Performance of horizontal sub-surface flow constructed wetlands with different flow patterns using dual media for low-strength municipal wastewater: a case of pilot scale experiment in a tropical climate region

A new surface runoff treatment system has been designed for London Heathrow Airport, which incorporates separate floating constructed wetlands or reedbeds and sub-surface flow constructed wetlands as major pollutant removal systems. The primary requirement of the newly developed treatment system is to control the concentrations of glycols following their use as de-icers and anti-icers within the airport. The ability of reedbeds to contribute to this treatment role was fully tested through pilot scale, on-site experiments over a 2 year period. The average reductions in runoff BOD concentrations achieved by pilot scale surface flow and sub-surface flow reedbeds were 30.9% and 32.9%, respectively. The corresponding average glycol removal efficiencies were 54.2% and 78.3%, following shock dosing inputs. These treatment performances are used to predict the required full scale constructed wetland surface areas needed to attain the desired effluent water quality. The treatment system also incorporates aeration, storage and, combined with reedbed technology, has been designed to reduce a mixed inlet BOD concentration of 240 mg/l to less than 40 mg/l for water temperatures varying between 6°C and 20°C.

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Influent salinity affects substrate selection in surface flow constructed wetlands

10.21203/rs.3.rs-400950/v1 ◽

2021 ◽

Author(s):

Shenyan Zhou ◽

Ran Zhao ◽

Qiming Li ◽

Juan Du ◽

Chen Chen ◽

...

Keyword(s):

Constructed Wetlands ◽

High Salinity ◽

Chlorophyll Concentration ◽

Oxygen Demand ◽

Pilot Scale ◽

Surface Flow ◽

Substrate Selection ◽

Leaf Chlorophyll ◽

Rhizosphere Bacterial Community ◽

Surface Flow Constructed Wetlands

Abstract Conducted in pilot-scale surface flow constructed wetlands (SFCWs), this study’s objective is to identify the effect of influent salinity on substrate selection. Compared with gravel and sand SFCWs, soil SFCWs performed similarly to worse and similarly to better at low and high salinities, respectively, in removal efficiencies (REs) of salt, total nitrogen (TN), total phosphorous (TP) and chemical oxygen demand (COD). Soil generally increased macrophyte growth (especially at high salinity) in dry biomass, leaf chlorophyll concentration, root activity and root catalase and superoxide dismutase activities. The decrease of bacterial diversity in rhizosphere may be caused by high salinity, while soil improved rhizosphere bacterial community stability at varying salinities more than gravel or sand. At high salinity, soil support of macrophytes and rhizosphere microorganism increased pollutant REs in SFCWs or at least offset relatively poor biofilm attachment to soil. This highlights the necessity of the varying substrate selection in SFCWs with influent salinities for both increasing pollutant REs and reducing input cost.

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IDENTIFYING THE MOST SUITABLE AREAS FOR SURFACE FLOW WETLAND CONSTRUCTION IN LITHUANIA

Proceedings of the 7th International Scientific Conference Rural Development 2015 ◽

10.15544/rd.2015.060 ◽

2015 ◽

Author(s):

Antanas DUMBRAUSKAS ◽

Nijolė BASTIENĖ ◽

Petras PUNYS

Keyword(s):

Constructed Wetlands ◽

Ecological Status ◽

Surface Flow ◽

Gis Analysis ◽

Proximity Analysis ◽

Wetland Construction ◽

The Mean ◽

Two Phases ◽

Terrain Features ◽

Surface Flow Constructed Wetlands

GIS-based approach to find the suitable sites for surface flow constructed wetlands was employed for the Lithuanian river basins with low ecological status. According to the nature of the analysed criteria the flowchart consists of two phases. Criteria used include hydrographical network, soil properties, terrain features, land use, etc. Some of them have strictly defined values (constraints), and other ranges within certain limits (factors). Limited criteria were analysed using rejection principle and influencing factors using proximity analysis and overlay methods. Selecting the potential sites using standard GIS analysis tools there was estimated about 3286 sites for possible wetlands with the mean area of inflow basin about 4 km2 in the basins of water bodies at risk.

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