Nitrogen Removal in a Partially Saturated Vertical Subsurface Flow Constructed Wetland Used for Restaurant Wastewater Treatment

Abstract

The objective of this research was to evaluate the nitrogen removal efficiency of a partially saturated vertical subsurface flow constructed wetland (VSFCW) used on university restaurant (UR) effluent treatment. The research was conducted in southern Brazil (latitude:−23.34218; longitude:−51.172223) on constructed wetland with 1 m2 of surface area, and the saturation layer was .25 m upper bottom. The results of this monitoring research extended for 6 months in a cultivated Heliconia rostrata system. The average applied loads were 37.6 g/m2 of chemical oxygen demand (COD), 4.1 g/m2 of total Kjeldahl nitrogen (TKN), 1.74 g/m2 of ammoniacal nitrogen (N-NH4+), and 4.28 g/m2 of total nitrogen (TN). The mean efficiencies of removal/conversion were 95.34% for COD, 96.95% for TKN, 93.99% for N-NH4+, and 69.39% for TN. The removed loads were 35.9 g/m2 of COD, 3.98 g/m2 of TKN, 1.68 g/m2 of N-NH4+, and 3.2 g/m2 of TN. The results showed system operational stability and the high efficiency on organic matter and TN removal of this effluent type.