Treatment Eciencies of the Vertical Flow Pilot-Scale Constructed Wetlands for Domestic Wastewater Treatment (original) (raw)
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Ecological Engineering, 2005
In 2001, to foster the practical development of constructed wetlands (CWs) used for domestic wastewater treatment in Turkey, vertical subsurface flow constructed wetlands (30 m 2 of each) were implemented on the campus of the METU, Ankara, Turkey. The main objective of the research was to quantify the effect of different filter media on the treatment performance of vertical flow wetlands in the prevailing climate of Ankara. Thus, a gravel-filled wetland and a blast furnace granulated iron slag-filled wetland were operated identically with primarily treated domestic wastewater (3 m 3 d −1 ) at a hydraulic loading rate of 0.100 m d −1 , intermittently. Both of the wetland cells were planted with Phragmites australis. According to the first year results, average removal efficiencies for the slag and gravel wetland cells were as follows: total suspended solids (TSS) (63% and 59%), chemical oxygen demand (COD) (47% and 44%), NH 4 + -N (88% and 53%), total nitrogen (TN) (44% and 39%), PO 4 3− -P (44% and 1%) and total phosphorus (TP) (45% and 4%). The treatment performances of the slag-filled wetland were better than that of the gravel-filled wetland in terms of removal of phosphorus and production of nitrate. Since this study was a pioneer for implementation of subsurface constructed wetlands in Turkey using local sources, it has proved that this eco-technology could also be used effectively for water quality enhancement in Turkey.
Turkish Journal of Engineering and Environmental Sciences, 2004
To foster the practical development of the constructed wetlands used for water quality enhancement in Turkey, 2 vertical subsurface flow pilot-scale constructed wetlands were implemented on the METU campus, Ankara, Turkey. Both of the wetlands were planted with Phragmites australis and operated identically at a flowrate of 3 m 3 .d −1 and a hydraulic loading rate (HLR) of 0.100 m.d −1 , intermittently. The main objective of the research was to quantify the effect of different substrates (gravel and blast furnace granulated slag) on the nutrient removal performance of the constructed wetlands in the prevailing climate of Ankara. According to the monitoring study (July 2002-January 2003), concentration based average removal efficiencies for the slag and gravel reed beds were as follows: TSS (64% and 62%), COD (49% and 40%), NH + 4-N (88% and 58%), TN (41% and 44%), TP (63% and 9%) and PO 3− 4-P (60% and 4%). In general, the treatment performance of the slag system was better than that of the gravel system.
Domestic wastewater treatment performance using constructed wetland
Sustainable Water Resources Management, 2015
Constructed wetlands are treatment systems that use natural processes involving wetland vegetation, soils, and their associated microbial assemblages to improve water quality. These systems can be used commercially for efficient biological treatment of wastewater, and it will also act as a better eco-friendly method when compared with other conventional treatment methods. A constructed wetland pilot scale unit was constructed in the SRM University campus which was allowed to treat wastewater from the sewage treatment plant III. The pilot scale unit was designed based on EPA and CPCB guidelines. The dimension of the constructed wetland was 250 9 150 9 80 cm with a slope of 0.01 (1 %). The design is as per Darcy's law. The wetland unit has a cross section of 3.75 m 2 and has been designed with hydraulic loading of 0.8 m 3 /(m 2 /day) and recommended flow of 3 m 3 /day. The retention time provided for the unit was 24, 48, 72, 96, and 120 h. Phragmites australis also known as common reed was the wetland plant species planted in the unit. Six field trials were carried out during the project and with average removal efficiencies of 75.99 % for BOD, 76.16 % for COD, 57.34 % for TDS, 62.08 % for Nitrate, 58.03 % for Phosphate, 57.83 % for Potassium.
COMPARISON OF TREATMENT PERFORMANCE BETWEEN CONSTRUCTED WETLANDS WITH DIFFERENT PLANTS
Constructed wetlands have gained much importance for treating domestic, industrial and agricultural wastes and are considered as an effective secondary or tertiary treatment method. The main characteristics affect the removal efficiency of constructed wetland are the vegetation type, hydraulic residence time and substrate. The aim of the present study is to examine effect of vegetation type on organic and nutrient removal under varying hydraulic residence time in constructed wetlands. With this in mind, we have designed, constructed and operated two pilot-scale horizontal subsurface flow constructed wetlands having two different wetland vegetation plants in our open-air laboratory receiving pre-treated domestic wastewater by varying hydraulic residence time as 2, 4, 6 and 8 days. The influent wastewater is rich in orgnic matter with high variability presence of nutrients. In the first unit, the removal efficiency of COD, BOD, TN, and TP was increased from 39 to 69%, 29 to 56%, 23 to 45% and 25 to 75% when there was an increase in HRT from 2 days to 8 days respectively. In the second unit, the removal efficiency of COD, BOD, TN, and TP was increased from 31 to 68%, 25 to 52%, 26 to 36% and 40 to 77% when there was an increase in HRT from 2 days to 8 days respectively. It was found that vegetation type influenced concentration reduction. A 6-day hydraulic residence time is suggested for an acceptable level of treatment in these systems.
Linnaeus Eco-Tech, 2019
The efficiency of pollution removal from municipal sewage in two vertical flow constructed wetlands consisting of gravel filters with surface area 4 x 5 m, depth 60 cm, covered by reed was evaluated over a period of two years. The flow of wastewater was about 50 mm per day. Wastewater underwent only mechanical treatment before reed bed B, but reed bed A was supplied with wastewater after biological treatment with activated sludge. Sewage was sampled before and after filtration every IO days. Measurements were made of sewage supply and discharge, precipitation and wastewater temperatures. The main indicator of efficiency was the elimination of suspended solids, carbon, nitrogen and phosphorus from the wastewater during filtration. The elimination of the pollution load was 2-25 g per square meter per day for the BOD 5 and 0-3.5 g per square meter per day for total nitrogen. Rates of pollution removal were between 2 and 4 times as high in bed B as in bed A. The rate ofBOD 5 removal and the coefficient k for BOD5 were strongly dependent on temperature for reed bed B; less so far for bed A. The difference between summer and winter indicates that the surface area of constructed wetland B should be 3 times bigger during winter to obtain the summer rate ofBOD 5 pollution removal in the climatic conditions ofNorth Poland (54a° N).
REMOVAL EFFICIENCY OF CONSTRUCTED WETLAND FOR TREATMENT OF AGRICULTURAL WASTEWATERS
Constructed wetlands were proven to be the efficient method for treatment of agricultural wastewaters in last two decades. In this study, the performance of a constructed wetland for treating wastewater from small farm was tested. The constructed wetland for 75 PE with horizontal subsurface flow at Chrámce, Central Bohemian Uplands, Czech Republic, was built in 2011. A hybrid constructed wetland combining the horizontal (HF), vertical filter (VF) and horizontal (HF) filter stages has been designed to treat wastewater from the agriculture production (processing of fruits, sheep, pigs, production of jams, spirits and wine, etc.). The mechanical pretreatment consists of two accumulation tanks (for different wastewater types) from which the wastewater is intermittently pumped into a settling tank. The treatment system consists of two horizontal flow beds and one vertical flow bed with intermittent feeding. The filters are planted with Phragmites australis, Phalaris arundinacea, Iris pseudacorus, Iris sibirica, Glyceria maxima and Lythrum salicaria. For tertiary treatment, three shallow ponds with littoral vegetation were designed. During the feed batch operation the inflow values up to 25.400 mg/L COD and 2.640 mg/L BOD 5 were reduced by up to 99%. The volume of each feed batch was applied at one to five day intervals. Also, the effect of discharged water on the littoral zone of aquatic biotopes has been evaluated. This knowledge is necessary for the design of a stable, artificial water system.
Performance of Subsurface Vertical Flow Constructed Wetlands Receiving Municipal Wastewater
The efficiency of pollution removal from municipal sewage in two vertical flow con-structed wetlands consisting of gravel filters with a surface area of 4 ð 5 m, depth 60 cm, planted with reed (Phragmites) was assessed over a period of about two years. The flow of wastewater was 50 mm per day. Wastewater underwent only primary treat-ment before application to reed bed B, but reed bed A was supplied with wastewater after mechanical and biological treatment. Measurements were taken of sewage sup-ply and discharge, precipitation and wastewater temperatures. The main indicator of efficiency was the elimination of suspended solids, BOD 5 , nitrogen and phosphorus from the wastewater during treatment. The elimination of the pollution load was 2–25 g O 2 per square meter per day for the BOD 5 and 0–3.5 g per square meter per day for so-called "total nitrogen". Rates of pollution removal were between 2 and 4 times as high in bed B (after primary treatment) as in bed A (after biolo...
Revista AIDIS de Ingeniería y Ciencias Ambientales. Investigación, desarrollo y práctica
In this work, it is presented a summary of research articles on the main constituents of the constructed wetlands with vertical subsurface flow as well as the state of the art of this technology. Data collection was carried out at the databases Science Direct ® and Springer© and the words vertical, up flow, constructed wetland, treatment, macrophyte and substrate were used. In the first stage, they were found 164 articles and, among these, only 42 had reported aspects about the objective of this study. The results indicated that nearby 66% of wetlands constructed with vertical flow are on a pilot scale. In addition, 100% of the systems used emergent macrophytes, with the emerging species Phragmites australis (Cav.) Steud. (PH) in 21% of the wetlands. Conventional materials such as sandand gravel are still used as substrate in most systems (59%). It was also observed that 59% of the wetlands were used for domestic and/or municipal wastewater treatment and that the Asian continent had the largest number of publications of this type of system, with 50% of articles with Asian origin. The constructed wetlands with vertical subsurface flow stood out in nitrogen removal because of the depletion of oxygen in the medium existing in the base of the unit, creating anaerobic / anoxic conditions. In this way, the right choice of the constituents of this system presents an important alternative for the treatment of wastewater.
Performances of constructed wetlands for municipal wastewater treatment in rural mountainous area
Hydrobiologia, 2002
A global performance evaluation of an experimental Horizontal SubSurface Flow Constructed Wetlands (HSSF) was made after 6 years of functioning. This wetland is situated in French prealpine mountain, at 720 m elevation. The HSSF process treatment consists in a three-stage system dimensioned for 350 People Equivalent. Different helophytes were planted such as Typha latifolia, Phragmites australis and Scirpus maritimus. The mean hydraulic residence time for sewage was closed to 4-5 days, but in summer the mean pollutant residence time increases to 6 days due to an important evapotranspiration. There is no clogging of the gravel matrix and the hydraulic conductivity was very good and stabilized. Removal pollutant efficiency was determinate at each stages. There was a high removal of total suspended solids (TSS) all year around with an average of 95.6% (±3.6). More than 80% of removal occurred in the first stage. Physical processes (decantation, filtration) associated with biological oxidation were the principal factors of this removal. For COD and BOD 5 , removal efficiency in the first stage were close to 60% on average and more than 90% at the outlet of the wetland. These results are similar to those observed with SSFW in many cases. Influence of temperature seems very weak because there were no significant seasonal variations of the process efficiency. Minimum effluent quality standards (30 mg l −1 TSS; 120 mg l −1 COD; 40 mg l −1 BOD 5 ) were always respected. In cold periods, nutrients uptake was reduced but remained up to 60% in average. Mean bacterial removal efficiency was about two order of magnitude (99%) but can reach up to five order of magnitude in summer. These cyclic variations follow a sinusoidal variation around an annual mean. Pollutants removals were correlated to their respective loadings and no limits has been observed except for nitrogen. These results confirm that SSFW, an ecotechnology, should be considered as an alternative to conventional treatment methods (activated sludge, fixed biofilm) for small communities even in mountainous area.
International Journal of Innovative Research in Computer Science & Technology (IJIRCST), 2024
Experimental investigation on municipal wastewater treatment through 6 pilot scale Subsurface Vertical Flow Constructed Wetlands (SSVF CWs) was studied utilizing two conventional materials as substrate used as 12 mm size gravel overlain by 2 mm size uniformly graded coarse sand at SWINGS site of Aligarh Muslim University, Aligarh, India. Among 6 CW beds first bed was kept unplanted and rest of the 5 beds were planted with Phragmites Karka, Canna Indica, Iris, Sagittaria and Phragmites Australis for conducting comparative study among macrophytes species used in context of contaminants removal. The primary emphasis of this study was the initial few months of the CWs running in setup phase. This phase encompasses improving phases in development of substrate permeability, microbial growth on substrate and rhizosphere, until the steady state for operation was achieved. The aims of this research paper are to assess duration requirement in setup phase for SSVF CWs through variations in removal efficiencies, and also to analyse the efficacy of conventional materials as substrate in the treatment of biological oxygen demand (BOD) and chemical oxygen demand (COD). The findings indicated that following a period of 174 days of running, the CWs had achieved a state of consistent permeability and commenced a stable removal process. The removal efficiencies for BOD and COD are found as Unplanted < Iris < Canna Indica < Sagittaria < Phragmites Karka < Phragmites Australis.