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Simulation and performance results of a saturated vertical up-flow constructed wetland (SVU CW) operated under different operational conditions are presented. The SVU CW consists of two different systems planted with Cyperus alternifolius and Iris pseudacorus, and each system consists of three SVU beds operated in series. The SVU CW operates in continuous aeration (CA) mode using different air-water ratios from 0.5:1 to 4:1. The aerated SVU CW achieves a high (more than 85%) removal of chemical oxygen demand (COD), ammonium (NH4+-N), total nitrogen (TN) and total phosphorus (TP). Furthermore, we simulate the SVU CW using the HYDRUS Wetland Module using the CWM1 biokinetic model under CA mode. According to the simulation results, aeration intensity controls the substrate distribution and growth of bacteria with depth in the SVU CW. Organic matter (OM) and nitrogen are removed in the top region (0–30 cm) of the SVU CW. The root mean square error for COD and NH4+-N is >1.5, whereas R2 is >0.99. A good match between observed and simulated data suggests that the CWM1 model is a suitable tool for simulating various processes and bacterial dynamics in aerated SVU CWs.
Yasinta John; Guenter Langergraber; Tanveer M. Adyel; Victor Emery David. Aeration intensity simulation in a saturated vertical up-flow constructed wetland. Science of The Total Environment 2019, 708, 134793 .
AMA StyleYasinta John, Guenter Langergraber, Tanveer M. Adyel, Victor Emery David. Aeration intensity simulation in a saturated vertical up-flow constructed wetland. Science of The Total Environment. 2019; 708 ():134793.
Chicago/Turabian StyleYasinta John; Guenter Langergraber; Tanveer M. Adyel; Victor Emery David. 2019. "Aeration intensity simulation in a saturated vertical up-flow constructed wetland." Science of The Total Environment 708, no. : 134793.
This paper presents a comparative review of arsenite (As(III)), arsenate (As(V)), and fluoride (F−) for a better understanding of the conditions and factors during their adsorption with focus on (i) the isotherm adsorption models, (ii) effects of pH, (iii) effects of ionic strength, and (iv) effects of coexisting substances such as anions, cations, and natural organics matter. It provides an in-depth analysis of various methods of arsenite (As(III)), arsenate (As(V)), and fluoride (F-) removal by adsorption and the anions’ characteristics during the adsorption process. The surface area of the adsorbents does not contribute to the adsorption capacity of these anions but rather a combination of other physical and chemical properties. The adsorption capacity for the anions depends on the combination of all the factors: pH, ionic strength, coexisting substances, pore volume and particles size, surface modification, pretreatment of the adsorbents, and so forth. Extreme higher adsorption capacity can be obtained by the modification of the adsorbents. In general, pH has a greater influence on adsorption capacity at large, since it affects the ionic strength, coexisting anions such as bicarbonate, sulfate, and silica, the surface charges of the adsorbents, and the ionic species which can be present in the solution.
Yasinta John; Victor Emery David; Daniel Mmereki. A Comparative Study on Removal of Hazardous Anions from Water by Adsorption: A Review. International Journal of Chemical Engineering 2018, 2018, 1 -21.
AMA StyleYasinta John, Victor Emery David, Daniel Mmereki. A Comparative Study on Removal of Hazardous Anions from Water by Adsorption: A Review. International Journal of Chemical Engineering. 2018; 2018 ():1-21.
Chicago/Turabian StyleYasinta John; Victor Emery David; Daniel Mmereki. 2018. "A Comparative Study on Removal of Hazardous Anions from Water by Adsorption: A Review." International Journal of Chemical Engineering 2018, no. : 1-21.
To improve nutrient removal, a full-scale hybrid constructed wetland (CW) consisting of pre-treatment units, vertical-baffled flow wetlands (VBFWs), and horizontal subsurface flow wetlands (HSFWs) was installed in August 2014 to treat sewage wastewater. Artificial aeration (AA) was applied continuously in the VBFW stage to improve the aerobic condition in the hybrid CW. Water samples were collected and analyzed twice a month between the period of August 2015 and July 2016. The results suggest that this new hybrid CW can achieve a satisfactory reduction of chemical oxygen demand (COD), ammonium nitrogen (NH4+-N), total nitrogen (TN), and total phosphorus (TP) with average removal rates of 85% ± 10% (35% ± 19 g/m2 per day), 76% ± 18% (7% ± 2 g/m2 per day), 65% ± 13% (8% ± 2 g/m2 per day), and 65% ± 21% (1 g/m2 per day), respectively. AA significantly improved the aerobic condition throughout the experimental period, and the positive influence of AA on nitrogen removal was found to be higher during summer that during winter. A significant positive correlation between water temperature and nutrient removal (p < 0.01) was observed in the system. Overall, this study demonstrates the application of AA in a full-scale hybrid CW with satisfactory nutrient removal rates. The hybrid CW system with artificial aeration can serve as a reference for future applications areas where land availability is limited.
Jun Zhai; Jun Xiao; Hasibur Rahaman; Yasinta John; Jingsong Xiao. Seasonal Variation of Nutrient Removal in a Full-Scale Artificial Aerated Hybrid Constructed Wetland. Water 2016, 8, 551 .
AMA StyleJun Zhai, Jun Xiao, Hasibur Rahaman, Yasinta John, Jingsong Xiao. Seasonal Variation of Nutrient Removal in a Full-Scale Artificial Aerated Hybrid Constructed Wetland. Water. 2016; 8 (12):551.
Chicago/Turabian StyleJun Zhai; Jun Xiao; Hasibur Rahaman; Yasinta John; Jingsong Xiao. 2016. "Seasonal Variation of Nutrient Removal in a Full-Scale Artificial Aerated Hybrid Constructed Wetland." Water 8, no. 12: 551.