Treatment Of Landfill Leachate
Using Expanded Clay Aggregate (ECA®) In The Treatment Of Landfill Leachate In On-site Lagoons And Constructed Wetlands
- High-tech landfill leachate treatments systems are often shun due to high operation and construction costs. An alternative integrated technique in the treatment of landfill leachate was carried out.
- A biological treatment system was performed by collecting leachate from a community sanitary waste landfill on-site, as this area has a cool temperate continental climate.
- This treatment system was constructed in a ravine and this has been in used since June 1992.
- The filter used was Expanded Clay Aggregate (ECA®) of 12-20mm in size.
- As per the reference of National Center for Biotechnology Information, U.S. National Library of Medicine, Two (2) parallel constructed wetlands were introduced and they were planted with Typha latifolia and Phragmites australis.
- The integrated treatment system has no moving parts aside the aerators/mixers. At the end of the whole treatment process, the overall removal of Phosphorus, Nitrogen, Iron, pathogens and organic matters is about 75-96%.
- This research shows how Expanded Clay Aggregate (ECA®) is highly effective in the treatment of landfill leachate.
Physico-chemical Screening Of Phosphate-removing Substrates (Expanded Clay Aggregate) For Use In Constructed Wetland Systems
- The research objective was to show how Expanded Clay Aggregate (ECA®) as a substrate enhances phosphate removal from waste water in a constructed wetland system (subsurface horizontal flow).
- Measured properties where: Cation Exchange Capacity (CEC), pH, hydraulic conductivity, specific surface area, porosity, and phosphate (P) adsorption capacity.
- Out of the substrates used, Expanded Clay Aggregate (ECA®) showed the highest Phosphorus adsorption values, followed by limestone, and bauxite.
- On this basis, it was confirmed that Expanded Clay Aggregate (ECA®) had the great combination of properties as a substrate for constructed wetland systems.
Potential Application Of Adsorptive Media (Expanded Clay Aggregate) To Enhance Phosphorus Uptake In Stormwater Basins And Wetlands At Lake Tahoe
- Phosphorus removal by basins and wetlands in Lake Tahoe may be enhanced by fabricating the systems to filter storm-water through an aggregate media that has higher phosphorus removal capabilities than local parent material. Substrates that are rich in aluminum, calcium and iron mostly have enhanced phosphorus removal.
- The substrates can be engineered, naturally occurring, byproducts of water or industrial treatment processes, and so on.
- Phosphorus removal generally occurs through precipitation and/or chemical adsorption and much of the phosphorus can be irreversibly bound.
- The only standard medium and substrates that is highly effective in the removal of phosphorus is Expanded Aggregate Clay (ECA®).
- This medium, which possesses with a high positive surface charge, can also irreversibly remove phosphorus.
- Physical factors also affect Phosphorus removal. Particle size and specific surface area affect filtration capacity, contact area between the surface area and the water, and also blinding and clogging.
- Other non-performance factors such as costs, application logistics, and environmental considerations narrow the list of possible media for treatment or pretreatment of water bodies.
- 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 Expanded Clay Aggregate (ECA®).
- Also, high transportation costs rule out non-local products.
- Calcium products (amorphous) will eventually cementify and this will reduce the effectiveness in the filtration systems.
- Considering all these factors, Expanded Clay Aggregate, 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.