Annual cycle of nitrogen removal by a pilot-scale subsurface horizontal flow in a constructed wetland under moderate climate

2003 ◽  
Vol 37 (17) ◽  
pp. 4236-4242 ◽  
Author(s):  
P. Kuschk ◽  
A. Wießner ◽  
U. Kappelmeyer ◽  
E. Weißbrodt ◽  
M. Kästner ◽  
...  
2017 ◽  
Vol 105 ◽  
pp. 7-14 ◽  
Author(s):  
Reza Bakhshoodeh ◽  
Nadali Alavi ◽  
Monireh Majlesi ◽  
Pooya Paydary

2021 ◽  
Vol 13 (22) ◽  
pp. 12456
Author(s):  
Tao Wang ◽  
Liping Xiao ◽  
Hongbin Lu ◽  
Shaoyong Lu ◽  
Xiaoliang Zhao ◽  
...  

The quality of micropolluted water is unstable and its substrate concentration fluctuates greatly. The goal is to predict the concentration effect on the treatment of nitrogen in a river with an actual low C/N ratio for the proposed full-scale Xiaoyi River estuary wetland, so that the wetland project can operate stably and perform the water purification function effectively in the long term. Two pilot-scale multistage constructed wetland–pond (MCWP) systems (S1 and S2, respectively) based on actual engineering with the same “front ecological oxidation ponds, two-stage horizontal subsurface flow constructed wetlands and surface flow constructed wetlands (SFCWs) as the core and postsubmerged plant ponds” as the planned process were constructed to investigate the effect of different influent permanganate indexes (CODMn) and total nitrogen (TN) contents on nitrogen removal from micropolluted river water with a fixed C/N ratio from summer to winter in the field. The results indicate that the TN removal rate in the S1 and S2 systems was significant (19.56% and 34.84%, respectively). During the process of treating this micropolluted water with a fixed C/N ratio, the influent of S2 with a higher CODMn concentration was conducive to the removal of TN. The TN removal rate in S2 was significantly affected by the daily highest temperature. There was significant nitrogen removal efficiency in the SFCWs. The C/N ratio was a major determinant influencing the nitrogen removal rate in the SFCWs. The organic matter release phenomenon in SFCWs with high-density planting played an essential role in alleviating the lack of carbon sources in the influent. This research strongly supports the rule that there is seasonal nitrogen removal in the MCWPs under different influent substrate concentrations, which is of guiding significance for practical engineering.


Author(s):  
Maria Cristina Collivignarelli ◽  
Marco Carnevale Miino ◽  
Franco Hernan Gomez ◽  
Vincenzo Torretta ◽  
Elena Cristina Rada ◽  
...  

In the coming years, water stress is destined to worsen considering that the consumption of water is expected to increase significantly, and climate change is expected to become more evident. Greywater (GW) has been studied as an alternative water source in arid and semiarid zones. Although there is no single optimal solution in order to treat GW, constructed wetlands proved to be effective. In this paper, the results of the treatment of a real GW by a horizontal flow constructed wetland (HFCW) for more than four months are shown. In the preliminary laboratory-scale plant, Phragmites australis, Carex oshimensis and Cyperus papyrus were tested separately and showed very similar results. In the second phase, pilot-scale tests were conducted to confirm the performance at a larger scale and evaluate the influence of hydraulic retention time, obtaining very high removal yields on turbidity (>92%), total suspended solids (TSS) (>85%), chemical oxygen demand (COD) (>89%), and five-day biological oxygen demand (BOD5) (>88%). Based on the results of the pilot-scale HFCW, a comparison with international recommendations by World Health Organization and European Union is discussed.


Water ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 2007
Author(s):  
Qijun Ni ◽  
Tao Wang ◽  
Jialin Liao ◽  
Wansheng Shi ◽  
Zhenxing Huang ◽  
...  

In this study, pilot-scale vertical-flow constructed wetland (VFCW) and horizontal-flow constructed wetland (HFCW) were constructed to treat eutrophic water, and dissolved oxygen (DO) distributions, decontamination performances and key enzymes activities were compared under different influent loads. The influent load increase caused reductions of DO levels and removal efficiencies of chemical oxygen demand (COD), total nitrogen (TN), NH4+−N and organic nitrogen, but it had no remarkable effect on the removal of NO3−−N and total phosphorus (TP). The interior DO concentrations of VFCW were higher than those of HFCW, indicating a vertical hydraulic flow pattern was more conducive to atmospheric reoxygenation. The VFCW and HFCW ecosystems possessed comparable removal capacities for TN, NO3−−N and TP. VFCW had a remarkable superiority for COD and organic nitrogen degradation, but its effluent NH4+−N concentration was higher, indicating the NH4+−N produced from organic nitrogen degradation was not effectively further removed in the VFCW system. The activities of protease, urease and phosphatase declined with the increasing depth of substrate layers, and they were positively correlated with DO concentrations. The enzymatic activities of VFCW were significantly higher than that of HFCW in the upper layers. Taken together, VFCW and HFCW presented a certain difference in operational properties due to the different hydraulic flow patterns.


2010 ◽  
Vol 218 (1-4) ◽  
pp. 131-143 ◽  
Author(s):  
Ana Cristina Curia ◽  
Jair Carlos Koppe ◽  
João F. C. L. Costa ◽  
Liliana Amaral Féris ◽  
Wagner David Gerber

2020 ◽  
Author(s):  
Liping Xiao ◽  
Tao Wang ◽  
Hongbin Lu ◽  
Shaoyong Lu ◽  
Jiaxin Li ◽  
...  

Abstract Background Single-stage constructed wetlands (CWs) has a single ecological service function and is greatly affected by temperature, which are general in removal of total nitrogen. Multistage hybrid CWs were proven to capable of enhancing removal of nitrogen. Therefore, this study aimed to explore the variation in nitrogen removal in the combined CWs-pond process from summer to winter and the contribution of plant harvesting and the functions of bacteria to nitrogen removal. Methods A pilot-scale multistage constructed wetland-pond system (MCWP) with the process of "the pre-ecological oxidation pond + the two-level horizontal subsurface flow constructed wetland (HSCW) + the surface flow constructed wetland (SFCW) and the submerged plant pond (SPP)" was used to treat actual polluted river water in the field. During the 124 days of operation, the nitrogen concentrations in the units influent and effluent of the system were measured every two days, and the plant height in HSCWs and SFCW was measured once per month. When the system operated stably to the 72nd day, the substrates in the CWs were sampled to analyze the bacterial community structure and composition. Results The concentration of total nitrogen (TN) in the MCWP gradually decreased from 3.46 mg/L to 2.04 mg/L, and the average removal efficiency of TN was approximately 40.74%. The SPP performed the best among all units, and the TN removal efficiency was as high as 16.08%. The TN removal efficiency was significantly positively affected by the daily highest temperature. A formula between the total TN removal efficiency and the highest temperature was obtained by nonlinear fitting. The TN removal load rate in the HSCWs was 2.7–3.7 times that of the SFCW. Furthermore, the TN transformed by Iris pseudacorus L. accounted for 54.53% in the SFCW. Conclusion We found that the significant positive correlation between the daily highest temperature and the total TN removal rate a field MCWP system. The SFCW, as an advanced treatment unit, increased the proportion of nitrogen removed by plant harvesting. The bacteria completed the nitrogen cycle in the SFCW, which had high-density planting, through a variety of nitrogen removal pathways.


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