||In this study, the possibility of driving Anammox process in constructed wetland systems is investigated. The experimental designs are based on completely autotrophic nitrogen removal over nitrogen removal over nitrite (CANON), which can couple Anammox process with partial nitriﬁcation in one single unit. To reach the purpose, in this study a vertical-flow constructed wetland (VFCW) system with deep depth and high RT was used. The VFCW system was installed with gravels,on which biofilm was formed and attached, and fill with some anaerobic sludge for suspension growth in the system. In order to inhibit the effects of heterotrophic denitrification, low levels of chemical oxygen demand (10.14-11.59 mg/L) were controled in the inflow of the systems. |
The experimental results show that the process of nitrification is very significant in the first day of test run, while the concentrations of DO were decreased down to below 1 mg/L, and the concentrations of NH4+-N were decreased with increasing NOx(NO2--N+NO3--N). Comparing with the amounts of NH4+-N decreased, the amounts of NO2--N increased was far less than it, while the same situation was shown until the fifth day. The percentage of TN removed were reached to 97.5% (PS) in the fifth day, which was the end of test run. Though the test of Polymerase Chain Reaction (PCR),it was helpful to know the Anammox bacteria did exist in the VFCW system, which might occur from the first day to the fifth day. It was also shown that the plants in VFCW system could enhance the removal of TN. That was because the plants could absorb NO3--N, which was produced by those processes like nitrification and Anammox.