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Published on: May 15, 2017
Experiments on Pilot-Scale Constructed Floating Wetlands Efficiency in Removing Agrochemicals
George Pavlidis1, Ioanna Zotou1, Helen Karasali2
1Centre for the Assessment of Natural Hazards and Proactive Planning & Laboratory of Reclamation Works and Water Resources Management, School of Rural, Surveying and Geoinformatics Engineering, National Technical University of Athens, 9 Heroon Polytechniou St., Zographou, 15780 Athens, Greece.
Constructed floating wetlands effectively remove agrochemicals, with nutrient removal up to 100% and pesticide removal up to 98.8%. These systems offer a low-cost solution for treating agricultural wastewater.
Area of Science:
- Environmental Science
- Water Treatment Technologies
- Ecotoxicology
Background:
- Agrochemicals, including nutrients and pesticides, pose significant risks to water bodies.
- Constructed floating wetlands (CFWs) are a potential nature-based solution for wastewater treatment.
- The efficacy of different aquatic plant species in CFWs for agrochemical removal requires further investigation.
Purpose of the Study:
- To evaluate the efficiency of CFWs planted with specific aquatic macrophytes in removing nutrients and pesticides from agricultural wastewater.
- To compare the performance of CFWs with different plant species (Lemna minor, Azolla pinnata, Eichhornia crassipes) and a plant-free control.
- To assess the feasibility of CFWs as a sustainable pollution control technology for agrochemical wastewater under field conditions.
Main Methods:
- Pilot-scale CFWs were operated continuously for four months (May-September 2021).
- Three CFWs were planted with Lemna minor, Azolla pinnata, and Eichhornia crassipes, respectively; one served as a plant-free control.
- Agricultural wastewater spiked with fertilizers and pesticides was treated, with hydraulic residence time maintained at 14 days. Influent and effluent samples were analyzed weekly using HPLC-DAD and Ion Chromatography.
Main Results:
- Nutrient removal efficiencies ranged from 0% to 100%.
- Pesticide removal efficiencies varied from 0% to 98.8%.
- The control tank (algae only) demonstrated significant pesticide reduction, highlighting algae's role in organic pollution mitigation and suggesting limitations for certain plant applications in decontamination.
Conclusions:
- CFWs demonstrate significant potential for the efficient and low-cost removal of agrochemicals from wastewater.
- The presence of specific aquatic plants influences removal efficiencies, but algae also play a crucial role in pesticide degradation.
- CFWs represent a viable and sustainable technology for managing agrochemical pollution in agricultural runoff.
