Effect of vegetation on the performance of horizontal subsurface flow constructed wetlands with lightweight expanded clay aggregates

Abstract

This research evaluates the effect of both organic and ammonia loading rates and the presence of plants on the removal of chemical oxygen demand and ammonia nitrogen in horizontal subsurface flow constructed wetlands, 2 years after the start-up. Two sets of experiments were carried out in two mesocosms at different organic and ammonia loading rates (the loads were doubled); one without plants (control bed), the other colonized with Phragmites australis. Regardless of the organic loading rate, the organic mass removal rate was improved in the presence of plants (93.4 % higher for the lower loading rate, and 56 % higher for the higher loading rate). Similar results were observed for the ammonia mass removal rate (117 % higher for the lower loading rate, and 61.3 % higher for the higher loading rate). A significant linear relationship was observed between the organic loading rate and the respective removal rates in both beds for loads between 10 and 13 g m -2 day -1 . The presence of plants markedly increase removal of organic matter and ammonia, as a result of the role of roots and rhizomes in providing oxygen for aerobic removal pathways, a higher surface area for the adhesion and development of biofilm and nitrogen uptake by roots.

Efeito da vegetação em sistemas alagados construídos para tratar águas residuárias da suinocultura

“…Isso leva ao questionamento do papel das macrófitas nesses sistemas (BRIX, 1997;MARA, 2004;SHELEF;GROSS;RACHMILEVITCH, 2013), não havendo consenso entre pesquisadores a respeito da efetiva importância das macrófitas aquáticas nos SACs. No entanto novos trabalhos, notadamente aqueles que consideram as perdas de água por evapotranspiração no sistema, têm evidenciado essa importância (BIAŁOWIEC; JANCZUKOWICZ; RANDUSON, 2011;MESQUITA et al, 2013). Em algumas pesquisas, têm sido descritos melhores desempenhos em SACs cultivados com espécies aquáticas em relação aos não cultivados (DALLAS & HO, 2005).…”

Treatment of Bio-Oil Refinery Storm Water by a Simulated Constructed Wetland: A Sustainable Management Alternative

“…It also occurs when molecules dissolve in between the soils organic matter and the aqueous phase of the water, or from partitioning of dissolved molecules between the aqueous phase and soil organic matter (McCutcheon and Schnoor 2003). This process acts as a sink for contaminates when the soil and solid surface area of a system have reached their holding limit, pollutants will reside in the constructed wetlands longer and in turn becoming more exposed to the bioremediation process (Mesquita, Albuquerque et al 2013). …”

“…In regions, such as the southern U.S, temperatures can reach extreme highs in the summer months and increase volatilization of some of the pollutants, such as the phenols and furans (Langeveld, Liefting et al 2012). Low temperatures can affect plant growth and microbial mobility; therefore limiting the phytoremediation potential of the wetlands (Mesquita, Albuquerque et al 2013).…”

Effects of nitrogen fertilization on soil labile carbon fractions of freshwater marsh soil in Northeast China

“…The effects of ammonia nitrogen in horizontal subsurface flow and the performances of nutrients removal efficiency were different in the planted or the unplanted wetlands (Mesquita et al 2013;Cheng et al 2011). An undisturbed marsh with Deyeuxia angustifolia was also selected to study the effect of nitrogen fertilizer levels on dissolved organic carbon in the short term.…”