Related Experiment Video
Updated: May 25, 2026
08:24
Mesocosm-Scale Constructed Wetland Design for Wastewater Treatment
Published on: May 2, 2025
Clogging influence on metals migration and removal in sub-surface flow constructed wetlands
1Department of Environmental Engineering and Sustainable Development; Polytechnic University of Bari, Via De Gasperi, 74100, Taranto, Italy. e.ranieri@poliba.it
Journal of Contaminant Hydrology
|February 7, 2012
Summary
Sub-Surface Flow Constructed Wetlands effectively remove chromium and nickel from wastewater. Increased clogging enhances metal removal by promoting adsorption to sediments and the wetland matrix.
Area of Science:
- Environmental Engineering
- Water Treatment Technologies
- Ecotoxicology
Background:
- Secondary effluent often contains toxic heavy metals like chromium (Cr) and nickel (Ni).
- Constructed wetlands are a potential sustainable solution for wastewater treatment.
- Long-term performance and influencing factors of constructed wetlands require thorough investigation.
Purpose of the Study:
- To evaluate the long-term effectiveness of Sub-Surface Flow (SSF) Constructed Wetlands (cw(s)) for chromium and nickel removal.
- To assess the impact of clogging on metal removal efficiency in SSF cw(s).
- To investigate metal accumulation in sediments and plant tissues within the wetlands.
Main Methods:
- Conducted a four-year study using small-scale and full-scale SSF cw(s).
- Monitored chromium and nickel concentrations in effluent, sediments, and Phragmites australis tissues.
- Assessed wetland clogging by measuring hydraulic conductivity and analyzing Residence Time Distribution (RTD) curves over time.
Main Results:
- SSF cw(s) demonstrated effective removal of chromium and nickel.
- Increased clogging correlated with enhanced metal accumulation in sediments, particularly for nickel.
- Adsorption to the original matrix and accumulated sediment were identified as primary removal mechanisms.
Conclusions:
- Sub-Surface Flow Constructed Wetlands are effective for removing chromium and nickel from secondary effluent.
- Wetland clogging, while affecting hydraulic properties, contributes to metal removal through adsorption.
- Long-term operation of SSF cw(s) leads to metal sequestration in sediments and plant tissues.
More Related Videos
Related Concept Videos
01:06Coagulation
Colloidal solids are solid particles suspended in solution. They are usually negatively charged, attracting a compact primary layer of positively charged ions, which attract more counterions to form an electrical double layer. Electrostatic repulsion between the charged double layers prevents the particles from colliding, stabilizing the colloids. These solids are often undesirable because they can contain toxins that are difficult to remove. Coagulation is a technique that helps aggregate and...
01:27Microbial Leaching
Microbial leaching, also known as bioleaching, is an environmentally favorable method for extracting metals from low-grade ores using specific microorganisms. This biotechnological approach is particularly valuable for mining operations targeting copper, gold, and uranium, where traditional extraction methods may be economically or environmentally impractical.Copper Leaching and Microbial CatalysisIn copper bioleaching, crushed ore is arranged into heaps and irrigated with a dilute sulfuric...
01:24Microbial Corrosion
Microbiologically Influenced Corrosion (MIC) is a significant form of material degradation caused by the metabolic activities of microorganisms. This phenomenon poses substantial challenges across various industries, including oil and gas, maritime, and water treatment sectors.MIC occurs when microorganisms, such as bacteria, archaea, and fungi, colonize metal surfaces, forming biofilms that alter the local electrochemical environment. These biofilms can lead to the production of corrosive...
01:24Microbes and Other Elemental Cycles
Microbial activity plays a pivotal role in the biogeochemical cycling of iron and manganese, especially at the redox gradients characteristic of stratified aquatic environments. These cycles are driven by microbial transformations between oxidized and reduced forms of the metals, allowing organisms to exploit them for metabolic energy and structural purposes.Iron Cycling Across Redox GradientsIn neutral, oxygen-rich surface waters, iron is predominantly found in its oxidized, insoluble ferric...
01:25Microbial Bioremediation of Uranium
Microorganisms play a critical role in the transformation and immobilization of uranium in contaminated environments through four main pathways: bioreduction, biosorption, bioaccumulation, and biomineralization. These mechanisms reduce uranium’s toxicity and prevent its migration through groundwater systems, offering sustainable approaches for in situ bioremediation.Bioreduction of UraniumBioreduction is driven by anaerobic bacteria such as certain strains of Geobacter and Shewanella, which use...
00:46Bioremediation
Bioremediation is the use of prokaryotes, fungi, or plants to remove pollutants from the environment. This process has been used to remove harmful toxins in groundwater as a byproduct of agricultural run-off and also to clean up oil spills.