Abstract
Duckweed (Spirodela polyrrhiza) has the potential to treat anaerobically digested swine wastewater (ADSW), but the effects of antibiotics and heavy metals in ADSW on the treatment performance and mechanism of Spirodela polyrrhiza are not clear. Herein, an experiment was conducted to investigate the effects of sulfamethazine (SMZ) and cupric ion on NH4+-N and total phosphorus (TP) removal from synthetic ADSW. The activity of superoxide dismutase (SOD) and the contents of photosynthetic pigments, vitamin E, and proteins in duckweed were also evaluated. Under the stress of SMZ, duckweed showed excellent removal efficiency of nutrients, and the results of SOD activity and photosynthetic pigments content indicated that duckweed had good tolerance to SMZ. Interestingly, a combined application of SMZ and cupric ion would inhibit the nutrient removal by duckweed, but significantly increased the contents of photosynthetic pigments, proteins, and vitamin E. In addition, the consequence indicated that high value-added protein and vitamin E products could be produced and harvested by cultivating duckweed in ADSW. Furthermore, possible degradation pathways of SMZ in the duckweed system were proposed based on the analysis with LC-MS/MS. This research proposed a novel view for using duckweed system to remove nutrients from ADSW and produce value-added products under the stress of SMZ and cupric ion.
Highlights
Introduction published maps and institutional affilCommercial feed additives are extensively used in livestock for the prevention of diseases
To further understand the biodegradation process of SMZ in the Spirodela polyrrhiza system, three possible degradation pathways were proposed in Figure 7 based on the detected intermediates and results reported in previous studies
SMZ and cupric ion-polluted anaerobically digested swine wastewater (ADSW) were treated by Spirodela polyrrhiza
Summary
Spirodela polyrrhiza were collected from a fresh water pond, Hunan, China (113◦ 09 S, 29◦ 38 E). Before the experiment, duckweed was cultivated in buckets that contained diluted. ADSW and put in an incubator at 25 ◦ C. The light intensity was 75 μmol m− 2 s− 1 , and the light period was 15:9 h for culture preparation. The wastewater was artificially synthesized with chemical reagents. The pH of the wastewater was adapted to 6.5 ± 0.5 via using 0.1 M.
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