Evaluation of Purification Efficiency In Constructed Wetlands for Treating Livestock Wastewater.

To obtain optimum conditions were investigated in small-scale livestock wastewater treatment apparatus under various conditions (filer media, configuration method, and livestock wastewater loding). The optimum filter media in small-scale livestock wastewater treatment apparatus for treating livestock wastewater were studied. Removal rates of pollutants under different filter media were in the other of coarse sand �� broken stone > zeolite > calcite for COD, zeolite >> broken stone �� coarse sand �� calcite for T-N, and calcite > coarse sand �� broken stone �� zeolite for T-P. Based on the above results, the optimum filter media was coarse sand in small-scale livestock wastewater treatment apparatus. To obtain optimum configuration method and livestock wastewater loading in small-scale livestock wastewater apparatus by natural purification method for treating livestock wastewater, the small-scale livestock wastewater apparatuses were constructed with 9 kinds of combined systems such as aerobic bed(ae)-anaerobic bed(an), ae-ae, ae-anoxic bed(ox), an-an, an-ae, an-ox, ox-ae, ox-an and ox-ox livestock wastewater treatment apparatuses. Under different configuration methods, the removal rate of COD in Ae-Ae and Ae-An livestock wastewater treatment apparatus was higher than that in other configuration methods. The removal rate of T-N in Ae-An livestock wastewater treatment apparatus was higher than that in other configuration methods. Removal rates of SS and T-P were not different regardless of configuration methods in small-scale livestock wastewater treatment apparatus. Under different livestock wastewater loading, the removal rates of pollutants were higher in the order of 50 L m^-2 day^-1 �� 100 L m^-2 day^-1 > 200 L m^-2 day^-1. Therefore, optimum configuration method was Ae-An livestock wastewater treatment apparatus, and optimum livestock wastewater loading was 100 L m^-2 day^-1 in small-scale livestock wastewater treatment apparatus.