| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a drainage treatment system which fully reduces excessive sludge generated by biological treatment of organic drainage with a mild treatment condition and improves a quality of treated water. SOLUTION: In a drainage treatment equipment 10, a solid/liquid separation tank 2 is connected to a biological treatment tank 1 which raw water W is supplied to, and at the posterior stage a sludge thickener 3, a solubilization tank 4 and an oxidation apparatus 5 are installed in succession. Raw water W supplied to the biological treatment tank 1 is treated biologically, and solid and liquid materials are separated. A part of activated sludge is sent to the solubilization tank 4 through the sludge thickener 3 and is heated after an alkaline agent B is added, by which most of activated sludge S is solubilized and effluents are supplied to the oxidation apparatus 5. Under pressure of some hundred kPa or so, the oxygen-containing gas Go such as air, etc., is supplied, organic materials generated by solubilization and undissolved residues are decomposed in an oxidative condition, and the solution obtained therefrom is returned to the biological treatment tank 1.</p> |
