Combined ozonation and aquatic macrophyte (Vallisneria natans) treatment of piggery effluent: Water matrix and antioxidant responses

•Combined ozonation and V. natans process improved nutrient contents.•Combined ozonation and V. natans process enhanced degradation of organic matter.•Low concentration of ozonated water increased V. natans growth by 50.5%.•High ozonation concentration disrupted the antioxidant system in V. natans.•A low ozone concentration of 10 mg L−1 was found to be optimal in this experiment.

The efficiency of the combined process of ozonation with Vallisneria natans to improve the quality of piggery effluent was investigated in this study, and the effects of ozonated water on the antioxidant responses of V. natans were explored. The effluent was treated with ozone at 10, 30 and 50 mg L−1 for 30 min in combination with V. natans for 28−d. Combined treatment was successful at removing inorganic nutrients and organic compounds from piggery effluent. Low ozone concentration treatment of water was optimal for the growth of V. natans, while exposure to high levels for long periods of time increased reactive oxygen species (ROS) and damaged their antioxidant systems. The results demonstrate that combined ozonation and submerged macrophytes treatment, can remove inorganic nutrients and organic compounds from piggery effluent, reducing the pollution into aquatic ecosystem.