Wet extraction systems have been in use for some time. Rotoclones, wet scrubbers and more recently dust extractors all require expensive duct-work and create a secondary waste-stream of waste water to dispose of. They all have moving parts that can fail as seen in the photo. Wet dust can collect on rotating fans, creating an imbalance that can destroy bearings in short order.
Disadvantages of wet extraction compared to Dry Fog include:
1. Higher Capital and Operating Cost
2. Moving Parts to Repair and Replace
3. Requires Expensive Duct Work
4. Creates a Secondary Waste Stream to dispose of, possibly requiring new permits for waste water discharge.
5. Will not be very effective on large open dump pockets unless combined with Dry Fog