scholarly journals Influent salinity affects substrate selection in surface flow constructed wetlands

Author(s):  
Shenyan Zhou ◽  
Ran Zhao ◽  
Qiming Li ◽  
Juan Du ◽  
Chen Chen ◽  
...  

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.

2013 ◽  
Vol 68 (10) ◽  
pp. 2271-2278 ◽  
Author(s):  
Israa Abdulwahab Al-Baldawi ◽  
Siti Rozaimah Sheikh Abdullah ◽  
Nurina Anuar ◽  
Fatihah Suja ◽  
Mushrifah Idris

One of the appropriate development technology options for the treatment of wastewater contaminated with diesel is constructed wetlands (CWs). Throughout 72 days of exposure, sampling was carried out for monitoring of physical parameters, plant growth and the efficiency of total petroleum hydrocarbon (TPH) removal, as an indication for diesel contamination, to assess the pilot-scale performance. Four pilot CWs with a horizontal sub-surface flow system were applied using the bulrush of Scirpus grossus. The CWs were loaded with different diesel concentrations of 0, 0.1, 0.2 and 0.25% (Vdiesel/Vwater). The TPH removal efficiencies were 82, 71, and 67% at the end of 72 days for diesel concentrations of 0.1, 0.2, and 0.25% respectively. In addition, the high removal efficiency of total suspended solids and chemical oxygen demand (COD) were 100 and 75.4% respectively, for a diesel concentration of 0.1%. It was concluded that S. grossus is a potential plant that can be used in a well-operated CW for restoring 0.1% diesel-contaminated water.


Author(s):  
Chen-Chiang Chou ◽  
Wei-Ting Chen ◽  
Yung-Pin Tsai

Polluted river is a primary problem occurred in Changhua County, Taiwan because of rapid and massive developments of agriculture and industry. Water sample belongs to the water exhausted from influent of Yangzi-Cuo river, ci-tong jiao, Changhua County, and ecology technologies, which combined with gravel contact oxidation and surface flow constructed wetlands, are employed to enhance the water quality. Ecology technology is a useful and ordinary process which focuses on original treatment of pollution through chemical, physical, and biological procedures based on the mediums of soil, plant, water, and microorganism from pure environment. Moreover, this study aims on minimizing river pollution index (RPI) of Yangzi-Cuo river by using combinations of gravel contact oxidation and surface flow constructed wetlands. The inflow volume of water sample in suit is measured as 1,534-2,261 cubic meters per day (CMD). The major pollution in water sample involves of suspended solid (SS), ammoniacal nitrogen (NH3-N), total phosphorus (TP), total nitrogen (TN), and biochemical oxygen demand (BOD), and the values of above indexes is ranged as 10.0-26.7 mg/L, 0.9-14.0 mg/L, 1.2-14.1 mg/L, 11.1-18.2 mg/L, and 0.5-3.6 mg/L, respectively. Efficiencies of pollution elimination on SS, NH3-N, TP, TN, and BOD were depicted as 24.2-93.1%, 58.3-86.2%, 5.2-85.0%, 59.4-77.2%, and 46.3-76.4%, correspondingly, after purification treatment of ecology technology. As the result, ecology technology is benefit for the purification treatment of polluted river.


2001 ◽  
Vol 44 (11-12) ◽  
pp. 469-476 ◽  
Author(s):  
D.M. Revitt ◽  
P. Worrall ◽  
D. Brewer

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.


Author(s):  
Chen-Chiang Chou ◽  
Wei-Ting Chen ◽  
Yung-Pin Tsai

Polluted rivers are a primary problem in Changhua County, Taiwan, due to rapid and massive developments in agriculture and industry. In this study, samples consisted of water influent from the Yangzi-Cuo River, Ci-Tong Jiao, Changhua County. Ecology technology, a combination of gravel contact oxidation and surface flow constructed wetlands, was employed to enhance the water quality. Ecology technology is a useful and ordinary process that focuses on original treatment of pollution through chemical, physical, and biological procedures based on the mediums of soil, plant, water, and microorganisms from pure environments. Moreover, this study aimed to minimize the river pollution index (RPI) of the Yangzi-Cuo River by using combinations of gravel contact oxidation and surface flow constructed wetlands. The inflow volume of the water samples in situ was found to be 1534–2261 cubic meters per day (CMD). The pollution in the water sample mostly involved suspended solid (SS), ammoniacal nitrogen (NH3–N), total phosphorus (TP), total nitrogen (TN), and biochemical oxygen demand (BOD), and the values of the above indexes were found to be 10.0–26.7 mg/L, 0.9–14.0 mg/L, 1.2–14.1 mg/L, 11.1–18.2 mg/L, and 0.5–3.6 mg/L, respectively. Efficiencies of pollution elimination in SS, NH3–N, TP, TN, and BOD were found to be 24.2–93.1%, 58.3–86.2%, 5.2–85.0%, 59.4–77.2%, and 46.3–76.4%, correspondingly, after purification treatment via ecology technology. Thus, ecology technology is a valid means of purification treatment for polluted rivers.


Author(s):  
Antanas DUMBRAUSKAS ◽  
Nijolė BASTIENĖ ◽  
Petras PUNYS

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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