Mechanical Cleaning

This section was developed using information and original text from the Zebra Mussel (Dreissena polymorpha) Control Handbook for Facility Operators.

Mechanical removal of zebra mussels using wire brushes, scrapers, or other physical means is effective. However, manual means are generally less cost-effective than the preventative type of control methodology because they must be repeated at regular intervals, and removal and disposal of zebra mussel shells need to be considered.

Pigging systems involve forcing plugs (commonly called pigs) through mussel-infested lines to scrape mussels from pipe walls, forcing them out in front of the advancing pig. Pigs can be forced through lines by gas or fluid pressures or by hauling on cable systems. For smaller intakes (< 60 cm) mechanical pigging operations may be the method of choice. Pigs are available in a wide variety of designs and are manufactured to clean pipes up to 180 cm in diameter.

The drawbacks to using pigging as a solution are as follows:

• Generally, the piping needs some modifications to provide entrance and exit capabilities.
• The pipeline is unavailable for use during the pigging process.
• Because of the mass of mussel debris, disposal of waste may become a problem.
• There are concerns as to the ability of the pipelines to constantly withstand the pressure generated by the mechanical pigging process.

Further information may be obtained from Claudi and Mackie (1994).

Another form of mechanical cleaning involves the use of divers to scrape and clean infested surfaces. This method is especially useful for the cleaning of vertical walls and other submerged surfaces. Although it is labor-intensive, it may be the best available option. New underwater tools and techniques are also being developed.

Management and Control Contents

Management and Control Options

Reactive Control Methods