Using a compact combined constructed wetland system to treat agricultural wastewater with high nitrogen

2005 ◽  
Vol 51 (9) ◽  
pp. 47-53 ◽  
Author(s):  
S. Kantawanichkul ◽  
S. Somprasert
Keyword(s):  
Nitrogen Removal ◽  
Constructed Wetland ◽  
Rate Constants ◽  
Removal Rate ◽  
Operating Conditions ◽  
Horizontal Flow ◽  
Vertical Flow ◽  
Pig Farm ◽  
Wetland System ◽  
Farm Wastewater

The objectives of this study were to find appropriate conditions for nitrogen removal by a compact combined constructed wetland system and to evaluate the removal rate constant in a tropical climate. This study will present suitable operating conditions for a combined system to treat pig farm wastewater containing high ammonia-nitrogen. Four laboratory-scale combined constructed wetland units (0.5 × 1.0 × 1.0 m3): vertical flow vegetated bed over horizontal flow sand bed, were operated under an average temperature of 24 °C. Pig farm wastewater with COD and NH4+-N concentration of 1034 and 448 mg/L in average was fed to the system at different HLR from 2 to 8 cm/day. The performance of the system when operated with a vertical flow bed followed by a horizontal flow bed or vice versa did not show a significant difference but under high HLR, nitrogen removal efficiencies were clearly reduced. Nitrobacter and Nitrosomonas were found in a large number in vertical flow beds and the same for denitrifier bacteria in a horizontal flow beds. Removal rate constants for nitrification (kNH4-N) were 0.0413 m/d for H-Vmode and 0.0339 m/d for V-H mode. Removal rate constants for denitrification (kNOx-N) were 0.0979 m/d for H-Vmode and 0.0399 m/d for V-H mode, respectively.

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 Removing Organic Matter and Nutrients from Pig Farm Wastewater with a Constructed Wetland System

2018 ◽  
Vol 15 (5) ◽  
pp. 1031 ◽  
Author(s):  
Celia De La Mora-Orozco ◽  
Irma González-Acuña ◽  
Ruben Saucedo-Terán ◽  
Hugo Flores-López ◽  
Hector Rubio-Arias ◽  
...  
Keyword(s):  
Organic Matter ◽  
Constructed Wetland ◽  
Pig Farm ◽  
Wetland System ◽  
Farm Wastewater

Removal of indicator bacteria from municipal wastewater in an experimental two-stage vertical flow constructed wetland system

2003 ◽  
Vol 48 (5) ◽  
pp. 35-41 ◽  
Author(s):  
C.A. Arias ◽  
A. Cabello ◽  
H. Brix ◽  
N.-H. Johansen
Keyword(s):  
Constructed Wetland ◽  
Rate Constants ◽  
Indicator Bacteria ◽  
Vertical Flow ◽  
Faecal Coliforms ◽  
Total Coliforms ◽  
Sedimentation Tank ◽  
Vertical Flow Constructed Wetland ◽  
Wetland System ◽  
Faecal Streptococci

The removal of sanitary indicator bacteria (total coliforms, faecal coliforms, and faecal streptococci) was studied in an experimental constructed wetland system consisting of (1) a 2-m3 three-chamber sedimentation tank, (2) a 5 m2 vertical flow constructed wetland, (3) a filter-unit with calcite aimed at removing phosphorus, and (4) a 10 m2 vertical flow constructed wetland. The indicator bacteria were enumerated before and after each unit of the wetland system during four monitoring episodes with different loading conditions. At a hydraulic loading rate of 520-1,370 mm/d, the first-stage vertical flow beds removed about 1.5 log-units of total coliforms, 1.7 log-units of faecal coliforms and 0.8 log-units of faecal streptococci. In the second stage bed receiving lower loadings both in term of concentration and quantity (260-690 mm/day), the eliminations were lower. It was not possible in the present study to identify any seasonal effects, but no measurements were done during summer. Recycling of treated effluent back to the sedimentation tank did not affect elimination. Area-based rate constants for the vertical flow wetland receiving effluent from the sedimentation tank averaged 3.2 m/d for total coliforms, 3.3 m/d for faecal coliforms and 2.1 m/d for faecal streptococci. The rate constants depended on loading rates. It is suggested that filtration is a major removal mechanism for bacterial indicator organisms in vertical flow constructed wetland systems.

Nitrogen Removal Capacity in Horizon Subsurface Flow and Vertical Flow Constructed Wetland in Relation to Operational Mode

2011 ◽  
Vol 374-377 ◽  
pp. 118-121
Author(s):  
Tian Xie ◽  
Zong Lian She ◽  
En Shi ◽  
Lei Lei Li ◽  
Ying Jie Zhu
Keyword(s):  
Nitrogen Removal ◽  
Constructed Wetland ◽  
Removal Rate ◽  
Nitrate Removal ◽  
Subsurface Flow ◽  
Vertical Flow ◽  
Operational Mode ◽  
Removal Capacity ◽  
Vertical Flow Constructed Wetland ◽  
Operational Modes

Two laboratory scale constructed wetlands were designed as horizon subsurface flow constructed wetland (HFCW) and vertical flow constructed wetland (VFCW) and were utilized to study the treatment capacity to reduce nitrogen. According to different inflow concentration and height of water surface, HFCW was analyzed in two operational modes and VFCW in four operational modes. The semi-submerged VFCW had the best capacity to remove nitrogen and the total nitrogen removal rate reached to 92% and the removal rate of HFCW was 90%. Moreover, the un-submerged VFCW could reduce 93% ammonia but nitrate removal rate just was 9%. And the removal rates of NH4+-N, NO3--N and TN respectively were 85%, 80% and 81% in submerged VFCW.

scholarly journals Effects of Partial Saturation on Nitrogen Removal and Bacterial Community in Vertical-Flow Constructed Wetlands

2021 ◽  
Author(s):  
Khadija kraiem ◽  
Hamadi Kallali ◽  
Rim Werheni Ammeri ◽  
salma Bessadok ◽  
Naceur Jedidi
Keyword(s):  
Constructed Wetlands ◽  
Nitrogen Removal ◽  
Constructed Wetland ◽  
Removal Rate ◽  
Vertical Flow ◽  
Partial Saturation ◽  
Denitrifying Bacterium ◽  
Saturation Condition ◽  
Vertical Flow Constructed Wetland ◽  
Kjeldahl Nitrogen

Abstract The laboratory-scale pilot of constructed wetlands has been in operation for six months; (1) an unsaturated vertical flow constructed wetland (UVF-CW), this system was used to represent the classic vertical constructed wetlands, (2) a saturated vertical flow constructed wetland (SVF-CW), to evaluate the effects of the saturated condition on nitrogen removal and composition of the microbial community. The results showed that the saturation condition positiveley influenced the removal efficiencies of the nitrogen,, the aeverage removal rate of the total kjeldahl nitrogen increased from 56% in unsaturated vertical flow constructed wetland (UVF-CW) to 63% in saturated vertical flow constructed wetland ( SVF-CW). In addition, the microbial communities also was affected by the saturation condition, the relative abundances of nitrifying bacterium in UVF-CW are 13.8% (Nitrosomonas), 7.2% (Nitrosospira), 18.1% (Nitrospira) and 15.3% (Nitrobacter). In contrast, in SVF-CW, Nitrosomonas, Nitrosospira, Nitrospira and Nitrobacter only accounted for 6.8%, 5.6%, 7.4% and 10.6% respectively. However, the saturation condition seemed to increase denitrifying bacterium more than three times, in unsaturated vertical flow constructed wetland, only Pseudomonas (6.5%) and Paracoccus (4.85%) were detected, but in saturated vertical flow constructed wetland (SVF-CW), the abundance of Pseudomonas (13.08%) and Paracoccus (9.74%) were increased, and three other groups of denitrifying bacteria were also detected as Zoogloea (3.32%), Thauera (5.41%) and Thiobacillus (3).

Two-Stage Constructed Wetland for Treating Hospital Wastewater in Nepal

1999 ◽  
Vol 40 (3) ◽  
pp. 317-324 ◽  
Author(s):  
Johannes Laber ◽  
Raimund Haberl ◽  
Roshan Shrestha
Keyword(s):  
Water Level ◽  
Constructed Wetland ◽  
Loading Rate ◽  
Removal Rate ◽  
High Water ◽  
Horizontal Flow ◽  
Vertical Flow ◽  
Two Stage ◽  
Second Stage ◽  
Very High

To treat the wastewater of a hospital at Dhulikhel/Nepal, a two-stage constructed wetland was built with a settlement tank, a horizontal flow bed as first stage and a vertical flow bed as second stage. The plant is operated without electric power. The aim was the elimination of organic compounds, nitrification and a significant reduction of indicator bacteria. Different phases of operation (high and low water level within the soil profile, serial operation, one stage operation) were investigated, of which the serial operation with high water level in the horizontal flow bed and low water level in the vertical flow bed showed the best elimination performance. The areal removal rate constants (k-values) turned out to be very high (especially of the vertical flow bed) compared with literature values of other subsurface flow constructed wetlands. For the vertical flow bed kCOD was 0.22 m/d and kNH4-N was 0.85 m/d during serial operation. For kNH4-N a strong correlation with the hydraulic loading rate and the COD inlet concentration was found.

Treatment of agricultural wastewater in two experimental combined constructed wetland systems in a tropical climate

2003 ◽  
Vol 48 (5) ◽  
pp. 199-205 ◽  
Author(s):  
S. Kantawanichkul ◽  
S. Somprasert ◽  
U. Aekasin ◽  
R.B.E. Shutes
Keyword(s):  
Constructed Wetland ◽  
Tropical Climate ◽  
Nitrogen Loading ◽  
Horizontal Flow ◽  
Coliform Bacteria ◽  
Vertical Flow ◽  
Recycled Water ◽  
Hydraulic Loading ◽  
Pig Farm ◽  
Removal Efficiencies

Two designs of experimental combined constructed wetland systems were constructed: vegetated (Scirpus grossus Linn) subsurface horizontal flow bed followed by a vegetated vertical flow bed and a vegetated vertical flow bed over an unvegetated horizontal flow sand bed. The systems were used to compare the nitrification/denitrification efficiency in a tropical climate which has temperatures above an average of 25°C throughout the year. The effluent from a biogas digester of pig farm wastewater with TKN and COD concentrations of approximately 400 and 1,000 mg/L was fed every 4 hours intermittently. The effluent was recycled to the system with the ratio of 1:1 and the hydraulic loading rate was increased from 3 to 6 and 12 cm/d including recycled water. At higher hydraulic loading rates, nitrogen COD and BOD removal efficiencies were lower. The SS, TP and fecal coliform bacteria removal efficiencies were not clearly affected by the high hydraulic loading or the different layout of the system. Nitrogen uptake by plants was very low in relation to the nitrogen loading of the systems. In general, the removal efficiencies of both types were comparable but the system with a vertical flow over horizontal flow sand bed is more suitable for sites with limited land area, although its construction can be more difficult than the system with horizontal flow followed by a vertical flow bed.

Water Budget of Constructed Wetland System with Subsurface Vertical Flow in Sub-Humid Tropical Climate

2015 ◽  
Vol 1 (5) ◽  
pp. 235-242
Author(s):  
Édio Damásio da Silva Júnior ◽  
Rogério de Araújo Almeida ◽  
Elisa Rodrigues Siqueira ◽  
Ábio Roduvalho da Silva
Keyword(s):  
Constructed Wetland ◽  
Water Budget ◽  
Tropical Climate ◽  
Vertical Flow ◽  
Humid Tropical Climate ◽  
Wetland System

Study on De-Nitrification of Improved Step-Feed Progress

2014 ◽  
Vol 703 ◽  
pp. 171-174
Author(s):  
Bing Wang ◽  
Yi Xiao ◽  
Shou Hui Tong ◽  
Lan Fang ◽  
Da Hai You ◽  
...  
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Fluidized Bed ◽  
Removal Efficiency ◽  
Nitrogen Removal ◽  
Removal Rate ◽  
Operating Conditions ◽  
Removal Mechanism ◽  
Aerobic Zone

Improved step-feed de-nitrification progress combined with biological fluidized bed was introduced in this study. The progress had good performance and capacity of de-nitrification and organic matter. The experiment result showed that the de-nitrification efficiency of the improved biological fluidized bed with step-feed process was higher than the fluidized bed A/O process under the same water quality and the operating conditions. When the influent proportion of each segment was equal, the system showed good nitrogen removal efficiency with the change of influent C/N ratio, HRT and sludge return ratio. The removal rate of TN reached up to 88.2%. It showed that the simultaneous nitrification and de-nitrification phenomenon happened in the aerobic zone. The nitrogen removal mechanism was also studied.

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