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Model simulations of particle aggregation effect on colloid exchange between streams and streambeds
Trachu Areepitak1, Jianhong Ren
1Department of Environmental Engineering, Texas A&M University-Kingsville, Kingsville, Texas 78363, United States.
Environmental Science & Technology
|June 2, 2011
Summary
Colloid aggregation in streams can either increase or decrease pollutant retention in streambeds. This new model considers particle interactions, improving predictions of colloid and contaminant transport.
Area of Science:
- Environmental Science
- Geochemistry
- Hydrology
Background:
- Colloids in natural streams act as carriers for pollutants due to their large surface areas.
- Stream-subsurface exchange is crucial for regulating colloid and contaminant transport.
- Existing models overlook colloid-colloid interactions, particularly aggregation, which is a significant process.
Purpose of the Study:
- To develop a new colloid exchange model incorporating particle aggregation.
- To analyze the impact of colloid aggregation on colloid transport and retention in streams.
Main Methods:
- Developed a new colloid exchange model by integrating particle aggregation with colloid settling and filtration.
- Employed self-preserving size distribution concepts and classical aggregation theory to model aggregation.
- Conducted model simulations to assess the influence of aggregation under varying conditions.
Main Results:
- Aggregation's effect on colloid retention depends on initial particle size, potentially leading to enhanced deposition or facilitated transport.
- High particle-particle interaction and low filtration favor aggregation.
- Increased filtration and aggregation rates lead to greater particle retention by bed sediments, diminishing aggregation's impact on deposition.
Conclusions:
- Colloid aggregation significantly influences colloid and contaminant transport in streams.
- The developed model provides a more comprehensive understanding of colloid dynamics.
- Accurate prediction of colloid transport phenomena requires consideration of aggregation processes.
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