TEMPERATURE EFFECTS ON WASTEWATER NITRATE REMOVAL IN LABORATORY-SCALE CONSTRUCTED WETLANDS

1999 ◽  
Vol 42 (1) ◽  
pp. 185-190 ◽  
Author(s):  
S. L. Wood ◽  
E. F. Wheeler ◽  
R. D. Berghage ◽  
R. E. Graves
Keyword(s):  
Constructed Wetlands ◽  
Temperature Effects ◽  
Nitrate Removal ◽  
Laboratory Scale

Assessment of clogging in constructed wetlands by saturated hydraulic conductivity measurements

2019 ◽  
Vol 79 (2) ◽  
pp. 314-322 ◽  
Author(s):  
F. Licciardello ◽  
R. Aiello ◽  
V. Alagna ◽  
M. Iovino ◽  
D. Ventura ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Hydraulic Conductivity ◽  
Constructed Wetlands ◽  
Spatial Scales ◽  
Pilot Scale ◽  
Laboratory Scale ◽  
Test Method ◽  
Conductivity Measurements ◽  
Multiple Spatial Scales ◽  
Ks Values

Abstract This study aims at defining a methodology to evaluate Ks reductions of gravel material constituting constructed wetland (CW) bed matrices. Several schemes and equations for the Lefranc's test were compared by using different gravel sizes and at multiple spatial scales. The falling-head test method was implemented by using two steel permeameters: one impervious (IMP) and one pervious (P) on one side. At laboratory scale, mean K values for a small size gravel (8–15 × 10−2 m) measured by the IMP and the P permeameters were equal to 19,466 m/d and 30,662 m/d, respectively. Mean Ks values for a big size gravel (10–25 × 10−2 m) measured by the IMP and the P permeameters were equal to 12,135 m/d and 20,866 m/d, respectively. Comparison of Ks values obtained by the two permeameters at laboratory scale as well as a sensitivity analysis and a calibration, lead to the modification of the standpipe equation, to evaluate also the temporal variation of the horizontal Ks. In particular, both permeameters allow the evaluation of the Ks decreasing after 4 years-operation and 1–1.5 years' operation of the plants at full scale (filled with the small size gravel) and at pilot scale (filled with the big size gravel), respectively.

scholarly journals The contributions and mechanisms of iron-microbes-biochar in constructed wetlands for nitrate removal from low carbon/nitrogen ratio wastewater

RSC Advances ◽  
2020 ◽  
Vol 10 (39) ◽  
pp. 23212-23220
Author(s):  
Jian Xu ◽  
Xiawei Liu ◽  
Jiaolong Huang ◽  
Manqi Huang ◽  
Tao Wang ◽  
...  
Keyword(s):  
Constructed Wetlands ◽  
Nitrate Removal ◽  
Schematic Diagram ◽  
Low Carbon ◽  
Carbon Nitrogen Ratio ◽  
Nitrogen Ratio

Schematic diagram of RDCWs system and proposed mechanisms for nitrate removal.

scholarly journals Effects of Supplemental Cations on Growth and Nitrogen Accumulation in Canna indica L.

2021 ◽  
Vol 20 (4) ◽  
Author(s):  
Manutsawan Manokieng ◽  
◽  
Arunothai Jampeetong ◽  
Keyword(s):  
Plant Growth ◽  
Constructed Wetlands ◽  
Nitrate Removal ◽  
Nitrogen Accumulation ◽  
Total Biomass ◽  
Canna Indica ◽  
Whole Plant ◽  
Stimulate Plant Growth ◽  
Plant Level ◽  
Mineral Accumulation

Abstract The effects of supplemental cations on growth, nitrogen, and mineral accumulation were assessed in Canna indica L. Similar sized 45 days-old plants were grown on a nutrient solution modified from Hoagland and Arnon (1950). The different cations were added to generate 6 treatments (n=4): (i) control (no cation added), (ii) 2.5 mM K+, (iii) 2.5 mM Ca2+, (iv) 75 mM Na+, (v) 1.25 mM K+ + 1.25 mM Ca2+ and (vi) 2.5 mM Ca2+ + 75 mM Na+, respectively. An experiment was carried out in the greenhouse for 49 days. The study found that supplemental K+ and K++ Ca2+ increased plant growth and total biomass. The highest SER was found in plants receiving supplemental K+. In contrast, SERs, leaf areas, and total biomass decreased in Na+ or Na++Ca2+ supplemented plants. The accumulated NO3- concentration (at the whole plant level) was also highest in the plants with supplemental K+ and K++Ca2+. The total nitrogen accumulation was higher in the K+, Ca2+, and K++Ca2+ supplemented plants than in the control plants. The results suggest that supplemental cations particularly K+ can enhance plant growth and nitrogen accumulation in C. indica. Therefore, cation supplementation could be an alternative technique to stimulate plant growth and improve nitrate removal in constructed wetlands. Keywords: Constructed wetland, Nitrate removal, Potassium, Tropical wetland plants

Substrate Organic Matter to Improve Nitrate Removal in Surface-Flow Constructed Wetlands

2007 ◽  
Vol 36 (1) ◽  
pp. 194-207 ◽  
Author(s):  
Michael R. Burchell ◽  
R. Wayne Skaggs ◽  
Charles R. Lee ◽  
Steven Broome ◽  
George M. Chescheir ◽  
...  
Keyword(s):  
Organic Matter ◽  
Constructed Wetlands ◽  
Nitrate Removal ◽  
Surface Flow ◽  
Surface Flow Constructed Wetlands

Increasing nitrogen removal efficiency by intermittent aeration in partial areas of laboratory-scale vertical flow constructed wetlands

2020 ◽  
Vol 71 (12) ◽  
pp. 1686
Author(s):  
Chen Chen ◽  
Nannan Zhang ◽  
Zhe Liu ◽  
Shuqing An ◽  
Dehua Zhao
Keyword(s):  
Removal Efficiency ◽  
Constructed Wetlands ◽  
Nitrogen Removal ◽  
Amoa Gene ◽  
Laboratory Scale ◽  
Vertical Flow ◽  
Intermittent Aeration ◽  
Nitrate Reductase Gene ◽  
Partial Area ◽  
Reductase Gene

Intermittent aeration (IA) has been widely used in constructed wetlands (CWs) because it is economical and results in high nitrogen removal efficiency (RE). The aim of this study was to identify whether IA (4hday–1; the recommended frequency according to previous studies) in a partial area (PIA) can improve nitrogen RE compared with IA applied throughout the CW (TIA). Three types of laboratory-scale vertical flow CWs were constructed: PIA, TIA and non-aerated (NA). PIA achieved a higher RE of total nitrogen than TIA and NA (mean RE 60.6 v. 45.2 and 37.4% respectively). In the PIA, the ammonia mono-oxygenase subunit A (amoA) gene was abundant in aerated areas, whereas the nitrate reductase gene narG and nitrite reductase genes nirK and nirS were abundant in anaerobic areas. The results of this study suggest that PIA is an effective strategy for nitrogen removal when applying aeration in CWs because it preserves a constant anaerobic area for denitrification.

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