Abstract

TORRES BOJORGES, Ángeles Xitlalli; HERNANDEZ RAZO, Noemy Alejandra; FAUSTO URQUIETA, Airam Aseret  and  ZURITA MARTINEZ, Florentina. EVALUATION OF THREE PILOT-SCALE HYBRID WETLAND SYSTEMS FOR NITROGEN REMOVAL. Rev. Int. Contam. Ambient [online]. 2017, vol.33, n.1, pp.37-47. ISSN 0188-4999.  https://doi.org/10.20937/rica.2017.33.01.03.

In this two-year study, three hybrid constructed wetlands were evaluated and compared for Total-N removal, quantifying the content of each of the nitrogen compounds: Ammonium (NH4 +), nitrate (NO3 -) and organic nitrogen (Org-N). The first system (I) consisted of a subsurface flow horizontal wetland (SSFHW) followed by an aerobic stabilization pond (SP); the second one (II) consisted of a SSFHW followed by a subsurface flow vertical wetland (SSFVW); and the third one (III) was configured with a SSFVW followed by a SSFHW. The three systems were very effective for nitrification, reaching a high increase in nitrate concentrations in the effluents and high efficiencies in the N-NH4 + removal. These efficiencies were 76.2% and 78.7%, in the system I; 87.4% and 92.5% in the system II and 82.6% and 97.2% in the system III, during the first and the second year, respectively. With regard to the removal of Total-N, the system I (SSFHW-SP) was the most effective (p <0.05) with removal of 59.4% and 57.7% in the first and the second year, respectively. In the systems II (SSFHW-SSFVW) and III (SSFVW-SSFHW), the removals were 21.2% and 34.4%, and 25.0% and 36.3%, respectively for the first and the second year. The low removal of Total-N in the systems II and III, apparently were due to a low rate of denitrification because of the absence of a larger anoxic/anaerobic area; as a result of the shallow depth of the SSFHWs and the characteristics of the filter medium such as its grain size distribution (ground tezontle) and high porosity.

Keywords : ammonium; organic nitrogen; nitrate; vertical wetlands; Canna indica; Strelitzia reginae.

        · abstract in Spanish     · text in Spanish     · Spanish ( pdf )