Wastewater remediation by optimum dissolve oxygen enhanced by macrophytes in constructed wetlands

As new ways are being sought to treat wastewater in natural and constructed wetlands (CWs), the role of oxygen released by the macrophytes for degrading organic waste has inordinate significance. The current investigation assessed the optimum dissolve oxygen (DO) added by Typha latifolia and Phragmites australis when exposed to the optimum temperature and light intensity. A wireless network system (WSN) monitored the environmental conditions which was designed and deployed at the experimentation site. The plants were exposed to 16 different combinations of temperature and light intensity. The optimum DO in the rhizosphere of T. latifolia was recorded when plants were exposed to 30 °C and 35 °C implying that the optimum temperature range was 30-35 °C with 15 000 lx light intensity. The optimum DO in the rhizosphere of P. australis was recorded when plants were exposed to the 35 °C temperature and 10 000 lx to 15 000 lx light intensity. A strong correlation was found between DO, total chlorophyll and fresh plant biomass at the optimum temperature and light intensity combinations in both plants. The maximum DO in the substratum of CWs proved to play a significant role in reducing hydraulic retention time (HRT) in vegetated CWs.