Behavior of Typha angustifolia L. in a free water surface constructed wetlands for the treatment of swine wastewater

Abstract

The objective of this study was to evaluate the behavior of Typha angustifolia L. in nitrogen retention in a Free Water Surface Constructed Wetland (FWS) for the swine wastewater treatment over a three-year operating period. Results show that the behavior of Typha angustifolia L. in a FWS for treatment of swine wastewater is affected by nitrogen concentration, seasonal variation and plant establishment in the system. Indeed, the application of Nitrogen Loading Rates (NLR) between 7.1–14.3 kg TN/ha·d removes 40% of Total Nitrogen (TN), where the maximum removal (20–40%) takes place in the spring-summer seasons. However, concentrations higher than 120.3 mg NH₄ ⁺–N/L significantly decrease (P = 0.004) diametrical growth by 55%. However, it was possible to estimate that NLR >14.3 kg TN/ha·d increased biomass production and plant uptake in Typha angustifolia L. during the period analyzed. Additionally, aboveground biomass values were between 1.509.6–2.874.0 g/m² and nitrogen uptake 27.4–40.8 g/m², where this last value represents 29% of the TN applied during the study. Finally, the TN accumulation in sediments represents less than 2% of the TN incorporated during this period. These results show that an increase of 50% of the TN in sediments increases plant abundance in 73%, which is related to the mineralization processes favored in the system during the last year of operation.

Keywords:

• Typha angustifolia L.
• free water surface constructed wetlands
• swine wastewater
• nitrogen removal
• plant uptake

Acknowledgments

This work was supported by CONICYT (Grant 24110086) and Innova Bío-Bio Project (Grant 07–PC S1–198). The authors wish to thank Mr. César Contreras from the Yanine Succession for the use of their facilities.