The use of Expanded Clay Aggregate (ECA®) over other aggregates in the treatment or pretreatment of surface waters and lake bodies is dependent on the following factors:
- Expanded Clay Aggregate (ECA®) physical properties
- Expanded Clay Aggregate (ECA®) Performance propertie
The physical properties of Expanded Clay Aggregate (ECA®) includes the following:
- It’s dependable and consistent
- Expanded Clay Aggregate (ECA®) is chemically and physically inert
- Expanded Clay Aggregate (ECA®) has great hydraulic conductivity which allows fast and free drainage/binding of pollutants such as phosphorus.
- It has an increased surface area
- Due to its ceramic properties, it reduces material degradation
- Reduced handling costs
- Expanded Clay Aggregate (ECA®) has a lower maintenance cost and it’s economical
- It’s readily available and easy to use in treatment of waste water, sewage and industrial effluents.
- It has a predictable performance and longevity
- It employs ion exchange for an effective treatment process
- It removes solid material that can bring about clogging
- Effective reduction or removal of arsenic, phosphorus, metals, oil, grease and poisonous hydrocarbons.
- It combines effluent filtration and nutrients removal for cleaner discharge.
- It has a greater surface area which makes filtration of pollutants effective.
- Industrial by-products such as slags are very risky to introduce due to possible leaching properties of heavy metals and this cannot be easily foreseen.
- Substrates such as fly ash and other fine particles would be more difficult to use because they would have to be blended, making them less desirable and they are more costly to apply than larger diameter media such as ECA®.
- Also, high transportation costs rule out non-local products.
- Lastly, calcium products (amorphous) will eventually cementify and this will reduce the effectiveness in the filtration systems.
- Considering all these factors, Expanded Clay Aggregate (ECA®), dolomite and all other natural activated diatomaceous earth are the substrates most likely to be used for treatment or pretreatment of water at Tahoe.
- These materials are specifically, aluminum, iron or calcium based and many of these have a high specific surface area; and all have low transportation costs.