Phosphorus elimination of reclaimed water by different kinds of constructed wetlands

Because of water shortage in Beijing, most ponds and moats there have not enough water. In some times of each year, there is even no water. Therefore, wastewater reclamation and reuse has been paid more and more attention. Reclaimed water used as scenic water such as to supplement city moats, lakes etc. is considered. In this paper, some experiments were done to investigate whether constructed wetlands can reduce the nitrogen and phosphorus concentration further in order to avoid the eutrophication of water bodies through use of reclaimed water for scenic environment. As we know, phosphorus is an important factor to cause algae bloom directly in water bodies. So investigation on phosphorus elimination is a key object for this study, which is composed of two main parts. The first part is laboratory scale testing to select the appropriate substrates of constructed wetlands among some materials. The second part is pilot scale experiments to find out optimal operational condition of different kinds of constructed wetlands. Based on the lab tests, we found that foamy-brick could provide a good condition for plants and microorganisms. According to the pilot scale experiments, it could be concluded that under optimal operational conditions, horizontal flow wetlands could work well. The results of the experiments also showed that integrated vertical flow wetlands are not suitable for phosphorus elimination of reclaimed water.