Waste to Energy (WtE) by-products
Waste-to-Energy (WtE) treats residual waste: waste that cannot be recycled, ensuring a clean recycling stream and recovering energy for homes, offices and industry. Together with waste prevention, reuse and recycling, Waste-to-Energy contributes towards the achievement of less and safer landfills.
WtE plants recover the energy potential of waste generating electricity, heating and cooling with efficiencies of up to 95%.
The diversion of waste from landfills to Waste-to-Energy plants prevents the production of methane (CH4) emissions, which is around 100 times more potent than carbon dioxide (CO2) over a 20-year period.
Additionally, Waste-to-Energy produces electricity and heat, thereby saving emissions of CO2 that would otherwise be emitted by extracted fossil fuels.
Metals and minerals recycled from Waste-to-Energy processes prevent the unnecessary extraction of primary raw materials and the fuels needed for their extraction.
The emissions produced by Waste-to-Energy plants are among the lowest for any industry. The UK’s Environment Agency estimates that “in a year the whole Energy Recovery industry produces about one sixth of the dioxins produced by one 5th November Bonfire Night”.
Ashes and residues resulting from the combustion process of Waste-to-Energy plants are more and more channelled into recycling processes.
The reycled metals and minerals can be used for several purposes, such as road construction materials, additives to cement raw materials, in concrete manufacturing, etc.
The East Rockingham WtE in Perth, Western Australia, will start treating 300,000 tpy residual waste from mid-2020 onwards.
It will produce around 65,000 tpy bottom ash aggregate, 6,000 tpy metals, and up to 29 MW base-load electricity going into the grid. The bottom ash aggregate has pozzolanic properties and can be used in bound and un-bound applications as well as a hydraulic binder once milled.
The potential Australia wide is around 1 ton of residual waste per capita and year, equivalent to 25 mio tpy of residual waste, 5.4 mio tpy bottom ash aggregate, 541,000 tpy metals, and up to 2.4 GW base-load electricity going into the grid.
Application and Uses
WtE Bottom ash aggregate ash can be milled and used as a partial substitute for cement thanks to its hydraulic properties.
In addition to cement and concrete products, the WtE bottom ash aggregate can be used to create:
- Structural fills and embankments
- Flowable fills
- Manufactured products.