| 摘要 |
<p>PURPOSE:To satisfactorily remove phosphorus in sewage with inexpensive facilities by adding a phosphorus removing agent to eliminated liq. before return to a biological treating stage. CONSTITUTION:When eliminated liq. produced at the time of concentration in a sludge concentration tank or a sludge concentration and storage tank 4 is returned to a flow rate regulation tank or a precipitate separation tank 1, a phosphorus removing agent such as aluminum sulfate or ferric chloride is added to the liq. in a pipe or the like. The added removing agent reacts with phosphorus in the liq. to form flocks of Al(PO4), Fe(PO4) or the like. Since Al or Fe does not poison microorganisms, the treating ability of microorganisms in a biological treatment tank 2 can be satisfactorily utilized. Since the flocks are returned to the tank 1 without carrying out solid-liq. separation, a separator is made unnecessary.</p> |
