Nitrogen adsorption and reactivation of zeolite and soil in constructed wetland

Traditional physicochemical reactivation of packing needs high operating cost and makes against the activity of helophyte and microorganism. Development of reactivation method with low operation cost and ecological risk is important. Nitrogen adsorption performance of zeolite and soil in constructed wetlands treating agricultural wastewater, dynamic absorption and reactivation with aeration of zeolite were studied. Results show that the ammonia and nitrogen adsorption amount of packing is affected by the kinds, service time, filling mode and filling position. Ammonia and nitrogen adsorption amount of soil is three times of zeolite. Ammonia and nitrogen adsorption amount decreases with the increase of its using time in constructed wetland. Preposition zeolite has larger ammonia and nitrogen adsorption capacity than that of the top zeolite. Preposition zeolite belt from 0 to 90 cm has similar ammonia and nitrogen adsorption capacity after being used for 22 months. Ammonia and nitrogen adsorption capacity of superficial soil layer(0～10 cm) is twice of that of deeper soil layers(10～20 cm and 20～40 cm). The oxygen released by hydrophytes is helpful to the nitrification of ammonia. The lengthening hydraulic retention time is benefit for ammonia and nitrogen adsorption. Aeration has reactivation function on zeolite adsorbing some ammonia.