Surface-Flow Constructed Treatment Wetlands for Pollutant Removal: Applications and Perspectives

Wetlands ◽  
2011 ◽  
Vol 31 (4) ◽  
pp. 805-814 ◽  
Author(s):  
Hongjun Chen
Keyword(s):  
Surface Flow ◽  
Pollutant Removal ◽  
Treatment Wetlands ◽  
Constructed Treatment Wetlands

Do macrophytes play a role in constructed treatment wetlands?

1997 ◽  
Vol 35 (5) ◽  
pp. 11-17 ◽  
Author(s):  
Hans Brix
Keyword(s):  
Surface Flow ◽  
Treatment Wetlands ◽  
Treatment Processes ◽  
Aquatic Mosses ◽  
Flow Systems ◽  
Physical Effects ◽  
Removal Processes ◽  
Constructed Treatment Wetlands ◽  
Uptake Of Nutrients

The larger aquatic plants growing in wetlands are usually called macrophytes. These include aquatic vascular plants, aquatic mosses and some larger algae. The presence or absence of aquatic macrophytes is one of the characteristics used to define wetlands, and as such macrophytes are an indispensable component of these ecosystems. As the most important removal processes in constructed treatment wetlands are based on physical and microbial processes, the role of the macrophytes in these has been questioned. This paper summarizes how macrophytes influence the treatment processes in wetlands. The most important functions of the macrophytes in relation to the treatment of wastewater are the physical effects the presence of the plants gives rise to. The macrophytes stabilise the surface of the beds, provide good conditions for physical filtration, prevent vertical flow systems from clogging, insulate the surface against frost during winter, and provide a huge surface area for attached microbial growth. Contrary to earlier belief, the growth of macrophytes does not increase the hydraulic conductivity of the substrate in soil-based subsurface flow constructed wetlands. The metabolism of the macrophytes affects the treatment processes to different extents depending on the type of the constructed wetland. Plant uptake of nutrients is only of quantitative importance in low-loaded systems (surface flow systems). Macrophyte mediated transfer of oxygen to the rhizosphere by leakage from roots increases aerobic degradation of organic matter and nitrification. The macrophytes have additional site-specific values by providing habitat for wildlife and making wastewater treatment systems aesthetically pleasing.

scholarly journals A Review of the Influence of Design Parameters on the Performance of Constructed Wetlands

1970 ◽  
pp. 29-42 ◽  
Author(s):  
Ronnie AD Frazer-Williams
Keyword(s):  
Chemical Engineering ◽  
Surface Flow ◽  
Pollutant Removal ◽  
Treatment Wetlands ◽  
Design Parameters ◽  
Design Criteria ◽  
First Order ◽  
Hydraulic Loading ◽  
First Order Kinetics ◽  
Organic Removal

This study reviews the influence of wetland design criteria (Kickuth equation, area sizing, first order kinetics) and operation parameters (hydraulic and influent loading) on pollutant removal (organics, solids, nutrients and coliforms) in both subsurface and surface flow systems. Results showed that despite high removal efficiency reported for most wetlands, residual concentrations for BOD are frequently higher than those predicted based on the 95 percentile first-order Kickuth design equation. Also correlation results indicate that hydraulic and pollutant loading strongly influence wetland performance for organic removal (BOD, COD). In all cases, removal generally decreases as loading increases. Hydraulic loading was not found to correlate with nutrient removal. Overall, it can be concluded that organic removal can be modeled better compared to nutrient in treatment wetlands. Since removal of solids and coliforms are not primarily influenced by the key design parameters, it is expected that they will fit into any design model developed. Keywords design criteria; hydraulic loading; removal. DOI: 10.3329/jce.v25i0.7237Journal of Chemical Engineering, IEB Vol. ChE. 25, No. 1, December 2010 pp.29-42

Removal of Total Coliform and TSS for Hospital Wastewater by Optimizing the Role of Typha Angustifolia and Fine Sand-Gravel Media in Horizontal Sub Surface Flow Constructed Wetland

2021 ◽  
Vol 12 (1) ◽  
pp. 20-31
Author(s):  
Abdul Gani Akhmad
Keyword(s):  
Retention Time ◽  
Hydraulic Retention Time ◽  
Fine Sand ◽  
Pilot Scale ◽  
Total Coliform ◽  
Surface Flow ◽  
Pollutant Removal ◽  
Typha Angustifolia ◽  
Hospital Wastewater

This study aims to evaluate the performance of a pilot-scale HSSF-CW utilizing Typha angustifolia and fine sand-gravel media in removing total coliform and TSS from hospital wastewater. Three pilot-scale HSSF-CW cells measuring 1.00 x 0.45 x 0.35 m3 were filled with gravel sand media with a diameter of 5 - 8 mm as high as 35 cm with a submerged media depth of 0.30 m. There were three treatments, namely the first cell (CW1) without plants, the second cell (CW2) was planted with a density of 12 Typha angustifolia plants, and the third cell (CW3) was planted with a density of 24 Typha angustifolia plants. The three HSSF-CW cells received the same wastewater load with total coliform and TSS contents of 91000 MPN / 100 mg and 53 mg / L, respectively, with Hydraulic Loading Rates 3,375 m3 per day. Wastewater was recirculated continuously to achieve the equivalent HSSF-CW area requirement. The experimental results show that the performance of CW3 is more efficient than CW1 and CW2 in total coliform and TSS removal for hospital wastewater. The pollutant removal efficiency at CW3 reached 91.76% for total coliform with one day hydraulic retention time and 81.00% for TSS with two days of hydraulic retention time. This study concludes that the HSSF-CW system using sand-gravel media with a diameter of 5 - 8 mm with a submerged media depth of 0.30 m and planted with Typha angustifolia with a tighter spacing proved to be more efficient in removing total coliform and TSS from hospital wastewater.

Experimental reedbed systems for the treatment of airport runoff

1997 ◽  
Vol 36 (8-9) ◽  
pp. 385-390 ◽  
Author(s):  
D. M. Revitt ◽  
R. B. E. Shutes ◽  
N. R. Llewellyn ◽  
P. Worrall
Keyword(s):  
Pilot Scale ◽  
Surface Flow ◽  
Pollutant Removal ◽  
Biological Processes ◽  
Metal Concentrations ◽  
Physical Chemical ◽  
Flow Systems ◽  
Total Ammonia ◽  
Removal Efficiencies

The relative efficiencies of pollutant removal from airport runoff by three different designs of pilot scale reedbed treatment systems located at Heathrow airport are described. The sub-surface flow and surface flow systems generally performed more effectively than the rafted systems for reduction of BOD, COD, total ammonia, nitrate, phosphate and metal concentrations. The variable removal efficiencies are explained in terms of the physical, chemical and biological processes which are relevant to each reedbed system.

scholarly journals Role of Microorganisms in the Remediation of Wastewater in Floating Treatment Wetlands: A Review

2020 ◽  
Vol 12 (14) ◽  
pp. 5559 ◽  
Author(s):  
Munazzam Jawad Shahid ◽  
Ameena A. AL-surhanee ◽  
Fayza Kouadri ◽  
Shafaqat Ali ◽  
Neeha Nawaz ◽  
...  
Keyword(s):  
Bacterial Species ◽  
Complex Compounds ◽  
Pollutant Removal ◽  
Specific Role ◽  
Treatment Wetlands ◽  
Plant Microbe Interaction ◽  
Removal Process ◽  
Floating Treatment Wetlands ◽  
Insight Into

This article provides useful information for understanding the specific role of microbes in the pollutant removal process in floating treatment wetlands (FTWs). The current literature is collected and organized to provide an insight into the specific role of microbes toward plants and pollutants. Several aspects are discussed, such as important components of FTWs, common bacterial species, rhizospheric and endophytes bacteria, and their specific role in the pollutant removal process. The roots of plants release oxygen and exudates, which act as a substrate for microbial growth. The bacteria attach themselves to the roots and form biofilms to get nutrients from the plants. Along the plants, the microbial community also influences the performance of FTWs. The bacterial community contributes to the removal of nitrogen, phosphorus, toxic metals, hydrocarbon, and organic compounds. Plant–microbe interaction breaks down complex compounds into simple nutrients, mobilizes metal ions, and increases the uptake of pollutants by plants. The inoculation of the roots of plants with acclimatized microbes may improve the phytoremediation potential of FTWs. The bacteria also encourage plant growth and the bioavailability of toxic pollutants and can alleviate metal toxicity.

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