Simultaneous removal of ammonia, phosphate and COD from slaughterhouse wastewater by natural zeolite

Slaughterhouse wastewater contains ammonia, phosphate and COD, which lead to water body eutrophication. The static and dynamic characteristics for adsorption of ammonia, phosphate and COD were studied in this research by using natural zeolite. Static experiment results showed that the zeolite kinetic adsorption of ammonia simultaneously fitted the second-order model and Freundlich isotherm model, not for phosphate and COD. Phosphate and COD removal efficiency in synthetic wastewater were higher than that in single pollutant wastewater. The dynamic experiments showed the penetration times of the modified and natural zeolite for ammonia were about 62 h and 55 h, respectively. The dynamic saturated adsorption amount was 37.71 and 32.78 mg/g, respectively. Phosphate concentrations of the modified and natural zeolite reached equilibrium at 34 h and 70 h. COD concentrations of modified and natural zeolite both had no significant change. In the chemical desorption, optimal desorption efficiency for ammonia, phosphate and COD were 50%, 45% and 30%, respectively, and the corresponding pH values were 12, 2 and 10, respectively.