ABSTRACT
The outdoor multi-level subsurface flow constructed wetland system was designed and constructed by the guidance of Associate Professor Li Jiake, in Xi’an University of Technology. The system consists of three different matrix combinations in flumes which are six meters long, one meter wide, and connected in series (Fig. 1 and Table 1), to ensure good treatment effect for nitrogen, phosphorus and other pollutants; planting reeds and canna mixed which have good purification
1 INTRODUCTION
The constructed wetland is a new type of water treatment technology developed in the 1970s, which can effectively purify water, raise utilization efficiency of water resources and improve the water shortage situation significantly [1-3]. Constructed wetland is a simulation of natural wetland systems, which can achieve its purification effects through the synergy of matrix (filler), plants, and microorganisms. Its main principle is to use the physical, chemical and biological cooperative effects of matrix-plants-microorganisms system, through filtration, adsorption, precipitation, ion exchange of the matrix, plant uptake and microbial decomposition to achieve purification of water body [4-7]. At present studies on wetlands have become more mature, and also achieved some results in all aspects of the filler, plants, together with the design and operation mode of wetland system. Meanwhile, there are also studies on wetland treatment for different pollutant load of water such as domestic, industrial, agricultural and other waste water bodies. This paper dealing with the multilevel outdoor subsurface flow constructed wetland system, studies the Total Nitrogen (TN), Total Phosphorus (TP) and ammonia (NH4+-N) purifying effects under different Hydraulic Retention Times (HRT) and run-time intervals conditions for the Xi’an urban surface runoff treatment, analyze impact of the above two operating conditions for Figure 1. Diagram of the flume.
