| Constructed wetlands experiments were conducted by using shale and Typha latifolia L. as vertical subsurface flow constructed wetland substrate and plant for eutrophic Jin River water treatment, and part of shale with polypropylene pellet was replaced to investigate its effect on nitrogen and phosphorus removal. In this study, hydraulic loading rate was equal to 800 mm/d, theoretic residence time was equal to 12 h. During the entire running period, maximal monthly mean ammonia-nitrogen (NH+4-N), total nitrogen (TN), soluble reactive phosphorus (SRP) and total phosphorus (TP) removal rates were observed in August 2006. In contrast to the full shale used wetland, polypropylene pellet enhanced ammonia-nitrogen, total nitrogen, soluble reactive phosphorus and total phosphorus removal by 13.38%, 8.9%, 9.29% and 8.25% respectively. After finishing the experiment, aboveground plant biomass (stems and leaves) of Typha latifolia L. was harvested, and its weight and nutrient content (total nitrogen and total phosphorus) were measured. Analysis of aboveground plant biomass indicated that polypropylene pellet restrained the increase in biomass but stimulated assimilation of nitrogen and phosphorus into stems and leaves. The subsequent harvesting of the plants resulted in the additional removal of total nitrogen and phosphorus of about 29.382 g·m-2 and 13.469 g·m-2, respectively. |
