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Constructed wetlands (CWs) inoculated with exogenous microbes have great potential for removing pollutants in adverse environments. The rapid loss of functional bacteria and the high cost of repeated additions of inoculum, however, limit the practical application of this technology. In this study, C–F2 immobilized bacteria (i.e., immobilized salt-tolerant bacterium Alishewanella sp. F2 incorporated with a carbon source) were developed and utilized in CWs for solving the above problems. A 60-day experiment demonstrated that bioaugmented CWs (Bio-CWs) with the addition of C–F2 immobilized bacteria into the bottom gravel layer of CW microcosms (B-CF2 treatment) exhibited high nitrogen removal efficiency under a saline condition (electrical conductivity of 15 mS/cm). We measured mean nitrate nitrogen (NO3−-N) and total nitrogen (TN) removal percentages of 97.8% and 88.1%, respectively, which were significantly (p < 0.05) higher than those in Bio-CWs with microbial inoculum (MI-F2 treatment, 63.5% and 78.2%) and unbioaugmented CWs (CK, 48.7% and 67.2%). The TN content of the entire plant was significantly (p < 0.05) increased in B-CF2 (636.06 mg/microcosm) compared with CK (372.06 mg/microcosm). The relative abundances of the genera Alishewanella (i.e., the exogenous bacterium, 5.5%), Clostridium-XlVa (8.8%) and Bacteroides (21.1%) in B-CF2 were significantly (p < 0.05) higher than in MI-F2 and CK, which improved the denitrification capacity of CWs. Overall, a high denitrification efficiency and durability were achieved in the newly developed Bio-CWs (i.e., B-CF2 treatment) with immobilized bacteria under saline conditions, which provides an alternative technology for the rapid removal of nitrogen from saline wastewater.
Xinyi Wang; Hui Zhu; Baixing Yan; Brian Shutes; Gary Bañuelos; Huiyang Wen; Rui Cheng. Improving denitrification efficiency in constructed wetlands integrated with immobilized bacteria under high saline conditions. Environmental Pollution 2021, 287, 117592 .
AMA StyleXinyi Wang, Hui Zhu, Baixing Yan, Brian Shutes, Gary Bañuelos, Huiyang Wen, Rui Cheng. Improving denitrification efficiency in constructed wetlands integrated with immobilized bacteria under high saline conditions. Environmental Pollution. 2021; 287 ():117592.
Chicago/Turabian StyleXinyi Wang; Hui Zhu; Baixing Yan; Brian Shutes; Gary Bañuelos; Huiyang Wen; Rui Cheng. 2021. "Improving denitrification efficiency in constructed wetlands integrated with immobilized bacteria under high saline conditions." Environmental Pollution 287, no. : 117592.
Nitrogen removal in constructed wetlands (CWs) may be inhibited by salinity. The clarification of the response of microbial community to salt stress is a premise for developing strategies to improve nitrogen removal efficiency in CWs under saline conditions. Results showed that the ammonia nitrogen (NH4+-N), nitrate nitrogen (NO3−-N), and total nitrogen (TN) removal percentages significantly (p < 0.05) decreased in CWs with increasing salinity. The structure and abundance of the microbial community varied with different salinity levels and sampling depths in CWs. Compared with a non-saline condition, the abundances of some bacteria with a denitrification function (e.g., Arthrobacter) significantly (p < 0.05) decreased in CWs under saline conditions (i.e., EC of 15 and 30 mS/cm). Aerobic bacteria (e.g., Sphingomonas) exhibited more abundance in soil and upper gravel samples in CWs than those in bottom gravel samples, while the abundance of some denitrifying bacteria (e.g., Thauera and Azoarcus) was significantly (p < 0.05) higher in bottom gravel samples compared with soil and upper gravel samples, respectively. This study provides both microbiological evidence for explaining the impact of salt stress on nitrogen removal in CWs and scientific reference for developing enhanced strategies to improve the nitrogen removal capacity of CWs.
Xinyi Wang; Hui Zhu; Baixing Yan; Brian Shutes; Gary Bañuelos; Rui Cheng. Response of the microbial community to salt stress and its stratified effect in constructed wetlands. Environmental Science and Pollution Research 2021, 28, 18089 -18101.
AMA StyleXinyi Wang, Hui Zhu, Baixing Yan, Brian Shutes, Gary Bañuelos, Rui Cheng. Response of the microbial community to salt stress and its stratified effect in constructed wetlands. Environmental Science and Pollution Research. 2021; 28 (14):18089-18101.
Chicago/Turabian StyleXinyi Wang; Hui Zhu; Baixing Yan; Brian Shutes; Gary Bañuelos; Rui Cheng. 2021. "Response of the microbial community to salt stress and its stratified effect in constructed wetlands." Environmental Science and Pollution Research 28, no. 14: 18089-18101.
Constructed wetlands integrated with microbial fuel cells (MFC-CWs) have been recently developed and tested for removing antibiotics. However, the effects of carbon source availability, electron transfer flux and cathode conditions on antibiotics removal in MFC-CWs through co-metabolism remained unclear. In this study, four experiments were conducted in MFC-CW microcosms to investigate the influence of carbon source species and concentrations, external resistance and aeration duration on sulfamethoxazole (SMX) and tetracycline (TC) removal and bioelectricity generation performance. MFC-CWs supplied with glucose as carbon source outperformed other carbon sources, and moderate influent glucose concentration (200 mg L−1) resulted in the best removal of both SMX and TC. Highest removal percentages of SMX (99.4%) and TC (97.8%) were obtained in MFC-CWs with the external resistance of 700 Ω compared to other external resistance treatments. SMX and TC removal percentages in MFC-CWs were improved by 4.98% and 4.34%, respectively, by increasing the aeration duration to 12 h compared to no aeration. For bioelectricity generation performance, glucose outperformed sodium acetate, sucrose and starch, with the highest voltages of 386 ± 20 mV, maximum power density (MPD) of 123.43 mW m−3, and coulombic efficiency (CE) of 0.273%. Increasing carbon source concentrations from 100 to 400 mg L−1, significantly (p < 0.05) increased the voltage and MPD, but decreased the internal resistance and CE. The highest MPD was obtained when the external resistance (700 Ω) was close to the internal resistance (600.11 Ω). Aeration not only improved the voltage and MPD, but also reduced the internal resistance. This study demonstrates that carbon source species and concentrations, external resistances and aeration duration, all play vital roles in regulating SMX and TC removal in MFC-CWs.
Huiyang Wen; Hui Zhu; Yingying Xu; Baixing Yan; Brian Shutes; Gary Bañuelos; Xinyi Wang. Removal of sulfamethoxazole and tetracycline in constructed wetlands integrated with microbial fuel cells influenced by influent and operational conditions. Environmental Pollution 2020, 272, 115988 .
AMA StyleHuiyang Wen, Hui Zhu, Yingying Xu, Baixing Yan, Brian Shutes, Gary Bañuelos, Xinyi Wang. Removal of sulfamethoxazole and tetracycline in constructed wetlands integrated with microbial fuel cells influenced by influent and operational conditions. Environmental Pollution. 2020; 272 ():115988.
Chicago/Turabian StyleHuiyang Wen; Hui Zhu; Yingying Xu; Baixing Yan; Brian Shutes; Gary Bañuelos; Xinyi Wang. 2020. "Removal of sulfamethoxazole and tetracycline in constructed wetlands integrated with microbial fuel cells influenced by influent and operational conditions." Environmental Pollution 272, no. : 115988.
Organic matter and NH4+-N are two major pollutants in domestic sewage. This study evaluated the influence of plant and circuit operation mode on the performance of constructed wetlands integrated with microbial fuel cells (CW-MFCs) and investigated the removal mechanisms of organic matter and nitrogen. Better chemical oxygen demand (COD) removal was achieved in closed-circuit CW-MFCs regardless of planting or not, with average removal efficiencies of 83.19–86.28% (closed-circuit CW-MFCs) and 76.54–83.19% (open-circuit CW-MFCs), respectively. More than 70% organic matter was removed in the anaerobic region of all CW-MFCs. In addition, the planted CW-MFCs outperformed the unplanted CW-MFCs in ammonium, nitrate, and total nitrogen removal irrespective of circuit connection or not, for example, the NH4+-N removal efficiencies of 95.91–96.82% were achieved in planted CW-MFCs compared with 56.54–59.95% achieved by unplanted CW-MFCs. Besides, 33.14–55.69% of NH4+-N was removed in the anaerobic region. Throughout the experiment, the average voltages of planted and unplanted CW-MFCs were 264 mV and 108 mV, with the corresponding maximum voltage output of 544 mV and 321 mV, respectively. Furthermore, planted CW-MFCs, simultaneously producing a peak power density of 92.05 mW m−3 with a coulombic efficiency of 0.50%, exhibited better than unplanted CW-MFCs (3.29 mW m−3 and 0.21%, respectively) in bioelectricity generation characteristics. Graphical abstract
Huiyang Wen; Hui Zhu; Baixing Yan; Brian Shutes; Xiangfei Yu; Rui Cheng; Xin Chen; Xinyi Wang. Constructed wetlands integrated with microbial fuel cells for COD and nitrogen removal affected by plant and circuit operation mode. Environmental Science and Pollution Research 2020, 28, 3008 -3018.
AMA StyleHuiyang Wen, Hui Zhu, Baixing Yan, Brian Shutes, Xiangfei Yu, Rui Cheng, Xin Chen, Xinyi Wang. Constructed wetlands integrated with microbial fuel cells for COD and nitrogen removal affected by plant and circuit operation mode. Environmental Science and Pollution Research. 2020; 28 (3):3008-3018.
Chicago/Turabian StyleHuiyang Wen; Hui Zhu; Baixing Yan; Brian Shutes; Xiangfei Yu; Rui Cheng; Xin Chen; Xinyi Wang. 2020. "Constructed wetlands integrated with microbial fuel cells for COD and nitrogen removal affected by plant and circuit operation mode." Environmental Science and Pollution Research 28, no. 3: 3008-3018.
Cyanobacterial harmful algal blooms and microcystins (MCs) pollution pose serious threat to aquatic ecosystem and public health. Planted and unplanted constructed wetlands (CWs) filled with four substrates (i.e., gravel (G-CWs), ceramsite (C-CWs), iron-carbon (I-CWs) and slag (S-CWs)) were established to evaluate nutrients and a typical MCs variant (i.e., MC-LR) removal efficiency from eutrophic water affected by the presence of plant and different substrate. The response of the microbial community to the above factors was also analyzed in this study. The results indicate that the presence of plant can generally enhance nutrients and MC-LR removal efficiency in CWs, except for I-CWs. Throughout the experiment, all CWs exhibited good nitrogen removal efficiency with removal percentages exceeding 90%; TP and MC-LR average removal efficiency of C-CWs and I-CWs were greater than G-CWs and S-CWs irrespective of the presence of plant. The best MC-LR removal efficiency under different MC-LR loads was observed in planted C-CWs (ranged from 91.56%-95.16%). Except for I-CWs, the presence of plant can enhance relative abundances of functional microorganisms involved in nutrients removal (e.g., Comamonadaceae and Planctomycetaceae) and MCs degradation (e.g., Burkholderiaceae). The microbial community diversity of I-CWs was simplified, while the relative abundance of Proteobacteria was highest in this study. The highest relative abundances of Comamonadaceae, Planctomycetaceae and Burkholderiaceae were observed in planted C-CWs. Overall, ceramisite and iron-carbon were more suitable to be applied in CWs for nutrients and MC-LR removal. This study provides a theoretical basis for practical application of CWs in eutrophication and MCs pollution control.
Rui Cheng; Hui Zhu; Brian Shutes; Baixing Yan. Treatment of microcystin (MC-LR) and nutrients in eutrophic water by constructed wetlands: Performance and microbial community. Chemosphere 2020, 263, 128139 .
AMA StyleRui Cheng, Hui Zhu, Brian Shutes, Baixing Yan. Treatment of microcystin (MC-LR) and nutrients in eutrophic water by constructed wetlands: Performance and microbial community. Chemosphere. 2020; 263 ():128139.
Chicago/Turabian StyleRui Cheng; Hui Zhu; Brian Shutes; Baixing Yan. 2020. "Treatment of microcystin (MC-LR) and nutrients in eutrophic water by constructed wetlands: Performance and microbial community." Chemosphere 263, no. : 128139.
A salt-tolerant denitrifying bacterium strain F2 was isolated from seawall muddy water in Dalian City, Liaoning Province, China. Strain F2 was identified by morphological observations, physiological and biochemical characteristics and 16 S rDNA identification. The salt tolerance of strain F2 was verified and the factors affecting the removal ability of strain F2 to nitrous nitrogen (NO2 –N) and nitrate nitrogen (NO3 –N) in saline conditions were investigated. Strain F2 was identified as Alishewanella sp., named Alishewanella sp. F2. Strain F2 can tolerate NaCl concentrations up to 70 g/L, and its most efficient denitrification capacity was observed at NaCl concentrations of 0−30 g/L. In the medium with NaCl concentrations of 0−30 g/L, strain F2 exhibited high removal efficiencies of NO2 –N and NO3 –N, with the removal percentages for both NO2 –N and NO3 –N of approximately 99%. In saline conditions with 30 g/L NaCl, the optimum culture pH, NaNO2 initial concentrations and inoculation sizes of strain F2 were 8−10, 0.4−0.8 g/L and 5−7%, respectively. Strain F2 was highly effective in removing NO2 –N and NO3 –N in saline conditions, and it has a good application potential in saline wastewater treatment.
Rui Cheng; Xinyi Wang; Hui Zhu; Baixing Yan; Brian Shutes; Yingying Xu; Baorong Fu; Huiyang Wen. Isolation and characterization of a salt-tolerant denitrifying bacterium Alishewanella sp. F2 from seawall muddy water. Scientific Reports 2020, 10, 1 -11.
AMA StyleRui Cheng, Xinyi Wang, Hui Zhu, Baixing Yan, Brian Shutes, Yingying Xu, Baorong Fu, Huiyang Wen. Isolation and characterization of a salt-tolerant denitrifying bacterium Alishewanella sp. F2 from seawall muddy water. Scientific Reports. 2020; 10 (1):1-11.
Chicago/Turabian StyleRui Cheng; Xinyi Wang; Hui Zhu; Baixing Yan; Brian Shutes; Yingying Xu; Baorong Fu; Huiyang Wen. 2020. "Isolation and characterization of a salt-tolerant denitrifying bacterium Alishewanella sp. F2 from seawall muddy water." Scientific Reports 10, no. 1: 1-11.
Influent chemical oxygen demand (COD)/nitrogen (N) ratio plays a crucial role in the biogeochemical cycle of carbon and N in constructed wetlands (CWs). This study evaluated the greenhouse gas (GHG) emissions, pollutant removal efficiency and specific microbial gene abundances in subsurface flow CWs (SSFCWs) under various influent COD/N ratios. The GHG emissions and pollutant removal efficiency were markedly affected by influent COD/N ratios. The effluent concentrations of nitrate decreased with the increase of influent COD/N ratios, while the trend was completely reversed for COD. The lowest effluent total nitrogen concentration was observed with a COD/N ratio of 10. For GHG emissions, the CO2 fluxes increased with increasing influent COD/N ratios. However, the lowest CH4 (- 42.49 μg/m2/h) and N2O fluxes (31.77 μg/m2/h) were both observed under a COD/N ratio of 10. A significantly positive correlation between N2O fluxes and abundance of nirS and (nirS + nirK) (r2 = 0.64 and 0.61, p < 0.05, respectively) was observed. The highest ratio of nosZ/(nirS + nirK) observed at a COD/N ratio of 10 suggested the dominance of nosZ-harboring denitrifiers communities. The highest ratio of nosZ/(nirS + nirK) was also consistent with the lowest N2O flux observed at a COD/N ratio of 10. For the global warming potential (GWP), the lowest value (52.89 mg/m2/h) was observed at a COD/N ratio of 10. Overall, the influent COD/N ratio of 10 was determined to be optimal for simultaneously achieving relatively higher pollutant removal efficiency and lower GHG emissions.
Xin Chen; Hui Zhu; Baixing Yan; Brian Shutes; Liping Tian; Huiyang Wen. Optimal influent COD/N ratio for obtaining low GHG emissions and high pollutant removal efficiency in constructed wetlands. Journal of Cleaner Production 2020, 267, 122003 .
AMA StyleXin Chen, Hui Zhu, Baixing Yan, Brian Shutes, Liping Tian, Huiyang Wen. Optimal influent COD/N ratio for obtaining low GHG emissions and high pollutant removal efficiency in constructed wetlands. Journal of Cleaner Production. 2020; 267 ():122003.
Chicago/Turabian StyleXin Chen; Hui Zhu; Baixing Yan; Brian Shutes; Liping Tian; Huiyang Wen. 2020. "Optimal influent COD/N ratio for obtaining low GHG emissions and high pollutant removal efficiency in constructed wetlands." Journal of Cleaner Production 267, no. : 122003.
This study focused on the effect of saline and alkaline stress on six typical wetland plant species during seed germination and early seedling growth stages. Based on the indicators of germination, seedling growth and ionic absorption in seedlings, relatively saline and alkaline tolerant plant species were selected and tolerance mechanism was discussed. Results showed that the existence of saline and alkaline stress inhibited the capacity of germination and early seedling growth of most tested plant species to varying degrees, therein effects of saline-alkaline stress were greater than saline stress. Based on the results of principal component analysis (PCA), germination percentage, K+ content, plant height, Na+ content and Na+/K+ ratios can be selected as representative indicators for saline and alkaline tolerance evaluation during seed germination and early seedling growth stages. Among tested species, Juncus effusus and Vetiveria zizanioides exhibited relatively higher saline and alkaline tolerant capacity during their seed germination and early seedling growth. Additionally, both species increase K+ accumulation and retain lower Na+/K+ ratios, which might be their tolerance mechanisms at ion level. In conclusion, V. zizaniodes and J. effusus were recommended as potential plant species for restoring degraded saline-alkaline wetlands and/or establishing constructed wetlands for treating saline wastewater.
Xinyi Wang; Rui Cheng; Hui Zhu; Xianwei Cheng; Brian Shutes; Baixing Yan. Seed germination and early seedling growth of six wetland plant species in saline-alkaline environment. International Journal of Phytoremediation 2020, 22, 1185 -1194.
AMA StyleXinyi Wang, Rui Cheng, Hui Zhu, Xianwei Cheng, Brian Shutes, Baixing Yan. Seed germination and early seedling growth of six wetland plant species in saline-alkaline environment. International Journal of Phytoremediation. 2020; 22 (11):1185-1194.
Chicago/Turabian StyleXinyi Wang; Rui Cheng; Hui Zhu; Xianwei Cheng; Brian Shutes; Baixing Yan. 2020. "Seed germination and early seedling growth of six wetland plant species in saline-alkaline environment." International Journal of Phytoremediation 22, no. 11: 1185-1194.
Biochar was added into constructed wetlands (CWs) as an amendment to the main substrate (i.e., coarse gravel) for improving the removal efficiency of pollutants and mitigating greenhouse gas (GHG) emissions. Four types of mesocosm-scale CWs, i.e., unamended subsurface batch CWs (SSBCWs) and surface batch CWs (SBCWs), and biochar-amended SSBCWs and SBCWs, were established in this study. The SSBCWs outperformed SBCWs in both removing pollutants (particularly COD, NO3−-N and TN) and reducing the global warming potential (GWP), irrespective of adding biochar or not. The amendment of biochar improved the efficacy of CWs for removing pollutants and mitigating GHG emissions in both configurations of CWs. The highest removal percentages of COD (89.6%), NO3−-N (89.2%) and TN (92.5%) were obtained in biochar-amended SSBCWs, followed by unamended SSBCWs, biochar-amended SBCWs, and unamended SBCWs. The lowest GWP (5.252 mg/m2/h) was simultaneously obtained in biochar-amended SSBCWs, and the addition of biochar reduced GWP by 57.3% and 3.0% for SSBCWs and SBCWs, respectively. The abatement of GHG by biochar addition was mainly reflected in reduction of N2O fluxes, while the CH4 fluxes were promoted and the CO2 fluxes were not affected. The quantitative PCR results indicate that the reduced N2O fluxes in biochar-amended CWs were driven by the enhanced transcription of the nosZ gene and the ratio of nosZ/(nirS + nirK). This study demonstrates that biochar-amended SSBCWs can be an ideal alternative for design and application of CWs for removing pollutants and abating GHG emissions in the future.
Xin Chen; Hui Zhu; Gary Bañuelos; Brian Shutes; Baixing Yan; Rui Cheng. Biochar reduces nitrous oxide but increases methane emissions in batch wetland mesocosms. Chemical Engineering Journal 2020, 392, 124842 .
AMA StyleXin Chen, Hui Zhu, Gary Bañuelos, Brian Shutes, Baixing Yan, Rui Cheng. Biochar reduces nitrous oxide but increases methane emissions in batch wetland mesocosms. Chemical Engineering Journal. 2020; 392 ():124842.
Chicago/Turabian StyleXin Chen; Hui Zhu; Gary Bañuelos; Brian Shutes; Baixing Yan; Rui Cheng. 2020. "Biochar reduces nitrous oxide but increases methane emissions in batch wetland mesocosms." Chemical Engineering Journal 392, no. : 124842.
The inhibition of salt stress on plant and microbial functions has led to the reduction of nitrogen removal capacity of constructed wetlands (CWs) under saline conditions. The mechanisms and effectiveness of bioaugmented CW (Bio-CW) microcosms with a salt-tolerant microbial inoculum were evaluated for nitrogen removal at different salinity levels. The results showed that the denitrification capacity of CWs was improved under saline conditions by adding the salt-tolerant microbial inoculum. At an EC of 15 mS/cm, the removal percentages of ammonia nitrogen (NH4+-N) and total nitrogen (TN) in Bio-CW microcosms (95.7% and 99.4%) on Day 5 were significantly (p < 0.05) higher than that in unbioaugmented CW (un-Bio-CW) microcosms (68.5% and 76.4%), respectively. The high throughput sequencing data of substrate samples indicated that the microbial community in the CWs was changed by the addition of the salt-tolerant microbial inoculum and the frequency of bacteria with nitrogen removal function was increased in the CWs. Furthermore, both growth and the TN accumulation capacity of plants in Bio-CW microcosms were promoted compared with the un-Bio-CW microcosms. In conclusion, the addition of the salt-tolerant microbial inoculum can enhance the nitrogen removal efficiency of CWs under saline condition via boosting the function of both microorganisms and plants.
Xinyi Wang; Hui Zhu; Baixing Yan; Brian Shutes; Gary Bañuelos; Huiyang Wen. Bioaugmented constructed wetlands for denitrification of saline wastewater: A boost for both microorganisms and plants. Environment International 2020, 138, 105628 .
AMA StyleXinyi Wang, Hui Zhu, Baixing Yan, Brian Shutes, Gary Bañuelos, Huiyang Wen. Bioaugmented constructed wetlands for denitrification of saline wastewater: A boost for both microorganisms and plants. Environment International. 2020; 138 ():105628.
Chicago/Turabian StyleXinyi Wang; Hui Zhu; Baixing Yan; Brian Shutes; Gary Bañuelos; Huiyang Wen. 2020. "Bioaugmented constructed wetlands for denitrification of saline wastewater: A boost for both microorganisms and plants." Environment International 138, no. : 105628.
The increasing discharge of wastewater containing inorganic salts, sometimes accompanied by high pH, has been a worldwide environmental problem. Constructed wetlands (CWs) are considered a viable technology for treating saline and/or alkaline wastewater provided that saline-alkaline tolerant plant species are selected and applied. The influence of both saline and alkaline stress on four wetland plant species during their seed germination, early growth, vegetative propagation and continued growth stages was evaluated by three experiments. Principal component analysis (PCA) was conducted for selecting representative indicators for evaluating the saline and alkaline tolerance of plants during vegetative propagation and plant growth stages. The saline and alkaline stress inhibited the vegetative propagation and plant growth of all tested plant species to varying degrees, therein the influences of saline-alkaline stress on plants were more marked than saline stress. The length of new roots, Na+ accumulation in plant tissue, Na+/K+ ratios in aerial tissue and the total dry biomass were selected as most representative indicators for evaluating the saline and alkaline tolerance of plants. Iris sibirica and Lythrum salicaria showed better saline and alkaline tolerance ability among tested species and could be grown in CWs for treating saline and/or alkaline wastewater.
Rui Cheng; Hui Zhu; Xianwei Cheng; Brian Shutes; Baixing Yan. Saline and Alkaline Tolerance of Wetland Plants—What are the Most Representative Evaluation Indicators? Sustainability 2020, 12, 1913 .
AMA StyleRui Cheng, Hui Zhu, Xianwei Cheng, Brian Shutes, Baixing Yan. Saline and Alkaline Tolerance of Wetland Plants—What are the Most Representative Evaluation Indicators? Sustainability. 2020; 12 (5):1913.
Chicago/Turabian StyleRui Cheng; Hui Zhu; Xianwei Cheng; Brian Shutes; Baixing Yan. 2020. "Saline and Alkaline Tolerance of Wetland Plants—What are the Most Representative Evaluation Indicators?" Sustainability 12, no. 5: 1913.
This study evaluated the removal efficiencies of sulfamethoxazole (SMX), tetracycline (TC) and their common co-existing contaminants, i.e., chemical oxygen demand (COD) and nitrogen in constructed wetlands integrated with microbial fuel cells (MFC-CWs), as affected by plant, circuit operation mode and influent antibiotic loads. The results demonstrated that MFC-CWs with plant and circuit connection exhibited the best performance in SMX and TC removal. The removal percentages for SMX and TC were 99.70–100% and 99.66–99.85% at HRT of 1 d, respectively, in MFC-CWs with plant and circuit connection when the influent SMX and TC concentrations were 5–100 μg L−1 and 5–50 μg L−1. The removal efficiencies of both SMX and TC were mainly enhanced by the circuit connection, compared to the plants. The presence of plant and circuit connection also accelerated the accumulation of SMX and TC in electrode layers, and the residues of both antibiotics in the anode layer were higher than in the cathode layer. Besides, closed-circuit MFC-CWs showed better COD removal performance than open-circuit MFC-CWs, irrespective of the increasing influent COD and antibiotic concentrations. The NH4+-N removal in MFC-CWs was mainly promoted by the presence of plants and decreased with increasing influent antibiotic concentrations. Additionally, the bioelectricity generation of planted MFC-CWs was better than in unplanted systems. The coulombic efficiencies in both planted and unplanted MFC-CWs decreased with increasing influent antibiotic concentrations. In summary, MFC-CWs with plant and circuit connection have potential for the treatment of wastewater containing SMX and TC.
Huiyang Wen; Hui Zhu; Baixing Yan; Yingying Xu; Brian Shutes. Treatment of typical antibiotics in constructed wetlands integrated with microbial fuel cells: Roles of plant and circuit operation mode. Chemosphere 2020, 250, 126252 .
AMA StyleHuiyang Wen, Hui Zhu, Baixing Yan, Yingying Xu, Brian Shutes. Treatment of typical antibiotics in constructed wetlands integrated with microbial fuel cells: Roles of plant and circuit operation mode. Chemosphere. 2020; 250 ():126252.
Chicago/Turabian StyleHuiyang Wen; Hui Zhu; Baixing Yan; Yingying Xu; Brian Shutes. 2020. "Treatment of typical antibiotics in constructed wetlands integrated with microbial fuel cells: Roles of plant and circuit operation mode." Chemosphere 250, no. : 126252.
A salt-tolerant denitrifying bacterium F1 was isolated in this study, which has high nitrite (NO2−–N) and nitrate (NO3−–N) removal abilities. The salt tolerance capacity of strain F1 was further verified and the effects of initial pH, initial NaNO2 concentration and inoculation size on the denitrification capacity of strain F1 under saline conditions were evaluated. Strain F1 was identified as Pannonibacter phragmitetus and named Pannonibacter phragmitetus F1. This strain can tolerate NaCl concentrations up to 70 g/L, and its most efficient denitrification capacity was observed at NaCl concentrations of 0–10 g/L. Under non-saline condition, the removal percentages of NO2−–N and NO3−–N by strain Pannonibacter phragmitetus F1 at pH of 10 and inoculation size of 5% were 100% and 83%, respectively, after cultivation for 5 days. Gas generation was observed during the cultivation, indicating that an efficient denitrification performance was achieved. When pH was 10 and the inoculation size was 5%, both the highest removal percentages of NO2−–N (99%) and NO3−–N (95%) by strain Pannonibacter phragmitetus F1 were observed at NaCl concentration of 10 g/L. When the NaCl concentration was 10 g/L, strain Pannonibacter phragmitetus F1 can adapt to a wide range of neutral and alkaline environments (pH of 7–10) and is highly tolerant of NaNO2 concentration (0.4–1.6 g/L). In conclusion, strain Pannonibacter phragmitetus F1 has a great potential to be applied in the treatment of saline wastewater containing high nitrogen concentrations, e.g. coastal aquaculture wastewater.
Xinyi Wang; Hui Zhu; Brian Shutes; Baorong Fu; Baixing Yan; Xiangfei Yu; Huiyang Wen; Xin Chen. Identification and denitrification characteristics of a salt-tolerant denitrifying bacterium Pannonibacter phragmitetus F1. AMB Express 2019, 9, 1 -11.
AMA StyleXinyi Wang, Hui Zhu, Brian Shutes, Baorong Fu, Baixing Yan, Xiangfei Yu, Huiyang Wen, Xin Chen. Identification and denitrification characteristics of a salt-tolerant denitrifying bacterium Pannonibacter phragmitetus F1. AMB Express. 2019; 9 (1):1-11.
Chicago/Turabian StyleXinyi Wang; Hui Zhu; Brian Shutes; Baorong Fu; Baixing Yan; Xiangfei Yu; Huiyang Wen; Xin Chen. 2019. "Identification and denitrification characteristics of a salt-tolerant denitrifying bacterium Pannonibacter phragmitetus F1." AMB Express 9, no. 1: 1-11.
Anthropogenic activities and natural causes contribute to the increase of the area and degree of degraded saline wetlands in arid/semi‐arid and coastal regions. The objective of this study was to determine the salt tolerance of seven aquatic plant species during asexual reproduction and at continued growth stage. The species were exposed to five salinity treatments from 0.3 (control) to 20 dS/m during the 30 day experiment. Data were collected on asexual reproduction and growth, chlorophyll content index in leaves, Na+ and K+ concentrations and total nitrogen (TN) and total phosphorus (TP) concentrations in above‐ground biomass (AGB) and below‐ground biomass (BGB). The results of this study showed that: 1) the increase of salinity (especially at a salinity level of EC≥15 dS/m) generally inhibited the capacity for asexual reproduction and reduced the chlorophyll content index in leaves; 2) total dry biomass of plants was significantly and negatively related to asexual reproduction of plants; 3) species‐specific salt tolerance mechanisms were shown as indicated by the Na+ and K+ concentrations and Na+/K+ ratios in different parts of plants; and 4) the absorption of TN and TP were inhibited at high salinity level (i.e., EC=20 dS/m) in AGB and BGB of most tested plant species. Salinity may enhance plant uptake of TN and TP under certain condition (e.g., EC at 5, 10 and 15 dS/m). In general, giant reed (Arundo donax) and alligator weed (Alternanthera philoxeroides) showed better asexual reproduction and growth capacity under high salt stress, and they should be considered as potential plant species to be used in the restoration of degraded saline wetlands and/or in treatment wetlands for decontaminating saline wastewater. This article is protected by copyright. All rights reserved.
Xin Chen; Xianwei Cheng; Hui Zhu; Gary Bañuelos; Brian Shutes; Haitao Wu. Influence of salt stress on propagation, growth and nutrient uptake of typical aquatic plant species. Nordic Journal of Botany 2019, 37, 1 .
AMA StyleXin Chen, Xianwei Cheng, Hui Zhu, Gary Bañuelos, Brian Shutes, Haitao Wu. Influence of salt stress on propagation, growth and nutrient uptake of typical aquatic plant species. Nordic Journal of Botany. 2019; 37 (12):1.
Chicago/Turabian StyleXin Chen; Xianwei Cheng; Hui Zhu; Gary Bañuelos; Brian Shutes; Haitao Wu. 2019. "Influence of salt stress on propagation, growth and nutrient uptake of typical aquatic plant species." Nordic Journal of Botany 37, no. 12: 1.
The aim of this study was to track the fate of nitrogen derived from fertilizer (Ndff) after fertilization. A field in situ experiment covering an entire growing season by using 15N-doubly-labelled urea as fertilizer was conducted at a paddy field inSanjiang Plain in northeastern China. Results showed that approximately 70% of total nitrogen (TN) output load was from Ndff, and the lateral seepage contributed ~47% and ~40% of TN and Ndff output loads, and the rest of the TN and Ndff output loads were derived from runoff and artificial drainage. The Ndff contents in paddy root, stalk, foliage and kernel increased with increasing fertilization dosages – from the tillering stage to mature stage. Ndff accumulated in the root, stalk and foliage during tillering and the milk stage migrated to the kernel in the mature stage. Most of the residual Ndff in soil was distributed in the top layer (0-10 cm). Crop utilization and gaseous loss were the main fates of Ndff in the paddy field. The proportion of crop utilization with an average value of ~37% increased from 30.29% to 43.52% with increasing fertilization dosages, while the proportion of gaseous loss decreased from 49.61% to 32.74% with increasing fertilization dosages. 180 kg N hm-2 was the optimum fertilization dosage for crop utilization rate and non-point source pollution control in the rice-growing area of Sanjiang Plain.
Xiangfei Yu; Yingying Xu; Hui Zhu; Brian Shutes; Baixing Yan; Xin Chen; Rui Cheng. Tracking the Fate of Fertilizer Nitrogen in a Paddy Rice Field Using Isotope Technology. Polish Journal of Environmental Studies 2019, 29, 419 -428.
AMA StyleXiangfei Yu, Yingying Xu, Hui Zhu, Brian Shutes, Baixing Yan, Xin Chen, Rui Cheng. Tracking the Fate of Fertilizer Nitrogen in a Paddy Rice Field Using Isotope Technology. Polish Journal of Environmental Studies. 2019; 29 (1):419-428.
Chicago/Turabian StyleXiangfei Yu; Yingying Xu; Hui Zhu; Brian Shutes; Baixing Yan; Xin Chen; Rui Cheng. 2019. "Tracking the Fate of Fertilizer Nitrogen in a Paddy Rice Field Using Isotope Technology." Polish Journal of Environmental Studies 29, no. 1: 419-428.
Greenhouse gas (GHG) emissions from constructed wetlands (CWs) have raised environmental concern and thus offset their environmental and ecological benefits. This study evaluated the influence of plant species, i.e., Canna indica (C. indica), Cyperus alternifolius (C. alternifolius), Phragmites australis (P. australis) and unplanted control, on GHG emissions, pollutant removal and associated microbial abundance in subsurface flow constructed wetland (SSFCW) mesocosms. C. indica outperformed the other tested plant species in pollutant removal, and the presence of plants irrespective of species enhanced the removal efficiencies of nitrogen, phosphorus and organics in SSFCW mesocosms compared to unplanted control. The greatest carbon dioxide (CO2) flux (582.01 ± 89.25 mg/m2/h), methane (CH4) flux (21.88 ± 2.51 μg/m2/h) and nitrous oxide (N2O) flux (37.27 ± 15.82 μg/m2/h) were observed in mesocosms planted with C. indica, P. australis and C.alternifolius, respectively. Unexpectedly, the mcrA and pmoA genes were not detected in any mesocosms. For denitrifiers, the N2O fluxes showed a significantly (p < 0.05) positive correlation with nirS and nirK genes abundance. The abundance of nosZ gene (ranged from 0.18 × 104 to 0.75 × 104 copies/mg gravel) and nosZ/(nirS + nirK) (ranged from 1.29 × 10−4 to 2.12 × 10−4 copies/mg gravel) in this study was lower than that in most reported studies. Regarding the global warming potential (GWP), the lowest value was observed in mesocosms planted with C. indica. In conclusion, C. indica is selected as the optimal plant species in this study due to its lower GWP and excellent pollutant removal performance.
Xin Chen; Hui Zhu; Baixing Yan; Brian Shutes; Defeng Xing; Gary Banuelos; Rui Cheng; Xinyi Wang. Greenhouse gas emissions and wastewater treatment performance by three plant species in subsurface flow constructed wetland mesocosms. Chemosphere 2019, 239, 124795 .
AMA StyleXin Chen, Hui Zhu, Baixing Yan, Brian Shutes, Defeng Xing, Gary Banuelos, Rui Cheng, Xinyi Wang. Greenhouse gas emissions and wastewater treatment performance by three plant species in subsurface flow constructed wetland mesocosms. Chemosphere. 2019; 239 ():124795.
Chicago/Turabian StyleXin Chen; Hui Zhu; Baixing Yan; Brian Shutes; Defeng Xing; Gary Banuelos; Rui Cheng; Xinyi Wang. 2019. "Greenhouse gas emissions and wastewater treatment performance by three plant species in subsurface flow constructed wetland mesocosms." Chemosphere 239, no. : 124795.
Chlorpyrifos (CP) is frequently detected in agricultural effluent worldwide. Both CP and its hydrolytic metabolite 3,5,6-trichloro-2-pyridinol (TCP) can cause serious environment hazards, and require removal before discharged into rivers and/or lakes. The effectiveness and main influencing factors of CP and TCP removal in mesocosm-scale subsurface flow constructed wetlands (SSFCWs) were evaluated. Results indicated that CP in SSFCWs reduced to < detection limit in 4 d and TCP to 2 μg L-1 in 8 d. Higher influent CP concentrations lengthened the degradation process for both CP and TCP. The presence of co-existing inorganic nutrients restrained the degradation of CP during the hydraulic retention time of 2 h - 2 d. A higher pH resulting from the deterioration of soda saline-alkaline level accelerated the degradation of CP through the hydrolysis process. The SSFCWs with slag operating for another 88 d (i.e., 11 trails with HRT of 8 d for each trial) revealed a better and more stable treatment performance compared with previous studies. The results of this study demonstrated the positive feasibility of using SSFCWs with slag for the decontamination of CP-associated agricultural drainage or stormwater runoff.
Xiangfei Yu; Hui Zhu; Baixing Yan; Yingying Xu; Gary Bañuelos; Brian Shutes; Huiyang Wen; Rui Cheng. Removal of chlorpyrifos and its hydrolytic metabolite 3,5,6-trichloro-2-pyridinol in constructed wetland mesocosms under soda saline-alkaline conditions: Effectiveness and influencing factors. Journal of Hazardous Materials 2019, 373, 67 -74.
AMA StyleXiangfei Yu, Hui Zhu, Baixing Yan, Yingying Xu, Gary Bañuelos, Brian Shutes, Huiyang Wen, Rui Cheng. Removal of chlorpyrifos and its hydrolytic metabolite 3,5,6-trichloro-2-pyridinol in constructed wetland mesocosms under soda saline-alkaline conditions: Effectiveness and influencing factors. Journal of Hazardous Materials. 2019; 373 ():67-74.
Chicago/Turabian StyleXiangfei Yu; Hui Zhu; Baixing Yan; Yingying Xu; Gary Bañuelos; Brian Shutes; Huiyang Wen; Rui Cheng. 2019. "Removal of chlorpyrifos and its hydrolytic metabolite 3,5,6-trichloro-2-pyridinol in constructed wetland mesocosms under soda saline-alkaline conditions: Effectiveness and influencing factors." Journal of Hazardous Materials 373, no. : 67-74.
Haze is one of the most serious environmental problems affecting China. This study monitored the changes in dew amount and quality during a haze event that occurred in 2016. Water vapor migrated continuously to the near surface during the haze event. The period of dew condensation increased because of meteorological factors, and the daily dew amount (0.178 mm) was higher during the haze event than in non-haze weather (0.0607 mm). The concentrations of all ions in the dew increased gradually during the haze event, peaking during the most serious period of the haze. The concentrations of SO42− and NH4+ reached 15,325.95 and 13,865.45 μeq/L, which were 2.24 and 10.83 times greater than those obtained before the haze event, respectively. During the haze event, the particulate matter (PM) concentrations within the dew increased, and the mass concentrations of PM2.5 and PM2.5-10 during the worst haze event were 65.3 and 166.1 mg/L, respectively. The dew mainly removed coarse PM; the average removal rates of PM2.5 and PM2.5-10 during the haze event were 13.6% and 16.9%, respectively. Dew can capture PM throughout a haze event, and its purifying effect on the underlying surface was obvious, especially during the beginning of the event.
Yingying Xu; Zhaoqing Luan; Hui Zhu. Dew condensation during a typical haze event in Changchun, China. Journal of Water and Climate Change 2019, 11, 568 -576.
AMA StyleYingying Xu, Zhaoqing Luan, Hui Zhu. Dew condensation during a typical haze event in Changchun, China. Journal of Water and Climate Change. 2019; 11 (2):568-576.
Chicago/Turabian StyleYingying Xu; Zhaoqing Luan; Hui Zhu. 2019. "Dew condensation during a typical haze event in Changchun, China." Journal of Water and Climate Change 11, no. 2: 568-576.
A series of mesocosm-scale horizontal subsurface flow constructed wetlands (HSSF-CWs) were established. In Experiment 1, four artificial aeration (AA) modes, including pre-aeration at 24 h before the input of influent water (PA), aeration at 6 h (6AA) and 12 h (12AA) after the input of influent water and non-aeration (NA), were tested to obtain an optimal aeration mode for chemical oxygen demand (CODCr) and nitrogen removal. The results showed that aeration after the input of influent water could improve the removal efficiencies of CODCr and ammonia-nitrogen (NH4⁺-N), but lead to an accumulation of nitrate-nitrogen (NO3−-N). The above observation demonstrated that a single aeration cannot create an ideal alternation of aerobic and anaerobic conditions for simultaneous nitrification and denitrification. Therefore, HSSF-CWs with intermittent aeration (IA), after the input of influent water and NA were established to evaluate the combined effects of IA and influent COD/N ratios on pollutant removal in Experiment 2. The HSSF-CW with IA exhibited a better performance in CODCr and nitrogen removal compared to HSSF-CW with NA. The highest removal percentages of CODCr (90.1%), NH4+-N (99.8%) and total nitrogen (TN, 99.5%) were achieved at a COD/N ratio of 9.3 in HSSF-CW with IA.
Xin Chen; Hui Zhu; Yingying Xu; Brian Shutes; Baixing Yan; Qingwei Zhou. Effect of Aeration Modes and COD/N Ratios on Organic Matter and Nitrogen Removal in Horizontal Subsurface Flow Constructed Wetland Mesocosms. Water 2018, 10, 1530 .
AMA StyleXin Chen, Hui Zhu, Yingying Xu, Brian Shutes, Baixing Yan, Qingwei Zhou. Effect of Aeration Modes and COD/N Ratios on Organic Matter and Nitrogen Removal in Horizontal Subsurface Flow Constructed Wetland Mesocosms. Water. 2018; 10 (11):1530.
Chicago/Turabian StyleXin Chen; Hui Zhu; Yingying Xu; Brian Shutes; Baixing Yan; Qingwei Zhou. 2018. "Effect of Aeration Modes and COD/N Ratios on Organic Matter and Nitrogen Removal in Horizontal Subsurface Flow Constructed Wetland Mesocosms." Water 10, no. 11: 1530.
This study determined the saline-alkaline tolerance of seven hygrophilous plant species during their asexual reproduction and continued growth stages. Indicators of asexual reproduction capacities (e.g., number of new buds/seedlings) and growth potential (e.g., total biomass, chlorophyll content index, number and length of new roots), as well as the Na+ and K+ concentrations and Na+/K+ ratios were obtained in tested plant species exposed in five alkaline salt treatments (NaHCO3) ranging from 0.3 to 20 dS/m during the 30 day experiment. The following results were observed: 1) excessive NaHCO3 (especially at a salinity level of EC ≥ 10 dS/m) seriously inhibited the capacity of asexual reproduction and continued growth; 2) the number of new buds/seedlings was significantly (P < 0.05) and positively correlated with the number of new roots of plants, while the number of new buds/seedlings was significantly (P < 0.05) and negatively correlated with the total biomass of plants; and 3) species-specific salt-tolerance strategies were observed, i.e., the entry and compartmentalization of Na+ was controlled, and a low Na+/K+ ratios in different parts of plants was maintained. In general, common reed (Phragmites australis), giant reed (Arundo donax), bulrush (Scirpus validus), and fishscale bamboo (Phyllostachys heteroclada) exhibited better saline-alkaline tolerance during asexual reproduction and continued growth under moderate saline-alkaline conditions. These species are recommended as potential plant species for restoring degraded saline-alkaline wetlands.
X. Cheng; H. Zhu; G. Bañuelos; B. Yan; B. Shutes; Y. Liang. Saline-alkaline tolerance of hygrophilous plant species during their asexual propagation and continued growth stages. South African Journal of Botany 2018, 118, 129 -137.
AMA StyleX. Cheng, H. Zhu, G. Bañuelos, B. Yan, B. Shutes, Y. Liang. Saline-alkaline tolerance of hygrophilous plant species during their asexual propagation and continued growth stages. South African Journal of Botany. 2018; 118 ():129-137.
Chicago/Turabian StyleX. Cheng; H. Zhu; G. Bañuelos; B. Yan; B. Shutes; Y. Liang. 2018. "Saline-alkaline tolerance of hygrophilous plant species during their asexual propagation and continued growth stages." South African Journal of Botany 118, no. : 129-137.