Clean up & Disposal
Prompt ash clean-up in urban areas is essential to minimise damage and disruption.
Characteristics and effects of ash
- Some ashes may 'cement' over time, especially if saturated and then dried.
- Fine grained ash (<0.5 mm particle size) is readily remobilised by wind and machinery, so it may require a binding agent (removal suggestions available).
- Coarse ash (>1 mm) is less easily-remobilised, but may be crushed when driven on or moved.
- Some ash is extremely abrasive and can cause greatly accelerated wear on equipment.
Ashfalls of only a few millimeters depth will generate large volumes of ash for collection and disposal.
Removing, transporting, and disposing of volcanic ash is a dirty, time-consuming, and costly challenge. Coordinated action by the public and by organizations can significantly lower costs and speed up the time it takes to remove most of the ash. The fall of a few millimeters of ash on an urban community will likely result in the need for collection and disposal of large quantities of material.
Proper disposal sites are needed quickly so that (1) ash does not have to be moved a second or third time; and (2) cleanup operations can begin immediately. To aid with this readiness, appropriate preplanning of disposal sites should be considered.
The time and effort required to remove and dispose of ash depends on the depth and aerial extent of the deposits, especially in urban and populated areas, and the availability of machinery (for example, from areas outside the zone of ashfall) to clean it up. Cleanup operations can take weeks to months to complete.
Several uncontrollable factors can impact the time required to remove ash
and frustrate efforts of cleanup personnel:
Additional ashfall before the cleanup operations are completed.
Wind, which stirs and billows the ash into the air, can spread ash particles over areas already cleaned, subjecting the public and cleanup personnel to even more airborne ash and exposing machinery and equipment to increase wear or damage.
Rain, which may help wash ash from roofs, but also lead to damaged gutters, short circuiting of power distribution systems, deposition of ash in low areas, and clogged storm-water drains and wastewater systems. Ash deposits may harden after being wet, making cleanup more difficult.