Exploring simultaneous elimination of dimethyl phthalate and nitrogen by a novel constructed wetlands coupled with dielectric barrier discharge plasma

Dimethyl phthalate (DMP) contamination, as an emerging pollutant, has posed acute health risks to humans due to its potential disruption in reproductive function and endocrine system disorders. In this study, the dielectric barrier discharge (DBD) plasma and constructed wetlands (CWs) were coupled to explore the simultaneous enhancement of DMP and nitrogen removal. The results showed that the coupling DBD plasm and CWs obtained an efficient elimination of DMP (87.7-97.3%), and nitrogen removal was also improved simultaneously with higher removal of ammonia nitrogen (97.7-98.6%) and total nitrogen (TN, 22.6-40.6%). TN removal efficiency was promoted gradually by increasing the concentration of influent DMP due to the DMP decomposition into small molecules by DBD plasma, which could provide carbon source to promote denitrification for subsequent CWs. The DMP degradation processes in the coupling system were reflected by three-dimensional excitation emission matrix fluorescence spectrum and gas chromatograph-mass spectrometer, which indicated that DMP solution was activated in the DBD plasma and more organic by-products were produced. Additionally, mono -methyl phthalate and phthalic acid were main degradation intermediate products of DMP. It indicated that coupling DBD plasma and CWs broke the carbon-oxygen single bond of DMP and converted it into less toxic compounds with less-refractory substances. This study provides assistant information on the application of the coupling DBD plasma and CWs technology for treating wastewater containing toxic and non-biodegradable contaminants.

Automated summary

In this study, the coupling of dielectric barrier discharge (DBD) plasma and constructed wetlands (CWs) was found to be an efficient method for the simultaneous removal of dimethyl phthalate (DMP) and nitrogen. The coupling system achieved high removal rates of DMP and nitrogen, and the degradation processes and intermediate products were analyzed. The results showed that the coupling of DBD plasma and CWs can break the carbon-oxygen single bond of DMP and convert it into less toxic and less refractory compounds. This study provides valuable information for the treatment of wastewater containing toxic and non-biodegradable contaminants using the coupling of DBD plasma and CWs technology.