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.

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.

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.

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

scholarly journals Performance monitoring of a vertical flow constructed wetland treating municipal wastewater

2013 ◽  
Vol 9 (3) ◽  
pp. 277-285
Keyword(s):  
Water Quality ◽  
Constructed Wetland ◽  
Performance Monitoring ◽  
Municipal Wastewater ◽  
Monitoring Program ◽  
Vertical Flow ◽  
Total Coliforms ◽  
Vertical Flow Constructed Wetland ◽  
Reliable Performance ◽  
Removal Efficiencies

A two-year monitoring program was undertaken in a vertical flow constructed wetland treating wastewater from Gomati, a village in Chalkidiki, North Greece. This constructed wetland operates since 2003. The monitoring campaigns were organized every 15 days. Water quality samples were collected at the inlet, at intermediate points (i.e., at the end of each treatment stage) and at the outlet of the system. Measured mean removal efficiencies were as follows: 92.3% for BOD, 91.7% for COD, 80.3% for TKN, 87.5% for ΝΗ4 +, 61.3% for TP, 45.7% for ortho-phosphates, 93.2% for TSS and 99.9% for total coliforms, which suggests a satisfactory and reliable performance of such systems in Greece. The paper presents facility description, study details and monitoring results.

scholarly journals Reliability and Efficiency of Pollutant Removal in Four-Stage Constructed Wetland of SSVF-SSHF-SSHF-SSVF Type

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3153
Author(s):  
Magdalena Gizińska-Górna ◽  
Krzysztof Jóźwiakowski ◽  
Michał Marzec
Keyword(s):  
Organic Compounds ◽  
Constructed Wetland ◽  
Suspended Solids ◽  
High Efficiency ◽  
Total Suspended Solids ◽  
Pollutant Removal ◽  
Vertical Flow ◽  
Stage System ◽  
Removal Efficiencies ◽  
Very High

The present paper reports pollutant removal efficiencies and reliability for a four-stage hybrid constructed wetland (HCW) consisting of the following sequence of subsurface (SS), vertical flow (VF) and horizontal flow (HF) beds: SSVF-SSHF-SSHF-SSVF. The experiments were carried out over a period of three years, with sampling done in each season: winter, spring, summer and autumn. Grab samples of wastewater collected from different stages of treatment were tested for total suspended solids (TSS), BOD5, COD, total nitrogen (TN) and total phosphorus (TP). The wetland was found to have a very high efficiency of removal of suspended solids and organics, with relatively little seasonal variability. The three-year average TSS removal efficiency was approximately 92.7%. The effectiveness of elimination of organic compounds was very high throughout the study period at 96.6% BOD5 and 95% COD. The effluent from the four-stage system had significantly lower contents of TN and TP compared to the wastewater discharged from the first two beds of this facility.

Vertical flow constructed wetland for textile effluent treatment

2007 ◽  
Vol 55 (7) ◽  
pp. 127-134 ◽  
Author(s):  
L.C. Davies ◽  
A. Vacas ◽  
J.M. Novais ◽  
F.G. Freire ◽  
S. Martins-Dias
Keyword(s):  
Constructed Wetland ◽  
Effluent Treatment ◽  
Textile Effluent ◽  
Model Parameters ◽  
Vertical Flow ◽  
Mass Load ◽  
Vertical Flow Constructed Wetland ◽  
Pulse Feed ◽  
In Series ◽  
Removal Efficiencies

A pulse feed vertical flow constructed wetland (VFCW) proved to be efficient in the treatment of a textile effluent being able to buffer, dilute and treat an Acid Orange (AO7) accidental discharge. The influence of the flooding level (FL) and pulse feed (PF) duration on the removal efficiencies of a VFCW was examined. Average AO7 removal efficiencies of 70% were achieved for an AO7 Inlet concentration of 700 mg l−1 applied during 15 min cycle−1 (every three hours) at a hydraulic load of 13 l m−2 cycle−1 and an FL of 21%. The VFCW was modelled by analogy with a combination of ideal reactors. The simplest combination that best reproduced the experimental results was an association of 2 reactors in series plus 1 reactor accounting the dead volumes. The model parameters helped to understand the hydrological and kinetic processes occurring in VFCW. Through the model simulation it was shown that 3 VFCW in series were enough to efficiently treat an organic mass load of 76 gAO7 m−2 day−1 in 9 hours and fulfil the discharge legislation. In this work it was possible to establish that the overall degradation kinetics was of first order.

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 Purification ability of tail water and optimal hydraulic loading rates in vertical flow constructed wetland

2016 ◽  
Vol 28 (1) ◽  
pp. 114-123
Author(s):  
LIANG Kang ◽  
◽  
CHANG Junjun ◽  
WANG Feihua ◽  
LIU Shuangyuan ◽  
...  
Keyword(s):  
Constructed Wetland ◽  
Vertical Flow ◽  
Loading Rates ◽  
Hydraulic Loading ◽  
Vertical Flow Constructed Wetland ◽  
Tail Water

scholarly journals Performance of the first stage of the French system of vertical flow constructed wetlands with only two units in parallel: influence of pulse time and instantaneous hydraulic loading rate

2018 ◽  
Vol 78 (4) ◽  
pp. 848-859 ◽  
Author(s):  
Jorge A. García Zumalacarregui ◽  
Marcos von Sperling
Keyword(s):  
Constructed Wetlands ◽  
Loading Rate ◽  
Oxygen Demand ◽  
Feeding Time ◽  
Vertical Flow ◽  
Hydraulic Loading Rate ◽  
Hydraulic Loading ◽  
Vertical Flow Constructed Wetlands ◽  
Removal Efficiencies ◽  
Raw Wastewater

Abstract The technology of vertical flow constructed wetlands – French system for treating raw wastewater depends on several hydraulic factors, one of them being the duration of the pulse feeding and the resulting instantaneous hydraulic loading rate. This paper analyses two scenarios in the same system, the first of a faster feeding by pump and the second of a slower feeding by siphon, both with instantaneous hydraulic loading rate values lower than the literature recommendations. The system treated raw wastewater from a population equivalent of 100 p.e. in Brazil, and was comprised by only the first stage and two units in parallel. The shorter duration of feeding time and higher instantaneous hydraulic loading rate were associated with significantly higher chemical oxygen demand and total Kjeldahl nitrogen removal efficiencies, but with no significant differences in terms of biochemical oxygen demand (BOD) and suspended solids (SS). Oxygen concentrations and redox potential in the effluent were evaluated, together with the effluent flow rate profiles. The removal efficiencies were associated with the accumulation of solids in the upper part of the filter resulting from seven years of operation and to the operating hydraulic conditions, which are important elements in the performance of the system.

Sign in / Sign up

Export Citation Format

Share Document