scholarly journals Time plots, trends and seasonal growth/ decay of Cr removal in vertical subsurface flow sewage treatment wetland

2018 ◽  
Vol 1 (4) ◽  
Author(s):  
Celestin Defo 1 ◽  
Ravinder Kaur 2
Keyword(s):  
Constructed Wetlands ◽  
Sewage Treatment ◽  
Research Work ◽  
Subsurface Flow ◽  
Seasonal Growth ◽  
Treatment Wetland ◽  
Metal Concentrations ◽  
Adsorption Processes ◽  
The Media ◽  
Wastewater Samples

The present research work aimed at analysing the time series and estimation of seasonal growth/ decay of heavy metals dynamics in the vertical subsurface flow constructed wetlands (VSSFCWs) planted with Typha, Phragmites, Vaccha, Arundo and Vetiver on gravel media. Monthly plant and wastewater samples were collected for 15 months from the VSSF CWs. Plant and water samples were pre-treated in the laboratory, digested using diacid and their heavy metal concentrations were determined using atomic absorption spectrophotometer after filtration. The Main results indicated that the maximum uptakes of metals by plant occurred in summer while the minimum plant uptakes were recorded in winter, regardless of metal concentrations applied and the trends showed a slightly stable profile irrespectively to the level of concentration applied. For the adsorption processes of Cr in the media (gravel) of the constructed wetlands, it appeared that this process was not significantly changing as function of time, except for Cr 1.5 ppm.

Application of culture-independent methods to assess the bacteria removal efficiency of subsurface flow constructed wetlands

2007 ◽  
Vol 56 (3) ◽  
pp. 217-222 ◽  
Author(s):  
M. Alexandrino ◽  
E. Grohmann ◽  
R. Szewzyk ◽  
U. Szewzyk
Keyword(s):  
Removal Efficiency ◽  
Constructed Wetlands ◽  
Subsurface Flow ◽  
Current Standard ◽  
Enteropathogenic Bacteria ◽  
Culture Independent ◽  
Wastewater Quality ◽  
Subsurface Flow Constructed Wetlands ◽  
Wastewater Samples ◽  
Bacteria Removal

The bacteriologic treatment efficiency of vertical and horizontal subsurface flow constructed wetlands (SFCWs) was analysed in two multistage wastewater treatment systems by culture dependent and independent methods. When assessed with standard cultivation procedures, bacteria removal efficiency of the vertical and horizontal SFCWs was similar. However, microscopic enumerations of the wastewater bacteria after DNA staining revealed a completely different removal pattern: bacteria removal efficiency of the horizontal SFCWs was in general low and erratic, whereas the vertical SFCWs displayed high bacteria removal rates. The discrepancies in the results obtained by bacteria enumeration and cultivation was due to a strong decrease in bacterial culturability after treatment by the horizontal SFCWs, leading to overestimation of the real bacterial concentrations in these effluents. Additionally, a PCR based approach for the detection of the enteropathogenic bacteria Campylobacter jejuni and Yersinia enterocolitica was tested in the wastewater samples. The methods were specific and reproducible in the analysed samples and could be carried out within 12 h, proving very adequate as an alternative to cultivation. This work recommends a review of the current standard methodology for wastewater quality surveillance, as well as of the design of SFCW.

Fractional analysis of arsenic in subsurface-flow constructed wetlands with different length to depth ratios

2009 ◽  
Vol 60 (7) ◽  
pp. 1771-1778 ◽  
Author(s):  
C. Singhakant ◽  
T. Koottatep ◽  
J. Satayavivad
Keyword(s):  
Constructed Wetlands ◽  
Subsurface Flow ◽  
Volume Ratio ◽  
Pilot Scale ◽  
Sequential Fractionation ◽  
Fractional Analysis ◽  
The Media ◽  
Subsurface Flow Constructed Wetlands ◽  
Dispersion Number ◽  
Iron And Manganese

Arsenic (As) removal in subsurface-flow constructed wetlands (CW) planting with vetiver grasses was experimented by comparing between two different configurations; (i) deep-bed units (dpCW) with length to depth (L:D) ratio = 2 and (ii) shallow-bed units (shCW) with L:D ratio = 8; operating at hydraulic retention time (HRT) of 6, 9, and 12 days. The tracer study of CW units revealed that no effect of L:D ratio on dispersion number could be determined, but affecting to the effective volume ratio. Based on the data obtained from the pilot-scale experiments of CW units for 117 days, it is apparent that the dpCW could achieve relatively high As removals (52.9%, 59.2%, and 72.1% at HRT of 6, 9, and 12 days, respectively). Analysis of As mass balance showed that only 0.2–0.4% of As input was uptaken by vetiver grasses whereas the major portion was retained in the CW media (38.9–77.6%). Forms of the retained As was determined by sequential fractionation which could indicate As complexation with iron and manganese on the media surface of 31–38% and As trapping into the media of 42–52% of the total. No obvious difference of As fractions in bed of between dpCW and shCW units was observable.

scholarly journals Performance of a Pilot Subsurface Flow Treatment Wetland System, Used for Arsenic Removal from Reverse Osmosis Concentrate, in the Municipality of Julimes, Chihuahua, Mexico

2020 ◽  
Vol 24 ◽  
Author(s):  
Mario Alberto Olmos-Márquez ◽  
Jesús Manuel Ochoa-Rivero ◽  
María Teresa Alarcón-Herrera ◽  
Eduardo Santellano-Estrada ◽  
José Humberto Vega-Mares ◽  
...  
Keyword(s):  
Reverse Osmosis ◽  
Constructed Wetlands ◽  
Arsenic Removal ◽  
Arsenic Concentration ◽  
Subsurface Flow ◽  
Treatment Wetlands ◽  
Agricultural Irrigation ◽  
Treatment Wetland ◽  
Wetland System ◽  
Flow Treatment

The objective of this study was to implement a pilot system of treatment wetlands, using phytoremediation as an alternative technology to remove arsenic from the concentrate of a reverse osmosis system. The pilot system was composed of two subsurface flow constructed wetlands, planted with Eleocharis macrostachya and Shoenoplectus americanus. The wetlands were fed concentrate from a reverse osmosis system for seven months, with an average flow of 962 Ld-1 and an average arsenic concentration of 0.241 mgL-1. Removal rates between 43 % and 86 % were obtained for wetland 1 and between 35 % and 79 % for wetland 2 throughout the experiment. The two plant species developed normally despite the high levels of electrical conductivity in the range of 3584 to 5455 µscm-1 in wetland intake waters. The pilot wetland system removed significant levels of arsenic from the reverse osmosis concentrate, resulting in arsenic levels in the output waters that meet Mexican standard for using water in agricultural irrigation.

scholarly journals Arsenic Removal Using Horizontal Subsurface Flow Constructed Wetlands: A Sustainable Alternative for Arsenic-Rich Acidic Waters

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1447 ◽  
Author(s):  
Katherine Lizama-Allende ◽  
Ignacio Jaque ◽  
José Ayala ◽  
Gonzalo Montes-Atenas ◽  
Eduardo Leiva
Keyword(s):  
Constructed Wetlands ◽  
Arsenic Removal ◽  
Mine Drainage ◽  
Subsurface Flow ◽  
Neutralization Capacity ◽  
Media Type ◽  
The Media ◽  
Acidic Waters ◽  
Horizontal Subsurface Flow ◽  
Removal Of Arsenic

Constructed wetlands (CW) have been widely used to treat different types of water, including acid mine drainage (AMD). However, little is known about their performance in the removal of As from AMD. In this study, a laboratory-scale horizontal subsurface flow (HSSF) CW system was tested to evaluate its capacity to treat highly acidic, As-rich contaminated water resembling AMD. Vegetated and non-vegetated cells, having limestone or zeolite as the main supporting media, were built and operated to evaluate the effect of the media type and the presence of Phragmites australis on the removal of arsenic, iron (Fe), lead (Pb), and zinc (Zn), and on the neutralization capacity. The four types of cells were highly effective in the removal of As and Pb (removal > 99%), and Fe (removal > 98%), whereas Zn removal rates depended on the cell type. Limestone cells raised the pH from ~1.9 to ~7.5, while zeolite cells raised it to ~4. These results suggest that the media type has a key role in the neutralization capacity, and that the presence of vegetation affected mainly the removal of Zn. Knowledge from this study will contribute to guiding the implementation of HSSF CW for treating As-rich AMD.

Performance evaluation of wastewater treatment using horizontal subsurface flow constructed wetlands optimized by micro-aeration and substrate selection

2015 ◽  
Vol 71 (9) ◽  
pp. 1317-1324 ◽  
Author(s):  
Fei Zhong ◽  
Juan Wu ◽  
Yanran Dai ◽  
Dongfang Xiang ◽  
Shuiping Cheng ◽  
...  
Keyword(s):  
Constructed Wetlands ◽  
Sewage Treatment ◽  
Subsurface Flow ◽  
Oxygen Demand ◽  
Ammonium Nitrogen ◽  
Domestic Sewage ◽  
Substrate Selection ◽  
N Removal ◽  
Horizontal Subsurface Flow ◽  
The Individual

The effects of micro-aeration and substrate selection on domestic sewage treatment performance were explored using three pairs (with or without micro-aeration) of horizontal subsurface flow (HSSF) constructed wetlands (CWs) filled with zeolite, ceramsite or quartz granules. The individual and combined effects of micro-aeration and substrate selection on the purification performance of the experimental-scale HSSF CWs were evaluated. The results showed that micro-aeration significantly increased the treatment efficiencies for chemical oxygen demand, total nitrogen, total phosphorus (TP), ortho-phosphate (PO43−-P) and ammonium nitrogen (NH4+-N) using HSSF CWs, while the substrate selection significantly affected the TP, PO43−-P and NH4+-N removal efficiencies (p < 0.05). A two-way analysis of variance (ANOVA) indicated that there was a significant interaction term (i.e. micro-aeration × substrate selection) for NH4+-N removal (p < 0.05). Among the three substrates, ceramsite was the best substrate for the treatment of domestic sewage using HSSF CWs. Therefore, the results of this study suggest that a ceramsite-filled HSSF CW with micro-aeration could be the optimal configuration for decentralized domestic sewage treatment.

Media selection for sustainable phosphorus removal in subsurface flow constructed wetlands

2001 ◽  
Vol 44 (11-12) ◽  
pp. 47-54 ◽  
Author(s):  
H. Brix ◽  
C.A. Arias ◽  
M. del Bubba
Keyword(s):  
Sorption Capacity ◽  
Constructed Wetlands ◽  
Binding Capacity ◽  
Subsurface Flow ◽  
P Sorption ◽  
P Sorption Capacity ◽  
The Media ◽  
Subsurface Flow Constructed Wetlands ◽  
Clay Aggregates ◽  
P Removal

Sorption of phosphorus (P) to the bed sand medium is a major removal mechanism for P in subsurface flow constructed wetlands. Selecting a sand medium with a high P-sorption capacity is therefore important to obtain a sustained P-removal. The P-removal capacities of 13 Danish sands were evaluated and related to their physico-chemical characteristics. The P-removal properties of sands of different geographical origin varied considerably and the suitability of the sands for use as media in constructed reed beds thus differs. The P-sorption capacity of some sands would be used up after only a few months in full-scale systems, whereas that of others would subsist for a much longer time. The most important characteristic of the sands determining their P-sorption capacity was their Ca-content. Also the P-binding capacities of various artificial media were tested (light-expanded-clay-aggregates (LECA), crushed marble, diatomaceous earth, vermiculite and calcite). Particularly calcite and crushed marble were found to have high P-binding capacities. It is suggested that mixing one of these materials into the sand or gravel medium can significantly enhance the P-sorption capacity of the bed medium in a subsurface-flow constructed wetland system. It is also possible to construct a separate unit containing one of these artificial media. The media may then be replaced when the P-binding capacity is used up.

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