Nutrient accumulation in five plant species grown in bioretention systems dosed with wastewater

Abstract

Many studies have concluded that vegetation has a significant role in the removal of nutrients from wastewater, but few have investigated nitrogen and phosphorus accumulation in plant biomass in bioretention mesocosms. This study quantifies the nutrients accumulated in five native plant species grown in bioretention mesocosms established in Queensland, Australia. The species Banksia integrifolia, Callistemon pachyphyllus, Carpobrotus glaucesens, Dianella brevipedunculata and Pennisetum alopecuroides were grown in gravel, loam and sand media. The plants with higher growth rate and biomass retained a higher amount of nutrients in roots, stem and leaves. Callistemon and Pennisetum were the best species to remove nutrients from wastewater in subtropical Australia. The average total nitrogen retained in plant biomass was 4999 mg/m2/yr in sand, 7899 mg/m2/yr in loam and 8131 mg/m2/yr in gravel media. The average total phosphorus retained in plant biomass was 1980 mg/m2/yr in sand, 2073 mg/m2/yr in gravel and 4286 mg/m2/yr in loam.