What is the best filler for constructed wetlands?

In this experiment, the adsorption of ammonia nitrogen by zeolite, limestone, columnar carbon, ceramsite, fly ash, steel slag, dolomite, anthracite, manganese sand and shell carbon in constructed wetland for 24 hours, 48 hours and 72 hours was studied. Among them, the concentration of ammonia nitrogen in the wastewater used in the experiment is 25.4 mg/L.

Experiments show that zeolite as a single substrate has the best adsorption and absorption rate of ammonia nitrogen, and the adsorption effect in the first 24 hours is better than that in the later period. Secondly, in the first 48 hours, the adsorption effect of columnar carbon on ammonia nitrogen was better, but by 72 hours, the adsorption effect of columnar carbon decreased, and the adsorption effect of ceramsite was second only to zeolite.

▲ Effect diagram of ammonia nitrogen adsorption by single substrate.

In addition, the experiment proves that the selection of zeolite filler in constructed wetland system can obviously improve the removal effect of pollutants, at the same time, it can effectively avoid clogging and improve the operation cycle of constructed wetland system.