scholarly journals Role of Natural Wetlands in Arsenic Removal from Arsenic-Contaminated Runoff

2019 ◽  
pp. 8-21
Author(s):  
Vanlop Thathong ◽  
Netnapid Tantamsapya ◽  
Chatpet Yossapol ◽  
Chih-Hsiang Liao ◽  
Wanpen Wirojanagud
Keyword(s):  
Surface Water ◽  
Plant Species ◽  
Water Flow ◽  
Removal Efficiency ◽  
Arsenic Removal ◽  
Natural Wetlands ◽  
Wetland System ◽  
Vegetation Species ◽  
Translocation Factors

This research aims to identify the role of natural wetlands in arsenic (As) removal. Phu Lek wetland in Loei Province, Thailand, was selected as the study area. Monthly samples of water (144), plant (360), and sediment (144) were collected from the wetland for 24 months. As concentration in the surface water at the wetland inlet was 0.85±0.26 mg L-1, and 0.02±0.01 mg L-1 at the wetland outlet. It was observed that the As level in water decreased significantly along its flow path, with an As removal efficiency of 98 %. As concentration in the sediment was 89.53-356.22 mg kg-1 at the inlet of wetland, but decreased gradually downstream of the water flow. Three dominant emergent plant species were observed in this wetland. As accumulation (0.02-2.37 mg kg-1) was noted in all the parts of the three plant species. As content was the highest in the rootlet (0.00-1.27 mg kg-1) compared to that in foliage (0.00-0.84 mg kg-1), leaf stalk (0.00-1.86 mg kg-1), and rhizome (0.00-2.64 mg kg-1). The level of As in the different vegetation species was in the order Diplazium esculentum > Colocasia esculenta > Lasia spinose. Further, As entrapment in the different plant plants followed the order rootlet > rhizome > foliage > leaf stalk. All the three plant species showed high bioconcentrationfactors, with values of 0.03-1.28, 0.02-0.93, 0.00-0.84, and 0.00-0.38at the rootlet, rhizome, foliage, and leaf stalk, respectively, but had low translocation factors (foliage/rootlet: 0.02-0.90 and leaf stalk/rootlet: 0.00-0.44). In summary, As present in the surface water could be effectively removed by the wetland system.

scholarly journals Evaluation of Tannery Wastewater Treatment by Integrating Vesicular Basalt With Local Plant Species in a Constructed Wetland System

2021 ◽  
Vol 9 ◽  
Author(s):  
Agegnehu Alemu ◽  
Nigus Gabbiye ◽  
Brook Lemma
Keyword(s):  
Plant Species ◽  
Removal Efficiency ◽  
Constructed Wetland ◽  
Subsurface Flow ◽  
Oxygen Demand ◽  
Tannery Wastewater ◽  
Local Plant ◽  
Vesicular Basalt ◽  
Wetland System ◽  
Horizontal Subsurface Flow

Tannery wastewater is composed of a complex mixture of organic and inorganic components from various processes that can critically pollute the environment, especially water bodies if discharged without treatment. In this study, integrated vesicular basalt rock and local plant species were used to establish a horizontal subsurface flow constructed wetland system and to investigate the treatment efficiency of tannery wastewater. Four pilot units were vegetated with P. purpureum, T. domingensis, C. latifolius, and E. pyramidalis, and a fifth unit was left unvegetated (control). The constructed wetland units in horizontal subsurface flow systems were effective in removing total chromium (Cr), chemical oxygen demand (COD), and 5-day biological oxygen demand (BOD5) from the inflow tannery wastewater. The removal efficiency reached up to 99.38, 84.03, and 80.32% for total Cr, COD, and BOD5, respectively, in 6 days of hydraulic retention time (HRT). The removal efficiency of total suspended solid (TSS), total phosphorus (TP), and nitrate (NO3−) of the constructed wetland units reached a maximum of 70.59, 62.32, and 71.23%, respectively. This integrated system was effective for treating tannery wastewater, which is below the Ethiopian surface water standard discharge limit set to BOD5 (200 mg L−1), COD (500 mg L−1), total Cr (2 mg L−1), NO3− (20 mg L−1), TSS (50 mg L−1), and TP (10 mg L−1).

Radon removal by aeration: observations on testing, installation and maintenance of domestic treatment units

2009 ◽  
Vol 9 (4) ◽  
pp. 469-475
Author(s):  
T. Turtiainen
Keyword(s):  
Water Quality ◽  
Water Flow ◽  
Removal Efficiency ◽  
Flow Rate ◽  
Test Protocol ◽  
Household Water ◽  
Medium Flow ◽  
Removal Efficiencies ◽  
Frequent Sampling

Radon is one of the contaminants that sometimes impair the water quality of wells, especially those drilled in bedrock. Domestic radon removal units based on aeration have been commercially available for more than ten years. In order to determine how effectively these units remove radon a new test protocol applying frequent sampling while letting 100 litres of water flow, was developed. This way, removal efficiencies can be more accurately calculated and possible malfunctions detected. Seven models of domestic aerators designed for removing radon from household water were tested. The aerators were based on diffused bubble aeration, spray aeration or jet aeration. The average removal efficiencies for 100 litres with a medium flow rate were 86–100% except for a unit that circulated the aerated water back to the well that had removal efficiency of 80% at the maximum. By conducting a questionnaire study usual problems related to the aeration units were localized and recommendations on maintenance and installation are given accordingly.

Kinetics and Removal Efficiency of Nitrogen in Constructed Wetlands Cultivated with Different Plant Species for Treating Swine Wastewater Applied at Different Rates

2021 ◽  
Vol 232 (1) ◽  
Author(s):  
Fátima Resende Luiz Fia ◽  
Antonio Teixeira de Matos ◽  
Ronaldo Fia ◽  
Mateus Pimentel de Matos ◽  
Alisson Carraro Borges ◽  
...  
Keyword(s):  
Plant Species ◽  
Removal Efficiency ◽  
Constructed Wetlands ◽  
Swine Wastewater

Plant species surplus in recent peri-urban forests: the role of forest connectivity, species’ habitat requirements and dispersal types

2021 ◽  
Vol 30 (2) ◽  
pp. 365-384
Author(s):  
Elena Tello-García ◽  
Nancy Gamboa-Badilla ◽  
Enrique Álvarez ◽  
Laura Fuentes ◽  
Corina Basnou ◽  
...  
Keyword(s):  
Plant Species ◽  
Urban Forests ◽  
Habitat Requirements ◽  
Forest Connectivity ◽  
Dispersal Types

scholarly journals Invasion landscapes as social‐ecological systems: Role of social factors in invasive plant species control

2021 ◽  
Author(s):  
Johanna Yletyinen ◽  
George L. W. Perry ◽  
Olivia R. Burge ◽  
Norman W. H. Mason ◽  
Philip Stahlmann‐Brown
Keyword(s):  
Plant Species ◽  
Social Factors ◽  
Invasive Plant ◽  
Ecological Systems ◽  
Invasive Plant Species ◽  
Social Ecological Systems ◽  
Social Ecological

scholarly journals Arsenic Removal by Advanced Electrocoagulation Processes: The Role of Oxidants Generated and Kinetic Modeling

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 928
Author(s):  
Micah Flor V. Montefalcon ◽  
Meliton R. Chiong ◽  
Augustus C. Resurreccion ◽  
Sergi Garcia-Segura ◽  
Joey D. Ocon
Keyword(s):  
Kinetic Modeling ◽  
Arsenic Removal ◽  
Fold Increase ◽  
Electrochemical Treatment ◽  
Promising Alternative ◽  
Iron Electrodes ◽  
Removal Capacity ◽  
Naturally Occurring ◽  
Treatment Technologies

Arsenic (As) is a naturally occurring element in the environment that poses significant risks to human health. Several treatment technologies have been successfully used in the treatment of As-contaminated waters. However, limited literature has explored advanced electrocoagulation (EC) processes for As removal. The present study evaluates the As removal performance of electrocoagulation, electrochemical peroxidation (ECP), and photo-assisted electrochemical peroxidation (PECP) technologies at circumneutral pH using electroactive iron electrodes. The influence of As speciation and the role of oxidants in As removal were investigated. We have identified the ECP process to be a promising alternative for the conventional EC with around 4-fold increase in arsenic removal capacity at a competitive cost of 0.0060 $/m3. Results also indicated that the rate of As(III) oxidation at the outset of electrochemical treatment dictates the extent of As removal. Both ECP and PECP processes reached greater than 96% As(III) conversion at 1 C/L and achieved 86% and 96% As removal at 5 C/L, respectively. Finally, the mechanism of As(III) oxidation was evaluated, and results showed that Fe(IV) is the intermediate oxidant generated in advanced EC processes, and the contribution of •OH brought by UV irradiation is insignificant.

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