Phytoremediation of Domestic Wastewater Using Coontail for Enhanced Biochemical Oxygen Demand Removal

Abstract

Domestic wastewater containing high organic loads can adversely affect receiving water bodies when discharged without adequate treatment. This study evaluated the potential of Coontail (Ceratophyllum demersum) as a low-cost, environmentally friendly phytoremediation agent to reduce Biochemical Oxygen Demand (BOD) in the effluent of the Centralised Domestic Wastewater Treatment System (SPALD-T) in Sungai Langka Village, Indonesia. Four reactors containing 10 L of wastewater were used: a control without plants (Reactor A) and three treatment reactors containing 50 g (Reactor B), 60 g (Reactor C), and 70 g (Reactor D) of Coontail. The experiment was conducted for 18 days, with BOD measurements taken on days 0, 6, 12, and 18, and pH and temperature monitored throughout the treatment period. The results showed that temperatures remained relatively stable at 25–27.5°C, whereas the planted reactors experienced an increase in pH to approximately 9–10. At the end of treatment, Reactor D achieved the highest BOD removal efficiency of 68.18%, followed by Reactors B and C at 66.67% and 63.64%, respectively. In contrast, the control reactor showed a negative removal efficiency of −27.27%. Statistical analysis indicated that treatment duration (p = 0.996) and plant biomass (p = 0.533) had no significant effects on BOD removal efficiency. Overall, Ceratophyllum demersum demonstrated potential as a sustainable post-treatment option to improve the quality of rural domestic wastewater effluent, although further optimisation of operating conditions and experimental replication are required.