Synthetic black water treatment by aeroponic cultivation of water spinach: Effect of the pump run time

Abstract

In this study, we report the treatment of simulated black water using a decentralised aeroponic system for the cultivation of water spinach. The effect of the pump run time on the treatment efficiency of black water at low temperature (15ºC±5ºC) in winter was systematically investigated. The results show that aeroponic cultivation process yields average chemical oxygen demand (COD) removal of 90.04%, ammonia nitrogen (NH4+-N) reduction of 35.02%, total nitrogen (TN) abatement of 28.14%, and total phosphorus (TP) elimination of 14.71%. The increase in the pump run time from stop time (min) to spray time (s) ration of 45:30 (QW3) to 15:30 (QW1) significantly promotes the efficiency of the COD, NH4+-N, TN, and TP removals. The sequence of the removal efficiency is as follows: QW1 (15:30)>QW2 (30:30)>QW3 (45:30). The higher efficiency of the COD and NH4+-N removals in QW1 is due to the enhanced action of aerobic microorganisms because of the increased amount of dissolved oxygen. We believe that this study provides a simple and potential option for decentralised sewage.