Abstract: A wastewater treatment equipment is provided with a reaction tank and a separate reaction unit installed in the reaction tank. In the separate reaction unit, a reaction different from a reaction in the reaction tank is carried out with returned sludge and a acid or alkali. Reactants are generated from the returned sludge in the separate reaction unit and then introduced from a bottom portion of the separate reaction unit into the reaction tank so as to be used for wastewater treatment.

Abstract: In the waste water treatment apparatus, organic matter-containing fluorine waste water is treated in a reaction tank into which biological sludge and calcium-containing chemical sludge are introduced, thus making it possible to treat organic matters in the waste water by microorganisms contained in the biological sludge, and simultaneously to treat fluorine in the waste water by the calcium-containing chemical sludge. Therefore, since organic matters in the waste water and fluorine in the waste water, which differ in chemical properties from each other, can be treated with one reaction tank, it is no longer necessary to provide two reaction tanks, thus allowing the initial cost to be reduced. That is, this waste water treatment apparatus is capable of reducing the quantity of waste materials and reducing both initial cost and running cost.

Abstract: In a waste water treatment apparatus, sludge settled in a settling tank is treated by being introduced (returned) into a return sludge reaction tank having a settling section in its rear portion. Therefore, unreacted chemicals contained in the sludge that has settled in the settling tank can be utilized in the return sludge reaction tank. Therefore, the unreacted chemicals are not discharged as sludge. Accordingly, as compared with the conventional treatment method of discharging a sludge from the settling tank, it is possible to reduce the amount of generated sludge remarkably and consequently, reduce a sludge disposal fee, the use amount of slaked lime, and a running cost such as maintenance cost of a dehydrator.

Abstract: A wastewater treatment equipment is provided with a reaction tank and a separate reaction unit installed in the reaction tank. In the separate reaction unit, a reaction different from a reaction in the reaction tank is carried out with returned sludge and a acid or alkali. Reactants are generated from the returned sludge in the separate reaction unit and then introduced from a bottom portion of the separate reaction unit into the reaction tank so as to be used for wastewater treatment.