Phytoremediation of urea fertilizer factory wastewater by teak (Tectona grandis)

Urea manufacturing discharge contains a high load of nitrogen, a pollutant which needs advanced technologies to be reduced to desirable levels. However, these advanced technologies are expensive due to the complex process and cost of chemicals and maintenance. Phytoremediation has been recently considered for N removal from various wastewaters. However, the common phytoremediation plants (reeds and grasses) are not able to remove N effectively due to the recyclable nature of N through decomposition processes. Therefore, they require periodic harvestings which impose a high cost on system. In this study, the growth and phytoremediation potential of teak (Tectona grandis), a tropical timber plant, to treat the urea manufacturing wastewater was evaluated. Eight month old teak seedlings received 4 different concentrations of N in bench-scale constructed wetlands every 4 days for 8 weeks. The solution volumes supplied to each container and plant biomass, N recovery, and tissue nutrient concentration were measured. Teak plants showed an escalation in wastewater N uptake with increasing amount of supplied N. Total dry weight was positively correlated with total N supplied. Teak seedlings showed a considerable potential for removing nitrogen when they were supplied with up to 5 g N per pot volume (4 dm³) during a two-month experiment.