scholarly journals Operational Performances and Enzymatic Activities for Eutrophic Water Treatment by Vertical-Flow and Horizontal-Flow Constructed Wetlands

Water ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 2007
Author(s):  
Qijun Ni ◽  
Tao Wang ◽  
Jialin Liao ◽  
Wansheng Shi ◽  
Zhenxing Huang ◽  
...  
Keyword(s):  
Constructed Wetland ◽  
Organic Nitrogen ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Enzymatic Activities ◽  
Horizontal Flow ◽  
Vertical Flow ◽  
Remarkable Effect ◽  
Hydraulic Flow ◽  
Eutrophic Water

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.

scholarly journals Pilot-scale study of vertical flow constructed wetland combined with trickling filter and ferric chloride coagulation: influence of irregular operational conditions

2015 ◽  
Vol 71 (7) ◽  
pp. 1088-1096 ◽  
Author(s):  
B. Kim ◽  
M. Gautier ◽  
G. Olvera Palma ◽  
P. Molle ◽  
P. Michel ◽  
...  
Keyword(s):  
Constructed Wetland ◽  
Phosphorus Removal ◽  
Water Saturation ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Saturation Level ◽  
Vertical Flow ◽  
Trickling Filter ◽  
Operational Conditions ◽  
Vertical Flow Constructed Wetland

The aim of this study was to characterize the efficiency of an intensified process of vertical flow constructed wetland having the following particularities: (i) biological pretreatment by trickling filter, (ii) FeCl3 injection for dissolved phosphorus removal and (iii) succession of different levels of redox conditions along the process line. A pilot-scale set-up designed to simulate a real-scale plant was constructed and operated using real wastewater. The influences of FeCl3 injection and water saturation level within the vertical flow constructed wetland stage on treatment performances were studied. Three different water saturation levels were compared by monitoring: suspended solids (SS), total phosphorus (TP), dissolved chemical oxygen demand (COD), ammonium, nitrate, phosphate, iron, and manganese. The results confirmed the good overall efficiency of the process and the contribution of the trickling filter pretreatment to COD removal and nitrification. The effects of water saturation level and FeCl3 injection on phosphorus removal were evaluated by analysis of the correlations between the variables. Under unsaturated conditions, good nitrification and no denitrification were observed. Under partly saturated conditions, both nitrification and denitrification were obtained, along with a good retention of SSs. Finally, under saturated conditions, the performance was decreased for almost all parameters.

scholarly journals Horizontal Flow Constructed Wetland for Greywater Treatment and Reuse: An Experimental Case

2020 ◽  
Vol 17 (7) ◽  
pp. 2317 ◽  
Author(s):  
Maria Cristina Collivignarelli ◽  
Marco Carnevale Miino ◽  
Franco Hernan Gomez ◽  
Vincenzo Torretta ◽  
Elena Cristina Rada ◽  
...  
Keyword(s):  
Constructed Wetland ◽  
Oxygen Demand ◽  
Optimal Solution ◽  
Water Source ◽  
Pilot Scale ◽  
World Health ◽  
Horizontal Flow ◽  
Second Phase ◽  
Alternative Water ◽  
Health Organization

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.

scholarly journals Potential of integrated vertical and horizontal flow constructed wetland with native plants for sewage treatment under different hydraulic loading rates

2017 ◽  
Vol 76 (2) ◽  
pp. 434-442 ◽  
Author(s):  
Xuan Cuong Nguyen ◽  
Dinh Duc Nguyen ◽  
Nguyen Thi Loan ◽  
Soon Woong Chang
Keyword(s):  
Constructed Wetland ◽  
Sewage Treatment ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Ammonium Nitrogen ◽  
Horizontal Flow ◽  
Most Probable Number ◽  
Probable Number ◽  
Loading Rates ◽  
Hydraulic Loading

In this study, a pilot-scale integrated constructed wetland with vertical flow (VF) and horizontal flow (HF) in series was designed and investigated to evaluate sewage wastewater treatment capacity. The VF unit was planted with Canna indica and was 1.2 m long, 1.2 m wide, and 1.2 m high; whereas the HF unit contained Colocasia esculenta and was 3.0 m long, 1.0 m wide, and 1.0 m high. The system was operated under different hydraulic loading rates (HLRs) of 0.1, 0.2, and 0.15 m/d. The effluent concentrations differed as HLR changed, and the means were total suspended solids (TSS): 87 mg/L; biological oxygen demand (BOD5): 31 mg/L; chemical oxygen demand (CODCr): 59 mg/L; ammonium nitrogen (NH4-N): 5.3 mg/L; nitrate nitrogen NO3-N: 8.4 mg/L; total nitrogen (TN): 7.1 mg/L; phosphate (PO4-P): 0.9 mg/L; and total coliforms (TCol): 1,485 most probable number (MPN)/100 mL. The average removal efficiencies for TSS, BOD5, TN, NH4-N, PO4-P, and TCol were 28.3, 74.9, 79, 76.2, 3.6, and 82%, respectively. There were significant differences in the effluent concentrations among the three HLRs (P < 0.05), except for PO4-P.

Nitrogen removal in a combined system: vertical vegetated bed over horizontal flow sand bed

2001 ◽  
Vol 44 (11-12) ◽  
pp. 137-142 ◽  
Author(s):  
S. Kantawanichkul ◽  
P. Neamkam ◽  
R.B.E. Shutes
Keyword(s):  
Loading Rate ◽  
Low Cost ◽  
Oxygen Demand ◽  
Nitrogen Loading ◽  
Horizontal Flow ◽  
Vertical Flow ◽  
Combined System ◽  
Cost Treatment ◽  
Pig Farm ◽  
Farm Wastewater

Pig farm wastewater creates various problems in many areas throughout Thailand. Constructed wetland systems are an appropriate, low cost treatment option for tropical countries such as Thailand. In this study, a combined system (a vertical flow bed planted with Cyperus flabelliformis over a horizontal flow sand bed without plants) was used to treat settled pig farm wastewater . This system is suitable for using in farms where land is limited. The average COD and nitrogen loading rate of the vegetated vertical flow bed were 105 g/m2.d and 11 g/m2.d respectively. The wastewater was fed intermittently at intervals of 4 hours with a hydraulic loading rate of 3.7 cm/d. The recirculation of the effluent increased total nitrogen (TN) removal efficiency from 71% to 85%. The chemical oxygen demand (COD) and total Kjeldahl nitrogen (TKN) removal efficiencies were 95% and 98%. Nitrification was significant in vertical flow Cyperus bed, and the concentration of nitrate increased by a factor of 140. The horizontal flow sand bed enhanced COD removal and nitrate reduction was 60%. Plant uptake of nitrogen was 1.1 g N/m2.d or dry biomass production was 2.8 kg/m2 over 100 days.

scholarly journals Pollutant removal and growth dynamics of macrophyte species for faecal sludge treatment with constructed wetland technology

2019 ◽  
Vol 80 (6) ◽  
pp. 1145-1154
Author(s):  
Agyemang Richard Osei ◽  
Yacouba Konate ◽  
Felix Kofi Abagale
Keyword(s):  
Constructed Wetland ◽  
Growth Parameters ◽  
Oxygen Demand ◽  
Growth Dynamics ◽  
Pilot Scale ◽  
Pollutant Removal ◽  
Local Context ◽  
Organic Chemical ◽  
Bambusa Vulgaris ◽  
Faecal Sludge

Abstract Constructed wetland technology is an innovative engineering technique for faecal sludge (FS) management. The presence of emergent macrophytes enhances the important processes of evapotranspiration, sludge mineralisation, and contaminant reduction. Consequently, selecting a species that can withstand the difficult sludge contaminated conditions within a local context is vital. This study monitored the pollutant removal potentials and growth dynamics of Bambusa vulgaris and Cymbopogon nardus as promising macrophytes for the constructed wetland technology in the Sudano-Sahelian context. The experiment, at pilot scale, consisted of plastic reactors (27 litre) filled with filter media of sand and fine gravels at the base, and planted with the selected species. Pollutant removal efficiencies were evaluated based on differences between influent and effluent concentrations, and physiological growth parameters of plant height, number of leaves and number of plants were monitored monthly. Total annual sludge loading rate of 31.4 and 103.4 kg TS/(m2·yr) (TS: total solids) were determined for FS + wastewater (acclimatisation phase) and FS load respectively. Both species recorded appreciable pollutant removal efficiency >80% for the organic (chemical oxygen demand), nutrients (PO43_P and NH4-N) and solid (total suspended solids and total volatile solids) contents. The species thus demonstrated satisfactory performance of resistance for faecal polluted wetland conditions.

Compost leachate treatment by a pilot-scale subsurface horizontal flow constructed wetland

2017 ◽  
Vol 105 ◽  
pp. 7-14 ◽  
Author(s):  
Reza Bakhshoodeh ◽  
Nadali Alavi ◽  
Monireh Majlesi ◽  
Pooya Paydary
Keyword(s):  
Constructed Wetland ◽  
Pilot Scale ◽  
Horizontal Flow ◽  
Leachate Treatment ◽  
Compost Leachate

The effect of a vertical flow filter bed on a hybrid constructed wetland system

2005 ◽  
Vol 51 (9) ◽  
pp. 137-144 ◽  
Author(s):  
A. Noorvee ◽  
E. Põldvere ◽  
Ü. Mander
Keyword(s):  
Constructed Wetland ◽  
Flow System ◽  
Subsurface Flow ◽  
Oxygen Demand ◽  
Vertical Flow ◽  
Efficient Removal ◽  
Loading Rates ◽  
Purification Efficiency ◽  
Wetland System ◽  
Filter Bed

Data from 18 sampling wells in Kodijärve horizontal subsurface flow (HSSF) constructed wetland (CW) (South Estonia) is presented and differences in purification efficiencies inside the HSSF CW are calculated. Temporarily anaerobic conditions in the Kodijärve HSSF system did not allow efficient removal of BOD7, NH4-N, Ntot and Ptot. In 2002 a vertical subsurface flow filter was constructed to enhance aeration. The design of the system was based simply on the oxygen demand of the wastewater and on the aeration potential of vertical flow wetlands. The vertical flow system has shown satisfactory results. The purification efficiency of BOD7 in the Kodijärve CW has improved significantly and there has been a slight increase in purification efficiencies of NH4-N and Ntot. On the ohther hand, the removal efficiency of Ptot has decreased significantly. Although, the mass loading rates have increased, mass removal rates of all four parameters have improved significantly. Nevertheless, optimization of the constructed wetland system is essential in order to meet effluent standards during wintertime.

Effects of a saturated layer and recirculation on nitrogen treatment performances of a single stage Vertical Flow Constructed Wetland (VFCW)

2013 ◽  
Vol 68 (7) ◽  
pp. 1461-1467 ◽  
Author(s):  
S. Prigent ◽  
J. Paing ◽  
Y. Andres ◽  
F. Chazarenc
Keyword(s):  
Constructed Wetland ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Single Stage ◽  
Vertical Flow ◽  
Saturated Layer ◽  
Vertical Flow Constructed Wetland ◽  
Hydraulic Load ◽  
Nitrogen Concentrations ◽  
Kjeldahl Nitrogen

Upgrades to enhance nitrogen removal were tested in a 2 year old pilot vertical flow constructed wetland in spring and summer periods. The effects of a saturated layer and of recirculation were tested in particular. Two pilots (L = 2 m, W = 1.25 m, H = 1.2 m), filled with expanded schist (Mayennite®), were designed with hydraulic saturated layers of 20 and 40 cm at the bottom. Each pilot was fed with raw domestic wastewater under field conditions according to a hydraulic load of 15–38 cm d−1 (i.e. 158–401 g COD (chemical oxygen demand) m−2 d−1) and to recirculation rates ranging from 0% up to 150%. The initial load during the first 2 years of operation resulted in an incomplete mineralized accumulated sludge leading to total suspended solids (TSS), COD and biochemical oxygen demand (BOD5) release. A 40 cm hydraulic saturated layer enabled an increase of 5–10% total nitrogen (TN) removal compared to a 20 cm saturated layer. Recirculation allowed the dilution of raw wastewater and enhanced nitrification in a single stage. A design of 1.8 m² pe−1 (48 cm d−1, 191 g COD m−2 d−1) with a 40 cm saturated layer and 100% recirculation enabled the French standard D4 (35 mg TSS L−1, 125 mg COD L−1, 25 mg BOD5 L−1), nitrogen concentrations below 20 mg TKN (total Kjeldahl nitrogen) L−1 and 50 mg TN L−1, to be met.

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