The invention provides an economic and efficient dephosphorization method, comprising the steps of
microfiltration and
ion exchange. In the method, (1) phosphoric
sewage is filtered by a
microfiltration membrane to intercept and remove suspended matters,
bacteria and
colloid substances larger than 0.1micron,
produced water subjected to pretreatment is lead to an
ion exchange column,
phosphorus in the
sewage is adsorbed by a dephosphorization adsorbent, and the
produced water is finally lead to a clear water tank; and (2) the saturated dephosphorization adsorbent is regenerated by suing a
sodium hydroxide solution, and an eluent is condensed and separated through an
evaporator. In the invention, an
organic polymer microfiltration membrane or an inorganic
microfiltration membrane is adopted, and the dephosphorization adsorbent is filled in the
ion exchange column; and the bore
diameter of the
microfiltration membrane is 0.05-10 mum, the
porosity of the
microfiltration membrane is 30-95%, and a membrane
assembly is of a plate type, or a tube type, or a roll type or a hollow
fiber type. The invention is used for the
direct treatment of the
phosphorus sewage or the advanced treatment of the
phosphorus sewage treated by a biological method so as to ensure that the phosphorus content of the final
produced water is lower than 0.5mg / L and avoid excessive phosphorus discharged into a
water body to result in
eutrophication, and meanwhile, the
ion exchange eluent containing high-content phosphorus is further condensed and separated to achieve the purpose of recycling the sewage.