Biodegradation and kinetics of organic compounds and heavy metals in an artificial wetland system (AWS) by using water hyacinths as a biological filter

ABSTRACT

The objective of the present study was to investigate the ability of water hyacinth (Eichhornia crassipes) to absorb organic compounds (potassium hydrogen phthalate, sodium tartrate, malathion, 2,4-dichlorophenoxy acetic acid (2,4-D), and piroxicam). For the aforementioned purpose, an artificial wetland system (AWS) was constructed and filled with water hyacinth collected from the Valsequillo Reservoir, Puebla, Mexico. Potassium hydrogen phthalate and sodium tartrate were measured in terms of chemical oxygen demand (COD) and biological oxygen demand (BOD). The present study indicated that the water hyacinths absorbed nearly 1.8–16.6 g of COD kg⁻¹ dm (dry mass of water hyacinth), while the absorbance efficiency of BOD was observed to be 45.8%. The results also indicated that the maximum absorbance efficiency of malathion, 2,4-D, and piroxicam was observed to be 67.6%, 58.3%, and 99.1%, respectively. The kinetics of organic compounds fitted different orders as malathion followed a zeroth-order reaction, while 2,4-D and piroxicam followed the first-order reactions. Preliminary assessment of absorption of heavy metals by the water hyacinth in the AWS was observed to be (all values in mg g⁻¹) 7 (Ni), 13.4 (Cd), 16.3 (Pb), and 17.5 (Zn) of dry biomass, thus proving its feasibility to depurate wastewater.

KEYWORDS:

• malathion
• 2,4-D
• heavy metals

Acknowledgments

The authors wish to thank the Laboratory of External services of the Institute of Chemistry at the University of Guanajuato, Mexico.

Additional information

Funding

The authors acknowledge the financial assistance awarded by Secretariat of Rural Development, Sustainability and Land Management (Secretaria de Desarrollo Rural, Sustentabilidad y Ordenamiento Territorial, Gobierno del Estado de Puebla, SDRSOT), through the project “Proyecto Demostrativo de Biofiltro en la Presa Valsequillo, Puebla (2015)” and support from projects: IPN-SIP20140618, IPN-SIP20150055, IPN-SIP20120725, and IPN-SIP20131892. Rodriguez-Espinosa P.F. wishes to express his thanks to Sistema Nacional de Investigadores (SNI), CONACyT, EDI, COFAA (IPN). Tabla-Hernandez J. would like to thank CONACyT (Consejo Nacional de Ciencia y Tecnologia) for providing a scholarship to conduct this study.