ABSTRACT
ABSTRACT: This study investigated the influence of outflow dynamics on the treatment efficiency of NH4 +-N in a pilot-scale Vertical Flow Constructed Wetland (VFCW) designed for septage treatment. Continuous samplings had been carried out to measure the temporal effluent flux and the associated concentration of nitrogen compounds. The effluent shows a dependency on the sludge thickness at the wetland surface. The proposed system demonstrated a promising treatment for Total Nitrogen (TN), where the average removal reaches 69.21 ± 16.75%. Nevertheless, it was observed that the overall removal of NH4 +-N is still below 50% and the concentration of NO3 −-N is high in the effluent. Comparisons between the peak of effluent flux and removal rate and linear regression analysis of the outflow and NH4 +-N dynamics revealed that the removal of NH4 +-N was greatly affected by the hydraulic behavior. As the nitrification is the main process in removing NH4 +-N, the percolating rate through the wetland bed determines the contact time with the attached-growth biofilm which eventually govern the treatment performance.
