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.

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.

scholarly journals Development of downflow hanging sponge (DHS) reactor as post treatment of existing combined anaerobic tank treating natural rubber processing wastewater

2016 ◽  
Vol 75 (1) ◽  
pp. 57-68 ◽  
Author(s):  
Takahiro Watari ◽  
Trung Cuong Mai ◽  
Daisuke Tanikawa ◽  
Yuga Hirakata ◽  
Masashi Hatamoto ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Loading Rate ◽  
Oxygen Demand ◽  
Nitrogen Loading ◽  
Post Treatment ◽  
Organic Loading Rate ◽  
Anammox Bacteria ◽  
Rrna Gene ◽  
Sequencing Analysis ◽  
Reactor Performance

Conventional aerated tank technology is widely applied for post treatment of natural rubber processing wastewater in Southeast Asia; however, a long hydraulic retention time (HRT) is required and the effluent standards are exceeded. In this study, a downflow hanging sponge (DHS) reactor was installed as post treatment of anaerobic tank effluent in a natural rubber factory in South Vietnam and the process performance was evaluated. The DHS reactor demonstrated removal efficiencies of 64.2 ± 7.5% and 55.3 ± 19.2% for total chemical oxygen demand (COD) and total nitrogen, respectively, with an organic loading rate of 0.97 ± 0.03 kg-COD m−3 day−1 and a nitrogen loading rate of 0.57 ± 0.21 kg-N m−3 day−1. 16S rRNA gene sequencing analysis of the sludge retained in the DHS also corresponded to the result of reactor performance, and both nitrifying and denitrifying bacteria were detected in the sponge carrier. In addition, anammox bacteria was found in the retained sludge. The DHS reactor reduced the HRT of 30 days to 4.8 h compared with the existing algal tank. This result indicates that the DHS reactor could be an appropriate post treatment for the existing anaerobic tank for natural rubber processing wastewater treatment.

scholarly journals Effects of selection and compiling strategy of substrates in column-type vertical-flow constructed wetlands on the treatment of synthetic landfill leachate containing bisphenol A

2021 ◽  
Author(s):  
Rajani Ghaju Shrestha ◽  
Daisuke Inoue ◽  
Michihiko Ike
Keyword(s):  
Activated Carbon ◽  
Bisphenol A ◽  
Landfill Leachate ◽  
Low Cost ◽  
Oxygen Demand ◽  
Ammonium Nitrogen ◽  
Pollutant Removal ◽  
Vertical Flow ◽  
Batch Mode ◽  
Synthetic Leachate

Abstract A constructed wetland (CW) is a low-cost, eco-friendly, easy-to-maintain, and widely applicable technology for treating various pollutants in the waste landfill leachate. This study determined the effects of the selection and compiling strategy of substrates used in CWs on the treatment performance of a synthetic leachate containing bisphenol A (BPA) as a representative recalcitrant pollutant. We operated five types of lab-scale vertical-flow CWs using only gravel (CW1), a sandwich of gravel with activated carbon (CW2) or brick crumbs (CW3), and two-stage hybrid CWs using gravel in one column and activated carbon (CW4) or brick crumbs (CW5) in another to treat synthetic leachate containing BPA in a 7-d sequential batch mode for 5 weeks. CWs using activated carbon (CW2 and CW4) effectively removed ammonium nitrogen (NH4-N) (99–100%), chemical oxygen demand (COD) (93–100%), and BPA (100%), indicating that the high adsorption capacity of activated carbon was the main mechanism involved in their removal. CW5 also exhibited higher pollutant removal efficiencies (NH4-N: 94–99%, COD: 89–98%, BPA: 89–100%) than single-column CWs (CW1 and CW3) (NH4-N: 76–100%, COD: 84–100%, BPA: 51–100%). This indicates the importance of the compiling strategy along with the selection of an appropriate substrate to improve the pollutant removal capability of CWs.

Septage dewatering in vertical-flow constructed wetlands located in the tropics

2001 ◽  
Vol 44 (2-3) ◽  
pp. 181-188 ◽  
Author(s):  
T. Koottatep ◽  
C. Polprasert ◽  
N. T.K. Oanh ◽  
U. Heinss ◽  
A. Montangero ◽  
...  
Keyword(s):  
Constructed Wetlands ◽  
Low Cost ◽  
Drainage System ◽  
Oxygen Demand ◽  
Free Water ◽  
Total Solid ◽  
Solid Loading ◽  
Flow Mode ◽  
Vertical Flow ◽  
N Removal

Constructed wetlands (CWs) have been proven to be an effective low-cost treatment system, which utilizes the interactions of emergent plants and microorganisms in the removal of pollutants. CWs for wastewater treatment are normally designed and operated in horizontal-flow patterns, namely, free-water surface or subsurface flow, while a vertical-flow operation is normally used to treat sludge or septage having high solid contents. In this study, three pilot-scale CW beds, each with a surface area of 25 m2, having 65 cm sand-gravel substrata, supported by ventilated-drainage system and planting with narrow-leave cattails (Typha augustifolia), were fed with septage collected from Bangkok city, Thailand. To operate in a vertical-flow mode, the septage was uniformly distributed on the surface of the CW units. During the first year of operation, the CWs were operated at the solid loading rates (SLR) and application frequencies of, respectively, 80-500 kg total solid (TS)/m2.yr and 1-2 times weekly. It was found that the SLR of 250 kg TS/m2.yr resulted in the highest TS, total chemical oxygen demand (TCOD) and total Kjeldahl nitrogen (TKN) removal of 80, 96 and 92%, respectively. The TS contents of the dewatered septage on the CW beds were increased from 1-2% to 30-60% within an operation cycle. Because of the vertical-flow mode of operation and with the effectiveness of the ventilation pipes, there were high degrees of nitrification occurring in the CW beds. The nitrate (NO3) contents in the CW percolate were 180-250 mg/L, while the raw septage had NO3 contents less than 10 mg/L. Due to rapid flow-through of the percolates, there was little liquid retained in the CW beds, causing the cattail plants to wilt, especially during the dry season. To reduce the wilting effects, the operating strategies in the second year were modified by ponding the percolate in the CW beds for periods of 2 and 6 days prior to discharge. This operating strategy was found beneficial not only for mitigating plant wilting, but also for increasing N removal through enhanced denitrification activities in the CW beds. During these 2 year operations, the dewatered septage was not removed from the CW beds and no adverse effects on the septage dewatering efficiency were observed.

scholarly journals Nitrogen removal from wastewater in an anoxic–aerobic biofilm reactor

2012 ◽  
Vol 2 (3) ◽  
pp. 165-174 ◽  
Author(s):  
M. F. Hamoda ◽  
R. A. Bin-Fahad
Keyword(s):  
Municipal Wastewater ◽  
Loading Rate ◽  
Oxygen Demand ◽  
Fold Increase ◽  
Nitrogen Loading ◽  
Biofilm Reactor ◽  
Specific Substrate ◽  
Substrate Removal ◽  
Fixed Film ◽  
Oxidised Nitrogen

A pilot plant, using a four-compartment reactor packed with Biolace media, was operated in the anoxic/aerobic submerged fixed-film (A/ASFF) and the aerobic (ASFF) modes at loadings 0.03 to 0.3 g BOD. g−1 BVS. d−1, 0.01 to 0.11 g NH3. g−1 BVS d−1, HRTs 0.7 to 8 h, C/N of 6, and 28 ± 2 °C. The system proved to be very effective in treating municipal wastewater, achieving removals up to 98% for biological oxygen demand (BOD), 75% for chemical oxygen demand (COD) and 97% for ammonia. Performance was not adversely affected by a 10-fold increase in loading rate. Both modes of operation showed high specific nitrification rates up to 96 mg N. g−1 BVS d−1, but the A/ASFF was more stable and efficient at higher loadings. Its anoxic stage removed more than 90 and 60% for BOD and COD, respectively. The A/ASFF reactor also achieved denitrification, which eliminated 3.35 mg BOD (or 6.6 mg COD) versus 1 mg denitrified NO3-N, that resulted in higher organic removals. Denitrification rate increased linearly with the TON (total oxidised nitrogen) loading applied, and specific substrate removal reached up to 114 mg TON. g−1 BVS. d−1.

scholarly journals Application of horizontal-flow anaerobic immobilized biomass reactor for bioremediation of acid mine drainage

2015 ◽  
Vol 14 (3) ◽  
pp. 399-410 ◽  
Author(s):  
R. P. Rodriguez ◽  
D. V. Vich ◽  
M. L. Garcia ◽  
M. B. A. Varesche ◽  
M. Zaiat
Keyword(s):  
Sulfate Reduction ◽  
Mine Drainage ◽  
Low Cost ◽  
Mining Industry ◽  
Oxygen Demand ◽  
Horizontal Flow ◽  
Sulfate Removal ◽  
Effluent Recirculation ◽  
Initial Ph ◽  
Immobilized Biomass

The production of low-pH effluent with sulfate and metals is one of the biggest environmental concerns in the mining industry. The biological process for sulfate reduction has the potential to become a low-cost solution that enables the recovery of interesting compounds. The present study analyzed such a process in a horizontal-flow anaerobic immobilized biomass (HAIB) reactor, employing ethanol as the carbon and energy source. Results showed that a maximal efficiency in the removal of sulfate and ethanol could only be obtained by reducing the applied sulfate load (225.1 ± 38 g m−3 d−1). This strategy led to over 75% of chemical oxygen demand (COD) and sulfate removal. Among the COD/SO42− studied ratios, 0.67 showed the most promising performance. The effluent's pH has naturally remained between 6.8 and 7.0 and the complete oxidation of the organic matter has been observed. Corrections of the influent pH or effluent recirculation did not show any significant effect on the COD and sulfate removal efficiency. Species closely related to strains of Clostridium sp. and species of Acidaminobacter hydrogenomorfans and Fusibacter paucivorans that can be related to the process of sulfate reduction were found in the HAIB reactors when the initial pH was 5 and the COD/SO42− ratio increased to 1.0.

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.

Tolerance to hydraulic and organic load fluctuations in constructed wetlands

2007 ◽  
Vol 56 (3) ◽  
pp. 39-48 ◽  
Author(s):  
F. Masi ◽  
N. Martinuzzi ◽  
R. Bresciani ◽  
L. Giovannelli ◽  
G. Conte
Keyword(s):  
Low Cost ◽  
Central Italy ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Total Coliform ◽  
Single Stage ◽  
Organic Load ◽  
Secondary Treatment ◽  
Vertical Flow ◽  
Remote Areas

This paper describes a two-year performance evaluation of four different constructed wetland (CW) treatment systems designed by IRIDRA Srl, located in central Italy. All four CW systems were established to treat wastewater effluent from different tourist activities: (1) one single-stage CW for secondary treatment of domestic wastewater (30 p.e.) at a holiday farm site; (2) a hybrid compact system consisting of two stages, a horizontal flow (HF) system followed by a vertical flow (VF) system for the secondary treatment of effluent from a 140 p.e. tourist resort; (3) a single-stage vertical flow (VF) CW for a 100 p.e. mountain shelter; and (4) a pair of single-stage, HF CWs for the secondary treatment of segregated grey and black water produced by an 80 p.e. camping site. These tourism facilities are located in remote areas and share some common characteristics concerning their water management: they have high variability of water consumption and wastewater flow, depending on the season, weather and weekly regularities; they have no connection to a public sewer and most sites are located in a sensitive environment. Total suspended solids (TSS), chemical oxygen demand (COD), biochemical oxygen demand (BOD5), ammonium (N-NH+4), nitrate (N-NOx), total nitrogen (Ntot), total phosphorus (Ptot), total coliform (TC), faecal coliform (FC), E. coli removal efficiencies for all four CW systems are presented. The results from this study demonstrate the potential of CWs as a suitable technology for treating wastewater from tourism facilities in remote areas. A very efficient COD reduction (83–95%) and pathogen elimination (3–5 logs) have been achieved. Furthermore, the CWs are easily maintained, robust (not sensitive to peak flows), constructed with local materials, and operate with relatively low cost.

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