Evaluación De Tres Sistemas De Humedales Híbridos a Escala Piloto Para La Remoción De Nitrógeno

Abstract

Palabras clave: nitrógeno amoniacal, nitrógeno orgánico, nitrato, humedales verticales, Canna indica, Strelitzia reginae RESUMENEn este estudio se evaluaron y compararon tres sistemas de humedales híbridos para la remoción de nitrógeno total (N total ) durante dos años. Se cuantificó el contenido de cada uno de los componentes nitrogenados: nitrógeno amoniacal (N-NH 4 + ), nitrato (NO 3 -) y nitrógeno orgánico (N Org ). El primer sistema (I) estuvo compuesto de un humedal subsuperficial de flujo horizontal (HSSFH), seguido de una laguna de estabilización (LE) aerobia; el segundo (II) por HSSFH seguido de un humedal subsuperficial de flujo vertical (HSSFV); y el tercero (III), por HSSFV seguido de HSSFH. Los tres sistemas fueron muy efectivos para la nitrificación. Se registraron incrementos elevados en la concentración de NO 3 -en los efluentes y eficiencias altas en la remoción de N-NH 4 + . Estas eficiencias fueron de 76.2 % y 78.7 %, en el sistema I; de 87.4 % y 92.5 % en el sistema II y de 82.6 % y 97.2 % en el sistema III, en el primer y segundo año, respectivamente. Respecto a la remoción de N total , el sistema I (HSSFH-LE) fue el más efectivo (p < 0.05) con remociones de 59.4 % y 57.7 % en los años 1 y 2, respectivamente. En los sistemas II (HSSFH-HSSFV) y III (HSSFV-HSSFH) las remociones fueron de 21.2 % y 34.4 %, y de 25.0 % y 36.3 %, respectivamente. La baja remoción de N total en los sistemas II y III, aparentemente se debió a una baja tasa de desnitrificación ante la ausencia de zonas anóxicas/anaerobias más extensas como resultado de la baja profundidad de los HSSFH y de las características del medio filtrante, tales como su distribución de tamaño de partícula (tezontle molido) y su elevada porosidad.Key words: ammonium, organic nitrogen, nitrate, vertical wetlands, Canna indica, Strelitzia reginae ABSTRACTIn 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 (NH 4 + ), nitrate (NO 3 -) 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, Rev. Int.

Nitrogen Removal from Domestic Wastewater and the Development of Tropical Ornamental Plants in Partially Saturated Mesocosm-Scale Constructed Wetlands

“…Although the VPS CW systems have good oxygenation, due to the lower presence of oxygen in the saturated zone, these systems could make possible a greater elimination of nitrate. On the other hand, another mechanism for nitrate removal is the assimilation by plants (although plants prefer ammonium over nitrate) that in this study allowed the generation of high densities of tissues, corroborated with the biomass production (Figure 4) [10]. Additionally, in the mesocosms, greater removal was observed with rapid plant growth, so that this could be an indicator of the presence of high nutrient content in the plant tissues [20].…”

“…In the second step, in denitrification that develops in an anoxic/anaerobic environment, nitrate is transformed into a removable gaseous product [7,8]. According to Metcalf and Eddy [9] and Bojorges et al [10], in domestic wastewater, nitrogen is present as organic nitrogen (Norg), ammonium (N-NH 4 ), and nitrate (NO 3 +). A cost-effective natural alternative to conventional wastewater treatment is constructed wetlands (CWs), which are engineered systems that mimic the functions of natural wetlands in terms of their phytoremediation capacity [11,12].…”

“…The different mechanisms for transforming nitrogen in wetlands depend on the type of wetland. Those with a horizontal subsurface flow are constantly saturated, prevailing anoxic/anaerobic conditions that favor denitrification (if organic matter is present), while in those with vertical flow, the presence of oxygen is greater, given their intermittent feeding, so nitrification is favored [10,20]. Although combined systems (vertical and horizontal flow wetlands) have been used to solve this problem, they increase the construction and implementation costs, as well as the space required for their operation [23,24].…”

Effects of Ornamental Plant Density and Mineral/Plastic Media on the Removal of Domestic Wastewater Pollutants by Home Wetlands Technology

“…Ammonium is removed in CWs, through the action of aerobic and anaerobic microorganisms, taking into account that under anaerobic conditions the reductions are slow [48], which may explain its behavior in this study. The concentrations of ammonium (Figure 5a,b) in the influent oscillated in a ranged of 18.88 ± 0.51 mg/L; these were significantly reduced (P = 0.001) in presence of plants and in the systems without plant species.…”

“…Another way of reducing NO 3 -N is through denitrification. NO 3 -is reduced in anoxic conditions by heterotrophic bacteria (such as Pseudomonas, Micrococcus, Achromobactor and Bacillus), in this process, denitrifying bacteria decreases inorganic nitrogen such as nitrate and nitrite into innocuous fundamental nitrogen gas [48,52]. In HSSF-CWs, anoxic conditions occur where there is no contact with the vegetation roots.…”