Combined treatment of swine wastewater by electron beam irradiation and ion-exchange biological reactor system

•Organic matter removal was dependent on the solubilization of organic matter.•The optimal dose for solubilization of swine wastewater was 20–75kGy.•Nitrogen removal was significantly affected by the current density.•Phosphorus precipitation was prohibited by calcium ion in the IEBR. Swine wastewater was treated using an ion-exchange biological reactor after an electron beam irradiation. Organic matter and nutrient in swine wastewater were pre-treated by an electron beam irradiation. The optimal dose for the solubilization of organic matter in swine wastewater ranged from 20kGy to 75kGy. To investigate solubilized organic fraction of swine wastewater, carbohydrates, proteins and lipids were measured. Most solubilized organic matter was proteins and lipids. The maximum chemical oxygen demand (COD) removal efficiency was 85.1% at an organic loading rate of 1.41kg/m3day (75kGy). For the removal of nitrogen, the nitrogen removal was significantly affected by the current density. The maximum total nitrogen removal efficiency was 75.0% at 1.09A/m2. On the other hand, amorphous phosphorus precipitation was formed in the IEBR because calcium ions competed highly with magnesium.