Adsorption characteristics of different constructed wetland substrates

Substrate as an important component of constructed wetlands, played an important role in the purification of nitrogen and phosphorous. The nitrogen and phosphorus adsorption properties of four substrates, including gravel, clinoptilolite, limestoneand and lytag, were studied through the basic experiments. The results revealed that the nitrogen and phosphorus adsorption rates of clinoptilolite were the highest among the four substrates. The adsorption performances of the four substrates were all greatly affected by pH. The phosphorus Adsorption capacity of clinoptilolite and limestone increased as pH rose, and the opposite is true for lytag and gravel; neutral and acidic conditions were conducive to clinoptilolite absorption of ammonia nitrogen, while for the other three substrates, the ammonia nitrogen Adsorption capacity increased with the rise of pH, and the surface characteristics of the substrates were analyzed by scanning electron microscopy. © 2011 IEEE.