The use of constructed wetlands (CWs) is a promising approach for the remediation of hydrocarbon-polluted wastewater. The amendments of CWs with nutrients, surfactants, and aeration enhances the removal of pollutants from wastewater. The objective of the present study was to explore the effect of external stimulants, i.e., nutrients, surfactant, and aeration on hydrocarbons degradation potential of CWs. The CWs mesocosms were developed by the vegetation of Phragmites australis and amendments with nutrients (20 mg l-1 N, 2.6 mg l-1 P, and 16.4 mg l-1 K), surfactant Tween 20 (0.2%, v/v), and aeration (7 mg l-1) for the remediation of diesel-spiked water (2%, w/v). The comparative analysis showed that the addition of nutrients, surfactant, and aeration individually enhanced total petroleum hydrocarbons (TPHs) reduction, and maximum TPHs reduction (88.4%) was achieved after 60 days in the mesocosms amended with the combination of nutrients, surfactant, and aeration. Among different individual treatments, the aeration (alone) also played a pivotal role in TPHs reduction (61%). The least (12%) reduction in TPHs was achieved in the mesocosms supplied with surfactant only. This study revealed that the combined application of nutrients, surfactant, and aeration in CWs enhanced its hydrocarbons degradation performance.
Keywords: Constructed wetlands; aeration; amendments; hydrocarbons; nutrients; surfactant.
The biodegradability of crude oil-polluted wastewater is not efficient. It is mainly due to the low bioavailability of hydrocarbons, and less amount of nutrients and dissolved oxygen in the wastewater. This study explores the importance of the amendments of nutrients, surfactant, and aeration on the enhanced performance of constructed wetlands (CWs) for the remediation of hydrocarbon-contaminated water. The application of nutrients, surfactant, and aeration in CWs not only enhanced hydrocarbon degradation and toxicity reduction but also improved plant growth.