Treatment of anaerobic digester effluent using Typha angustifolia l.: Growth responses and treatment efficiency

Abstract

© 2020 Japan Society on Water Environment. Constructed wetlands are an eco-friendly technology used for decades for treating various types of wastewater. To gain new insight into plant selection for wastewater treatment systems in tropical areas, this research investigated growth and ecophysiological responses of Typha angustifolia to different concentrations of anaerobic digester effluent from a swine farm and assessed their influence on wastewater treatment effectiveness. Twelve plants (n = 4 per treatment) were separately grown in 3 concentrations of wastewater (25% and 50% diluted wastewater and undiluted wastewater). All plants grew well in all concentrations. However, the plants tended to have reduced root biomass, root length and decreased pigment contents when exposed to high concentrations. High removal efficiency for electrical conductivity, total dissolve solids, total suspended solids, biochemical oxygen demand, chemical oxygen demand, ammonium nitrogen and orthophosphate was found (73%, 70%, 93%, 99%, 82%, 99% and 80%, respectively, from undiluted wastewater). The dissolved oxygen concentration in the anaerobic digester effluent increased over time because of released root oxygen. The study showed that T. angustifolia developed aerenchyma in its root cortex even under stress conditions. This ability makes this plant tolerant to high strength wastewater. Furthermore, oxygen released from its roots also supports growth of microorganisms and enhances microbial biodegradation processes leading to highly efficient treatment systems.