Repurpose Ash, The Useful Byproduct Of An Air Curtain Burner

After efficiently burning your debris with an air curtain burner, you will be left with ash. Some people will bring their ash to a local dump. That requires finding one within a reasonable distance that doesn’t have a high dump fee. Normally the amount of ash left over is very small, so this is often a viable solution. However, if someone would like to avoid spending money on dump fees, they can often get rid of the ash for free- or even make a little money. So how much ash will be left over after you use an air curtain destructor and what are other uses for it?

How much ash is left after burning?

After using an air curtain incinerator to burn your debris, the amount of ash left over is normally equivalent to 2-5% of your original debris volume. Oftentimes, it can be covered over or spread out on the property. This is perhaps the simplest way to get rid of the resulting ash.

However, there are also practical uses for ash that could be of real benefit to you.

What can you use ash for?

One option is that ash can be used to reinforce unpaved, low-traffic forest roads. (Click Here for more details.) This is a process that is currently being used in Europe to utilize the overflow of ash being produced. Their goal is to prevent this nutrient-rich material from being landfilled and to use it in an effective way. For a large-scale example of using ash to reinforce roads, read this article “WOOD ASH UTILISATION AS A STABILISER IN ROAD CONSTRUCTION”.

Another effective and beneficial way to utilize wood ash is to add it to cement. The addition of ash has been found to be a promising method of increasing the strength and thermal insulation of cement blocks. (Click Here for more detailed information) The reason why wood ash can be so useful for cement work is that it contains important elements, like calcium, potassium, and lime substitutes.

These minerals also make ash a great additive to soil in gardens and for farming. It can increase the pH of soil, helping maintain proper soil pH levels.

For information on using wood ash in agriculture, see this article from the University of New Hampshire.

For more information on using wood ash in gardens, see this article from the University of Wisconsin

Wood ash has many other usages, but these are just a few that take a product that is being thrown away and turn it into a usable asset.

For more detailed information about the useful elements in and applications of wood ash, check out this article from University of Georgia.

The Effects of Adding Water to Ash:

When you wet down ash, its volume will decrease due to compaction, but the exact reduction depends on several factors, including the amount of water added, the ash’s composition, and how much it settles. Here’s what happens:

Compaction & Volume Reduction

Dry ash is light and fluffy, with significant air pockets.

Adding water causes the ash particles to bind together and settle, reducing air space.

Estimated Reduction: Volume can decrease by 20-50%, depending on saturation levels.

Increased Weight

While volume decreases, weight increases significantly.

Wet ash is much heavier than dry ash, making transportation and disposal more challenging.

Potential for Hardening

If wetted excessively, ash can harden and form a crust, especially if it contains mineral content like calcium or silica (similar to cement behavior).

This can reduce dust, but it may also create disposal or spreading difficulties.

Example: 5,000 Cubic Yards of Ash

Minimal Water Added (Light Moistening) → Volume Reduction: 10-20% → Final Volume: 4,000 to 4,500 CY

Moderate Water (Fully Saturated but Not Pooling) → Volume Reduction: 20-30% → Final Volume: 3,500 to 4,000 CY

Excessive Water (Heavily Saturated, Mud-Like) → Volume Reduction: 30-50% → Final Volume: 2,500 to 3,500 CY

Final Takeaway:

Adding water will significantly reduce ash volume (by 20-50%) due to compaction.

The more water added, the more the volume shrinks, but the weight increases.

Excess water can cause hardening, making it difficult to spread or dispose of.

If you’re considering wetting ash for dust control or compaction, you may want to test a small section first to determine the ideal moisture level for your needs.