiber-like articles having a diameter of 0.1 to 50 .mu.m. This gel has a large surface area and high capability of adhering microorganisms and permeating liquid, thereby exhibiting excellent purifying function. Processes for producing the above hydrogel are also provided.

Polyvinyl alcohol hydrogel and process for producing the same

A waste water treatment apparatus which is compact, and excellent in durability, has a high treatment performance and can stably operate for a long time is provided. In a waste water treatment apparatus at least comprising a waste water treatment tank in which a carrier particle immobilizing a microbe is charged and decomposing and eliminating an organic matter and/or an inorganic matter contained in a waste water, and a membrane module for filtrating a water to be treated which flows out from said treatment tank, a non-permeating water not passing thorough the membrane module is returned and circulated to said treatment tank. In a waste water treatment apparatus at least comprising a waste water treatment tank in which a carrier particle immobilizing a microbe is charged and decomposing and eliminating an organic matter and/or an inorganic matter contained in a waste water, a carrier immobilizing a microbe is an acetalized polyvinyl alcohol hydrogel.

Waste water treatment apparatus

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Kurashiki, Japan

Hiroaki Fujii