MODEL OF NITROGEN TRANSFORMATION MECHANISM AND REMOVAL IN DOMESTIC WASTEWATER WITH WETLAND

• Main Author: Agustine Putri, Ratih
• Format: Theses
• Language: Indonesia
• Subjects: Teknik saniter dan perkotaan; teknik perlindungan lingkungan
• Online Access: https://digilib.itb.ac.id/gdl/view/63063
• Institution: Institut Teknologi Bandung

The mechanism of nitrogen transformation and removal from domestic wastewater treated using constructed wetland involves complex processes. Various prior studies have shown that nitrification-denitrification are the major pathways of nitrogen removal in the wetland system, but several other studies have shown different major pathways upon nitrogen removal. The objectives of this study are to determine the major pathways of nitrogen transformation and removal treated using constructed wetland and determine the major pathways’ influencing factors based on the kinetic parameters of the model simulation results and from the use of different plant species. This study was conducted by taking secondary data from an existing study by modeling 2 (two) horizontal subsurface flow constructed wetland reactors planted with different vegetations (reactor Iris martinicensis and reactor Pontederia cordata) and applying the mathematical model with the parameters reviewed were Org-N, NH3-N, and NO3-N. The results have shown that the model can predict nitrogen effluent more accurately in reactor Iris martinicensis. The process kinetics generated by the model showed the major pathways of nitrogen transformation and removal are ammonia nitrification (4,2236 mg/L.day) and uptake of nitrate by the plant (3,6263 mg/L.day). The nitrification rate obtained was low, this is explained by the kinetics value from the model which showed the low affinity of bacteria to the substrate. The plant roots in reactor Iris martinicensis were not too long, causing less oxygen transfer to stimulate the growth of nitrifying bacteria and not enough active surface for the growth of more microorganisms. In addition, the effective location for attaching the biofilm was also not much. This factor encourages the biological role of plants in nitrogen uptake in reactor Iris martinicensis was greater than its denitrification mechanism. Meanwhile, despite inaccurate results have shown by reactor 2, yet the model showed its major pathways of nitrogen transformation and removal are ammonia nitrification (7,5360 mg/L.day) and nitrate denitrification (4,4214 mg/L.day).